NoMachine is a cornerstone of my daily workflow, enabling seamless remote desktop access across diverse environments, including virtual machines on Azure, AWS, and Google Cloud, as well as local LAN systems. Its performance and flexibility make it indispensable for managing complex, multi-environment setups. However, installing NoMachine 9.1.24 on openSUSE Leap 16 presented unexpected challenges that disrupted its out-of-the-box functionality:

• Missing systemd service files: The installation did not include systemd service files, preventing proper management of the nxserver service.
• SELinux denials: With SELinux enabled in enforcing mode, critical NoMachine operations were blocked.
• Executable stack issue: The nxplayer component required an executable stack, triggering both functional failures and security concerns.

While disabling SELinux with a single command (setenforce 0) is a common shortcut for bypassing these issues, this approach must be avoided. Disabling SELinux compromises system security and undermines the integrity of a hardened environment. Instead, I addressed each issue methodically by creating a custom systemd unit, developing a tailored SELinux policy module, and resolving the executable stack requirement securely.

This article provides a detailed, step-by-step guide to configuring NoMachine on openSUSE Leap 16 in a secure, maintainable, and production-ready manner.

2.0 Environment details

This section outlines the system and software configuration where the NoMachine installation issues were encountered. These details are relevant for users operating in similarly hardened or minimal Linux environments, particularly those with SELinux in enforcing mode. The chosen desktop environment (GNOME, in this case) has no bearing on the steps described in this guide, as the solutions apply to any desktop environment.

2.1 System information

2.2 NoMachine information

3.0 NoMachine installation issues and solutions

This section outlines issues encountered during the installation of NoMachine 9.1.24 on openSUSE Leap 16. It provides detailed solutions to resolve these problems, ensuring proper service management and enabling remote access functionality.

3.1 Problem: Failed installation and missing systemd service

The primary issue encountered when installing the NoMachine RPM package (nomachine_9.1.24_6_x86_64.rpm) was the failure to deploy the necessary systemd service files. This omission prevents the nxserver daemon from being managed by systemctl, which is critical for automatic startup on boot and reliable service control in a production environment.

3.1.1 Diagnosis of installation errors

The installation attempt produced the following output, which highlights three distinct issues that require analysis.

Installation log output:

Refreshing service 'openSUSE'.
...
nomachine_9.1.24_6_x86_64.rpm: Package header is not signed!
nomachine-9.1.24-6.x86_64 (Plain RPM files cache): Signature verification failed [6-File is unsigned]
Abort, retry, ignore? [a/r/i] (a): i
...
NX> 700 Starting installation at: Thu, 09 Oct 2025 09:50:28.
NX> 700 Using installation profile: SUSE.
NX> 700 Installation log is: /usr/NX/var/log/install.log.
NX> 700 Installing nxrunner version: 9.1.24.
NX> 700 Installing nxplayer version: 9.1.24.
NX> 700 Installing nxnode version: 9.1.24.
/usr/NX/scripts/setup/nxnode: line 11303: /usr/etc/pam.d/su: No such file or directory
NX> 700 Installing nxserver version: 9.1.24.
NX> 700 ERROR: Cannot enable systemd service: nxserver.service.
NX> 700 ERROR: Cannot enable systemd service: .
NX> 700 Server install completed with warnings.
NX> 700 Please review the install log for details.
NX> 700 Installation completed with errors at: Thu, 09 Oct 2025 09:50:47.
NX> 700 NoMachine was configured to run the following services:
NX> 700 NX service on port: 4000
...

Analysis of key observations:

1. Unsigned RPM package: The signature verification failure is an intentional design choice by NoMachine. From NoMachine knowledge base article AR05S01128:

NoMachine packages for Linux are at the moment not signed to prevent warnings when the user doesn't have the installed publisher certificate.

2. Missing PAM file: The error related to /usr/etc/pam.d/su is a known issue specific to openSUSE's directory structure and does not affect functionality. From NoMachine knowledge base article TR10V11223:

During the installation of NoMachine on openSUSE, the following message is issued: ... /usr/NX/scripts/setup/nxnode: line 11247: /usr/etc/pam.d/su: No such file or directory ... Sessions are working properly and such message can be ignored.

3. Critical error: systemd service failure: The message ERROR: Cannot enable systemd service: nxserver.service is the most critical issue. While the unsigned RPM and missing PAM file are cosmetic issues, the systemd failure is a functional blocker that must be resolved manually.

3.1.2 Solution: Manual systemd service configuration

The NoMachine package includes a predefined systemd unit file, typically located at /usr/NX/scripts/systemd/nxserver.service after installation. However, depending on the installation method or errors, this unit file may not be automatically registered with systemd. The following procedure describes how to manually configure and enable the nxserver systemd service.

3.1.2.1 Step 1: Deploy the systemd unit file

Manually copy the nxserver.service file from the NoMachine installation directory to the system-wide systemd directory.

# Optional: Check if a custom service file already exists to avoid overwriting
ls /etc/systemd/system/nxserver.service

# Copy the service file
sudo cp /usr/NX/scripts/systemd/nxserver.service /etc/systemd/system/

3.1.2.2 Step 2: Reload the systemd daemon

Instruct systemd to reload its configuration to recognize the new service file.

sudo systemctl daemon-reload

3.1.2.3 Step 3: Enable and start the service

Enable the nxserver service to start automatically on boot and then start it manually for the current session.

# Enable the service
sudo systemctl enable nxserver.service

# Expected Output:
# Created symlink /etc/systemd/system/multi-user.target.wants/nxserver.service → /etc/systemd/system/nxserver.service.

# Start the service
sudo systemctl start nxserver.service

3.1.2.4 Step 4: Verify the service status (and anticipate failure)

Check the status of the service. Note that it is expected to fail at this stage due to SELinux policy restrictions.

sudo systemctl status nxserver.service

You will likely see output indicating a failure, which confirms that systemd is attempting to manage the service but is being blocked by SELinux.

× nxserver.service - NoMachine Server daemon
     Loaded: loaded (/etc/systemd/system/nxserver.service; enabled; preset: disabled)
     Active: failed (Result: start-limit-hit) since Thu 09 Oct 2025 09:52:45 CEST; 5s ago
   Duration: 15ms
 Invocation: 99bc681d83be4325b9e070a8596bf80b
    Process: 9476 ExecStart=/etc/NX/nxserver --daemon (code=exited, status=203/EXEC)
   Main PID: 9476 (code=exited, status=203/EXEC)

Oct 09 09:52:45 systemd[1]: nxserver.service: Start request repeated too quickly.
Oct 09 09:52:45 systemd[1]: nxserver.service: Failed with result 'start-limit-hit'.
Oct 09 09:52:45 systemd[1]: Failed to start NoMachine Server daemon.

3.1.3 Firewall Configuration

The installation log confirms that NoMachine listens on TCP port 4000. Ensure your system's firewall allows incoming connections on this port. If you are using firewalld, execute the following commands:

sudo firewall-cmd --add-port=4000/tcp --permanent
sudo firewall-cmd --reload

With the systemd service file in place, proceed to the next section to address the SELinux policy conflict.

4.0 Resolving NoMachine systemd service failures due to SELinux denials

This guide outlines how to fix NoMachine service (nxserver) startup failures caused by SELinux denials and provides a reusable framework for troubleshooting similar SELinux-related service issues.

4.1 Problem: SELinux denials

The nxserver may fail to start after installation due to SELinux in enforcing mode blocking required permissions for nxserver binaries. The systemctl status output often indicates errors like start-limit-hit or code=exited, status=203/EXEC.

4.2 Solution: Custom SELinux policy for NoMachine

Follow these steps to create and apply a custom SELinux policy to allow nxserver to run.

4.2.1 Step 1: Verify service failure

Confirm the NoMachine service is failing to start.

sudo systemctl start nxserver.service
sudo systemctl status nxserver.service

Check for a failed state in the output. If confirmed, proceed to the next step.

4.2.2 Step 2: Generate SELinux policy from audit logs

Use ausearch and audit2allow to identify SELinux denials and create a policy module.

sudo ausearch -c '(nxserver)' --raw | audit2allow -M nxserver-policy

This command generates:

• nxserver-policy.te: A readable Type Enforcement file with the rules.
• nxserver-policy.pp: A compiled policy module for installation.

4.2.3 Step 3: Install policy and retest

Apply the policy and attempt to restart the service.

sudo semodule -i nxserver-policy.pp
sudo systemctl start nxserver.service
sudo systemctl status nxserver.service

If the service still fails (which it will), a new SELinux denial may have surfaced. Repeat Step 2 to capture the new denial and update the policy files, then repeat Step 3 to install the updated policy. Iterate until the service starts successfully.

4.2.3.1 Merge .te files for a clean policy

To address two separate SELinux denials encountered during the NoMachine service setup, I merged the corresponding .te files into a single consolidated .te file to simplify management and ensure a clean policy structure:

module nxserver-daemon 1.0;

require {
    # from the first .te file
    type init_t;
    type nx_exec_t;
    class file execute;

    # from the second .te file
    class file { execute open read };
}

#============= init_t ==============
# from the first .te file
allow init_t nx_exec_t:file execute;

# from the second .te file
allow init_t nx_exec_t:file { open read };

The above .te file can be further refined:

module nxserver-daemon 1.0;

require {
    type init_t;
    type nx_exec_t;
    class file { execute open read };
}

#============= init_t ==============
# Allow the systemd init process to execute, open, and read the nxserver binary
allow init_t nx_exec_t:file { execute open read };

Saved this as nxserver-daemon.te.

checkmodule -M -m -o nxserver-daemon.mod nxserver-daemon.te
semodule_package -o nxserver-daemon.pp -m nxserver-daemon.mod

4.2.4 Step 5: Confirm success

Verify the service is running.

sudo systemctl status nxserver.service

The output should show active (running)

● nxserver.service - NoMachine Server daemon
     Loaded: loaded (/etc/systemd/system/nxserver.service; enabled; preset: disabled)
     Active: active (running) since Thu 2025-10-09 10:16:33 CEST; 6s ago
 Invocation: 2c5da753407a4266a8129f2ed3b8f421
   Main PID: 12546 (nxserver.bin)
      Tasks: 69 (limit: 9428)
        CPU: 2.766s
     CGroup: /system.slice/nxserver.service
             ├─12546 /usr/NX/bin/nxserver.bin --daemon
             ├─12603 /usr/NX/bin/nxd
             ├─12677 /usr/NX/bin/nxexec --node /usr/NX/bin/nxexec --nopam --user msiyer --priority realtime --mode 0 --pid 47
             ├─12678 /usr/NX/bin/nxnode.bin
             └─12704 /usr/NX/bin/nxrunner.bin --monitor --pid 4519

4.3 General framework for SELinux service troubleshooting

This iterative framework can resolve SELinux-related issues for any service, ensuring minimal permissions are granted (principle of least privilege).

1. Start the service:
   • Run sudo systemctl start <service-name>.service.
   • Check status with sudo systemctl status <service-name>.service to confirm failure.
2. Identify SELinux denials:
   • Search audit logs for denials related to the service’s process:
3. Create and apply policy:
   • Generate a policy module from denials:
   • Install the policy:
4. Iterate as needed:
   • Restart the service and check its status.
   • If it fails, repeat steps 2–3 to address additional denials until the service runs.
5. Verify operation:
   • Confirm the service is active (running) with sudo systemctl status <service-name>.service.

This framework is reusable for any SELinux-blocked service, such as httpd, sshd, or custom applications.

4.4 Optional: Manage with Cockpit web UI

For a user-friendly alternative, use Cockpit to manage SELinux and services via a web interface.

4.4.1 Install Cockpit

• openSUSE:
• RHEL/Fedora-based systems:

4.4.2 Enable Cockpit

Start and enable the Cockpit socket for persistent access.

sudo systemctl enable --now cockpit.socket

4.4.3 Access Cockpit

Navigate to https://<server-ip>:9090 in a web browser and log in with system credentials.

4.4.4 Features for SELinux and service management

• SELinux Denials: View and resolve denials with suggested policy fixes.
• Policy Management: Install or remove SELinux policy modules with one click.
• Service Control: Start, stop, or monitor systemd services like nxserver.
• Log Access: Review system and audit logs directly in the UI.

5.0 Resolving NoMachine Player GUI launch failure

When attempting to launch the NoMachine Player GUI, the application fails silently due to SELinux denial related to executable stack. ausearch will show the exact cause for the denial:

type=AVC msg=audit(1759996484.184:482): avc: denied { execstack } for pid=9676 comm="nxplayer.bin" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=process permissive=0

If /usr/NX/bin/nxplayer is run from terminal, the following output can be observed:

/usr/NX/bin/nxplayer.bin: error while loading shared libraries: libnxcim.so: cannot enable executable stack as shared object requires: Permission denied

5.1 Problem: Executable stack SELinux denial

The libnxcim.so library contains an internal flag requesting an executable stack. Modern Linux distributions enforce security policies (like NX/DEP and SELinux) that strictly block shared libraries from enabling an executable stack to mitigate memory exploit risks, such as buffer overflows. Since the library likely doesn't require this flag, it results in a launch failure.

5.2 Solution: Clear the executable stack flag

For libnxcim.so, the executable stack flag is usually unnecessary and can be safely cleared using the execstack utility.

5.2.1 Step 1: Verify the flag status

Use execstack -q to check if the executable stack flag is set on the library.

execstack -q /usr/NX/lib/libnxcim.so

5.2.2 Step 2: Clear the flag

Use execstack -c with sudo to remove the executable stack flag.

sudo execstack -c /usr/NX/lib/libnxcim.so

5.2.3 Step 3: Verify the fix

Re-check the flag status. The output should now show a dash (-).

execstack -q /usr/NX/lib/libnxcim.so
# Output: - /usr/NX/lib/libnxcim.so

5.2.4 Step 4: Test NoMachine Player

Launch the player. The GUI should now open successfully.

/usr/NX/bin/nxplayer

5.3 General framework for executable stack issues

This procedure applies to resolving the "cannot enable executable stack" error for any binary or library on a Linux system.

5.4.1 Identify and locate the library

• Error: Run the failing binary (<path-to-binary>) in the terminal and note the name of the problematic library (e.g., libXYZ.so).
• Path: Find the library's full path using the find command:

5.4.2 Check and clear the flag

• Check: execstack -q <library-path> (look for an X).
• Clear: sudo execstack -c <library-path>.
• Recheck: execstack -q <library-path> (ensure it now shows -).

5.4.3 Handle crashes (if necessary)

If clearing the flag results in a crash, the library requires the executable stack. Do not run the binary as root. Instead, temporarily allow the executable stack via a targeted SELinux policy:

# 1. Inspect audit logs and generate a policy module file (.te)
sudo ausearch -m avc -ts recent | grep <binary-name> | audit2allow -M <policy-name>

# 2. Compile and install the policy module
sudo semodule -i <policy-name>.pp

This approach allows the specific application/library to use an executable stack without disabling the security feature system-wide.

5.4.4 Optional: Batch clearing for multiple libraries

You can automate the process for a directory of libraries, but extreme caution and thorough testing are required as it might cause instability if a library genuinely needs the flag.

# Finds all .so files in the target directory with the 'X' flag and clears it.
find /path/to/libs -type f -name "*.so" -exec execstack -q {} \; | \
grep "X" | awk '{print $2}' | xargs -I {} sudo execstack -c {}

6.0 Conclusion

Configuring NoMachine 9.1.24 on openSUSE Leap 16 with SELinux in enforcing mode required addressing three primary challenges:

1. Missing systemd service: resolved by manually deploying and enabling the nxserver.service unit file.
2. SELinux denials blocking nxserver: addressed by generating, merging, and installing a consolidated SELinux policy (nxserver-daemon.te) to grant the necessary permissions while maintaining a secure, least-privilege environment.
3. Executable stack issue with nxplayer: mitigated by clearing the unnecessary executable stack flag on libnxcim.so using execstack, ensuring the GUI launched successfully without weakening overall system security.

From my hands-on experience, these solutions create a production-ready NoMachine setup that preserves the integrity of a hardened system. The frameworks provided for SELinux troubleshooting and executable stack resolution are reusable across other SELinux-enabled distributions such as RHEL 10, Fedora, and AlmaLinux, offering a consistent methodology for resolving similar issues.

By avoiding shortcuts like disabling SELinux, this approach maintains a secure, maintainable, and auditable environment for remote desktop access. Additionally, version-controlling .te policy files using tools like Git facilitates policy management, tracking, and collaboration over time, ensuring long-term maintainability.

7.0 References

GitHub - SELinuxProject/selinux-notebook: The SELinux Notebook

The SELinux Notebook. Contribute to SELinuxProject/selinux-notebook development by creating an account on GitHub.

GitHubSELinuxProject

Configuring SELinux | openSUSE Leap 15.6

In this chapter, you learn how to set up and manage SELinux on openSUSE Leap. The following topics are covered:

openSUSE Leap 15.6

Using SELinux | Red Hat Enterprise Linux | 8 | Red Hat Documentation

Using SELinux | Red Hat Enterprise Linux | 8 | Red Hat Documentation

Red Hat DocumentationRed Hat Customer Content Services

System and Service Manager

The linker’s warnings about executable stacks and segments

This article talks about some new warning messages that have been added to the BFD linker. What they mean, why they are important and what can be done to prevent or silence them.

Red HatNick Clifton

Too Subtle to Notice: Investigating Executable Stack Issues in Linux Systems - NDSS Symposium

The Network and Distributed System Security (NDSS) Symposium

NDSS Symposium

In C#, 42.ToString() works on an int, but in Java, int has no methods. Yet, C#’s Type.IsPrimitive marks System.Int32 as primitive, clashing with Java’s Class.isPrimitive(), which uses JVM metadata to identify int as a true primitive (enabling boxing-free operations like setting a field to 42) and Integer as non-primitive. Which int is the real primitive?

This sparked a Reddit debate, muddled by vague specs and conflicting claims. The issue: primitive has different meanings across languages, with C#’s int being both primitive and non-primitive depending on context.

Quick comparison

The problem with primitive

Java’s int is methodless and outside the object hierarchy, while C#’s int (System.Int32) has methods and acts like an object. C#’s Type.IsPrimitive returns true for System.Int32, reflecting runtime efficiency (ECMA-335 §I.8.2.2) but hiding its object-like nature (ECMA-334 §8.2.3). This causes two layers of confusion:

1. C# developers expect built-in types to be primitive when calling Type.IsPrimitive.
2. Java developers transitioning to C# expect Type.IsPrimitive to give results similar to Class.isPrimitive; however, System.Int32 behaves like an object, whereas Type.IsPrimitive returns true.

These issues, evident in a Reddit debate, fuel cross-language confusion. Java’s Class.isPrimitive() avoids this by clearly marking int as primitive and Integer as not, supporting boxing-free operations like field setting. The core issue: primitive has distinct meanings, requiring clear separation of its properties.

The LAX/LAT/R taxonomy

To clarify, I propose the Lₐₓ/Lₐₜ/R (LAX/LAT/R) taxonomy, separating “primitive” into three axes:

Rule: LAT ⊆ LAX: every atomic type is axiomatic, but not all axiomatic types are atomic.

Applying it

• Java’s int = LAX + LAT + R
• C#’s int = LAX + R (not LAT, due to methods like .ToString(); Type.IsPrimitive reflects R)

This taxonomy sidesteps vague debates by pinpointing which properties a type has, explaining why Type.IsPrimitive fuels misunderstanding among C# developers expecting Java-like atomicity. But how deep does this divergence go? Could a language on the .NET runtime optimize System.Int32 without exposing it in source code? [[Section 5.6]]

This article is also a case study in tribal knowledge, terminology drift, and process gaps: how developer communities talk past each other with informal definitions.

In this article, we’ll unpack:

1. The technical reality of primitives in C#, Java, and beyond, using LAX/LAT/R.
2. The social dynamics behind terminology drift, amplified by Type.IsPrimitive, and how to foster clear technical discourse.

1 The Lₐₓ/Lₐₜ/R (LAX/LAT/R) taxonomy

1.1 Introduction to type properties

The long-running argument over whether C#’s int is a primitive type, like the one in this Reddit thread, shows that primitive means different things depending on whether you’re talking about syntax, runtime behaviour, or just developer slang. To make the conversation precise, we can split the overloaded term into three separate axes of classification: axiomatic, atomic, and runtime primitive. This lets us talk about why Java’s and C#’s int behave differently, and why “primitive” means one thing in one community and something else in another.

• Axiomatic primitive: Built directly into the language’s syntax and rules, as defined in the specification, and not creatable in user code.

  • Standard-library types do not qualify: you can recreate or replace the library, but you cannot recreate int without altering the language (ECMA-334 § 8.2.1, JLS § 4.2).
  • Examples: Java int, C# int, Python int.

• Atomic primitive: Has no programmer-accessible internal structure: no fields, no methods, and sits entirely outside any object hierarchy. In OO terms, an object is a composite of state and behaviour (JLS § 4.3.1, ECMA-334 § 4.1.5, Kay 1993).

  • Examples: C int (pure value), Java int (no members).
    C# int is not atomic; it has methods like ToString() and implements interfaces.

• Runtime primitive: Receives special handling from the runtime/ABI, such as dedicated opcodes, intrinsic support, or special metadata element types (ECMA-335 § I.8.2.2, JVMS § 2.3).

  • Examples: JVM int (iadd), CLI System.Int32 (ldc.i4, add).

1.2 Definition

We can formalise the above as the Lₐₓ/Lₐₜ/R (LAX/LAT/R) taxonomy:

Rules:

• Strict subset: Lₐₜ ⊆ Lₐₓ (LAT ⊆ LAX) means that every atomic type is axiomatic, but not all axiomatic types are atomic. C#’s int is axiomatic but not atomic because it has members.
• Runtime specificity: R is defined relative to a given runtime; e.g., the CLR treats System.Int32 as primitive with specific IL instructions, while Python’s runtime optimises int differently.

Note on R: I am not a compiler expert; my knowledge of JITs and optimizations is limited. The idea of R can be sharpened by specialists: some types are R-axiomatic (built-ins always treated as primitives), while others are R-empirical (user types that the JIT promotes through optimizations like scalarization or escape analysis). This distinction does not change the core taxonomy, but clarifies how runtime primitiveness can be either guaranteed by the language or earned dynamically through optimization.

Note on notation: In informal contexts such as blogs or forums, the plain-text form LAX/LAT/R may be clearer. In more formal writing, the subscript form Lₐₓ/Lₐₜ/R highlights the distinct properties (axiomatic, atomic, runtime primitive). Both are equivalent.

1.3 Applying it: C# vs Java int

• C# int = LAX + R
• Java int = LAX + LAT + R

This avoids the vague “is it primitive?” question by spelling out exactly which properties apply.

1.4 Academic foundations

Although the unified Lₐₓ/Lₐₜ/R (LAX/LAT/R) model is new, each property has roots in type theory and programming-language design:

1.5 Why Primitive as the anchor

Historical trajectory:

1.6 The Hallmark: Separation from OO

Across languages that follow the traditional primitive model, one invariant appears:

A primitive type is built-in, atomic, and manipulated entirely via language-defined operations, with no participation in the object model.

C#’s int is object-integrated; Java’s int is OO-separated.

1.7 Applying the taxonomy beyond C# and Java

(* = hybrid behaviour via traits/boxing)

2 Divergent primitive definitions in C# and Java

The Reddit debate began with a comparison of C#’s int and Java’s int. The Microsoft .NET engineer claimed:

int is a runtime and compile-time primitive in C# and .NET, per their respective specs
— Microsoft .NET Libraries Engineer (source)

This is partly true, but only if primitive is taken to mean different things depending on whether you read the C# language spec, the CLI runtime spec, or developer “tribal knowledge.” In Java’s spec, however, primitive has a single, formal meaning.

2.1 Formal primitive definitions compared

2.2 How int exists at different layers

2.3 System.Int32: Already in Schrödinger's box

System.Int32 already exists in Schrödinger's Box, while Java's int lives in classical reality:

// C# - Opens different boxes, gets different answers
typeof(int).IsPrimitive  // true - it's primitive!
42.ToString()           // has methods - it's not primitive!
// Superposition until you specify observation layer

// Java - Same answer regardless of how you look
int x = 42;
// x.toString()        // Error - no methods, it's primitive
// No superposition - primitive at all layers

Just like Schrödinger's cat demonstrates the measurement problem in quantum mechanics, C#'s System.Int32 demonstrates the layer problem in type systems. Java's int is like a classical object; always in a definite state. C#'s is quantum; existing in superposition until observed.

3 C#’s deliberate break from Java’s LAX + LAT + R profile

Java’s int satisfies all three properties of the taxonomy: LAX (axiomatic), LAT (atomic), and R (runtime primitive). C#’s int is also LAX and R, but deliberately omits LAT. This is a direct result of C#’s unified type system, in which even primitive-like types are structs that participate fully in the object model.

In Java’s split hierarchy, int is LAX + LAT (OO-separated), while Integer is object-integrated (non-LAT). C# instead defines int as a keyword alias for System.Int32 (ECMA-334 §8.2.3), a value type inheriting from System.ValueType → System.Object. It has members (e.g., 42.ToString()), implements interfaces, and is optimized as an R type via IL opcodes (ECMA-335 §III.1.8). The int keyword exists for syntactic familiarity (ECMA-334 §8.2.1); internally, it’s a non-atomic LAX type. As Eric Lippert explains: “We avoided ‘primitive’ to prevent implying ‘not an object’.” (source)

Note:
In .NET, all value types (including System.Int32) implicitly derive from System.ValueType, which in turn derives from System.Object.

This hierarchy is significant:

• It explains why value types expose methods such as ToString() and GetHashCode().
• It also explains why boxing is required when a value type is passed to an API expecting an object.

Console.WriteLine(typeof(int).BaseType); 
// Output: System.ValueType
Console.WriteLine(typeof(System.ValueType).BaseType); 
// Output: System.Object

3.1 Taxonomy perspective

3.2 Design choice: unified object model

3.3 Key features mapped to LAX / LAT / R

Generics without wrappers

// C#

var list = new List<int>(); // LAX type, no boxing
list.Add(42);

// Java
List<Integer> list = new ArrayList<>(); // boxing + erasure
list.add(42); // int → Integer

Object capabilities vs. OO separation

// C#

int x = 42;              // LAX, not LAT
string s = x.ToString(); // object capability

// Java

int x = 42; // LAX and LAT
// x.toString(); // compile error
String s = Integer.toString(x);

Runtime efficiency with IL

// C#

int x = 42, y = 58;
int z = x + y; // IL: add opcode, R-type optimization

Runtime mechanisms:

• Intrinsic recognition in the JIT (.NET intrinsics)
• Special ABI rules for primitive element types (ECMA-335 §I.8.2.2)
• Zero-allocation nullability via Nullable<T> (ECMA-334 §8.2.2)

Nullability contrast

// C#

int? y = null; // LAX, no heap allocation

// Java

Integer y = null; // boxing, heap allocation

3.4 Avoiding the wrapper tax: Costs of Java's split model

// Java

Map<Integer, String> dict = new HashMap<>();
dict.put(42, "value");        // boxing
int z = dict.get(42);         // unboxing

Java’s Project Valhalla is narrowing this gap with inline value types, moving toward C#’s unified model.

3.5 Two specs, two perspectives

3.6 Official stance

3.7 Trade-offs at a glance: Java int vs. C# int

4 C# design philosophy: Aligning with the LAX/LAT/R taxonomy

C#’s rejection of traditional Java-style primitives (LAX + LAT + R) in favor of LAX + R reflects Anders Hejlsberg’s guiding principles: simplexity, golden handcuffs, pragmatic performance, and reified generics. These choices produced a unified type system where even primitive-like types participate fully in the object model, aligning naturally with the LAX/LAT/R taxonomy.

4.1 Taxonomy alignment at a glance

4.2 Simplexity: A unified type system for LAX types

// C#

int x = 42;              // LAX: built-in alias for System.Int32
string s = x.ToString(); // not LAT: has methods, object-integrated

// Java

int x = 42;       // LAX + LAT: no members, outside object model
Integer y = x;    // boxing to use in object contexts

4.3 Golden handcuffs: Safety for LAX types

Checked conversions

// C#

int x = int.MaxValue;
checked { int y = x + 1; } // throws OverflowException

Nullability

// C#

int? y = null; // no heap allocation

// Java

Integer y = null; // boxing, heap allocation

4.4 Pragmatism and versioning: Stability for LAX types

Java: Virtual by default (accidental override / fragile base risk)

// Java

// v1.0
class Database {
  void connect() { /* ... */ }   // virtual by default
  void run() { connect(); }       // calls overridable method
}

class CustomDB extends Database {
  void connect() { /* different semantics */ } // overrides, maybe unintentionally
}

// v1.1 (library update): Base adds behavior that assumes a specific connect() contract.
// CustomDB's override may now violate that hidden assumption, changing behavior at call sites.

C#: Non-virtual by default (opt-in override)

// C#

// v1.0
class Database {
  internal void Connect() { /* ... */ }  // non-virtual by default
  public virtual void Open() { /* ... */ } // explicit: opt-in to virtualization
  public void Run() { Connect(); }          // safe: sealed call by default
}

class CustomDB : Database {
  // Cannot accidentally override Connect(); must be explicit:
  public override void Open() { /* intended override */ }
}

// v1.1: Adding logic to Database.Connect() is version-stable;
// consumers couldn’t have overridden it unless it was marked virtual.

This default shapes the LAX-only (not LAT) object model in C#: you get full object features, but with safer versioning because overrides are explicit and intentional.

4.5 Getting generics right: Efficiency for LAX types

// C#

var list = new List<int>(); // LAX type, no boxing
list.Add(42);

// Java

List<Integer> list = new ArrayList<>(); // boxing, erasure
list.add(42); // int → Integer

C#’s LAX + R profile delivers Java’s primitive-level performance while avoiding the semantic split between primitives and objects. By unifying the type system and relying on runtime primitives for speed, Hejlsberg’s design sidesteps Java’s OO-separation cost model and aligns cleanly with the LAX/LAT/R framework.

5 How C# and Java handle primitives: A taxonomy-driven comparison

Tl;dr: C#’s int is a value type in a unified system (LAX, not LAT, with R optimizations), while Java’s int is atomic (LAX/LAT, with R). The LAX/LAT/R taxonomy classifies only types shipped by the language (e.g., C#’s int, decimal; Java’s int), excluding user-defined (e.g., MyInt) and standard library types (e.g., Java’s BigDecimal). This section proves key distinctions in primitive handling, grounded in the taxonomy, highlighting C#’s avoidance of LAT primitives and the CLR’s role in defining primitivity.

The term “primitive” varies by level and community usage:

5.1 int in C# vs. int in Java

Major point: C#’s int is not a primitive like Java’s int, both generally (unified type system vs. atomic primitive) and in the taxonomy (LAX, not LAT, with R vs. LAX/LAT with R).

C# IL examination:

// C#

int a = 3;
int b = 4;
int c = a + b;

// C# IL

IL_0000: ldc.i4.3  // Push LAX integer constant 3
IL_0001: stloc.0   // Store in local variable 'a'
IL_0002: ldc.i4.4  // Push LAX integer constant 4
IL_0003: stloc.1   // Store in local variable 'b'
IL_0004: ldloc.0   // Load 'a'
IL_0005: ldloc.1   // Load 'b'
IL_0006: add       // R: Direct opcode, JIT maps to CPU instruction
IL_0007: stloc.2   // Store result in 'c'

• Taxonomy alignment: LAX (built-in alias), not LAT (has methods), R (optimized via add opcode).
• Reflection: typeof(int).IsPrimitive == true (reflects R status).

Java bytecode:

// Java

int a = 3;
int b = 4;
int c = a + b;

// Java Bytecode

iconst_3  // Push LAX/LAT integer constant 3
istore_1  // Store in local variable 1 ('a')
iconst_4  // Push LAX/LAT integer constant 4
istore_2  // Store in local variable 2 ('b')
iload_1   // Load 'a'
iload_2   // Load 'b'
iadd      // R: Direct opcode for addition
istore_3  // Store result in 'c'

• Taxonomy alignment: LAX (built-in), LAT (no methods), R (optimized via iadd).
• Limitation: no methods; requires Integer (JLS §5.1.7).

5.2 decimal, BigDecimal, DateTime, LocalDateTime

Major point: C#’s decimal and DateTime are language-built-ins (LAX) but not runtime primitives (not R), which is why typeof(decimal).IsPrimitive == false and typeof(DateTime).IsPrimitive == false. Java’s BigDecimal and LocalDateTime are standard library classes, outside LAX/LAT/R.

C# IL (decimal addition)

// C#

decimal x = 1.0m, y = 2.0m;
decimal z = x + y;

// C# IL

call valuetype [System.Runtime]System.Decimal [System.Runtime]System.Decimal::op_Addition(...) // Library method, not R

Java bytecode (BigDecimal addition)

// Java

BigDecimal x = BigDecimal.ONE;
BigDecimal y = BigDecimal.TEN;
BigDecimal z = x.add(y);

// Java Bytecode

invokevirtual java/math/BigDecimal.add (Ljava/math/BigDecimal;)Ljava/math/BigDecimal; // Method call, not R

5.3 Why MyInt can’t fully be int

Major point: MyInt can mimic the surface area of int, but it is neither language-shipped (LAX) nor runtime-primitive (R), so it sits outside LAX/LAT/R.

// C#

struct MyInt
{
    public int Value;
    public static implicit operator MyInt(int value) => new MyInt { Value = value };
    public static implicit operator int(MyInt my) => my.Value;
    public static MyInt operator +(MyInt a, MyInt b) => new MyInt { Value = a.Value + b.Value };
    public override string ToString() => Value.ToString();
}

5.4 Autoboxing vs. boxing

Major point: Java’s autoboxing/unboxing addresses the primitive/object split; C#’s unified system needs only boxing when a value type is used as a reference.

// Java

int x = 5;
Integer y = x; // Autoboxing: Integer.valueOf(x)
int z = y;     // Unboxing: y.intValue()

// C#

int x = 5;
object y = x;     // Boxing: LAX to reference type
int z = (int)y;   // Unboxing: type check and copy

5.5 When boxing occurs in C#

Boxing happens when LAX value types cross to reference-type contexts:

• As object or System.ValueType:

  // C#
  
  int number = 42;
  object boxed = number; // Boxing: LAX to reference type
  

• As interfaces:

  // C#
  
  IComparable comparable = 42; // Boxing: LAX implements interface
  

• Legacy APIs:

  // C#
  
  ArrayList list = new ArrayList();
  list.Add(42); // Boxing: stores as `object`
  

• Dynamic dispatch:

  // C#
  
  dynamic d = 42;
  string s = d.ToString(); // Boxing: `dynamic` uses `object`
  

• Taxonomy alignment: Boxing is limited to LAX types in reference-type contexts; generics (List<int>) avoid it (ECMA-334 §8.2.4).

Key takeaway: C#’s reified generics minimize boxing for LAX types, unlike Java’s type erasure, which boxes LAT primitives.

5.6 A thought experiment: A language without int, and why it breaks primitive debates

Major point: NoIntLang shows that the CLR’s Common Type System (CTS) does not require System.Int32 to exist at the language level. A language can expose a completely different LAX numeric type (e.g., integer → System.Int64) while still benefiting from full R optimizations and without ever having an LAT atomic type.

In fact, the System.Int32 CLR primitive is not even visible to the developer in this design. The language never exposes it as a keyword or type; it only exists in runtime metadata. Framework APIs can still use it internally, and the compiler can auto-generate interop shims so the developer never needs to know it exists.

This is exactly the kind of case that trips up “is it primitive?” debates:

• At the language level, integer is LAX, not LAT.
• At the runtime level, the CLR sees it as an R-type primitive element (int32).
• Both sides of the argument could be right — but they’re answering different questions.

IL for NoIntLang integer multiplication:

// NoIntLang: integer result = 150 * 2;


ldc.i8 150 // Load LAX Int64 constant
ldc.i8 2   // Load LAX Int64 constant
mul        // R: Multiply opcode
stloc.0    // Store result

Interoperability shim:

// NoIntLang

public static class Int32Lib {
    public static int ToSystemInt32(integer value) => (int)value; // Emits conv.i4
}

// NoIntLang: File.WriteAllText("file.txt", text, Int32Lib.ToSystemInt32(offset));

In a production compiler, this shim could be compiler-generated and inlined, so System.Int32 never appears in user code. The developer would simply call File.WriteAllText("file.txt", text, offset); and the compiler would silently insert the conv.i4 to satisfy the API’s CLR signature.

Compiled IL:

// NoIntLang IL

ldstr "file.txt"
ldloc text
ldloc offset
call int32 Int32Lib::ToSystemInt32(int64) // conv.i4 for Int32
call void [System.IO]System.IO.File::WriteAllText(string, string, int32)

• Taxonomy alignment: integer is LAX and R; no LAT types are needed.
• Developer experience: The existence of System.Int32 is entirely hidden.

Implications for API design and performance

Real-world alignment

LAX = language-declared/axiomatic; LAT = language-atomic (no members, outside object model); R = runtime-primitive (special runtime/IL handling). See taxonomy overview.

Debate context

This example makes the primitive argument even messier:

• A language designer could say “NoIntLang has no primitives” because its only numeric type (integer) is LAX, not LAT.
• A runtime engineer could say “It still has primitives” because the JIT uses hardware opcodes for int64 and still recognizes int32 for API calls.
• Both would be correct, and the disagreement would stem entirely from whether they are talking about the language surface or the runtime substrate.

Developers in NoIntLang could ship full apps without ever seeing System.Int32 in their code, even though the runtime is constantly using it under the hood. This is the clearest proof that language-level primitivity and runtime-level primitivity can diverge entirely, and why Type.IsPrimitive surprises developers.

Schrödinger's primitive

NoIntLang reveals something profound: System.Int32 exists in a superposition state, simultaneously primitive and non-existent until you specify which system layer you're observing. This mirrors Schrödinger's famous thought experiment perfectly.

Once you grasp that System.Int32 can be simultaneously everywhere (in the runtime) and nowhere (in the language), you can never again have a simplistic debate about primitives. Like physicists post-quantum mechanics, we must always specify our frame of reference.

5.7 Why .NET Type.IsPrimitive API misleads developers

Type.IsPrimitive identifies types the CLR treats as runtime primitives (R), mapping to hardware instructions (e.g., ldc.i4 for System.Int32 ECMA-335 §III.1.8) and optimized by the JIT ECMA-335 §I.12.1.1. Developers often assume it reflects language-level primitives—axiomatic to the language (LAX ECMA-334 §8.2.1) or atomic without methods (LAT, like Java’s int JLS §4.2). In C#, types like int are LAX and R but not LAT (they have methods, e.g., ToString), unlike Java’s LAX+LAT+R model JLS §4.2. Type.IsPrimitive’s runtime focus (R) misaligns with C#’s unified type system ECMA-334 §8.2.1, causing confusion, as seen in debates where C#’s int was mistaken for a Java-like primitive (section 6). For example, System.String is LAX but not R ECMA-334 §8.2.5, so IsPrimitive’s false is correct for the CLR but overlooks its LAX role. F#’s int64 literals (42L ECMA-334 §8.2.1) hide Int32 via conv.i4 ECMA-335 §III.1.8, yet Type.IsPrimitive marks both as primitive, ignoring language flexibility. The LAX/LAT/R taxonomy (section 1) resolves this by separating axiomatic (LAX), atomic (LAT), and runtime-optimized (R) properties.

C# types and Type.IsPrimitive results

Java types and Class.IsPrimitive results

In contrast, Java’s Class.isPrimitive, reflects Java’s language view and developer expectations for its primitive/object dichotomy, as shown below.

6 Logical fallacies and process gaps in the Reddit debate

The Reddit discussion on whether C#’s int is a “primitive” type devolved from a technical exchange into a stalemate due to logical fallacies and process gaps. This section analyzes these issues, using the LAX/LAT/R taxonomy to highlight how misaligned assumptions and flawed reasoning derailed the debate, offering lessons for precise technical communication on a blog.

6.1 Core argument: A cross-language definition of “primitive”

My position was grounded in a cross-language definition of “primitive”:

• Primitives are built-in (LAX), atomic with no methods (LAT), and often runtime-optimized (R), separate from the object-oriented system.

  • C/C++: int is methodless, outside any object hierarchy.
  • Java: int lacks methods, isn’t an object, and requires Integer for object contexts (JLS §4.2).
  • C#: int (alias for System.Int32) is a struct with methods (e.g., ToString()), inherits from System.Object, and integrates with generics without wrappers (ECMA-334 §8.2.1), making it LAX and R but not LAT.

C#’s unified type system eliminates Java’s primitive-object split, enabling:

• Nullability: int? without boxing.
• Generics: List<int> without wrappers.
• Uniformity: consistent syntax across types.

The Microsoft .NET engineer’s counterargument emphasized .NET’s runtime usage of “primitive” (ECMA-335 §12.1), ignoring the LAX/LAT context.

6.2 Logical fallacies in the debate

The engineer’s responses (source) introduced logical fallacies that shifted focus from evidence to authority:

6.3 Process gaps in the debate

Systemic issues exacerbated the misalignment:

Taxonomy link: The LAX/LAT/R framework clarifies these gaps by separating language-level (LAX/LAT) and runtime (R) definitions, exposing jargon-driven ambiguity.

6.4 A constructive approach: Learning from Eric Lippert

Contrast this with Eric Lippert’s response to a similar issue (source):

“The whole para is incoherent. It should say that when an object that is a value type must be treated as a reference type, boxing happens. I’ll make a note to have the specification committee look at that.”

Lippert’s approach models effective technical communication:

This contrasts with the Reddit debate’s authority-driven responses, showing how evidence-based, open dialogue prevents misalignment.

6.5 Lessons for technical blog communication

To foster clear discourse in technical blogs:

1. Ground in standards: Use specs (e.g., ECMA-334, ECMA-335) as authoritative, updating them if outdated.
2. Define terms early: Establish frameworks like LAX/LAT/R to clarify “primitive” across contexts.
3. Engage evidence: Address citations (e.g., specs, academic texts) rather than relying on authority.
4. Avoid personalization: Focus on arguments, not personal traits.
5. Use frameworks: Leverage LAX/LAT/R to disentangle complex concepts and enable cross-language clarity.

The Reddit debate shows how logical fallacies (appeal to authority, strawman, circular reasoning, ad hominem) and process gaps (dismissing specs, tribal knowledge, lacking context, ignoring evidence) derail technical discourse. The LAX/LAT/R taxonomy clarifies why C#’s int (LAX, R) differs from Java’s (LAX/LAT, R) and serves as a tool for alignment. By adopting Lippert’s evidence-based approach, bloggers can ensure precise, constructive communication, enhancing clarity for their audience.

7 Conclusion

A Reddit debate on why C# lacks Java’s Integer became a case study in how terminology drift derails technical discourse. My argument that C#’s int isn’t a traditional primitive (Reddit comment) was met with claims of misinformation, revealing conflicting meanings of primitive across specs, runtimes, and team jargon. Grounded in ECMA-334, ECMA-335, and Eric Lippert’s insights, this analysis highlights lessons for clarity and evidence-based communication.

This analysis resolves the debate by clarifying C#’s int (LAX, R) vs. Java’s (LAX/LAT, R) and exposes process gaps like dismissing standards. The LAX/LAT/R taxonomy fosters precise, evidence-based discourse, offering bloggers a tool to elevate technical communication across domains.

Note on document structure and license

This document is intentionally styled in a manner that echoes the organizational approach of ECMA-334 and ECMA-335. The resemblance is limited to structural and stylistic conventions for clarity and comparative analysis.

This is an independent work. It introduces original concepts (such as the LAX/LAT/R taxonomy) and is not affiliated with, endorsed by, or derived from ECMA International.

License: Except where otherwise noted, this work is licensed under the Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0). You are free to share and adapt this material for any purpose, including commercial use, provided that proper attribution is given and any derivative works are distributed under the same license.

I was a die-hard Doplhin user when I was on KDE Plasma 5. I was squeezing so much performance out of Dolphin that it started leaking memory. Then, I migrated to Gnome many months ago due to the bugginess of KDE Plasma 5. Dolphin can be installed on Gnome. However, Dolphin pulls in a lot of KDE dependencies. To avoid polluting Gnome with KDE binaries, I killed my double-pane file manager dreams and endured Files: Simple file manager for Gnome. However, once you have tasted the double-pane elixir, single-pane is just not enough.

The Other Double-pane File Managers I Tried

My quest for a simple double-pane file manager led me to Midnight Commander. It is functional and elegant. It will always remain in my arsenal. However, it is an ncurses-based terminal app, and there are times I like to touch, feel, click... I need GUI. I was guided to Double Commander by the "eternal Linux noob":

I like Double Commander and plan to keep using it. However, it is written in Pascal and that makes it difficult for me to read the code (or contribute if I am in the mood).

Then, there is also Krusader. However, like Dolphin, it too pulls in KDE dependencies. So, I cannot use it. I have heard good things about it. Therefore, if you are not bothered about the limitations mentioned in this article, please go ahead and give it a try.

Worker File Manager

Worker is a 24-year old file manager (initial release was on 6 March, 1999). There are binaries or packages available for all important distributions other than openSUSE Tumbleweed. Such limitations cannot stop me. I will simply compile. A configure, make and make install should have sufficed in an ideal world. So, I downloaded the source archive, extracted the archive, rode cd into the directory containing the extracted source, and issued the following command:

./configure

No C++ compiler on my machine. What? Not an ideal world:

configure: error: The C++ compiler doesn't work or doesn't exists at all!
*********************************************************************
* Check your C++ installation (many distributions have a separate   *
* package for the C++ compiler).                                    *
*********************************************************************

I remedied the missing compiler problem:

sudo zypper in gcc-c++

Issued the configure command again:

./configure

Failure again. Missing libx11-dev:

configure: error: X Window libraries and headers not found!
*********************************************************************
* Check your X installation (many distributions have these files in *
* the ...devel-packages (e.g. libx11-dev or libX11-devel)).         *
*********************************************************************

Searched in openSUSE repositories:

zypper se libx11-dev

The following output was spewed by zypper in response:

I decided to install  libX11-devel:

sudo zypper in libX11-devel

Issued the configure command again and a beautiful success message appeared:

Configuration finished:
  AVFS usage                  : no
    *** Get at least version 0.9.5 from http://avf.sourceforge.net/ ***

  Large file support          : yes
  Regular expressions support : yes
  X11 XIM usage               : yes
  X11 Xinerama support        : no
    *** To enable support, install libraries:
    ***  - libxinerama-dev or libXinerama-devel

  UTF8 support                : yes
  Libmagic support            : no
    *** To enable support, install libraries:
    ***  - libmagic-dev or file-devel
    *** or get a recent version from ftp://ftp.astron.com/pub/file/ ***

  DBUS device handling        : no (fallback to fstab mounting)
    *** To enable support, install libraries:
    ***  - libdbus-1-dev or dbus-1-devel
    ***  - udisks or udisks2 (newer systems)
    ***  - hal-storage (older systems)

  Inotify support             : yes
  LUA support                 : no
    *** To enable support, install libraries:
    ***  - liblua5.x-dev or lua53-devel

  Font engine                 : X11
    *** To enable support for Xft, install libraries:
    ***  - libxft-dev or libXft-devel

  OpenSSL SHA256              : no
    *** install openssl-dev for checksumming support
  Maximum command line length : 1572864

Installation prefix           : /usr/local

 To compile do

   make

It was time for me to issue the make  followed by the make install commands:

make
make install

There is nothing more left to do other than launch Worker:

Conculsion

What is there not to love about this beauty? Looks stunningly beautiful, has all features you would demand of a file manager, can be configured, has internal and external commands, and much more (just RTFM)

Worker supports several internal commands that work on the selected entries, as well as using external commands to execute arbitrary applications.

I will continue exploring this beauty.

For all this to work on Windows, ASUS supplies an ACPI BIOS with WMI objects embedded in it. ACPI is an open standard while WMI is a proprietary implementation of another open standard called CIM. So, on Windows, the ACPI BIOS with embedded WMI objects interfaces seamlessly. However, all of this makes it difficult for the Linux kernel to interface with platform devices. You know where I am going with this ;)

Setting a charge threshold using a systemd service

Check the battery name

Confirm if laptop supports ASUS Battery Health Charging. If it does, find the battery name:

ls /sys/class/power_supply/

In my case it returns:

AC0  BAT0

To be double sure, list what is available in BAT0:

ls /sys/class/power_supply/BAT0

If the output contains charge_control_end_threshold, we are good to go. If it does not, then one of the following statements must be true:

• Linux Kernel version running on the laptop is older than 5.4;
• The laptop does not support ASUS Battery Health Charging.

Deploy a systemd unit file

Create a systemd unit file with the following content:

[Unit]
Description=Set the battery charge threshold
After=multi-user.target
StartLimitBurst=0

[Service]
Type=oneshot
Restart=on-failure
ExecStart=/bin/bash -c 'echo 60 > /sys/class/power_supply/BAT0/charge_control_end_threshold'

[Install]
WantedBy=multi-user.target

I have set the threshold to 60 percent because that is exactly what the MyASUS software would do in Maximum Lifespan Mode on Windows.

Save it as /etc/systemd/system/battery-charge-threshold.service. The unit file can be named anything.

Enable and start the service:

systemctl enable battery-charge-threshold.service
systemctl start battery-charge-threshold.service

If no mistakes were made in following the above steps, the following should be the result:

cat /sys/class/power_supply/BAT0/status
Not charging

My GNOME 41 DE also prominently displays the status of the battery as Not charging in the UI.

Will my Linux Kernel version support setting battery charge threshold?

Examine the history of charge threshold in Linux source

I had tried setting a charge threshold on the same laptop when it was running openSUSE Leap 15.3; openSUSE Leap uses 5.3.18 Linux Kernel which obviously does not support the charge threshold. It worked fine with the MX Linux Advanced Hardware Support edition as long as I used it. I then moved to openSUSE Tumbleweed.

For those who like to dig deeper, git clone the Linux source code. git commands will help in obtaining various details about the history of linux/drivers/platform/x86/asus-wmi.c. An example is given below.

git log --all drivers/platform/x86/asus-wmi.c | grep -i "charge threshold"

The output is:

The WMI method to set the charge threshold does not provide a
Fixes: 7973353e92ee ("platform/x86: asus-wmi: Refactor charge threshold to use the battery hooking API")
platform/x86: asus-wmi: Refactor charge threshold to use the battery hooking API
platform/x86: asus-wmi: Add support for charge threshold

Further, pick the oldest commit message and search:

git log --grep="asus-wmi: Add support for charge threshold"

This command gives the following output:

commit d507a54f5865d8dcbdd16c66a1a2da15640878ca
Author: Kristian Klausen kristian@klausen.dk
Date:   Mon Aug 5 21:23:05 2019 +0200

platform/x86: asus-wmi: Add support for charge threshold

Most newer ASUS laptops supports limiting the battery charge level, which
help prolonging the battery life.

Tested on a Zenbook UX430UNR.

Signed-off-by: Kristian Klausen <kristian@klausen.dk>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Pick the commit hash (d507a54f5865d8dcbdd16c66a1a2da15640878ca, in this case) and do the following to see the changes compared to previous version:

git show d507a54f5865d8dcbdd16c66a1a2da15640878ca 

Now, it is time to check what Linux Kernel versions this commit found its way into. The oldest is the most relevant in our investigation:

git tag --contains d507a54f5865d8dcbdd16c66a1a2da15640878ca

Use GitHub for better usability; terminal for speed

Once the commit hash is determined using the terminal, it can be used in GitHub to analyze the history of ASUS ACPI WMI kernel drive/module. GitHub hosts a mirror of Linux Kernel and has a much better user experience than the terminal.

Latest Linux Kernel 5.9 and above

The latest Linux Kernel supports all available battery names for ASUS laptops that support ASUS Battery Health Charging (BAT0, BAT1, BATC and BATT). BATC support added via commit 1d2dd379bd99ee4356ae4552fd1b8e43c7ca02cd. It is quite evident if we analyze linux/drivers/platform/x86/asus-wmi.c:

static int asus_wmi_battery_add(struct power_supply *battery)
{
	/* The WMI method does not provide a way to specific a battery, so we
	 * just assume it is the first battery.
	 * Note: On some newer ASUS laptops (Zenbook UM431DA), the primary/first
	 * battery is named BATT.
	 */
	if (strcmp(battery->desc->name, "BAT0") != 0 &&
	    strcmp(battery->desc->name, "BAT1") != 0 &&
	    strcmp(battery->desc->name, "BATC") != 0 &&
	    strcmp(battery->desc->name, "BATT") != 0)
		return -ENODEV;

	if (device_create_file(&battery->dev,
	    &dev_attr_charge_control_end_threshold))
		return -ENODEV;

	/* The charge threshold is only reset when the system is power cycled,
	 * and we can't get the current threshold so let set it to 100% when
	 * a battery is added.
	 */
	asus_wmi_set_devstate(ASUS_WMI_DEVID_RSOC, 100, NULL);
	charge_end_threshold = 100;

	return 0;
}

Arch Linux and its derivatives, or openSUSE Tumbleweed or Debian Sid or Fedora have full support.

Linux Kernel 5.8 and above

BAT0, BATT and BAT1 battery names supported. BAT1 support added via commit 9a33e375d98ece5ea40c576eabd3257acb90c509:

static int asus_wmi_battery_add(struct power_supply *battery)
{
	/* The WMI method does not provide a way to specific a battery, so we
	 * just assume it is the first battery.
	 * Note: On some newer ASUS laptops (Zenbook UM431DA), the primary/first
	 * battery is named BATT.
	 */
	if (strcmp(battery->desc->name, "BAT0") != 0 &&
	    strcmp(battery->desc->name, "BAT1") != 0 &&
	    strcmp(battery->desc->name, "BATT") != 0)
		return -ENODEV;

	if (device_create_file(&battery->dev,
	    &dev_attr_charge_control_end_threshold))
		return -ENODEV;

	/* The charge threshold is only reset when the system is power cycled,
	 * and we can't get the current threshold so let set it to 100% when
	 * a battery is added.
	 */
	asus_wmi_set_devstate(ASUS_WMI_DEVID_RSOC, 100, NULL);
	charge_end_threshold = 100;

	return 0;
}

Linux Kernel 5.7 and above

BAT0 and BATT battery names supported. BATT support added via commit 6b3586d45bba14f6912f37488090c37a3710e7b4:

static int asus_wmi_battery_add(struct power_supply *battery)
{
	/* The WMI method does not provide a way to specific a battery, so we
	 * just assume it is the first battery.
	 * Note: On some newer ASUS laptops (Zenbook UM431DA), the primary/first
	 * battery is named BATT.
	 */
	if (strcmp(battery->desc->name, "BAT0") != 0 &&
	    strcmp(battery->desc->name, "BATT") != 0)
		return -ENODEV;

	if (device_create_file(&battery->dev,
	    &dev_attr_charge_control_end_threshold))
		return -ENODEV;

	/* The charge threshold is only reset when the system is power cycled,
	 * and we can't get the current threshold so let set it to 100% when
	 * a battery is added.
	 */
	asus_wmi_set_devstate(ASUS_WMI_DEVID_RSOC, 100, NULL);
	charge_end_threshold = 100;

	return 0;
}

Linux Kernel 5.4 and above

Linux ACPI WMI driver/module for ASUS implements support for ASUS Battery Health Charging and BAT0 via commit d507a54f5865d8dcbdd16c66a1a2da15640878ca and commit 7973353e92ee1e7ca3b2eb361a4b7cb66c92abee

static int asus_wmi_battery_add(struct power_supply *battery)
{
	/* The WMI method does not provide a way to specific a battery, so we
	 * just assume it is the first battery.
	 */
	if (strcmp(battery->desc->name, "BAT0") != 0)
		return -ENODEV;

	if (device_create_file(&battery->dev,
	    &dev_attr_charge_control_end_threshold))
		return -ENODEV;

	/* The charge threshold is only reset when the system is power cycled,
	 * and we can't get the current threshold so let set it to 100% when
	 * a battery is added.
	 */
	asus_wmi_set_devstate(ASUS_WMI_DEVID_RSOC, 100, NULL);
	charge_end_threshold = 100;

	return 0;
}

References

Understanding Systemd Units and Unit Files | DigitalOcean

Increasingly, Linux distributions are adopting or planning to adopt the systemd init system. This powerful suite of software can manage many aspects of your …

DigitalOceanJustin Ellingwood

Writing a WMI driver - an introduction

Windows Management Instrumentation (WMI) is a set of extensions to the Windows Driver Model that provides an operating system interface for dealing with platform devices. WMI objects can be embedded within ACPI, a configuration which Microsoft recommends. Like ACPI, WMI is not really standardized…

LWN.net

Kernel/Reference/WMI - Ubuntu Wiki

Ubuntu Wiki

The Linux Kernel Archives

GitHub - torvalds/linux: Linux kernel source tree

Linux kernel source tree. Contribute to torvalds/linux development by creating an account on GitHub.

GitHubtorvalds

Laptop/ASUS - ArchWiki

ArchWiki

ACPI battery and power subsystem firmware implementation

This topic details how the platform should expose power subsystem information to the Windows power manager.

Microsoft Docswindows-driver-content

Advanced Configuration and Power Interface (ACPI) BIOS - Windows drivers

ACPI BIOS

Microsoft Docstedhudek

WMI Architecture - Win32 apps

WMI provides a uniform interface for any local or remote applications or scripts that obtain management data from a computer system, a network, or an enterprise.

Microsoft Docsstevewhims

WMI ACPI Sample - Code Samples

Contains ACPI BIOS and WMI sample code that enables instrumentation of the ACPI BIOS from within ACPI Source Language (ASL) code.

Microsoft DocsVSC-Service-Account

Redis is an open source (BSD licensed), in-memory data structure store, used as a database, cache, and message broker. Redis provides data structures such as strings, hashes, lists, sets, sorted sets with range queries, bitmaps, hyperloglogs, geospatial indexes, and streams.

FreeBSD is an outstanding operating system and I just love it. Netflix, Apple, Sony, and many others would concur.

Setting up FreeBSD 13 as a Desktop Operating System

The installation process is pretty straightforward and very well documented. The only thing special about my install is the ZFS file system in stripe mode on a single disk. What this means is that:

• the performance benefits of striping as available in a multi-disk setup, will not be available;
• ZFS snapshots can be taken, but this is not a backup of any sort;
• backups are my responsibility as stripe mode, even in a multi-disk setup, is bereft of any redundancy.

The section 2.6.4. Guided Partitioning Using Root-on-ZFS describes how to configure  ZFS in FreeBSD during install.

Once the installation is done, log in to the system as root, fetch, and install security updates:

freebsd-update fetch
freebsd-update install

A fresh FreeBSD installation has nothing other than command line user interface. The X Window System needs to be installed to get a Graphical User Interface running:

pkg install xorg

FreeBSD graphics driver on bare metal

With xorg installed, it is time to install DRM kmod graphics driver for Intel\AMD GPUs.

amdgpu, i915, and radeon DRM modules for the linuxkpi-based KMS components. Currently corresponding to Linux 5.4.144 DRM. This version is for FreeBSD 13. https://github.com/freebsd/drm-kmod/

pkg install drm-fbsd13-kmod
sysrc kld_list+="i915kms"

FreeBSD graphics driver in virtualized environment

Do not install the bare metal drivers in a virtualized environment. Instead do the following:

pkg install xf86-video-vmware

Mate Desktop Environment and the rest

The following will install a minimal Mate Desktop Environment:

pkg install mate-base mate-terminal

Get sudo:

pkg install sudo

Add user to wheel group and use visudo command to edit the sudoers file to allow users in wheel group to run system tools with authentication:

pw usermod msiyer -G wheel

Create a ~\.xinitrc file with the below content. This will let startx command know that it is supposed to start a Mate session:

exec mate-session

I also installed a few very important applications – chromium browser, peazip archive manager, eom image viewer:

pkg install chromium flameshot peazip eom

It is now time to reboot:

pkg reboot

ZFS snapshots

Once rebooted, login and execute startx command to start a Mate session. A snapshot of the file system is in order now. The power of zfs is simply mind blowing. The only other file system that comes close is btrfs on Linux:

zfs list                                           
NAME                 USED  AVAIL     REFER  MOUNTPOINT
zroot               8.37G   113G       96K  /zroot
zroot/ROOT          6.67G   113G       96K  none
zroot/ROOT/default  6.67G   113G     6.67G  /
zroot/tmp            136K   113G      136K  /tmp
zroot/usr           1.59G   113G       96K  /usr
zroot/usr/home       216M   113G      216M  /usr/home
zroot/usr/ports      711M   113G      711M  /usr/ports
zroot/usr/src        702M   113G      702M  /usr/src
zroot/var            111M   113G       96K  /var
zroot/var/audit       96K   113G       96K  /var/audit
zroot/var/crash      110M   113G      110M  /var/crash
zroot/var/log        240K   113G      240K  /var/log
zroot/var/mail       148K   113G      148K  /var/mail
zroot/var/tmp         96K   113G       96K  /var/tmp

Recursive snapshots of zroot/ROOT/default mounted at / and zroot/usr mounted at /usr should suffice:

sudo zfs snapshot -r zroot/ROOT/@2022-01-15-fullStack
sudo zfs snapshot -r zroot/usr/@2022-01-15-fullStack

List snapshots created above:

zfs list -t snapshot                                   
NAME                                      USED  AVAIL     REFER  MOUNTPOINT
zroot/ROOT/default@2022-01-15-fullStack    68K      -     6.67G  -
zroot/usr@2022-01-15-fullStack              0B      -       96K  -
zroot/usr/home@2022-01-15-fullStack       164K      -      216M  -
zroot/usr/ports@2022-01-15-fullStack        0B      -      711M  -
zroot/usr/src@2022-01-15-fullStack          0B      -      702M  -

To rollback to the pristine-state snapshots created above, all I have to do is:

zfs rollback -r zroot/ROOT/default@2022-01-15-fullStack
zfs rollback -r zroot/usr@2022-01-15-fullStack

Setting up FreeBSD as a Redis development environment

Redis is written in C language. The source code is hosted on GitHub. Need git to get it. Compiling it is simple. As per documentation, just make it in the source code root directory. However, FreeBSD has its own implementation of make, which is not fully compatible with GNU Make. On FreeBSD one needs to install gmake to get the GNU implementation. Also, TCL is required to run tests. Do the following to get everything needed to fetch sources, compile, run tests and debug:

pkg install git gmake cmake tcl87 gcc gdb

Now let us get the sources:

cd <DESIRED_LOCATION>
git clone https://github.com/redis/redis.git

Running the gmake and gmake test commands in the <DESIRED_LOCATION>\redis directory will compile the project and execute all tests. Thereafter, if one is adventurous enough, a debugging session with appropriate breakpoints can be launched in the terminal using gdb. Also, gdb has a curses-based tui (Text User Interface) mode that improves usability:

For others that need an IDE to feel at home, vim or emacs can be configured to behave as an IDE. There is also a modern alternative for the venerable vim known as neovim. I spent a few hours configuring neovim and gave up. I just do not have the time right now to fiddle with configurations.

JetBrains has a great C\C++ IDE called CLion. It is available in FreeBSD repos and I happen to have a license. This is an option for those who want to hit the ground running rather than fiddling with config\dotfiles:

pkg install jetbrains-clion

Setting up JetBrains CLion for Redis debugging

Use the File -> Settings menu option to launch the following dialog to set up Toolchains. Make sure to use gmake for Make option:

I had downloaded the source manually and asked CLion to load an existing project. CLion informed me that the import works best when clean is executed. I let it do its thing and ended up with a successfully imported project.

CLion detects all configurations from the makefile and lists them as shown below. We can use the highlighted ones for debugging redis-cli (client executable) and redis-server (server executable). The target executable needs to be filled in in the Executable field of the dialog.

That is all there is to set up CLion. So simple.

Ricing FreeBSD (optional)

Material Design from Google is quite important in the UX Design world. Materia GTK theme tries to bring the same UX to Unix desktop. Get it:

sudo pkg install materia-gtk-theme

Papirus Icons are a must for me:

sudo pkg install wget
wget -qO- https://git.io/papirus-icon-theme-install | DESTDIR="$HOME/.icons" sh

Now comes the ricing of the terminal emulator. What better to spice up the terminal than Oh My ZSH with the agnoster theme. Installing it is as simple as (install curl is not already available):

$ sh -c "$(curl -fsSL https://raw.github.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"

To activate agnoster theme, open .zshrc and update the ZSH_THEME key's value to agnoster.

agnoster theme requires powerline-fonts:

pkg install powerline-fonts

References

The FreeBSD Project

FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms.

The FreeBSD Project

FreeBSD Handbook

A constantly evolving, comprehensive resource for FreeBSD users

FreeBSD Documentation Portal

MATE Desktop Environment

The MATE Desktop Environment is the continuation of GNOME 2. It providesan intuitive and attractive desktop environment using traditionalmetaphors for Linux and other Unix-like operating systems.MA

MATEThe MATE Team

Redis

CLion: A Cross-Platform IDE for C and C++ by JetBrains

A powerful IDE from JetBrains helps you develop in C and C++ on Linux, macOS and Windows.

JetBrainsJetBrains

Coreutils - GNU core utilities

GNU core utilities

GCC, the GNU Compiler Collection- GNU Project

Nick’s Blog

GDB: The GNU Project Debugger

Oh My Zsh - a delightful & open source framework for Zsh

Oh-My-Zsh is a delightful, open source, community-driven framework for managing your ZSH configuration. It comes bundled with several helpful functions, helpers, plugins, themes, and a few things that make you shout... OH MY ZSH!

Oh My Zsh!

Sudoers - Community Help Wiki

Community Help Wiki

Assume the environment does not allow you to store 64-bit integers (signed or unsigned).

Solutions

Naive solution

The first goal is to arrive at a solution. I do not care about the aesthetics of it as long as it works for all inputs. I also do not care about the constraints.

The remainder operator of C# is a great way to extract the last digit of any given integer x. The remainder is the last digit when x is divided by 10.

int remainder = x % 10;

The remainder thus obtained is to be stored in a List<int>. Also, the following will give us the integer x, with its last digit removed

x = (x - remainder)/10;

With these two simple concepts sorted out, the bulk of the conceptual work is done. The algorithm to be followed is:

1. extract digits out of the input integer and store the digits in a List<int>
2. once all digits have been extracted and stored, get the stored digits and create an integer

The step 1 of the algorithm can be coded as

while(true)
{
	/* if during the process of truncating the input integer x,
     * it becomes smaller that 10 or in other words only the last
     * digit remains, add it to the list and break loop
     */
	if(x < 10)
    {
    	list.Add(x);
       	break;
	}
    int remainder = x % 10;
    /* this will remove the last digit from the input integer x.
     * the above step has already detected the last digit of x and
     * stored it in the "remainder" variable.
     */
    x = (x - remainder)/10;
    list.Add(remainder);
}

The step 2 of the algorithm can be coded as

double returnNumber = 0;
for(int i = 0; i < list.Count; i++)
{
	int item = list[i];
    if(item == 0)
    	continue;
    /* the digits stored in the list need to be multiplied by the appropriate
     * power of 10 to generate the output integer.
     * the first digit in the list is multiplied by 
     * 10 ^ (number of digits in x - 1), second digit is
     * multiplied by 10 ^ (number of digits in x - 1) and so on...
     */
    returnNumber += item * Math.Pow(10, list.Count - i - 1);
}

The complete implementation follows. The code has enough comments to explain what is going on:

public class Solution 
{
    public int Reverse(int x)
    {
        List<int> list = new List<int>();
        
        /* we need to keep track of the negativity :)
         * if we do not, we forget about it during the extraction of digits
         * while loop and also while creating the result integer 
         * in the for loop. The negativity will come back to bite us
         * when we return the result. */
        bool isNegative = x < 0 ? true : false;
        if(isNegative)
            x = x * -1;
        
        /* how does this loop work?
         * Example input = 123.
         * first iteration:
         * 		- is 123 < 10? No.
         * 		- remainder = 123 % 10 = 3
         *      - x = (123 - 3)/10 = 12
         *      - list.Add(3)
         * second iteration:
         * 		- is 12 < 10? No.
         * 		- remainder = 12 % 10 = 2
         *      - x = (12 - 2)/10 = 1
         *      - list.Add(2)
         * third iteration:
         * 		- is 1 < 10? Yes.
         *      - list.Add(1) and break */
        while(true)
        {
            /* x has had its negativity removed above. if we had not done
             * that this check would have let all negative x just pass
             * through and break the loop.
             *
             * why not Math.Abs(x)?
             * because it does not work for the following boundary value:
             * -2147483648 (Int32.MinValue)
             /* It throws a Runtime Error Message for -2147483648:
             Unhandled exception. System.OverflowException: Negating the
             minimum value of a twos complement number is invalid. */
            if(x < 10)
            {
                list.Add(x);
                break;
            }
            int remainder = x % 10;
            x = (x - remainder)/10;
            list.Add(remainder);
        }
        
        /* how does this loop work?
         * list = {3, 2, 1}
         * first iteration:
         * 		- returnNumber = 0 + 3 * Math.Pow(10, 3 - 0 - 1) = 300
         * second iteration:
         * 		- returnNumber = 300 + 2 * Math.Pow(10, 3 - 1 - 1) = 320
         * third iteration:
         * 		- returnNumber = 320 + 1 * Math.Pow(10, 3 - 2 - 1) = 321 */

        double returnNumber = 0;
        for(int i = 0; i < list.Count; i++)
        {
            int item = list[i];
            if(item == 0)
                continue;
            /* there is no power operator in C#. there is only
             * Math.Pow() and it only deals with doubles (not integers).
         	 * this is a blatant disregard of the following constraint:
             * Assume the environment does not allow you to store 64-bit
             * integers (signed or unsigned)
            returnNumber += item * Math.Pow(10, list.Count - i - 1);
        }
        
        /* Convert.ToInt32() throws an OverflowException when input larger
         * than Int32.MaxValue or Int32.MinValue.
         * the other option of casting does not alert in any way if the
         * conversion from double to integer fails.
         * in effect, OverflowException in Convert.ToInt32() is the only way
         * to know if the integer we generated as output is a valid one. */
        try
        {
            if(isNegative)
                Convert.ToInt32(returnNumber * -1);
            else
                Convert.ToInt32(returnNumber);
        }
        catch(Exception)
        {
            returnNumber = 0;
        }

        if(isNegative)
            return (int)returnNumber * -1;
        else
            return (int)returnNumber;
    }
}

Optimized solution

Analyzing the naive solution thoroughly we can easily see that the individual digits obtained by the application of remainder operator of C# need not be stored in a List<int>. Rather, an integer variable would suffice

/* replace */
int remainder = x % 10;
list.Add(remainder);
/* with */
returnNumber = returnNumber * 10 + x % 10;
/* to get rid of List<int> storage */

Also, the digit extraction can be trivially optimized. Maybe, the compiler does this. However, nothing wrong in being exact in the code itself rather than hoping the compiler will optimize away our sloppiness

/* replace */
x = (x - remainder)/10;
/* with */
x = x/10;

The first optimization has a great cascading effect:

• We can get rid of the for loop we had employed for constructing the return value
• With the for loop goes the Math.Pow()
• With removal of Math.Pow() goes away the need to Convert.ToInt32() and the OverflowException handling abomination
• With all of the above we also have now gotten rid of the constraint violation.

The final optimized code is

public class Solution 
{
    public int Reverse(int x)
	{
   		int returnNumber = 0;

        while(true)
        {
            returnNumber = returnNumber * 10 + x % 10;
            x = x/10;
            
            if(Math.Abs(x) < 1) break;

            if(returnNumber > Int32.MaxValue/10) return 0;
            else if(returnNumber < Int32.MinValue/10) return 0;
        }
        return returnNumber;
	}
}

Windows 11 and VirtualBox

The first attempt was a failure as Windows 11 refused to install on "incompatible hardware". Found a solution soon enough. If the link goes missing, the PDF should serve as an alternative:

What is IceWM

IceWM is a Window Manager (WM) for the X Window System:

The goal of IceWM is speed, simplicity, and not getting in the user’s way. It comes with a taskbar with pager, global and per-window keybindings and a dynamic menu system.

A WM is the foundation on which a Desktop Environment (DE) stands. KDE Plasma 5 DE, for example, uses KWin while GNOME uses Mutter as default WMs. However, these can be swapped out for other WMs.

A window manager is system software that controls the placement and appearance of windows within a windowing system in a graphical user interface.

Why not a Desktop Environment?

Desktop Environments (DE) are great for people who want a fully-configured, working system right after install. I had been using KDE Plasma 5 for a very long time. I would run it on old hardware too without much trouble. I have used Xfce too.

There are a few reasons for not wanting to use a DE:

• Complexity
  Desktop Environments are very complex systems. Complexity means too many moving parts. Too many moving parts means huge potential for bugs and breakages. Especially important if one intends to use a rolling release GNU Linux distribution.
• Black Box
  Presented with a computer running GNOME or KDE Plasma 5, a normal user may not even be able to tell what lies beneath the GUI glitz. Is this GNOME abstracting away a GNU Linux or a FreeBSD running on x86 or x86_64 or ARM? A normal user does not know and does not care as long as their computing needs are met. For a student, this may not be the ideal situation.
• Control
  Since a good DE abstracts away the underlying system software, the hardware and does almost everything on behalf of the user, there is a loss of control for the power user.

How to get IceWM during openSUSE installation

Very simple. Choose the Generic Desktop option during installation:

IceWM also powers the YaST Installer (image above). So, it is quite important.

Setting up the workstation

VirtualBox Extension Pack

Since no polkit exists in base IceWM install, elevation prompt does not work and error occurs:

> sudo VBoxManage extpack install --replace '<Path_To_Oracle_VM_VirtualBox_Extension_Pack.vbox-extpack'

which results in

--accept-license=33d7284dc4a0ece381196fda3cfe2ed0e1e8e7ed7f27b9a9ebc4ee22e24bd23c
to the VBoxManage command line.

0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%
Successfully installed "Oracle VM VirtualBox Extension Pack".

Screenshot application

Tried gnome-screenshot

> sudo zypper in gnome-screenshot

Does not list in IceWM menu. Can be launched from command line, takes screenshot, but no control whatsoever:

> gnome-screenshot
** Message: 01:38:15.430: Unable to use GNOME Shell's builtin screenshot interface, resorting to fallback X11.

Tried flameshot

> sudo zypper in flameshot

Works flawlessly. Has all the desired bells and whistles.

Networking

Wicked did not work properly with my Broadcom BCM43228 wifi card. Installed NetworkManager.

> sudo zypper in NetworkManager

The nmcli works flawlessly. In any case, I use NetworkManager in Arch also. So, it is easy to work with.

Audio

Followed openSUSE documentation and tried to install PulseAudio:

> sudo zypper in pulseaudio pavucontrol paprefs padevchooser paman

The last two, padevchooser and pamando do not exist.

> sudo zypper in pulseaudio pavucontrol paprefs

Everything works. pavucontrol lets me control everything.

Archiver

Downloaded and tried to run peazip

> ./peazip
./peazip: error while loading shared libraries: libgthread-2.0.so.0: cannot open shared object file: No such file or directory

Who provides libgthread-2.0.so.0?

> zypper se --provides libgthread-2.0.so.0
Loading repository data...
Reading installed packages...

S | Name                   | Summary                                        | Type
--+------------------------+------------------------------------------------+--------
  | libgthread-2_0-0       | Portable API from glib wrapping system threads | package
  | libgthread-2_0-0-32bit | Portable API from glib wrapping system threads | package

Installed libgthread-2.0.so.0

> sudo zypper in libgthread-2_0-0

Remove Display Manager

Got rid of lightdm and xdm. The sequence is important. First get rid of lightdm and all its dependencies:

> sudo zypper rm --clean-deps lightdm

Then, get rid of xdm. Running --clean-deps for xdm will nuke the X Window System. So, no --clean-deps:

> sudo zypper rm xdm

NoMachine on openSUSE Leap

NoMachine provides rpm, deb, and tar.gz packages. The rpm is officially supported on openSUSE 15.x, with no mention of Tumbleweed. I chose the 64-bit tar.gz package for greater control if something went wrong.

The general installation steps are straightforward:

1. Download and save the tar.gz file in /usr.
2. Extract the archive:
3. Run the installer:

Within a minute, NoMachine was up and running.

NoMachine on openSUSE Tumbleweed

Performing the same steps on Tumbleweed led to a failure:

NX> 700 Running: systemctl restart nxserver.service.
NX> 700 ERROR: Cannot enable systemd service: .
NX> 700 Server install completed with warnings.
NX> 700 Please review the install log for details.
NX> 700 Install completed with errors at: Mon Apr 05 16:17:09 2021.

Trying to start nxserver.service manually revealed that the service didn’t exist.
The following confirmed it:

systemctl list-units --type=service | grep nx

Nothing.

In /etc/systemd/system/, there was no nxserver.service unit.
On my openSUSE Leap machine, however, /etc/systemd/system/multi-user.target.wants/nxserver.service was a symlink to /usr/lib/systemd/system/nxserver.service.

Armed with this clue, I checked my Tumbleweed system — and sure enough, /usr/lib/systemd/system/nxserver.service was missing.

Two possibilities came to mind:

• the unit might be dynamically generated during installation, in which case I could copy it from Leap, or
• it might already exist in the extracted tar.gz directory.

It turned out to be the latter. I found nxserver.service inside /usr/NX/scripts/systemd.
Here’s what it contained:

[Unit]
Description=NoMachine Server daemon

After = syslog.target network.target network-online.target sshd.service http-daemon.target.service htd.service
Wants = network-online.target

[Service]
User=nx
Group=nx

ExecStart=-/etc/NX/nxserver --daemon

KillMode=process
SuccessExitStatus=0 SIGTERM
Restart=always

[Install]
WantedBy=multi-user.target

There were no environment-specific values, so I proceeded as follows:

1. Copied the file to the systemd directory:
2. Created a symbolic link:
3. Enabled the service:
4. Started it and verified functionality:

Everything worked perfectly after that.

Conclusion

NoMachine remains an excellent remote desktop solution for Linux.
It installs cleanly on openSUSE Leap, but on Tumbleweed the nxserver.service unit file doesn’t get installed automatically.
Once manually copied and linked, the service functions flawlessly.

openSUSE Leap's status when I jumped off:

Operating System: openSUSE Leap 15.2
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.71.0
Qt Version: 5.12.7
Kernel Version: 5.3.18-lp152.33-default
OS Type: 64-bit
Processors: 8 × Intel® Core™ i7-4770 CPU @ 3.40GHz
Memory: 31.3 GiB of RAM
Graphics Processor: Mesa DRI Intel® HD Graphics 4600

I nuked my hard drive and installed openSUSE Tumbleweed in the hope that the someone might have buried the Dolphin bug six-feet under the newer KDE Plasma releases. However, I was surprised when the bug eerily smiled at me in Tumbleweed.

Operating System: openSUSE Tumbleweed 20200727, openSUSE Leap 15.2
KDE Plasma Version: 5.19.3, 5.18.5
KDE Frameworks Version: 5.72.0. 5.71.0
Qt Version: 5.15.0, 5.12.7
Kernel Version: 5.7.9-1-default, 5.3.18-lp152.33-default
OS Type: 64-bit
Processors: 8 × Intel® Core™ i7-4770 CPU @ 3.40GHz
Memory: 31.3 GiB of RAM
Graphics Processor: Mesa DRI Intel® HD Graphics 4600

As a good citizen, I immediately made  it known to the authorities that a bug had been spotted. I filed an official bug report in KDE Bugzilla - 424902.

THE DOLPHIN BUG

SUMMARY

When working with PDF and Djvu files, if previews for files is enabled in Dolphin Preferences, too many instances of thumbnail.so are launched. They eventually flood the system as evidenced by the KSysGuard screenshot attached. It becomes impossible to launch any other application unless the thumbnail.so instances are **killed** or a reboot is performed. When previews are disabled, this issue does not occur.

STEPS TO REPRODUCE

1. Launch Dolphin without changing the default settings (Preferences).
2. Start working with PDF and Djvu files.
3. Wait for a long time. In my experiment, I had to wait for 4-5 hours.

OBSERVED RESULT

Given enough time, thumbnail.so instances start to flood the system. It becomes impossible to start any application. I was cleaning up my ebooks library when I faced this issue for the first time.

The below error message is displayed when an attempt is made to launch an application from the terminal (I used Konsole):

Maximum number of clients reached
qt.qpa.xcb: could not connect to display :0 qt.qpa.plugin: 
Could not load the Qt platform plugin "xcb" in "" even though it was found. 
Failed to create wl_display (No such file or directory) qt.qpa.plugin:
Could not load the Qt platform plugin "wayland" in "" even though it was found. This application failed to start because no Qt platform plugin could be initialized. 
Reinstalling the application may fix this problem. Available platform plugins are: 
wayland-org.kde.kwin.qpa, eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb. 

EXPECTED RESULT

User should be able to use the system for as many hours as they please without the system getting inundated with thumbnail.so instances.

VIRTUALBOX 6.1.10 AND LINUX KERNEL 5.8 INCOMPATIBILITIES

I remained on openSUSE Tumbleweed till Linux kernel 5.8 arrived. VirtualBox stopped functioning. Linux kernel 5.8 and VirtualBox 6.1.10 are incompatible. It became impossible to exist in Tumbleweed land. I moved back to openSUSE Leap 15.2.

THE PROCESS

• Install FreeBSD:

Downloaded FreeBSD-12.1-RELEASE-amd64-bootonly.iso from the official repository. Followed the very intuitive installer and got FreeBSD installed as a virtual machine.

• Install xorg:

# pkg install xorg

• Install KDE Plasma 5 minimal:

# pkg install plasma5-plasma

Now, add the following lines to /etc/rc.conf:

dbus_enable="YES"
hald_enable="YES"

• This installation of KDE Plasma 5 is so minimal that even konsole, the terminal emulator, needs to be installed explicitly:

# pkg install konsole

• Install VirtualBox Guest Additions:

# pkg install virtualbox-ose-additions

• Add the following lines into /etc/rc.conf:

vboxguest_enable="YES"
vboxservice_enable="YES"

• Now it is time for configuring how to start KDE Plasma 5. There are two ways of doing this - startx or sddm. The former is a terminal command while the latter is a Display Manager. KDE chose sddm as a successor of KDM. I did not install SDDM for unknown reasons (or because I am too lazy). So, add the following line into ~/.xinitrc:

exec ck-launch-session startplasma-x11

Now, if you add this line as root, you will have KDE Plasma 5 waking up with startx only if you login as root. For the above step to work for any other user, perform the above step once logged in as the other user.

CONCLUSION

The above steps gave me a FreeBSD 12.1 VirtualBox virtual machine with minimal KDE Plasma 5 desktop. The whole setup works well.

REFERENCES

• https://community.kde.org/FreeBSD/Setup
• https://www.freebsd.org/doc/handbook/x11-wm.html

INSTALLING VIRTUALBOX GUEST ADDITIONS

Installing VirtualBox Guest Additions in Linux guests is surprisingly more involved than on FreeBSD.

First, we need to get the tools to build the VirtualBox drivers:

sudo dnf install dkms kernel-devel gcc make bzip2 perl

I had downloaded the VirtualBox Guest Additions version 6.0.18 ISO for the openSUSE Tumbleweed guest earlier. So, I inserted it into the Fedora 32 VM and:

cd /run/media/msiyer/VBox_GAs_6.0.18
sudo ./VBoxLinuxAdditions.run

Did not work. I was asked to check logs to see what went wrong. So, that is what I did. Saw compilation errors:

Building the main Guest Additions 6.0.18 module for kernel 5.6.12-300.fc32.x86_64.
Error building the module.  Build output follows.
make V=1 CONFIG_MODULE_SIG= CONFIG_MODULE_SIG_ALL= -C /lib/modules/5.6.12-300.fc32.x86_64/build M=/tmp/vbox.0 SRCROOT=/tmp/vbox.0 -j4 modules
make[1]: warning: -jN forced in submake: disabling jobserver mode.
test -e include/generated/autoconf.h -a -e include/config/auto.conf || (		\
echo >&2;							\
echo >&2 "  ERROR: Kernel configuration is invalid.";		\
echo >&2 "         include/generated/autoconf.h or include/config/auto.conf are missing.";\
echo >&2 "         Run 'make oldconfig && make prepare' on kernel src to fix it.";	\
echo >&2 ;							\
/bin/false)
make -f ./scripts/Makefile.build obj=/tmp/vbox.0 \
single-build= \
need-builtin=1 need-modorder=1

I suspected this could be the result of a great version mismatch between VirtualBox Guest Additions and Fedora 32 Kernel version. So, I decided to download a newer version Guest Additions ISO. I was pleasantly surprised to see that 6.1.8 had arrived. Immediately downloaded it and:

cd /run/media/msiyer/VBox_GAs_6.1.8
sudo ./VBoxLinuxAdditions.run

The compilation was a success

Verifying archive integrity... All good.
Uncompressing VirtualBox 6.1.8 Guest Additions for Linux........
VirtualBox Guest Additions installer
Removing installed version 6.0.18 of VirtualBox Guest Additions...
Copying additional installer modules ...
Installing additional modules ...
VirtualBox Guest Additions: Starting.
VirtualBox Guest Additions: Building the VirtualBox Guest Additions kernel 
modules.  This may take a while.
VirtualBox Guest Additions: To build modules for other installed kernels, run
VirtualBox Guest Additions:   /sbin/rcvboxadd quicksetup <version>
VirtualBox Guest Additions: or
VirtualBox Guest Additions:   /sbin/rcvboxadd quicksetup all
VirtualBox Guest Additions: Building the modules for kernel 
5.6.12-300.fc32.x86_64.
VirtualBox Guest Additions: Running kernel modules will not be replaced until 
the system is restarted

Resolution issue was resolved.

CONCLUSION

• Resolution issue resolved
• The openSUSE Leap 15.1 host has VirtualBox version 6.0.8 installed in it while the Fedora 32 guest has VirtuaBox Guest Addtions version 6.1.8 running the show.
• Clipboard copy does not work. Most probably due to the above issue.

One LAN to rule them all, one LAN to find them, One LAN to bring them all. and in the darkness bind them.

TEST MACHINES

I chose two machines for my tests:

• Dell XPS M1330, Pentium Core 2 Duo T8100 CPU, 4GB RAM, openSUSE Leap 15.1 with KDE Plasma 5 - a 12-year old laptop acting acting as VNC and RDP server.
• Dell Inspiron 3543, Core i3-5005U, 8GB RAM, openSUSE Leap 15.1 with KDE Plasma 5 - a 5-year old laptop that has the VNC and RDP clients installed.

So, with my wlan0 interface configured in to the home zone in both machines, I began my quest.

TigerVNC - VIRTUAL NETWORK COMPUTING SERVER

TigerVNC is available in openSUSE Leap 15.1 by default. Nothing to install, but a few things to configure.

TigerVNC is a high-performance, platform-neutral implementation of VNC (Virtual Network Computing), a client/server application that allows users to launch and interact with graphical applications on remote machines.

Instaed of using vncviewer, the client component of TigerVNC, I decided to use Remmina:

sudo zypper in remmina

Opened firewall

The openSUSE firewall is configurable using the YaST Firewall GUI or firewall-cmd command. Both are functionally equal. I used the GUI to allow TigerVNC server to listen unhindered at its favourite ports.This did not work at all.

Enabled Remote Administration

Further research led me to YaST Remote Administration. Followed all the steps mentioned. No matter what I did, nothing could let me connect.

SDDM does not work with TigerVNC

I simply love KDE Plasma 5. Plasma 5 comes with SDDM (Simple Desktop Display Manager). SDDM hates TigerVNC:

SDDM (Simple Desktop Display Manager), which is the default display manager in KDE5 doesn't support XDMCP. You must switch to different display manager to get login screen in VNC sessions.

I was in no mood to nuke SDDM just so that TigerVNC could have my machines. I decided to look for alternatives.

xrdp - THE REMOTE DESKTOP PROTOCOL SERVER

I installed xrdp:

sudo zypper -n in xrdp
sudo systemctl enable xrdp
sudo systemctl start xrdp
sudo firewall-cmd --add-port=3389/tcp --permanent
sudo firewall-cmd --reload

I had to terminate xrdp experiments when Remmina endlessly tried to reconnect. It was obvious that Remmina was able to connect, but the connection was dropping immediately. Also, it is very much possible that xrdp server tries to start another GUI session and fails since I was already logged in in a KDE Plasma 5 session. Needs more research and experiments.

krfb - KDE DESKTOP SHARING

Tired of TigerVNC and xrdp, I needed an alternative. My search led me to krfb:

KDE Desktop Sharing (krfb)  is a small server for the RFB protocol, better known as VNC. Unlike most other Unix/Linux RFB servers, KRfb allows you to share your X11 session instead of creating a new X11 session.

Since krfb share X11 session instead of creating a new X11 session, it should theoretically not suffer from the xrdp issues. Also,:

Krfb (server) is one of a pair of KDE programs - Krdc (client) is the other - that let you share your desktop (make it visible remotely) through the local network with another user, probably somebody like the tech downstairs who you wants to help you figure out how to do something you are having trouble with. You can call the tech on the phone and be talking with her while she assists you.

So, I installed krfb and krdc on both my test machines:

sudo zypper in krfb
sudo zypper in krdc

Since krfb listens on port 5900, openSUSE firewall needs to be opened on both machines:

sudo firewall-cmd --zone=home --permanent --add-port=5900/tcp
sudo firewall-cmd --reload

The above commands are functionally equal to adding ports manually in the YaST Firewall GUI.

Success at last and connection was established from both machines. However, krdc was extremely slow. Barely usable. Remmina works satisfactorily.

CONCLUSION

In openSUSE Leap 15.1 with KDE Plasma 5, only krfb, the VNC server, works with Remmina, the VNC client. TigerVNC made me angry although it was SDDM's fault. xrdp did not work at all.

RESOLUTION STUCK AT 800x600

Installation was smooth and uneventful. The only issue is that the resolution is 800x600. The Display utility in KDE Plasma 5 lets me change the resolution and it works for a couple of seconds and reverts to 800x600.

My experience with openSUSE Tumbleweed as a VirtualBox guest has always been good. Not this time. However, before blaming  it, I wanted to understand the root cause of the problem.

Looked around on the world wide web and found that the VirtualBox bug tracker has Ticket #19496 already open for the same issue:

The virtualbox 6.1.6 update seems to be okay, but if the matching guest  additions is applied to the guest, the auto-resize or resize to any  resolution is unavailable.  I applied guest additions to several hosts  before discovering this issue, including Centos-6, Centos-7, Centos-8,  kali linux, and OracleLinux-8.  Guests that have not gotten the update  seem to be working fine.

MY EXPERIMENTS

VirtualBox Guest Additions from openSUSE repositories

I checked if VirtualBox Guest Additions were installed by default or not:

zypper se --installed-only | grep virtualbox
i  |  virtualbox-kmp-default  |  Kernel modules for VirtualBox  |  package

Surprisingly, found the packages missing. I was expecting them to be present. I installed virtualbox-guest-tools and virtualbox-guest-x11 and restarted the machine:

sudo zypper in virtualbox-guest-tools virtualbox-guest-x11
sudo reboot

Did not work. So, the bug seems to be affecting openSUSE Tumbleweed too. I purged the packages:

sudo zypper rm virtualbox-guest-tools virtualbox-guest-x11

VirtualBox Guest Additions from VirtualBox repositories

On the host running openSUSE Leap 15.1:

VirtualBox UI -> Devices -> Insert Guest Additions CD image...

The download began, but failed. Twice. So,:

• Confirmed my VirtualBox version - 6.0.18_SUSE r136238.
• Downlaoded the matching VirtualBox Guest Additions iso file.
• Install build tools

sudo zypper in  kernel-devel gcc make

• Inserted it into the  virtual machine and:

cd /run/media/msiyer/VBox_GAs_6.0.18
sudo ./VBoxLinuxAdditions.run

The output was a bit confusing:

Verifying archive integrity... All good.
Uncompressing VirtualBox 6.0.18 Guest Additions for Linux........
VirtualBox Guest Additions installer
Copying additional installer modules ...
Installing additional modules ...
VirtualBox Guest Additions: Starting.
VirtualBox Guest Additions: Building the VirtualBox Guest Additions kernel 
modules.  This may take a while.
VirtualBox Guest Additions: To build modules for other installed kernels, run
VirtualBox Guest Additions:   /sbin/rcvboxadd quicksetup <version>
VirtualBox Guest Additions: or
VirtualBox Guest Additions:   /sbin/rcvboxadd quicksetup all
VirtualBox Guest Additions: Building the modules for kernel 5.6.11-1-default.

VirtualBox Guest Additions: Look at /var/log/vboxadd-setup.log to find out what 
went wrong
VirtualBox Guest Additions: Running kernel modules will not be replaced until 
the system is restarted

Even without a restart the resolution was properly set and all was beautiful. I restarted for good measure. All is well.

CONCLUSION

• Virtualbox 6.1.6 is broken - Ticket #19496
• Packages virtualbox-guest-tools and virtualbox-guest-x11 not available by default in openSUSE Tumbleweed. The packages do not work even when installed.
• Installed VirtualBox Guest Additions by downloading iso from VirtualBox website.
• Success.
  

The installation was trouble-free, every single time. The installer could successfully scan and list all WiFi access points. And there were many. I have a couple of Jio WiFi dongles and a Motorola G5S Plus mobile whose hot-spot I had enabled. The Android USB tethering also worked during installation. However, it was the reboot after installation that drove me nuts every single time.

No network after reboot. No amount of wpa_supplicant and rc.conf tweaking could help me. No ifconfig command variation or dhclient could save me. Even with status: associated the access point would not let me access anything on the internet.

wlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
ether 00:21:5c:6a:6c:61
hwaddr 00:21:5c:6a:6c:61
inet 192.168.1.102 netmask 0xffff0000 broadcast 192.168.255.255
nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
media: IEEE 802.11 Wireless Ethernet MCS mode 11ng
status: associated
ssid my_ssid channel 11 (2462 MHz 11g ht/20) bssid bc:8a:e8:0a:27:f1
regdomain APAC2 country IN authmode WPA2/802.11i privacy ON
deftxkey UNDEF AES-CCM 2:128-bit txpower 30 bmiss 10 scanvalid 60
protmode CTS ampdulimit 32k ampdudensity 16 -amsdutx amsdurx shortgi
-stbc wme roaming MANUALgroups: wlan

I checked resolv.conf, but did not see anything wrong there either. I tried a few other things, but no luck. I looked in the forums, but nothing. I deleted resolv.conf and rebooted the PC. It worked.

I still have not figured out why it worked. I will get into it when I have time. However, now I can connect to all access points by tweaking the wpa_supplicant file.

ctrl_interface=/var/run/wpa_supplicant
eapol_version=2
ap_scan=1
fast_reauth=1

network={
ssid="my_ssid"
scan_ssid=0
psk="my_password"
priority=5
}
network={
        priority=0
        key_mgmt=NONE
}

The rc.conf values added by the installer is good for all access points.

hostname="my_hostname"
wlans_iwn0="wlan0"
ifconfig_wlan0="WPA DHCP"
create_args_wlan0="country IN regdomain APAC2"
local_unbound_enable="YES"
sshd_enable="YES"
dbus_enable="YES"
moused_enable="YES"
ntpd_enable="YES"
powerd_enable="YES"
dumpdev="AUTO"
zfs_enable="YES"