x86

Linux & Systems Administration

How the CFS Scheduler Controls Process Timeslices and Preemption
ByWeiwei Jia Dec 1, 2016Apr 12, 2026

The Completely Fair Scheduler (CFS) is the default process scheduler in Linux kernels since 2.6.23. It allocates CPU time proportionally based on process priority, but the actual timeslices and preemption behavior depend on three key tunable parameters: sched_latency_ns, sched_min_granularity_ns, and sched_wakeup_granularity_ns. Understanding how these work together is essential for tuning scheduler behavior on production systems….

Read More How the CFS Scheduler Controls Process Timeslices and Preemption
Linux & Systems Administration

Building 32-bit Wine on CentOS 7, Rocky Linux, and AlmaLinux
ByEric Ma Oct 16, 2016Apr 12, 2026

RHEL-based distributions only provide 64-bit Wine packages in their standard repositories. Many Windows applications—especially legacy software—require 32-bit Wine. Building Wine from source is the most reliable approach to get a working 32-bit installation alongside 64-bit support. Prerequisites and Resource Requirements Building Wine requires significant resources: ~2GB temporary disk space, ~500MB installed Compilation takes 20-40 minutes…

Read More Building 32-bit Wine on CentOS 7, Rocky Linux, and AlmaLinux
Linux & Systems Administration

Running Flash Content on Linux: Ruffle and Legacy Options
ByEric Ma Oct 18, 2015Apr 12, 2026

Flash is dead on the web. Adobe ended support on December 31, 2020, and all modern browsers removed plugin support years ago. If you need to view Flash content in 2026, you have two practical options: the Ruffle emulator or running legacy applications in isolated environments. Why Fresh Player Plugin and PPAPI Don’t Work Anymore…

Read More Running Flash Content on Linux: Ruffle and Legacy Options
Linux & Systems Administration

Configuring Video Modes on UEFI and Legacy BIOS Systems
ByEric Ma Sep 25, 2014Apr 12, 2026

The Linux kernel handles video mode configuration through bootloader parameters and kernel graphics drivers. Modern UEFI systems use Kernel Mode Setting (KMS) automatically, but you can override modes when needed. Legacy BIOS systems still use older mechanisms if you’re maintaining older hardware. UEFI Systems: Modern Video Mode Configuration On UEFI systems with GRUB2, add video…

Read More Configuring Video Modes on UEFI and Legacy BIOS Systems
Linux & Systems Administration

Static Linking C and C++ Programs with GCC on Linux
ByEric Ma Jan 1, 2014Apr 12, 2026

Static linking embeds all library code directly into your binary. On Linux, this sounds straightforward but glibc introduces complications that pure static binaries don’t truly exist — the C library still loads dynamic features at runtime like NSS (Name Service Switch), locale data, and character set converters. Understanding these constraints is essential before committing to…

Read More Static Linking C and C++ Programs with GCC on Linux
Linux System Configuration

Choosing the Right Timer: clock_gettime vs TSC in Linux
ByEric Ma Sep 5, 2013Apr 12, 2026

Measuring time accurately matters for performance profiling, benchmarking, and latency-sensitive applications. Linux provides several APIs with different tradeoffs in resolution, overhead, and reliability. Understanding which to use prevents subtle bugs in production code. POSIX Time APIs: gettimeofday and clock_gettime gettimeofday() and clock_gettime() are the standard POSIX calls for reading system time. gettimeofday() returns seconds and…

Read More Choosing the Right Timer: clock_gettime vs TSC in Linux
Algorithms & Data Structures

Hash Tables in C: Building and Using Them Effectively
ByEric Ma Jul 13, 2013Apr 12, 2026

When building applications requiring fast key-value lookups, hash tables are fundamental. C offers several options—from POSIX standard library functions to specialized third-party libraries. The right choice depends on your dataset characteristics, memory constraints, and whether you need dynamic resizing. Standard Library: hsearch() The simplest option is hsearch() from <search.h> in POSIX-compliant systems. It provides basic…

Read More Hash Tables in C: Building and Using Them Effectively
Development Best Practices

x86-64 Assembly: Essential Reference Guide
ByEric Ma Jul 13, 2013Apr 12, 2026

x86-64 (Intel 64, AMD64) is the dominant 64-bit instruction set architecture for consumer and enterprise computing. Whether you’re reverse-engineering binaries, writing performance-critical code, or understanding system internals, a solid grasp of x86-64 assembly is essential. Learning Foundations CMU’s Introduction to Computer Systems (15-213) course materials remain the gold standard for foundational machine-level programming. The accompanying…

Read More x86-64 Assembly: Essential Reference Guide
Linux & Systems Administration

GCC Inline Assembly on Linux: Extended Syntax and Examples
ByEric Ma Jul 13, 2013Apr 12, 2026

GCC allows you to embed assembly code directly in C/C++ programs through inline assembly (asm and __asm__). This is useful when you need fine-grained control over processor execution—forcing variables into specific registers, reading CPU state efficiently, or hand-optimizing critical sections verified by profiling. Basic Syntax GCC uses AT&T syntax by default on x86/x86-64. The simplest…

Read More GCC Inline Assembly on Linux: Extended Syntax and Examples
Languages & Frameworks

Debugging C/C++ with GDB on Linux
ByEric Ma Jul 13, 2013Apr 12, 2026

GDB is the standard debugger for C/C++ development on Linux. This reference covers essential commands for breakpoints, execution control, inspection, and troubleshooting common debugging scenarios. Starting GDB gdb ./program gdb ./program core.dump # Debug with core file gdb -p <pid> # Attach to running process gdb –args ./program arg1 arg2 # Pass arguments to program…

Read More Debugging C/C++ with GDB on Linux
Linux & Systems Administration

Generating Mixed C and Assembly Listings with GCC and objdump
ByEric Ma Jul 13, 2013Apr 12, 2026

When debugging and optimizing C/C++ programs, you need to see how the compiler translates your source code into assembly. A mixed source and assembly listing lets you trace exactly what machine instructions correspond to each line of your source. Using objdump (Recommended Modern Approach) The most straightforward method is to compile with debugging symbols and…

Read More Generating Mixed C and Assembly Listings with GCC and objdump
Development Best Practices

MFC Grid Controls: GridCtrl and Modern Alternatives
ByEric Ma Jul 13, 2013Apr 12, 2026

Building tabular data displays in MFC requires significant effort since the framework lacks a native grid control. Developers historically filled this gap with third-party solutions, but the landscape has shifted considerably. GridCtrl: The Legacy Choice The GridCtrl implementation from CodeProject was the de facto standard for years. If you’re maintaining MFC applications in 2026, you’ll…

Read More MFC Grid Controls: GridCtrl and Modern Alternatives
Development Best Practices

Enabling Modern Visual Styles in MFC Applications
ByEric Ma Jul 13, 2013Apr 12, 2026

MFC applications built with older Visual C++ versions often render with the classic Windows 95 appearance, ignoring modern system visual styles. This happens because the application isn’t explicitly linked to Common Controls v6.0, which provides visual styles support. On modern Windows systems (Windows Vista and later), this looks particularly jarring compared to contemporary applications. The…

Read More Enabling Modern Visual Styles in MFC Applications
Development Best Practices

Calling C/C++ DLLs from Java with JNI on Windows
ByEric Ma Jul 13, 2013Apr 12, 2026

JNI lets you call native C/C++ functions from Java on Windows. This guide covers the complete workflow with modern tooling. Prerequisites JDK 17 or later (JDK 21 LTS recommended) Microsoft Visual Studio 2022 or Visual Studio Build Tools MSVC C/C++ compiler javac for compilation and header generation Step 1: Write the Java Code Create your…

Read More Calling C/C++ DLLs from Java with JNI on Windows
Linux & Systems Administration

Installing Flash Plugin on 64-bit Firefox for Linux
ByEric Ma Jul 13, 2013Apr 12, 2026

Flash Player reached end-of-life on December 31, 2020, and modern browsers no longer support it. However, if you’re working with legacy systems, archived content, or old web applications that still require Flash, here’s what you need to know about the historical setup and modern alternatives. The Original Setup (Historical Reference) On 64-bit Linux with Firefox,…

Read More Installing Flash Plugin on 64-bit Firefox for Linux
Linux & Systems Administration

Installing 32-bit Firefox on 64-bit Fedora
ByEric Ma Jul 13, 2013Apr 13, 2026

Running 32-bit Firefox on a 64-bit Linux system is less common than it used to be, but there are still valid reasons: testing web compatibility across architectures, supporting legacy plugins, or working with older systems. This guide covers Fedora and RHEL-based systems, though the core approach applies to other distributions. Prerequisites Ensure you have multilib…

Read More Installing 32-bit Firefox on 64-bit Fedora
Linux & Systems Administration

Understanding Xen’s Codebase Architecture
ByEric Ma Jul 13, 2013Apr 12, 2026

Xen remains a production hypervisor used by AWS EC2, Citrix Hypervisor, and other cloud providers, though most general-purpose Linux distributions have shifted toward KVM as their default. If you’re working with Xen in production or developing drivers, understanding its source code layout is essential. Top-Level Directory Structure The Xen source repository (hosted on xenbits.xen.org) is…

Read More Understanding Xen’s Codebase Architecture