The NAS Parallel Benchmarks (NPB) remain a standard tool for evaluating HPC system performance, though landscape has shifted toward additional metrics like HPCG and memory bandwidth tests. This guide covers installation and basic usage. Prerequisites Before installing NPB, you’ll need: Fortran compiler — gfortran is the standard choice on most systems MPI implementation — OpenMPI…
Most modern systems have thermal sensors built into the CPU and motherboard. Reading these sensors is essential for monitoring system health, diagnosing performance issues, and preventing thermal throttling or hardware damage. Install lm-sensors The standard tool for reading hardware sensors on Linux is lm-sensors. Install it on your system: Debian/Ubuntu: sudo apt install lm-sensors RHEL/CentOS/Fedora:…
MATE Desktop provides a traditional GNOME 2-style interface that many users prefer over modern GNOME Shell. Here’s how to install it on Linux Mint 17 Qiana. Install MATE Desktop sudo apt-get update sudo apt-get install mate-desktop-environment For the full MATE experience with extras: sudo apt-get install mate-desktop-environment-extras This adds additional applets, themes, and utilities not…
After installing Xen on AMD systems, you may see continuous “powernow-k8 transition frequency failed” messages on the console. This happens because the powernow_k8 driver (AMD CPU power management) is incompatible with Xen’s CPU handling and tries to manage frequencies that Xen controls. Quick Fix The simplest solution is to unload the conflicting module: sudo rmmod…
Xen hypervisor command line options are kernel parameters passed during boot that control how the Xen hypervisor initializes and operates. These affect CPU scheduling, memory management, virtualization features, debugging, and more. Finding Xen Command Line Options The official documentation is the authoritative source for Xen hypervisor parameters. For your installed Xen version, consult: Official Xen…
Converting between Simplified Chinese (SC) and Traditional Chinese (TC) characters on Linux is straightforward with OpenCC, a mature open-source tool designed specifically for this task. Installing OpenCC Most distributions include OpenCC in their standard repositories: # Debian/Ubuntu sudo apt install opencc # RHEL/CentOS/Fedora sudo dnf install opencc # Arch sudo pacman -S opencc Alternatively, build…
MPlayer has been largely superseded by mpv in most Linux distributions, but if you need the classic MPlayer with DVD navigation support, building from source remains the way to get libdvdnav integrated. Most distribution packages omit this feature due to licensing complexity. Prerequisites You’ll need a C compiler, build tools, and development libraries. On Fedora/RHEL-based…
Measuring the execution time of a function is useful for profiling and optimization work. OCaml provides straightforward tools for this. Basic approach with Unix.gettimeofday The simplest method uses Unix.gettimeofday(), which returns wall-clock time as a float with microsecond precision: let time f = let t = Unix.gettimeofday () in let res = f () in…
Listing active services is essential for system monitoring and troubleshooting. Whether you’re investigating a hung process, checking if a daemon started correctly, or auditing what’s actually running on your system, knowing how to query service status quickly saves time. Basic Command The standard way to list running services across all modern Linux distributions is: systemctl…
When you hit the open files limit on Linux, you’ll see errors like “Too many open files” — typically when running applications that create many temporary file handles. The default limit is often 1024, which isn’t enough for resource-heavy workloads. Check your current limit: ulimit -n Understanding soft and hard limits Linux maintains two types…
Monitoring hardware temperatures is essential for laptop health and performance. On Linux, lm-sensors provides CPU and system temperatures, while smartctl (from smartmontools) gives you drive health data including temperature readings. Installation Debian/Ubuntu/Linux Mint: sudo apt install lm-sensors smartmontools Fedora/RHEL/CentOS: sudo dnf install lm_sensors smartmontools Arch Linux: sudo pacman -S lm_sensors smartmontools Detecting Sensors Before reading…
Converting FLV files to MP4 is straightforward with FFmpeg. The basic command takes just seconds: ffmpeg -i input.flv output.mp4 FFmpeg will automatically select suitable video and audio codecs for MP4 format. This works for most FLV files without additional configuration. Preserving original quality If you want to skip re-encoding and copy the streams as-is, use…
Getting video files from your Linux machine to an iPhone for offline viewing doesn’t require iTunes or complex workarounds. Here are the practical methods that actually work in 2026. Quick Upload via VLC’s WiFi Interface VLC for iOS remains the most straightforward approach for occasional transfers. It’s free, open-source, and handles virtually any codec you…
You can fetch a webpage as if you’re requesting from a mobile device by setting curl’s User-Agent header to match a mobile browser. Remote servers use the User-Agent header to decide whether to serve mobile or desktop versions of pages. Basic syntax Use the -A (or –user-agent) flag to specify a mobile User-Agent string: curl…
MPlayer is effectively unmaintained. If you’re starting fresh, use mpv — the actively maintained fork with better codec support, hardware acceleration, and improved filter performance. That said, if you’re working with existing MPlayer setups, you can still improve playback quality through filters. When to Use Filters vs. When to Switch Before spending time tuning MPlayer,…
SSH is fast enough for most tasks, but when you’re transferring large files, running multiple commands, or managing hundreds of servers, every millisecond counts. Here’s how to squeeze real performance gains from SSH and SCP on Linux. Choose the Right Cipher Cipher selection has the biggest impact on throughput. Modern CPUs have AES-NI hardware acceleration,…
YARN (Yet Another Resource Negotiator) fundamentally restructured Hadoop 2.0 by decoupling resource management from application logic. If you’re transitioning from Hadoop 1.x or building systems on top of YARN, understanding its architecture is essential for effective cluster administration and application development. Essential Reading The foundational paper Start with “Apache Hadoop YARN: Yet Another Resource Negotiator”…
Linux systems can have multiple timer sources available, and the kernel selects one as the active clocksource. Understanding what’s available and how to view or change the current source is essential for performance tuning and troubleshooting timing-related issues. View the Current Timer Source Check which clocksource is currently in use: cat /sys/devices/system/clocksource/clocksource0/current_clocksource This will output…
Xen HVM (Hardware Virtual Machine) guests require a configuration file that defines virtual hardware, networking, and boot parameters. Here are practical examples for common scenarios. Installation Configuration Use this configuration when installing a guest OS from an ISO: name=”10.0.1.235″ vcpus=2 memory=2048 shadow_memory=8 disk=[‘file:/lhome/xen/vm-10.0.1.235/vmdisk0,xvda,w’, ‘file:/lhome/Linux-x86_64-DVD.iso,xvdc:cdrom,r’] vif=[‘bridge=xenbr0′] kernel=’/usr/lib/xen/boot/hvmloader’ builder=’hvm’ device_model=’/usr/lib64/xen/bin/qemu-dm’ vnc=1 vnclisten=”0.0.0.0″ vncpasswd=’your-secure-password’ on_reboot=’restart’ on_crash=’restart’ Key points…
Linux gives you top and htop to monitor CPU and memory by process, but network traffic is different. You need specific tools designed to show which processes are consuming bandwidth. Here are the practical options. nethogs nethogs remains the most straightforward tool for real-time network usage per process: sudo nethogs It displays incoming and outgoing…