Linux Kernel Labs’ Post

What do we mean when we say system is 32bit or 64 bit system ? ░▒▓█► ✿✿✿✿ 𝐂𝐒𝐄𝐏𝐫𝐚𝐜𝐭𝐢𝐜𝐚𝐥𝐬 ✿✿✿✿◄█▓▒░ A 32-bit or 64-bit system predominantly refers to the type of central processing unit (CPU), or processor, that a computer has. The bit designation is a measure of the size of the data types that it can handle, its memory limit, and the number and type of software programs it can run simultaneously. A 32-bit system can access 232 memory addresses, equating to 4 gigabytes of RAM, whereas a 64-bit can access 264 memory addresses, theoretically capable of handling 18.4 million terabytes of RAM. Because a 64-bit processor can handle more data at once - a larger number of wider 'bits' of data with each instruction cycle - it is usually faster than a 32-bit processor. Also, a 64-bit system can run both 32-bit and 64-bit software, while a 32-bit system can only run 32-bit software. Currently, most computers use 64-bit processors as they provide superior performance and can accommodate larger amounts of RAM, making them more suitable for memory-heavy applications like gaming, programming, or video editing. Ultimately, the bit designation reflects the computing capability of a system. In addition, in operating systems, the bit-degree indicates whether the system can use more or less physical memory. For instance, 32-bit versions of Windows can handle up to 4GB of memory, while 64-bit versions can manage up to 128GB or more, depending upon the version. 🆅🅸🆂🅸🆃 : https://lnkd.in/d3NzBDzE tgram grp : https://lnkd.in/gy93YX9 #programming #operatingsystem #systemprogramming #networking #linux #C/C++ #linux #datastructures #algorithms #sql #RDBMS #TCP #UDP #Router #loadbalancer #Coding #OOps #protocoldevelopment

A succinct diagram describing how software deployed in the user space translates to communication to hardware. Most applications operate in the user space (stop at sys calls), conveniently abstracted over pre-packaged OS drivers in the kernel space, be it Windows or Unix based systems. With prior experience on #RaspberryPi - 4B running on a #Linux based kernel, references specific to file systems are mentioned to provide context. Terminology: 1️⃣ Bus: A device that serves as an attachment point for other devices. For example: The CPU is connected to low speed peripherals like bluetooth, I2C via one bus and high speed interfaces like DRAM, ethernet via a different bus 2️⃣ Device: Physical or virtual object that attaches to a bus 3️⃣ Driver: Software entity which may probe for and be bound to devices at runtime. These can be loaded in or removed. Kernel space compiled drivers end in '.ko' The space in red is un-privileged, which means any bug in the application code will only affect that application and leave the background processes on the machine intact. The kernel space is for daredevil coders, who are willing to endanger the state of the entire machine if something goes wrong. 💡 The kernel space is heavily based on file operations, where a read/write to a file in the user space, could be translated to read/write operations to kernel driver. The driver then manipulates the registers of the hardware via a bus that recognizes a registered device driver fit to speak to that piece of hardware. ❓ Why make a driver in the kernel space at all when I have efficient languages like C, C++, Rust and Go to work with in the user space? When performance or timing accuracy of high speed hardware devices are the objective, many applications require a direct line of sight to the hardware with minimal overhead from CPU background processes, priority queues and context switches to the user space and back. When implemented well, they offer a far lower runtime error count in timing sensitive applications. #Drivers #Kernel #Embedded

Last week, I spent some time learning about random number generators and entropy pooling. Suppose you're in a Linux machine and you generate a random number in C++: std::random_device rd; std::uniform_int_distribution<int> dist(1, 10); dist(rd); But what does this do under the hood? std::random_device gives you a true random number and it pretty opaque. You don't really know exactly what it is, what it's going to do, or how efficient it will be. You don't even know if it can actually be acquired -- it might throw an exception when you attempt to create it. If you look at the libc++ code for std::random_device, it's just a thin wrapper over std::fopen("/dev/urandom"). So each time you create a std::random_device you are getting a filesystem handle and whenever you read from it, you are simply making a system call. When using GCC on Linux, std::random_device will try to use Intel's RDRAND instruction. RDRAND has a single entropy source and provides a stream of entropy data as zeros and ones. It is essentially a hardware circuit which jumps between 0 and 1 based on thermal noise fluctuations within the CPU. On Linux, the root of all randomness is something called the kernel entropy pool. This entropy pool is used in two ways: random numbers are generated from it and it is replenished with entropy by the kernel. When random numbers are generated from the pool the entropy of the pool is diminished, as the person receiving the random number has some information about the pool itself. You can even check a rough estimate of the number of bits of entropy in the pool with this command: cat /proc/sys/kernel/random/entropy_avail Hope this was useful, I might write a bit more in detail about this as I found it super intriguing!

Operating systems (their kernel specifically) orchestrate many processes, allow access to memory, disk, network and execute processes by scheduling them to the CPU. Sounds simple when we put it this way but this task is vast. Writing efficient programs depends on how much understanding the engineer has in OS kernel. When we access a 32 bit integer in memory or write 6 bytes to disk, the kernel and hardware work together through several steps and layers to handle those tasks, simple as may seem. Each step and layer may add unpredictable costs. As a result we as engineers are bound to write inefficient code as we grind across the grain of the kernel. I built this course to demystify what I believe are the fundamentals operating systems to software engineers. By knowing how the kernel works, you will start writing software differently and naturally as you will start questioning what happens in each line you author. Like all my courses, I recommend the student having some programming experience to take this course, it just makes the course relatable. The course is focused on Linux but I do explain how Windows and Mac are different in certain situations. I hope you enjoy it. I'm happy I was able to finish it after 2 years of work. Use code "KERNEL" or head to https://lnkd.in/gWFufJA7

📌 𝐓𝐡𝐞 𝐋𝐢𝐧𝐮𝐱 𝐁𝐨𝐨𝐭 𝐏𝐫𝐨𝐜𝐞𝐬𝐬 𝐢𝐧 8 𝐬𝐢𝐦𝐩𝐥𝐞 𝐬𝐭𝐞𝐩𝐬 - 𝐀𝐍 𝐈𝐍𝐓𝐄𝐑𝐕𝐈𝐄𝐖 𝐅𝐀𝐕𝐎𝐔𝐑𝐈𝐓𝐄 - - - 🟠 Step 1: Power On! Just like turning on a light, when you power up your computer, it kicks off a process called BIOS (Basic Input/Output System) or UEFI (Unified Extensible Firmware Interface). 🟠 Step 2: Checking the Essentials Next, the BIOS/UEEFI does a roll call of the computer's essentials - CPU, RAM, and storage devices. It's like checking if all players are present before starting a game! 🟠 Step 3: Picking the Boot Device Now, the computer needs to decide where to start the actual booting from. It could be the hard drive, a network server, or even a CD ROM. It's like choosing which door to open to enter a room. 🟠 Step 4: GRUB Time! Here comes GRUB (Grand Unified Bootloader). This is a friendly menu that lets you choose which operating system or specific settings you want to boot into. Think of it as a restaurant menu for your computer. 🟠 Step 5: Kernel & User Space Once you've made your choice, the kernel (core of the operating system) gets ready. Then, we switch to the user space where systemd, a kind of manager for the system, takes over. It sets up everything else like hardware and file systems. 🟠 Step 6: systemd In Charge systemd isn't just a manager; it's the default one that activates when the system boots. It ensures everything runs smoothly and other required components are started. 🟠 Step 7: Running Startup Scripts Now, the system runs a series of startup scripts. These are like instructions to set up and configure the environment. 🟠 Step 8: Ready to Log In! Finally, you'll see the login window, Welcome! And there you have it - from a quiet machine to a fully operational system, ready for your commands. #linux #devops #interviewtips

linux boot process

we all use Linux Server in our Day to Day Tasks !! "Ever wondered how a Linux server boots? 🚀 Let's unravel the mystery! The Linux boot process involves a series of stages, from the initial firmware startup to the loading of the kernel and essential system services. This captivating GIF provides a visual journey through the intricacies of the Linux boot sequence. 🔄✨ Explore the layers of initialization, service activation, and system readiness. Check out the below Image and discover the orchestration behind a seamless Linux server startup. 🌐🔍 #Linux #ServerBoot #TechMagic"

How Do Operating Systems Use Multiprocessing and Multithreading Operating systems (OS) use both multi-threading and multi-processing depending on the tasks and goals they need to accomplish. Here's how and why an OS might use each:   Read more... https://lnkd.in/g9PHPTNn #OperatingSystem #OS #Linux #Windows #macOS #OpenSource #Tech #Software #IT #SysAdmin #CyberSecurity #Unix #DevOps #SystemAdmin #CloudComputing #TechNews #Programming #TechTrends #Server #TechCommunity

Discover how to optimize U-Boot boot time on the AM6254 embedded platform! Our latest guide offers a detailed breakdown of the U-Boot boot process and key strategies to reduce boot time. Learn about hardware initialization, environment configuration, and code modifications to enhance performance. 👇 #ForlinxEmbedded #EmbeddedSystems #SoM #UbootOptimization #AM6254 #BootTimeReduction #EmbeddedTechnology #TexasInstruments #HardwareDevelopment #Linux

Discover how to create multi-node #CAN networks in Antmicro's #Renode simulation framework with the help of #SocketCAN, including integration with #Wireshark and illustrated with a #ZephyrRTOS demo. https://lnkd.in/dD9JvzJE Wireshark Foundation The Zephyr Project The Linux Foundation Maemalynn Nokdhes Meanor