𝐄𝐱𝐩𝐥𝐨𝐫𝐢𝐧𝐠 𝐭𝐡𝐞 𝐒𝐲𝐬𝐭𝐞𝐦 𝐜𝐚𝐥𝐥𝐬

To transition from user space to kernel space, system calls are essential for executing actions on the kernel’s behalf. One example is the use of dynamic memory allocators like malloc() and realloc(), which rely on system calls such as sbrk() and brk(). Additionally, system calls like system(), clone(), wait(), and rt_sigaction() play key roles in process management.

Scheduling in OS

Schedulers are vital in determining process execution. The Job Queue stores submitted processes, while the Ready Queue houses processes ready for execution. The Device Queue lists blocked processes. Long-term Scheduler admits processes from the Job Queue, while Short-term Scheduler selects processes for immediate execution. The Medium-term Scheduler manages swapped-out processes.

The Shell – Terminal

The shell, acting as a command language interpreter, serves as the interface between the user and the system. It relies on the system kernel to execute programs and finds its home within a terminal emulator, like “bash,” enabling various operations and scripting capabilities in the UNIX and Linux world.

Auto Backup Files in Linux

This article provides a step-by-step guide on creating an automatic backup command for files in Linux. It covers checking directory existence, creating a file, adding commands, testing the backup, and additional notes on updating and file management within Vim. The process ensures a backup file is created for every new file opened.

Initialization of OS in MicroC/OS-II

One of the key strengths of 𝐮𝐂/𝐎𝐒-𝐈𝐈 lies in its lightweight and independent task model. Each task executes specific functions or operations, allowing for efficient task switching and context switching. Let’s start by unraveling the software file structure, which sets the foundation for a deep dive into the workings of 𝐎𝐒_𝐈𝐧𝐢𝐭(). We’ll delve into the […]

About Operating Systems

In today’s technological era, embedded systems have become an integral part of our daily life. From smart homes to smart cities, embedded systems are everywhere, and they are making our lives easier and more comfortable. Embedded systems are designed to perform specific tasks, and they are often used in applications where reliability and efficiency are […]

Addressing Modes

ALL ABOUT ADDRESSING MODES: Moving into the depths of low-level programming, we land upon assembly language. Assembly language is the closest language to us programmers and hardware. The assembly language is hardware dependent. You can’t write the same code for all the devices that you are about to use. Before you write any assembly code, […]

The allocators behind dynamic memory allocators

We know the common memory allocators as 𝐦𝐚𝐥𝐥𝐨𝐜(), 𝐜𝐚𝐥𝐥𝐨𝐜(), 𝐫𝐞𝐚𝐥𝐥𝐨𝐜(). Although having a different functionality, almost all of the above function as the same. 𝐌𝐚𝐥𝐥𝐨𝐜() allocates a chunk of memory with respect to the data type they are provided with.𝐒𝐲𝐧𝐭𝐚𝐱: pointer = (typecast*) malloc(byte-size) 𝐂𝐚𝐥𝐥𝐨𝐜() allocates given chunk of memory with size of each element, […]

Some UNIX Utilities

GREP: Exploration of the metacharacters: ^ – It matches the beginning of a line $ – It matches the end of a line \ – It matches with a character placed next to it. Ex; * matches with the character * (asterisk) , \, with a comma, ] with a closing rectangular bracket and so […]

Stages of a Compiler

( Stage-1 ) About Preprocessor: ( Stage-2 ) About Compiler: ( Stage-3 ) About Assembler: ( Stage-4 ) About Liner or Link Editor: ( Stage-5 ) About Librarians and Libraries: During linking, a standard library, libc.a is automatically linked. If gcc -c is used:– The code is compiled but not linked. If gcc -Dname is […]