system programming

OS development over time We all know that kernel is the core part of any OS. It is the set of code running in privileged mode (kernel mode or Ring3 security level). Operating Systems can be classified based on the architecture of their kernel as below: Monolithic kernel OS This is the old style of […]

What is RCU? Read-Copy-Update(RCU) is way of implementing wait-free synchronization between multiple processes/threads (alternative to lock mechanism). It works well in multiple reader and writer scenarios (especially ready heavy scenario). The key idea in RCU is doing a write/update operation in 2 steps namely ‘removal’ and ‘reclaim’.In step 1 (removal step), we have to remove references to […]

Everyone of us are familiar with RAM (Random Access Memory), this post is an attempt to explore the different types of RAM and how they store the data. We typically have 2 types of RAM SRAM (Static RAM) DRAM (Dynamic RAM) SDRAM (Synchronous DRAM) — is simply DRAM, which is synchronized with System Bus (newer […]

System calls are used by user programs in order get service from the operating system. Some of the popular system calls are we normally use are open, read, write, close, wait, exec, fork, exit, and kill. There are usually 100’s of system call available in OS. For example, Linux has 300+ system calls. Why we […]

Device drivers and OS In the beginning almost all OS were implemented as a single huge kernel with all device drivers included as part of the kernel. If we think further this design make sense, as almost all device drivers require the hardware/resource access and these accesses are provided by being part of the kernel […]