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Articles by Alex Onsman
144 articles
Major Activities of an Operating System with Regard to Memory Management
Memory management is one of the most critical functions of an operating system. It handles the allocation and deallocation of memory space to processes, manages the movement of processes between primary memory (RAM) and secondary storage (disk), and ensures optimal utilization of available memory resources. The major activities of an operating system with regard to memory management include memory allocation, swapping, paging, and segmentation. Each technique serves specific purposes in managing system memory efficiently. Memory Allocation Memory allocation involves assigning available memory blocks to processes that request them. The operating system uses various algorithms to determine which ...
Read MoreGoogle Android Architecture
Android is an operating system developed by Google for mobile systems. It is based on the Linux kernel and mainly designed for touchscreen devices such as tablets and smartphones. Android's layered architecture ensures modularity, security, and efficient resource management across diverse hardware platforms. The Android architecture is divided into four main layers and five sections, creating a structured environment where each layer serves specific functions and communicates with adjacent layers. Android Architecture Applications Contacts | Phone | Browser | Games ...
Read MoreHash Functions and Hash Tables
Hashing is the process of generating a value from a text or a list of numbers using a mathematical function known as a hash function. Hash functions convert input data of arbitrary size into fixed-size hash values, which are used as indices in hash tables for efficient data storage and retrieval. Hash Functions Hash functions are algorithms that map data to fixed-size hash values. Here are the most commonly used hash functions − Division Method This is the simplest method to create a hash function. The hash function can be described as − h(k) ...
Read MoreSolaris OS Loadable Modules
Solaris is a Unix-based operating system originally developed by Sun Microsystems and now maintained by Oracle as Oracle Solaris. It is renowned for its enterprise-grade scalability and innovative features such as DTrace (dynamic tracing), ZFS (Zettabyte File System), and Time Slider backup functionality. Solaris Kernel Architecture The Solaris kernel serves as the core component that manages hardware resources and system operations. Unlike monolithic kernels, Solaris employs a modular kernel design that allows dynamic loading and unloading of kernel modules, providing flexibility and efficient memory usage. Solaris Boot Process The Solaris boot sequence involves several distinct phases, ...
Read MoreComputer Storage Structure
Computer Storage Structure refers to the hierarchical organization of storage devices in a computer system. It is traditionally divided into primary storage, secondary storage, and tertiary storage, each serving different purposes based on speed, capacity, and cost considerations. Computer Storage Hierarchy CPU Cache RAM ROM Primary Storage Fast Access • ...
Read MoreUser-level threads and Kernel-level threads
A thread is a lightweight process that can be managed independently by a scheduler. It improves the application performance using parallelism. A thread shares information like data segment, code segment files etc. with its peer threads while it contains its own registers, stack, counter etc. The two main types of threads are user-level threads and kernel-level threads. A diagram that demonstrates these is as follows − User-level vs Kernel-level Threads User-level Threads Kernel-level Threads Application Process ...
Read MoreShared Memory Model of Process Communication
Process communication is the mechanism provided by the operating system that allows processes to communicate with each other. This communication could involve a process letting another process know that some event has occurred or transferring of data from one process to another. One of the models of process communication is the shared memory model. The shared memory in the shared memory model is the memory that can be simultaneously accessed by multiple processes. This is done so that the processes can communicate with each other. All POSIX systems, as well as Windows operating systems use shared memory. ...
Read MoreMulti-Threading Models
Multithreading allows the execution of multiple parts of a program at the same time. These parts are known as threads and are lightweight processes available within the process. Therefore, multithreading leads to maximum utilization of the CPU by multitasking. The main models for multithreading are one-to-one model, many-to-one model, and many-to-many model. Each model defines how user-level threads are mapped to kernel-level threads, affecting performance and system behavior. One-to-One Model The one-to-one model maps each user thread to a kernel thread. This means that many threads can run in parallel on multiprocessors and other threads can run ...
Read MoreMessage Passing vs Shared Memory Process communication Models
Interprocess Communication (IPC) allows processes to exchange data and coordinate their activities. The two primary models for IPC are Message Passing and Shared Memory. Each model has distinct characteristics, advantages, and use cases that make them suitable for different scenarios. Message Passing Process Communication Model In the message passing model, processes communicate by exchanging messages through the operating system kernel. Processes do not share memory directly; instead, they send and receive messages via system calls like send() and receive(). The OS manages message queues, pipes, or sockets to facilitate this communication. Message Passing ...
Read MoreWhat is a Debugger Program?
A debugger program is a software tool that allows developers to execute another program in a controlled environment, examining it line by line. This enables users to identify incorrect code, understand program flow, and see how their program is interpreted by the computer. Debuggers are essential for finding semantic errors that may not be caught during compilation but cause runtime issues. A debugger helps programmers visualize program execution and understand the internal state of their applications. While debuggers may require practice to master, they significantly reduce the time needed to identify and fix program defects, making them indispensable tools ...
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