Operating Systems: Application Programs vs System Programs vs System Calls

Ankur Kulhari

The difference among Application Programs, System Programs and System Calls: Application program: a program used to interpret the semantic content of messages entered by the end user of the system. System Program: a program, that provides system services to application programs and also controls some aspect of the operation of a computer is termed as system program. System services here …

Contiki Operating System and Cooja Simulator for Wireless Sensor Networks

Raju Pal

What is Operating System? Operating system (OS) provides an interface between user programs and specified hardware. For different types of hardwares, we require different types of operating systems. For example, Hardware Operating System Mobile Phones Android, iOS, Windows Laptops and Desktops Linux, Window and Mac Sensor Motes TinyOS, Contiki, YATOS, MANTIS We choose the operating systems based on our hardware …

Introduction to Operating Systems

Ankur Kulhari

What is an operating system? Before moving ahead, I would like to ask you “what comes in your mind regarding Operating System?” some of them can be: Windows Ubuntu A complected software Buttons and icons Desktop Folders Media player and so on….. Operating system An operating system is a program which provides you: An interface through which you can use …

Process Management: Operating Systems

Ankur Kulhari

What is a process A program in execution is called as a process. A process is an active entity, means it can be a cause of change in system’s state/data/elements. when does a program becomes a process A program is a file stored on secondary storage which contains, set of instruction written for some specific purpose. When this program is …

fork() system call – Operating System

Ankur Kulhari

When a process invokes/calls fork() function, a new process is created which has the same address space. As the address space is copied => PC (program counter) will also has the same value as old process has. That means the newly created process (also called as child process) will start executing from the instruction, parent process is currently executing => …

What is an operating system?

Ankur Kulhari

An operating system is a bundle of various software programs which control the allocation and usage of various hardware resources in the system. It is the first program to be loaded in the computer and it runs in the memory till the system is shut down. Some of the today’s popular Operating Systems are Red Hat, CentOS, Fedora, DOS, Windows, …

What are the main functions of a Kernel?

Ankur Kulhari

Process management Device management Memory management Interrupt handling I/O communication File system management To handle the communication between software and hardware Kernel’s services can be invoked through system calls. A layer of software called shell wraps around the Kernel.