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 …

Operating Systems: Introduction

Ankur Kulhari

Definition: Operating systems are those programs that interface the machine hardware with the user’s applications programs. The main objective of these is to dynamically allocate the shared system resources to the executing programs to achieve optimal utilization. Some of the key points about OS: A operating system can be viewed as a resource manager. Enforces boundaries among users and processes. …

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. Post Views: 8

What is micro-kernel architecture?

Ankur Kulhari

In Microkernels, parts which really require to be in a privileged mode are in kernel space: Inter-Process Communication, Basic scheduling Basic memory handling Basic I/O primitives Post Views: 19

What is Monolithic Kernel?

Ankur Kulhari

Monolithic kernel is the architecture in which every part which is to be accessed by most programs which cannot be put in a library is in the kernel space: Device drivers Scheduler Memory handling File systems Network stacks Post Views: 12