Download 5. What is an Operating System? Explain its components Answer An

5. What is an Operating System? Explain its components Answer
An Operating System, or OS, is a software program that enables the computer hardware
tocommunicate and operate with the computer software. Without a computer Operating System,
acomputer would be useless.
Examples of operating systems are,· Windows Vista, Windows XP, Windows ME, Windows 2000,
Windows NT, Windows 95, and allother members of the Windows family.· UNIX, Linux, Solaris,
Irix, and all other members of the UNIX family· MacOS 10 (OSX), MacOS 8, MacOS 7, and all other
members of the MacOS family.The nucleus/OS (OS is also called nucleus)
deals with the following:1.
Interrupt / Trap Handling
OS contains interrupt service routines (interrupt handlers), typically one for each possible type
of interrupt from the hardware.Example: clock handler: handles the clock device, which ticks 60 (or
more) times per second OSalso contains trap service routines (trap handlers), typically one for each
possible type of trap fromthe processor2.
Short Term Scheduling:
Choosing which process to run next 3.
Process Management:
–
Creating and deleting processes
–
Assigning privileges and resources to processes4.
Interprocess Communication (IPC):
Exchanging information between processes
Within the OS there are routines for- Managing Registers- Managing Time- Handling Device Interrupts
OS provides the environment in which processes exist
Every process depends on services provided by the OS
Components of Computer Systems
The following are the major components of computer systems,1.
Hardware:
Provides basic computing resources (CPU, memory, I/O devices).2.
Operating System:
Controls and coordinates the use of the hardware among the variousapplication programs for the
various users.3.
Application Programs:
Define the ways in which the system resources are used to solve thecomputing problems of the users
(compilers, database systems, video games, business programs).4.
Users:
(people, machines, other computers)
6
. What is process? Differentiate between a process and program? Answer
Process is a program which is in execution or A process is the unit of work in a system. The
processhas been given many definitions for instance· A program in Execution.· An asynchronous
activity.· The 'animated sprit' of a procedure in execution.· The entity to which processors are
assigned.· The 'dispatchable' unit.Operating system handles everything is terms of processes only.
Process is not the same asprogram. A process is more than a pr
ogram code. A process is an ‘active’ entity as oppose toprogram which consider to be a ‘passive’ entity.
Being a passive, a program is only a part of process. Process, on the other hand, includes.· Current
value of Program Counter (PC)· Contents of the processors registers· Value of the variables· The
Process Stack (SP) which typically contains temporary data such as subroutine parameter,return
address, and temporary variables.· A data section that contains global variables In Process model, all
software on the computer isorganized into a number of sequential processes. A process includes PC,
registers, and variables.Conceptually, each process has its own virtual CPU. In reality, the CPU
switches back and forthamong processes. (The rapid switching back and forth is called
multiprogramming).