computer system organisation notes class 11
Computer is an electronic device which can perform varieties of operation to perform (execute) a task.
Input device :-
input device receive symbols (input) from the the users and it converts into machine understandable form .
ex: keyboard , mouse , microphone.
It receive signals in machine form and it converts into human under stand-able form.
C.P.U -> Central process unit
it is also known as brain of the computer system as it govern all the operation which carried out in computer system it decide what to do, when to do and how to do.
parts of CPU(i) CU (ii) ALU
All the decisions and program including device management done by control units. it act as a manager which control variety of task for execution.
ALU(arithmetic and logical unit):-
It is responsible for all the calculation required by the program.
It is very high speed small memory used by the computer system to store recent programs which are executed.
1. random access memory 1. Read Only Memory
2. data stored in RAM will get erased 2. data stored permanently
automatically when power is off.
3. volatile memory 3. non volatile memory
It is used to store large amount of data permanently.
ex:- hard disc, CD,DVD,pen-drive,tape drive.
BRD–> Blue ray disk
1. 1 bits –> smallest unit
2. 4 bits –> 1 nibble
3. 8 bits –> 1 byte
4. 1024 byte –> 1 kilo byte (KB)
5. 1024 KB –> 1 MB ( mega)
6. 1024 MB –> 1 GB (Giga)
7. 1024 GB –> 1 TB (tera)
8. 1024 TB –> 1 PB (peta)
set of programs that governs the operation of the computer system and make the hardware run.
system software:-the software that controls internal computer operation is called system software.
it is the program which acts as a interface between user and computer.
function of operating system:-
(1) it provide interface between user and hardware .
(2) its loads necessary program in memory for execution.
(3) it is responsible for memory management,device management and input,output.
types of operating system:-
(1) single user operating system:-
only one user program can be executed at a time. ex- DOS
(2) multi user(OS):-
it can execute more than one users program simuntationaly.
ex: windows server, Linux
(3) time sharing:-
each users program allotted a fair CPU time for their program execution.
(4) real time(OS):-
it is mainly used in scientific calculation and associated project . the task must be executed in stipulated time.
(5) multi processing(OS):-
its supports more than one processor (CPU) and it is capable of load sharing. first CPU is known as master and other CPUs refereed as slave.
windows sever, Linux.
it converts high level language into machine language.
it converts assembly language program into machine language . it is mainly used in hardware programming.
1. it convert high language program 1. it converts high level language
into machine language in ”one go”. program into machine language
2 . compiler should not be present in 2. it must be present in the memory all
memory all the time . the time during program.
3. compiler execute the program only 3. interpreter execute the lines in sequence
when whole program is error free. which are error free and stop execution
when error found in a line.
4. ex- C++, JAVA 4. ex- visual basic , JAVA
visual C++, python
system utilities are small program designed to managed compute peripheral.
ex. text radiator,backup utilities,compression utilities disk defragmenter and antivirus software.
these software are designed to carried out operation for a specific application.these software runs under operating system.
general purpose software:-
these software program are designed to perform generalized task.
ex- ms word,ms excel,ms power point,photo shop.
these software are created as per customer requirement.
ex.-invoice management,railway reservation,banking system,student information system,hotel management system.
software libraries are set of predefined code which are available to programmer for use in development of new code.
computer system organisation notes