COMPUTER KNOWLEDGE FOR BANK EXAMS

COMPUTER KNOWLEDGE FOR BANK EXAMS

COMPUTER BASICS:

 

Central Processing Unit: This is the main unit of the computer,which is being responsible for processing.It consists of following sub units.

• Memory

• control Unit

• ALU

 Memory
         It is a device that can accept data,hold them and deliver them on demand at later time.This memory is also known as primary storage section (PSS). Various types of memories are discussed below.
Random Access Memory(RAM)
        During the execution of  a program, the data needed by the program is stored in RAM,which provides a volatile storage,i,e., the data is lost in the event of a power failure.Also whenever new data is stored in RAM,the earlier data is erased and the new data takes its place.So, RAM is used to stored a data and program temporarily.
Read Only Memory (ROM)
       The programs that are always needed for running the machine are stored in ROM. It provide a non-volatile storage ,i,e.,the data does not get erased ,when the power is switched off.Since this program is stored in ROM,so it starts as soon as the computer is switched on,and makes the system ready to load the OS program in the memory. But the contents of ROM cannot be change ,however for more specialised uses
where a user may like his own special functions or programs to be performed, it is preferable to fabricate a ROM,on which a user can write his own program. Such ROMs are called Programmable Read Only Memory (PROM). Although PROM is also not a flexible memory as the information in it cannot be altered. EPROM have been fabricated to meet this requirement.
Secondary Memory
      As the contents of RAM are stored on temporary basis that is all data and programs are erased as soon as power is switched off,so for storing the data/programs permanently secondary memory is used. Sometimes it is also known as Secondary Storage. A number of input/output devices are used for this purposes like floppy Disk,Hard Disk,Magnetic Disk or tape etc..
Cache Memory
     It is  very high speed memory which is used to store portion of a program from the main memory temporarily.Data is transfer automatically between cache memory(buffer) and the primary storage so that the buffer is usually invisible to the application programmer.