Page 16 - Viva ICSE Computer Studies 7 : E-book

• Static RAM (SRAM): The information stored in static RAM need not be refreshed, but it
remains stable as long as the power supply is provided. SRAM is costlier but has a higher
speed than DRAM.

ROM

Read Only Memory (ROM) is an essential component of the memory unit. A computer, being
a machine, itself has no intelligence or memory and it requires instructions which are given
by man. Whenever a computer is switched on, it searches for the required instructions. The
memory consisting of these essential instructions is known as read only memory. This memory
is permanent and is not erased when the system is switched off . So, ROM is a non-volatile
memory. As is clear from its name, it is read type of memory, i.e., it can be read only and not be
written by user/programmer.

Types of ROM

There are various types of ROM available for microcomputers like PROM, EPROM and EEPROM.
• PROM: It stands for Programmable Read Only Memory. In this type of ROM, the
information is stored by programmers after its manufacturing. It cannot be altered or
erased later on.
• EPROM: It stands for Erasable Programmable Think and Discuss
Read Only Memory. It is similar to PROM, but its
information can be erased later on by ultraviolet Which memory of computer is
light and it can be reprogrammed. non-volatile and what does it
contains?
• EEPROM: It stands for Electrically Erasable
Programmable Read Only Memory. It is similar to EPROM but its information can be
erased by using a high voltage current.

Disk Drive

A disk drive enables the users to read, write, delete and modify data on a storage disk. It
manages the input/output operations of the disk. It can be either external or inbuilt component
of a disk. The most common type of disk drive is a hard drive, but several other types of disk
drives exist as well. Some examples include removable storage devices, fl oppy drives and
optical drives.

Switched Mode Power Supply (SMPS)

SMPS is essential for safe running of power-consuming
appliances. Switching power supplies have high effi ciency
and are widely used in a variety of electronic equipments,
including computers and other sensitive equipments
requiring stable and effi cient power supply. It also
contains inbuilt fans to release excessive heat generated
during the computer use.

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