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RAM is a volatile memory i.e., when a computer is switched ‘OFF’ or the power supply is interrupted, all the
stored information in it disappears. RAM chip is made of Metal Oxide Semiconductor (MOS). RAM is available
in the form of chip a of different capacities, For example, 4 GB, 8 GB, 16 GB, 32 GB, 64 GB, etc. You can upgrade
the capacity of existing RAM in a computer by installing extra RAM chips in addition to the existing ones.
There are different types of RAM like SRAM, DRAM, SDRAM, EDRAM, ECRAM, etc.
ROM
It stores a set of predefined instructions for the internal operations of a computer. It is
also referred to as ‘non-volatile’ memory or ‘firmware’.
Once the user switches ‘ON’ the computer, the computer automatically does a series of
sequential tasks like Power On Self Test (POST) before the user starts its operation. The
instructions for such a predefined set of tasks are stored in the ROM. Such information on this memory can
only be read. There are different types of ROM like PROM, EPROM, EEPROM, Flash ROM, etc.
Basic Input Output System (BIOS) is stored in ROM and it operates when the computer is switched ‘ON’. It
contains a set of essential software that test the setup of hardware devices during startup. It helps to start the
operating system and supports the transfer of data among the hardware devices.
Cache Memory
Cache memory is like a quick-access storage close to the CPU, storing frequently used data and instructions.
It helps speed up the computer by saving time when retrieving data from the main memory. By keeping
important data nearby, cache memory helps the CPU work faster and makes your computer run smoother.
Secondary Memory
Secondary memory refers to the permanent storage of data. During the operation of a computer, the currently
used data lies in the temporary memory. It may be lost if the computer is suddenly switched ‘OFF’. For this
purpose, secondary memory is required, as it provides the necessary backup and storage of instructions or
data that are permanent and can be retrieved back as and when required. It is also known as backup memory.
It has a higher storage capacity than the primary storage/memory. There are various types of secondary
storage devices. Let us discuss some of these devices.
Magnetic Disks: Magnetic Disks are storage devices that are made up of several disks coated with magnetic
material. The surface of each disk is marked with invisible circular tracks. The data is stored in the form of
magnetic spots on a disk.
Hard Disk: It is the most widely used internal Platter
storage magnetic disk. It is made a higher Spindle
of spindles of smooth metallic plates coated Head
with a thin layer of magnetic material. Each
plate of a hard disk is called a platter. Actuator Axis Head Actuator Arm
& Pivot Screw
Each platter has two (read/write) heads,
one on each side. Over the years, hard disks Voice Coil Power Connector
have been available Actuator
in various storage Jumper Block
capacities. E.g. 20 Ide Connector On Printed
Circuit Board (Interface)
MB in earlier days to
160 GB, 320 GB, 500 GB, 1 TB, 5 TB, 6 TB, 12 TB, 16 TB and more in recent times.
ICT Skills-I 53

