Computer Storage Devices,

1. Computer Storage Devices

2. CONTENTS

Primary storage (Ram)

Secondary storage media

Removable media

3. Description removal media

ROM

RAM

HARD DISK

COMPACT DISK

USB STORAGE

MEMORY CARD

EXTERNAL HARD DISK

4. Computer Storage Devices
Without a significant amount of memory, a computer would merely be
able to perform fixed operations and immediately output the result
without storing them therefore some kind of memory is placed in the
computer to store instructions for processor and data to be processed and
also the output results for future use.
There are three types of storage devices in computer
Primary storage
Secondary storage
Removable storage

5. Primary storage
Primary storage, often referred to simply as memory, is the only one
directly accessible to the CPU. The CPU continuously reads instructions
stored there and executes them as required. Any data actively operated on
is also stored there in uniform manner.
There are two types of primary storage
ROM (Read Only Memory)
RAM (Random Access Memory)

6. ROM (Read Only Memory)
In this type of memory the information is stored permanently; it is not lost after the
system shuts down. The advantage of using this memory is that there are some complex
functions like translators that are used repeatedly. These functions are permanently
stored in the ROM and these instructions are hard wired in ROM so the execution is
very fast

7. RAM (Random Access Memory)
Unlike the ROM this is type of memory is volatile and can be erased by disconnecting
power going to it. Data can be written to it and may be retrieved from it according to
the address given. This type of memory is fast and a CPU access RAM to retrieve
data and instruction as fast as possible

8. Secondary storage
*Secondary storage,is not directly accessible by the CPU. The computer
usually uses its input output busses to access secondary storage and
transfers the desired data using primary storage. Secondary storage does
not lose the data when the device is powered down—it is non-volatile. it is
typically less expensive than primary storage. Computer systems have more
secondary storage than primary storage and data is kept for a longer time
there. In modern computers, hard disk drives (HDD) are usually used as
secondary storage.
Following are types of hard disk drives
a) Hard disk drives (HDD)

9. Hard disk drive is a magnetic device used to store data on the surface of metallic disks
with magnetic surfaces.Data can be written and read on it unlimited times. It is
slower then RAM but can store large amounts of data on both sides of magnetic disk
it is also heavy and big that’s why it is connected with wires on mother board.
*Optical disks(compact disk)
An optical disk is commonly known as CD or DVD. This is another kind of storage
technology which uses laser technology to make patterns on certain light sensitive
disks. A CD is a little old fashioned device and it can only store data of upto 700
MBs where as the mostly used DVD now a days can store upto 8.5 GBs of data.
All the optical disk types are as follows
CD (compact disks) upto 700 MBs storage
DVD (digital video disk) upto 8.5 GBs storage
HD DVD (high definition digital video disk) upto 51 GBs storage
Blu-ray Disk upto 400 GBs storage

10. Removable Storage Media
USB STORAGE
MEMORY CARD
EXTERNAL HARDISK

11. Removable storage media is that type of storage devices which can be used to
store data permanently but they are portable. The can be connected to
computer system to read or write data then it can be detached from system to
transfer it to other system or just for storage means.
Removable media include
1.Flash derives or commonly known as USB
2.Optical discs
3.Magnetic tapes
4.External hard disk derives.

12. THANK YOU FOR YOUR
COOPERATION
Presented by
Gaurav tyagi
MBA TTM