Secondary memory is where programs and data are kept on a long-term basis. Common secondary storage devices are the hard disk and optical disks. The hard disk has enormous storage capacity compared to main memory. The hard disk is usually contained inside the case of a computer.

1. Secondary Memory

2. WHAT IS SECINDARY MEMORY ?
PURPOSE OF SECONDARY MEMORY.
DIFFERENCE WITH PRIMARY MEMORY.
SHORTY DESCRIBE ABOUT HARD DISK.
Introduction :

3. What is secondary memory?
 A memory, which stores data and programs for a long period of
time, is called secondary memory. This memory can also be
called backup storage memory or mass storage media.
Although it is placed in lower position due to low speed, low
cost and large size, it has a very large storage capacity.
 Floppy disk, Hard Disk, CD-ROM, DVD, Zip Disk, pen drive,
micros card, etc are secondary memories

4. 1)Secondary storage is nonvolatile memory, that stored in
it is not lost when power is turned off.
2)The computer transfers instruction and data between
RAM and secondary storage.
3)As compared to primary memory it is slow, less costly
and possesses high capacity.
Purpose of secondary memory

5. What are the differences between Primary
and Secondary Memory?
Primary
memory
Secondary memory
The memory devices used for primary
memory are semiconductor memories
The secondary memory devices are
magnetic and optical memories.
The primary memory is categorized as
volatile and non volatile memories, RAM
is the volatile memory and ROM is the
non volatile memory
The secondary memory is always non
volatile
Primary memory is known as main
memory
Secondary memory is known as
additional memory or back memory
These memories are also called as
internal memory
These memories are also called as
external memory
The primary memory devices are The secondary memory devices are

6. Shorty describe about hard
disk.
 Hard disks are usually found inside computers to store programs
and data. They are increasingly cheap and more and more
companies are using them to back things up. Hard disks can vary
in physical size with some disks getting as small as your thumb.
The capacity of a commercial disk is currently up to about 2
terabytes allowing users to read and write to them. They are
constructed from several key components:
 Platter - Metallic disks where One or both sides of the platter are
magnetized, allowing data to be stored. The platter spins
thousands of times a second around the spindle. There may be
several platters, with data stored across them

7.  Head - The head reads magnetic data from the platter.
For a drive with several platters there may two heads
per platter allowing data to be read from top and bottom
of each
 Actuator Arm - used to move the read heads in and out
of the disk, so that data can be read and written to
particular locations and you can access data in a
Random fashion, you don't need to read your way
through the entire disk to fetch a particular bit of
information, you can jump right there. Seek time is very
low.

8.  Power connector - provides electricity to spin the platters,
move the read head and run the electronics
 IDE connector - allows for data transfer from and to the
platters
 Jumper block - used to get the disk working in specific
ways such as RAID

9.  how a hard disk works:
A. The platters spin around the spindle
B. data is requested to be read from a particular area of a
platter
C. the actuator arm moves the read head to that track
D. Once the data sector that is required has spun around
and under the read head, data is read
E. Read data is sent from the IDE connector to main
memory
END