4. INTRODUCTION
WHAT IS HARD DISK?
A HARD DISK DRIVE (HDD) is a data storage device
used for storing and retrieving digital information
using rapidly rotating disks (platters) coated with
magnetic material. An HDD retains its data even
when powered off. Data is read in a random-access
manner, meaning individual blocks of data can be
stored or retrieved in any order rather than
sequentially.
5. INTRODUCTION
Who Invented The Hard Disk?
The hard disk drive was originally
invented by an IBM team led by Rey
Johnson in 1954. However since his
teams invention of the technology
significant improvements have been
made.
6. MAIN COMPONENTS FOR HARD
DISK DRIVE
DISK PLATTER
STEPPER MOTOR
SPINDLE MOTOR
READ AND WRITE HEAD
ARM
7. COMPONETS
1. DISK PLATTER
The platter is made up of a magnetic
material, in the flat disk part of the drive.
The data stored in the platter.
Each set of magnetic particles is collection a
unit called a bit.
8. COMPONETS
2 STEPPER MOTOR
Use stepper motors for controlling
read/write head position.
Stepper motors usually use +12V power, but
some new low-power drives use +5V power
source.
9. COMPONETS
3 SPINDLE MOTOR
It control the platter.
This motor rotates at a speed of 3600
to 10,000 R.P.M
All the platter moves in the same
direction.
10. COMPONETS
4 READ AND WRITE HEAD
The heads read and write the information
to the drive platter.
The head writes magnetic information on
the platter.
11. COMPONETS
5. HEAD ARM
Used for read and write operations.
DISK STRUCTURE
(A)Track
(B)Sector
(C)Cylinder/Sector of a track
(D)Storage capacity/Cluster
12. DISK STRUCTURE
TRACK
The HDD is divided into number of concentric circles called
tracks. Circular path in sector is called track.
SECTOR
Data storage area in one track multiple divided into
the multiple block is called sector. Each sector can
have 512 bytes of the data.
13. DISK STRUCTURE
CYLINDER
A set of corresponding tracks in all sides of a
hard disk is called cylinder.
STORAGE CAPICITY
Its having a formula shown below:
Storage capacity=number of cylinder’s*tracks
per cylinder*
Sector per tracks*bytes per sector.
14. FILE SYSTEM IN HDD
1.FAT (File Allocation Table)
It’s not a security.
Partition size is max 32GB.
Does not support data compression.
Does not support disk quota.
Windows operating system
conformability (95,98.ms-dos)
15. FILE SYSTEM IN HDD
2.NTFS (New Technology File System)
It’s a security.
Partition size is 1 (Tera Bytes).
It support data compression.
It support disk quota.
Windows operating system
conformability (2000,xp ,vista , win 7)
16. CONCLUSION
A hard disk has revolutionized the digital age
as we know it. Hard disks are the most widely
used technology for storage of our information
and data. Without hard disks the computer digital
age we live in would not be the same.