The document provides an overview of hard disk drives including their history, working, characteristics, types, organization of data, and manufacturers. Hard disk drives were first introduced in 1956 to store data for IBM computers and now come in two main types - PATA and SATA. They work by magnetizing ferromagnetic material to represent binary digits and reading the data back by detecting magnetization. Proper shutdown is needed before unplugging a computer to allow the hard disk head to safely separate from the disk platter.

1. A Presentation On
Presented to:
Dr. Manju K.
Chattopadhyay
Presented By:
Sajid Khan
ECN 1st Sem

2. Content
1 – Introduction
2 – History
3 – Working
4 – Characteristics
5 – Need for a Proper Shutdown
6 – Types
7 – Tracks and Sector
8 – How Data Is Organized On Disk
9 – Disk Partitions
10 – Partitions
11 – Size Measurement and Actual Capacity
12 – Market Values and Prices
13 - Manufacturers
14 –SATA versus PATA

3. Introduction
A hard disk drive is
a non-volatile
storage device that
stores digitally
encoded data on
rapidly rotating
rigid platters with
magnetic surface.

4. History
Hard disk was first introduce in 1956 as
data storage for an IBM accounting
computer and were originally developed
for use in personal computers.

5. Working
HDD records data by magnetizing
ferromagnetic material directionally,
to represent either a 0 or a 1binary
digit. They read the data back by
detecting the magnetization of the
material.

6. Characteristics
1- Data Transfer Rate (Bytes / Second)
2- Seek Time (Second)
3- Power Consumption (Watt)
4- Shock Resistance

7. Need for a Proper Shutdown
Before plug off computer we need a
proper shutdown. But Why????
Because in hard disk head is
separated from platter by air force. In case
of power failure air force is absent and the
head fall down onto the platter this may
crash the platter and the data recorded on
that area may be lost.

8. Types :Now a days Two types of hard disk is common
in use.
1- IDE or PATA
(Parallel Advanced Technology Attachment
2- SATA
(Serial Advanced Technology Attachment )
PATA
SATA

9. Tracks and sectors
Can store
512 bytes
Sector =
small arc
of track
Track=
concentric
circle

10. How Data is Organized on Disk
• Tracks– circular areas of the disk
– Data first written to outer most track
• Sectors– Divides tracks sections
• Cylinders– Logical groupings of the the same track on
each disk surface in a disk unit

11. Partitions
Divides hard drive into logical
subdivisions which are seen by the
operating system as separate logical hard
disks.
Hard drives divided into primary and
extended partitions. The primary partition
boots the system.

12. Size Measurement
Number of cylinders by number of
heads by number of sectors by 512
Actual Capacity
0.93 x Capacity by manufacturer

13. Market Value & Price
• Hard disk is one the most purchased
spare. In 2009 516.2 Millions hard disk
were sold
Capacity
Price
Type
2 TB
12,000 Rs
SATA
500 GB
4,750 Rs
SATA
1.5 TB
250 GB
6,900 Rs
2,000 Rs
SATA
SATA
160 GB
2,050 Rs
PATA

14. Manufacturers
• Seagate
• Western Digital
• Hitachi
• Samsung
• Toshiba

15. PATA AND SATA CABLES
PATA CABLE
SATA CABLE

16. SATA V/S PATA
SATA
PATA
200
180
160
140
120
100
80
60
40
20
0
Speed
Length
Pins
Easier

18. Any Query
Don’t be confused ask
to us