WHAT IS HARD DISK DRIVE ?
The Hard Disk is secondary storage
device. The " hard disk is made of several
circular metal disk coated with magnetic
ink . They are also called as magnetic
disks . Each tracks is divided into different
sectors , which are further divided into
bytes . The time taken to reach to the
specified position is called as latency
time.
Hard Disk are also known as fixed disks.
It is available in many sizes and
capacities. Modern hard disks have
capacity of up to
1000 gigabytes. There are also special
types of hard disks available for personal
computers called Wichester disks. Their
capacity ranges from 20 gigabytes to 80
gigabytes. Hard disk is a very reliable
means of storing information permanently
and the speed of using them is also
sufficient. But they are very sensitive to
dust etc., due to which they are kept
permanently in a box and mounted inside
the system unit.
A block with a typical capacity of 512 bytes
is a section of a track within the sector
limit. Each block has its own read/write
head and sector address. The read/write
head floats above the disk surface and does
not come into contact with it, and therefore
the hard disk remains usable for a long
time. In small computers, such as PCs, the
size of the hard disk is very small.
Types of Head in Hard Disk Drive
The head in a hard disk drive can be
divided into the following two major parts
Fixed Head
Fixed Head in a hard disk drive with a
fixed head Next - do not move backwards
and the number of heads used to write and
read data on a surface is equal to the
number of tracks on the surface. A disk
drive is faster in speed than a hard disk
drive with a movable head.
Movable Head
The movable head in a hard disk drive
with a movable head can move back and
forth and has But only one head is used to
read and write data. This head moves back
and forth and writes data by going to the
sector of all the tracks. When the hard
disk.
The data is not being written and read in
the drive, then the read / write head ( Read
/ write Head ) of the platter Keep up, but
when data is written and read in the hard
disk drive, then the platter starts rotating.
Due to the air-pressure generated due to
their rotation, the head mounted on these
platters starts reading and writing data,
going up to 400th part of 1 inch. There is
no damage to the surface of the platter.
Types of Hard Disk
SATA
PATA
SCSI
SSD
SATA(Serial Advanced Technology Attachment)
SATA stands for Serial Advanced
Technology Attachment.SATA is a bus
interface that connects hard disks , optical
drives . It was introduced in 2001 after
PATA was slowly declining its demand by
the Serial ATA Working Group. SATA has
more advantages than PATA making its
demand more.SATA is the default interface
for most desktop and laptop hard drives.
They are referred to as SATA hard drives ,
but they are actually rotary hard drives
with spinning platters and a moving needle
that writes data to consecutive sectors on
each platter.
PATA(Parallel Advanced Technology Attachment )
PATA stands for Parallel Advanced
Technology Attachment .which is a bus
interface used for connecting secondary
storage devices like hard disks , optical
drives . It was first introduced in the year
1986 by Western Digital and Compaq . It
was later replaced by SATA .
PATA is the original " integrated drive
electronics " ( IDE ) technology that
transferred data from the hard disk over a
parallel data channel to the motherboard .
SCSI( Small Computer System Interface )
SCSI stands for Small Computer System
Interface .The Small Computer System
Interface ( SCSI ) is a set of parallel
interface standards used to attach disk
drives and other peripherals to a compute .
SCSI is an acronym for Small Computer
System Interface , pronounced " scuzzy ".
SCSI hard drives have been the backbone
of enterprise computing for nearly 20
years. Though they typically don't possess
much in the way of capacity ( the last
generation of SCSI drives consisting mostly
of 36GB , 73GB , and 146GB models ), SCSI
drives make up for it with speed .
SSD (Solid State Drive)
SSD stands for Solid State Drive. These
disks don't have any moving parts. Instead
, all of the data is stored on non - volatile
flash memory . That means that there isn't
a needle that has to move to read or write
data and that they are significantly faster
than SATA drives. It's difficult to find an
exact speed because it varies by
manufacturer and form factor, but even
the lower - performing drives are
comparable to SATA drives.
Read More :
What is ROM (Read Only Memory) ? & Types of ROM.
Output device and his types define and
0 Comments