disk drives
TRANSCRIPT
Introduction To Disk Drives
By
Ammar Tahir, Nofal Ejaz, Taha Fayyaz, Muhammad Mohsin Khan,
Haroon Siddique12F-8098, 12F-8014, 12F8006
12F-823912F-8235
FAST-NUSeptember 12, 2012
A device that allows a computer to read from and write data to computer discs.
What is disk drive?
Optical Disk DrivesA form of disk drives that
uses laser beams to read and write data on shinny
plastic discs.
Magnetic Disk DrivesA form of disk drives that
uses magnetization
processes to read and write data on shinny metallic discs.
Types of disk drives
Optical Disc Drives
Compact Disc◦ Uses red laser beam
Digital Video Disc◦ Uses red laser beam
Blu-ray◦ Uses blue laser beam
Types of Optical Disk Drives
CD-ROM◦ 700 Mbytes Read Only Data
CD-R◦ 700 Mbytes of Recordable Data
CD-RW◦ 700 Mbytes of Rewritable Data
Compact Discs
DVD-ROM◦ ~4.7 Gbytes of Read Only Data
DVD-R◦ ~4.7 Gbytes of Recordable Data
DVD-R DL◦ ~8.5 Gbytes of Read Only Data in Dual Layers
DVD-RW◦ ~4.7 Gbytes of Rewriteable Data
DVD-RW DL◦ ~8.5 Gbytes of Rewriteable Data in Dual Layers
Digital Video Discs
BD-ROM◦ 25 Gbytes of Read Only Data
BD-R◦ 25 Gbytes of Recordable Data
BD-R DL◦ 50 Gbytes of Recordable Data in Dual Layers
BD-RW◦ 25 Gbytes of Rewriteable Data
BD-RW DL◦ 50 Gbytes of Rewriteable Data in Dual Layers
Blu-ray Discs
Magnetic Disc Drives
Floppy DriveIt is composed of a disk of thin,flexible metallic coated storage mediumencased in a rectangular plastic shell
Hard DriveMain storage device which usesrotating metallic media and magneticrecoding systems to process and storedigital data encased in a metallic box.
Types of Magnetic Disk Drives
8 inch Floppy Drive
5.25 inch Floppy Drive
3.5 inch Floppy Drive
Floppy Disc Drives
ATA (Advanced Technology Attachment)
◦ Also know as IDE/PATA.◦ Offers up to 16~133 MB/sec transfer rate.◦ It sends 8 bit data at a time◦ ATA cables are use to
connect them.◦ Usually have 40 pins.
Hard Disk Drive
SATA (Serial ATA)
◦ Usually have 7 pins. 3 pins grounded and 4 pins for sending and receiving.
◦ Offers up to 300MB/sec transfer rate.
◦ It sends data bit by bit.◦ SATA Cables are used to
connect SATA HDD.
Hard Disk Drive
SCSI (Small Computer System Interface)
◦ Usually have 50 to 68 pins.◦ Offers up to 640MB/sec
transfer rate.◦ This drives are hot
swappable.◦ SCSI cables are used to
connect SCSI HDD. Maximum of 16 drives can be connected in a single SCSI cable.
Hard Disk Drive
SAS (Serial Attached SCSI)
◦ SAS Drives generally offers 805 MB/sec transfer rate.
◦ This drives are hot swappable.
◦ SAS Cables are used to connect SAS Drives.
◦ Maximum of 128 drives can be connected in a single sas cable.
Hard Disk Drive
How Magnetic Storage WorksWrite head
StorageMedium
Random particles(no data stored)
Current flow(write operation)
Organized particles(represent data)
As the mediumrotates, the headwrites the data.
Before a magnetic disk can be used, it must be formatted—
a process that maps the disk's surface and determines how
data will be stored.
During formatting, the drive creates circular tracks around
the disk's surface, then divides each track into sectors.
Formatting.
Formatted Disk
An optical drive uses reflected light to read data.
To store data, the disk's metal surface is covered
with tiny dents (pits) and flat spots (lands), which
cause light to be reflected differently.
When an optical drive shines light into a pit, the
light cannot be reflected back. This represents a bit
value of 0 (off). A land reflects light back to its
source, representing a bit value of 1 (on).
How Optical Storage Works
How Optical Storage Works
01
The End