Hard Drive Standards
November 15 (Day); October 31 (Night)
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Basic Hard Drive Terminology (p. 209):
o
ATA (Advanced Technology Attachment):
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o
ATAPI (ATA Programmable Interface):

o
o
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Umbrella term that includes IDE or EIDE
Allowed for the use of devices other than hard drives
EIDE (Enhanced Integrated Drive Electronics):

A term that covers ATA-2 through ATA-5 standards

Used in 95% of all computers (p. 208)

Support up to four ATA devices (CD-ROM, Hard Drives, etc.)

A term that refers to ATA-1 standard

Uses same cable as EIDE, but much slower

Supports a maximum of two hard drives
IDE:
EIDE Cables (p. 210):
o EIDE controllers can support two EIDE drives. Therefore, EIDE cables have three
connections: one for each drive and one for the motherboard.
o
There are two types of EIDE cables: older 40-wire version and newer 80-wire
versions.

Both types only have 40-pins. The 80-wire cable has 40 extra wires to
reduce interference.
80-wire ribbon cable (TOP); 40-wire ribbon cable (BOTTOM)
Notice that both connectors have only 40 pins. Notice that the wires on the 80-wire cable are narrower.

Master / Slave (p. 210):
o
Remember from an earlier lecture that all hard drives have their own onboard
controllers.
o
When two hard drives share a single ribbon cable, you have to configure one device
to handle control for both devices. This is done by moving jumpers on the back of
the drive. The jumper settings are typically clearly marked on the drive.

The master is the device that is in control.

The slave is the drive that is not in control.

The single-drive configuration is for a drive without a slave present.

The cable-select configuration is an alternative to the master or slave
configuration. It requires a special cable-select cable. The position on
the cable determines which drive will be the master and which will be
the slave.

ATA Speed Ratings:
o ATA Speed Ratings measure how fast the hard drive is capable of transferring data to
the rest of the system, expressed in MBps (p. 209).
o The standard speeds are 33, 66, 100, and 133 MBps and the common terms for these
speeds are ATA33, ATA66, ATA100, and ATA133 (p. 209).
o Nearly all motherboards come with two EIDE controllers. One controller is the
primary controller (marked IDE0) and the secondary controller (marked IDE1) (p.
211).
o On modern systems, the IDE0 controller works at ATA66 or better and IDE1 works
at the older ATA33 speed (p. 211).
o ATA33 uses a 40-wire cable. ATA66 and faster use 80-wire cables (p. 211).
o 80-wire cables have color-coded connectors. The colored connector (usually blue,
sometimes red) attaches to the controller on the motherboard. The black connector
attaches to the master (or single) drive. The gray connector attaches to the slave
drive (p. 211).
An 80-wire ribbon cable. The master drive attaches to the blue connector.
The slave drive attaches to the gray connector. The black connector attaches to the motherboard.

SCSI (Small Computer System Interface):
o
Pronounced “skuzzy”
o
Differences between SCSI and (E)IDE:

EIDE can support up to only four devices. SCSI can support from seven
to fifteen devices.

Just as with IDE drives, a SCSI drive has its controller mounted inside
the drive housing and not on the motherboard.

Just as with IDE drives, a SCSI hard drive can handle a varying number
of sectors per track.

IDE drives communicate directly with the system bus. SCSI drives
communicate first with what is known as the SCSI bus, which then
communicates with the system bus.

A SCSI hard drive costs more than on a EIDE hard drive.

A SCSI hard drive provides a faster data transfer rate (sometimes up to
160 MBps) than EIDE hard drive. This is due to the speed of the SCSI
bus, and not the hard drive itself.

Multiple internal devices can be connected together simply by using a
cable with enough connectors (p. 269).

SCSI devices are daisy-chained to form a string of interlinked devices
called a SCSI chain (p. 269).

SCSI devices installed on the same daisy chain must be assigned
a SCSI ID that serves a unique identifier (p. 270).

SCSI devices are connected by a 68-pin connector (p. 269).

Serial ATA (SATA):
o
SATA is the successor to the original ATA standard and will eventually replace
it. The original ATA standard has retroactively been renamed Parallel ATA
(PATA).
o
Improvements over the old PATA standard:

Thinner cables for better cooling
A 7-pin SATA connector
o
o

Hot-swapping

Better data integrity checks
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Faster transfers
Data Transfer Rates:

SATA 150 – 150 MB/sec

SATA 300 – 300 MB /sec
Power Connector:

Most SATA devices (although some still maintain compatibility with the
Molex connector) require a new 15-pin connector. If you are still using a
traditional power supply, it requires a Molex adapter.
A 15-pin SATA power connector