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Unformatted text preview: er to act as an intermediary between the device
and the rest of the computer system. On some computers, the controller is an integral part
of the computer's main motherboard. On others, the controller is an expansion board that
connects to the system bus by plugging into one of the computer's expansion slots. In
order that devices manufactured by independent vendors can be used with different
computer manufacturers, it is important that the controllers follow some drive interfacing
standard. The four commonly used drive interface standards are:
1. Integrated Drive Electronics (IDE). IDE incorporates much of the intelligence of the
controller into the drive itself. Because most of their controlling electronics are on the
drive itself, IDE controllers are small, simple cards that do little more than providing an
IDE drive with a place to plug into the computer's bus. In fact, some computer
manufacturers build IDE support right into their motherboards. IDE provides datatransfer rates of about 1 Megabytes per second under ideal conditions.
2. Enhanced Small Device Interface (ESDI).
Like IDE, ESDI (pronounced
"es-dee") also incorporates much of the intelligence of the controller into the drive.
This provides a simpler interface with the computer and leads to faster and more reliable
operation. An ESDI controller can theoretically address up to 1 terabyte (10 12 bytes) of
disk space and can reliably transfer up to 3 Megabytes per second.
3. Intelligent Peripheral Interface-level 3 (IPI-3). IPI-3 is used in minicomputers and
mainframe systems for interfacing faster, larger disks (having diameter of 8 inches or
more) with the main computer system. It allows faster data transfer from the disk to the
computer's memory as compared to IDE or ESDI.
Small Computer System Interface (SCSI). In case of IDE, ESDI and IPI-3, a
separate device controller is required in the computer system for each type of device that
has to be connected to it. SCSI (pronounced "scuzzy") is an interesting and important
variation of the separate device contr...
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This document was uploaded on 04/07/2014.
- Spring '14