The July 95 issue of PC Magazine has some good articles about current
IDE and SCSI protocols. It really helps to understand why some IDE drives
will not work with other IDE drives.
Here's some specs/info that might be of interest.
Acryonyms:
ATAPI stands for AT Attachment Packet Interface
PIO = Programmmed Input/Output
list of Acronyms that will be hitting the market in the next 18 months
(some are out now of course):
E-IDE, E-IDE-95, IDE bus mastering, Fast ATA, ATA-2, ATA-3, ATA-4,
ATAPI tape, ATAPI cdrom, SCSI-2, Wide SCSI-2, Fast SCSI,
SCSI-3 subset, SCSI-3, Wide SCSI-3, Ultra-SCSI, Wide Ultra-SCSI,
Fast 20, double-speed SCSI
--------------------------------------------------
Protocol Specs
------- -----
SCSI 5 MB / sec
Fast SCSI-2 10 MB / sec
Wide SCSI-2 (16 or 32 bit wide data path) 20 MB / sec {max}
Fast-and-Wide SCSI-2 40 MB / sec
IDE (also known as ATA) Seems limited to ISA speed, 3 MB/sec in practice
although ISA is alleged to have a max of 8 MB/sec
Fast ATA 11.1 MB/sec supports PIO mode 3 and multiword mode 1 DMA
Fast ATA-2 16.1 MB/sec supports PIO mode 4 and multiword mode 2 DMA
------------------------------------------------------------------------------
Maximum drive size for E-IDE and SCSI-2 = 8.4 GB
Seagate and Quantum use the terms "Fast ATA" and "Fast ATA-2" to avoid
ambiguity, while other companies just call them all "Enhanced IDE"
/Mike
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