8-bit IDE

From: Hans Franke <Hans.Franke_at_mch20.sbs.de>
Date: Mon Apr 17 09:23:06 2000

> > Recently, as part of my effort on an S-100 "hard-card" using a 2-1/2
> > inch ide drive, I've been revisiting the 1994 standard for the ATA
> > interface. There's a not-too-detailed mention of an 8-bit mode which is
> > set up using a bit in register. This feature was apparently obsoleted
> > as of 1996's standard.

> It's actually not that hard to use a normal 16 bit IDE drive in an 8 bit
> system (like an S100 card). You need a few buffers/latches to convert
> between 8 and 16 bits on read/write, that's about it.

> Actually, although it pains me to say this, IDE drives are so cheap per
> megabyte now that you could probably get away with wasting every other
> byte... Just use a 3-state buffer to always write the top 8 data lines as
> 0 (or FF or...) and ignore them on read. After all, people give away 1Gb
> IDE drives these days (or so I've heard), and 500M of storage (i.e.
> wasting every other byte) is massive for S100 systems.

Quite an inriguing idea. You also will get 256 Byte records ...
a more common size back then. Well, what about commands etc. pp ?


VCF Europa am 29./30. April 2000 in Muenchen
Received on Mon Apr 17 2000 - 09:23:06 BST

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