cctech Digest, Vol 78, Issue 3

[Chuck Guzis]

On 5 Feb 2010 at 18:17, allison wrote:

> Anywho the IDE interface chips from the PC market are all basically
> 16bit wide bus, IDE drive 0,1 address decode and some extra logic to
> do burst mode DMA, block DMA (Both required external DMA support) or
> PIO. in the x86 space.  FYI PIO unlike floppies is buffered on the
> disk so the IO can be does as fast or slow as the programmer wishes to
> the limits of ATAPI spec (all do minimally 33mbytes/sec and later are
> faster).

Just about any IDE disk drive made in the last 20 years also has a 16-
bit data path (very old XTIDE drives could do 8 bit, but they're hard 
to find.  I don't know about microdrives).  So that's a problem with 
or without an interface chip if what you want to do is interface to 
an 8-bit bus--and use all of the available space on the disk.

--Chuck