5 Oct
2009
5 Oct
'09
3:18 p.m.
On Mon, 5 Oct 2009, Chuck Guzis wrote:
On 4 Oct 2009 at 20:47, Steven Hirsch wrote:
Ah. Ok, thanks all. I didn't really consider the 8/16 bit issue, but
should know better. This is a big problem when trying to find a
replacement drive for Apple II drive systems such as the Applied
Engineering Vulcan. There are only a small handful of IDE drives that
will work with them.
What am I not understanding about the need for
this product? I have
about a half-dozen 8-bit ISA IDE controllers, mostly Seagate branded.
Didn't think they were particularly rare.
The overwhelming majority of those old 8-bit IDE controllers worked
with XTIDE drives, which supported 8-bit data transfers.
Unfortunately, even though the ATA standard kept the 8-bit transfer
as an option for quite some time, no vendor supported it. Any IDE
drive over about 100MB is likely to support only 16-bit transfers.
As I understand the subject controller project, it latches the upper
8 bits of a 16-bit data transfer and makes it available in a
subsequent cycle. However, one can use a CF memory card in an 8-bit IDE
application, as
I understand that all CF cards support the 8-bit mode of ATA.
That's an interesting fact I'll keep filed away!
Steve
--