17 Apr
2000
17 Apr
'00
12:38 p.m.
I've gotten little information from the drive makers so far, regarding how
extensively this feature was pursued in the drives. The intefaces certainly
existed, and, if you built an 8-bit interface on the ISA, the motherboard
hardware would steer the bytes correctly for you so the software essentially
was the same, though it talked in 16-bit mode to the drive channel. The
assertion that the standard provides for an 8-bit mode is not in dispute.
From where I sit, one should be able to condition the
interface during setup
to function in 8-bit mode and then, when the data channel is
accessed, the
interface should NOT assert the IOCS- signal when accessed. I've yet to try
this, but it seems reasonable. I'll probably get to it later in the week.
It's tax week, after all.
Dick
----- Original Message -----
From: Chuck McManis <cmcmanis(a)mcmanis.com>
To: <classiccmp(a)classiccmp.org>
Sent: Monday, April 17, 2000 11:10 AM
Subject: Re: 8-bit IDE
I didn't follow this too closely but there were a
couple of 8-bit IDE
interface boards in terms of "ISA 8 bit" vs "ISA 16 bit". JDR used to
sell
one as an "upgrade" option for the XT and its ilk. However, it was only
IDE
(no EIDE) and generally some BIOSes couldn't boot
from it (it had BIOS
boot
roms but not all systems (I think Leading Edge were a
big problem here)
actually used them.)
Now as far as talking to a drive across the 40 pin cable in "8 bit mode",
that I've no clue on.
--Chuck
At 12:33 PM 4/17/00 -0400, you wrote:
>> an answer to the question I've put forth. The 8-bit interface feature
is
>> written in the purported ANSI standard for
ATA interfacing, yet nobody
seems
>> to have experience with it. I was hopeful
that someone would know
about
>> this.
>
>Very simply. I tried that and it's bogus! It does not work. Therefor
>expereince with it is limited to trying to make it work.
>
>It may be proposed and would be nice but it's a no-op as far as I can
test
it.
features as shown in table 14.
+=====+=============================================================+
| 01h | Enable 8-bit data transfers (see 6.2.5) |
Allison