8-bit IDE

From: Richard Erlacher <edick_at_idcomm.com>
Date: Mon Apr 17 12:38:47 2000

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.

----- Original Message -----
From: Chuck McManis <cmcmanis_at_mcmanis.com>
To: <classiccmp_at_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
> (no EIDE) and generally some BIOSes couldn't boot from it (it had BIOS
> 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
> >> written in the purported ANSI standard for ATA interfacing, yet nobody
> >> to have experience with it. I was hopeful that someone would know
> >> 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
> >it.
> >
> >> features as shown in table 14.
> >>
> >> +=====+=============================================================+
> >> | 01h | Enable 8-bit data transfers (see 6.2.5) |
> >
> >
> >Allison
> >
> >
Received on Mon Apr 17 2000 - 12:38:47 BST

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