8-bit IDE

From: Richard Erlacher <edick_at_idcomm.com>
Date: Tue Apr 18 00:21:36 2000

Well, I've got one drive, an ST351, I think it is, that responds to the
8-bit conditioning. It's a 1.25"-tall 3-1/2" drive, of 44 MB capacity.
That's not what I want for the "hard-card" on the S-100.

All your assertions about the relative folly of expending effort/resources
to make the drive talk-8-bits wide has no real purpose except to bind it to
its historical roots. I'd bet that the logic in the 1003-WAH uses the
data-width bit to enable the IOCS16- signal and thereby lets the AT bus
control whether the transfer is 8 or 16 bits wide, since the AT bus is
required to do that.

The early IDE drives made for COMPAQ by Seagate, were half-high 5-1/4"
drives from which I've saved one or two of the PCB's. These have all the
same logic on them that I recognize from the 1003-WA2 which is a WAH with
the FDC missing, I think. Maybe it's the other way around . . .

Those guys undoubtedly supported the 8-bit mode, since their host was, in
some cases, an XT-class machine.


----- Original Message -----
From: allisonp <allisonp_at_world.std.com>
To: <classiccmp_at_classiccmp.org>
Sent: Monday, April 17, 2000 8:22 PM
Subject: Re: 8-bit IDE

> > "Has anyone got sufficient experience with the IDE in
> >applications to say, unequivocally, whether the 8-bit operating mode
> >described in section 6 of the standard for the ATA (IDE) interface, yes
> >SPELLED OUT, actually exists in drives of the pre-1996 vintage?" It was
> >dropped from the standard in 1996. There seem to be many folks with
> >suggestions about how to implement this extremely elementary interface.
> >There seem to be few who know whether the standard was every full
> >implemented.
> Why would they include that? NONE of the PC hardware they were intended
> for wants to run as 8bit bus. Even the crippled SL/SLC run as 16bit
> >Allison seems to be the only one who's tried this, and, I fear, it may be
> in
> >a PC-compatible, where all bets are off as to what really happens.
> Obviously visually impaired! I don't hack IO in PCs nor have I tried that
> yet.
> I may add why even bother, IDE works there as is.
> ALL of the IDE work I've done was with 8085, z80s either stand alone
> (bus less) or S100 Z80s. Further I'm currently working on a Z280 system
> with IDE (Zbus 16bit). This is where I need interfaces and so I can
> older MFM or non-existent hard disks. I currently have one S100 system
> running a connor3044A (40mb) IDE that will be upgraded to a ST3250
> (250mb) as it's a better drive.
> The drives I've tried include:
> Connor 2022
> Connor 3044
> WD2120
> WD2420
> St3096A
> St3144A
> St3250A
> St3660
> Fijitsu 528mb
> Quantum LPS 80 and 120
> Maxtor 124mb
> and afew other sub 60mb WD, NEC, Seagate drives.
> I now have two 2.5mb IDE in the 700-800mb region I may try one day.
> I do have two WD PS/2m30 compatable 8bit IDE 20meg drives.
> I think this is a good cross section
> Allison
> >
> >Dick
> >
> >----- Original Message -----
> >From: Mike Ford <mikeford_at_socal.rr.com>
> >To: <classiccmp_at_classiccmp.org>
> >Sent: Monday, April 17, 2000 7:22 PM
> >Subject: Re: 8-bit IDE
> >
> >
> >> I don't know a hoot about this, but I wonder if taking a look at the
> >> Sequential Systems Focus card for the Apple II might be instuctive. Its
> >> controller and notebook IDE drive that all fits on a Apple II slot
> >>
> >>
> >
Received on Tue Apr 18 2000 - 00:21:36 BST

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