ACB4070 ... (was Re: Whats the screwiest thing you collect?)

From: Richard Erlacher <edick_at_idcomm.com>
Date: Sat Nov 27 01:25:06 1999

Well, first of all the 4070's not an MFM bridge adapter at all, but rather
an RLL type.

Before we proceed, though, I'd like to ask how the floppy fits in. The
ACB4070 doesn't support floppy disks.

LINUX doesn't care about the parity, IIRC. It's just the SCSI channel
controller that has to be set up. It can either check or ignore parity,
your choice, generally. In the case of the 2825, you need to type control-A
at the appropriate moment during boot, and it will send you to the
controller's BIOS for controller-specific functions.

Where the trouble begins is in that modern SCSI drives know their
characteristics, but the 4070 doesn't know what kind of drive it's got until
it reads it. If it can't read it, it can't ask it for that data. The drive
doesn't know either, until the 4070's formatted it. The controller's
firmware formatter doesn't know how to TELL the drive/controller what's out
there either, so you have to write your own formatter. That's not terribly
difficult once you know the bridge controller and host adapter are talking.
Unfortunately, I doubt the 4070 is smart enough to help you much.

I've never used a bridge controller of any sort with the PC though I can't
see any reason it shouldn't work. Now, the ACB40xx series isn't entirely
true SCSI, and I have no idea how to make the typical modern host adapter
"see" it. If you have specific questions, perhaps I can help you, but it's
a big manual and I don't see myself scanning or copying it anytime soon.

Dick

-----Original Message-----
From: B'ichela <mdalene_at_home.ctol.net>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Friday, November 26, 1999 11:57 PM
Subject: Re: Whats the screwiest thing you collect?


>On Fri, 26 Nov 1999, Richard Erlacher wrote:
>
>> My own interest in bridge controllers has been as tools. As you may have
>> noticed, I have a number of hard/floppy controller bridges, but only a
few
>> different types. My goal is to be able to get hardware running in a
hurry
>> and bridge controllers are only helpful if you don't have to write new
>> driver software for each application.
>>
>> I guess you might say I tend to collect things that are "nearly" ready to
>> use, though they seldom see any use.
> Heres a question for anyone reguarding bridge adaptors. is there
>a Scsi 2 to Floppy bridge board around? I would like to find one that can
>be used with an XT or 486 system I have here with a scsi host adaptor. I
>have an Adaptec ACB-4070 or so, but it does not support parity. thus I
>cannot for the life of me get it to work with my 486 under Linux, Nor do I
>have any disks with any software for accessing an MFM HD that was attached
>to it. its a Scsi to MFM hard drive bridge board, I also have a Scsi to
>MFM bridge board made by Adaptive Data and Energy Systems, it
>came out of a verisys multiuser 286
>system. I have had NO luck even finding documentations at ALL on this one.
>the ACB-4070 (I might have the wrong numbers but the 70 part is right.)
>sorta wants to talk to my Adaptec 2825VL host adaptor, but aparently it
>lacks the Scsi device Identification string. thus when the host adaptor
>boots, it cannot figure out what the ACB=4070 IS for! Can this be used on
>a IBM compatible system? of so how?
>
> A pearl of wisdom from the y2K newsgroups:
>-------------------------------------------------------------------------
>Y2K appears to be the Baby Boomers mid-life crisis, and it has the
>potential to be a dandy.
> -- Anonymnous --
>--------------------------------------------------------------------------
>
> B'ichela
>
>
Received on Sat Nov 27 1999 - 01:25:06 GMT