Adaptec ACB-4000 MFM-SCSI protocol converter boards
I dont know if anyone would be looking at using these things anymore, but to
save my info from dissapearing into the great big black hole of time I have
written what I could still find down here.
These boards are MFM controllers that interface to a SCSI bus. Each board supports
up to two MFM hard-drives. Unfortunately they are not completely normal
SCSI hard-disks. They do not support the IDENTIFY command. This is
probably due to the fact that back then the "auto-config"ness of SCSI wasnt
such a high selling point as it is now. Also, they need you to send them a
vendor specific format command before they will work (fair enough, just like
normal MFM hard-drives, they need a low-level format). Also, this format
command stores the drive geometry somewhere so that the controller board
does not need to be told each time it is turned on.
When I got my first one of these boards, I didnt even have a SCSI
controller. Not long afer that, I got four more for a song at a local swap
meet on the assumption that they just HAD to be usefull for some project.
Sure enough, I almost got my hands on ~8 112Meg MFM hard-drives. Imagine my
glee at the thought of almost a whole Gigabyte of hard-disk space (things
have changed since then)
I still cant work out where I got my information from,.. but I do have the
program that I wrote which I have reverse engineered to get the following
vendor specific command information:
MODE_SELECT Command for setting device paramaters
cmd[0] = MODE_SELECT
cmd[1] = (lun & 7) <<5;
cmd[2] = cmd[3] = 0;
cmd[4] = 0x18; /* length of data block */
buf[0] = 0; /* reserved */
buf[1] = 0; /* medium type */
buf[2] = 0; /* reserved */
buf[3] = 0x08; /* block descriptor length */
buf[4] = 0; /* density code */
buf[5] = 0; /* no. blocks MSB */
buf[6] = 0; /* "" */
buf[7] = 0; /* "" LSB */
buf[8] = 0; /* reserved */
buf[9] = (blksize >> 16) & 0xff; /* block length MSB */
buf[10] = (blksize >> 8) & 0xff; /* "" */
buf[11] = blksize & 0xff; /* "" LSB */
/* vendor unique stuff */
buf[12] = 0x01; /* list format code 1= soft sectored fixed disks */
buf[13] = (cyls >> 8) & 0xff; /* high byte for cylinder count */
buf[14] = cyls & 0xff; /* low "" */
buf[15] = heads & 0xff; /* data head count */
buf[16] = (rwc >> 8) & 0xff; /* high byte RWC cylinder */
buf[17] = rwc & 0xff; /* low "" */
buf[18] = (wpc >> 8) & 0xff; /* high byte WPC cylinder */
buf[19] = wpc & 0xff; /* low "" */
buf[20] = lzone & 0xff; /* landing zone, 0=default, land on innermost track */
buf[21] = stime & 0xff; /* 0=non-buffered seek, 3ms / step; 1=28usec, 2=12usec */
buf[22] = 0; /* for hard sectored */
buf[23] = 0; /* "" */
FORMAT_UNIT command (standard SCSI command)
cmd[0] = FORMAT_UNIT;
cmd[1] = (lun & 7) <<5;
cmd[2] = 0;
cmd[3] = (tmp >> 8) & 0xff; /* Interleave */
cmd[4] = tmp & 0xff; /* " */
cmd[5] = 0;
I had some email conversation with a nice person with a manual, and he was
able to tell me what all the switches did:
From spoetnix.idca.tds.philips.nl!wilko Thu Feb 17 14:28:43 1994
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From: Wilko Bulte
Message-Id: <9402161759.AA00766@spoetnix.idca.tds.philips.nl>
Subject: Re: Adaptec ACB4000 protocol boards.
To: hamish@zot.apana.org.au (Hamish Coleman)
Date: Wed, 16 Feb 1994 18:58:59 +0100 (CET)
In-Reply-To: from "Hamish Coleman" at Feb 16, 94 01:41:55 pm
Return-Receipt-To: wilko@idca.tds.philips.nl
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> Firstly, the controler doesnt seem to support the SCSI inquiry command, thus
> making it hard to auto-detect - do you know of any 'approved' method of detecting
> this drive? (I currently assume that any time an inquiry command is rejected,
> an acb4000, or other block-device is attached)
It doesnot support inquiry. So you are stuck with just 'assuming' it is there.
Maybe you could try to do a TEST UNIT READY command?
> There are also two sets of jumpers on the board: one set near the radial MFM
> cables that is labeled 'PU' 'R' 'S' 'T' and has four pins - do you know what
> this is for?
R<->PU ---> write precomp off for both drives
R<->S ---> write precomp starts at same cyl as reduced write curr for both drives
R<->T ----> write precomp applied on all tracks, on both drives
Jumper in is 'feature selected'
> Then the block of eight pairs of jumpers labeled A-P, - I have found that A-B
> through E-F are the SCSI address settings, but what are the other five pairs for?
G<->H ---> DMA transfer rate, jumper in= SYSCLOCK/4, out= SYSCLOCK/2
I<->J ---> Extended command set with jumper in
K<->L ---> not used
M<->N ---> support for drives that drop seek complete during head switching (when in)
O<->P ---> self diagnostics
> And finally, for non-termination of the SCSI bus, do I remove the resistor packs
> marked RP4 and RP3 that are near the SCSI connector?
Correct.
Cheers,
WIlko
_ __________________________________________________________________________
| / o / / _ Wilko Bulte mail: wilko@idca.tds.philips.nl
|/|/ / / /( (_) |d|i|g|i|t|a|l| Equipment Corporation - WGF
voice: +3155-432062 PO Box 245 - 7300 AE Apeldoorn - The Netherlands
fax: +3155-439133 Easynet: HLDE01::BULTE_W DTN: 829 2062
--------------------------------------------------------------------------------
From spoetnix.idca.tds.philips.nl!wilko Fri Feb 18 16:52:08 1994
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From: Wilko Bulte
Message-Id: <9402171815.AA13008@spoetnix.idca.tds.philips.nl>
Subject: Re: Adaptec ACB4000 protocol boards.
To: hamish@zot.apana.org.au (Hamish Coleman)
Date: Thu, 17 Feb 1994 19:15:43 +0100 (CET)
In-Reply-To: from "Hamish Coleman" at Feb 17, 94 11:06:07 pm
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>
> > I<->J ---> Extended command set with jumper in
>
> Hmm - just one further question,. what is 'extended command set' ?? - I enabled
> it (hoping that it might have meant the I got 'extended error codes') and could
> see no visible difference.
>
The manual is rather vague on this. It seems to be usable to allow
the ACB4000 to replace a Xebec 1410 or Western Digital controller
without driver changes. I don't think it is usable for you.
Further detail I could not find
Wilko
_ __________________________________________________________________________
| / o / / _ Wilko Bulte mail: wilko@idca.tds.philips.nl
|/|/ / / /( (_) |d|i|g|i|t|a|l| Equipment Corporation - WGF
voice: +3155-432062 PO Box 245 - 7300 AE Apeldoorn - The Netherlands
fax: +3155-439133 Easynet: HLDE01::BULTE_W DTN: 829 2062
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