pjm654@csc.anu.edu.au (04/30/91)
This is a repost of a previous article that didn't get a reply. Just
in case anybody missed it.
I am having some difficulties with an Adaptec ACB 4000 SCSI hard disc
controller, and I would appreciate any helpful suggestions.
It is in fact an ACB 4000, not an ACB 4000A. One of the IC's, the processor
I think, has a label on it saying ACB 4000. Also, the "ACB-4000 Series
User's Manual" that Adaptec sent me says that certain jumpers are oriented
differently on the two controllers. These particular jumpers on the board
that I have do not match the orientation in the manual, which is for the
ACB 4000A and ACB 4070.
Having established the identity, I will describe the problems. I have
written the driver based on the description (and sample code) in the
manual, but I find that the interface is not completely reliable. When
copying data to the disc using a programme that verifies as it copies, it
complains occasionally, perhaps four or five times each time I fill the 20M
disc. As far as I can tell, the controller is not always following the correct
sequence. I am convinced that my driver follows the manual, and the
computer is correctly generating the handshaking REQ-ACK signals, although
I have not carefully analysed the timing of the signals.
I don't think that the problem is with the disc, because I have a Xebec S1410
SASI controller that works (using a different driver). I have also put the
drive into a PC/AT and it worked OK there.
Does anybody know what the difference between the ACB 4000 and ACB 4000A is?
Why was the 4000 upgraded? Any other suggestions would be appreciated. I
am particularly keen to get the Adaptec controller going because it is much
faster than the Xebec controller. It also stores hard disc parameters on the
disc and reads them at power up, so I don't have to initialise the controller
every time.
Thanks in advance for your help,
Peter Manson
pjm654@csc1.anu.edu.au