chris@mddc.UUCP (Chris Maloney) (02/24/84)
Has any one used or just have comments on the Systems
Industries 9900 or 9920 Massbus controller?
Has the 9900 been used on 4.2?
Thanks,
Chris Maloney
Management Decisions Development Corp.
7209 Dixie Highway
Fairfield, Ohio 45014
(513)874-6464
...{ucbvax,decvax,inhp4,mhuxi}!cbosgd!qusavx!mddc!chris (uucp)
cbosgd!qusavx!mddc!chris@BERKELEY (arpa)dmmartindale@watcgl.UUCP (Dave Martindale) (04/05/84)
A word of warning about SI: The 9800 controller has at least several bugs in it. The worst is incorrect emulation of the MBA byte count register on writes which fail due to errors. This renders the bad-sector forwarding code in the 4.2BSD driver useless. It is possible, but a pain, to fix this. At Waterloo, since we have real Massbus controllers as well as a 9800 running the same code, the code tries to determine what type of controller it has by looking at the drive serial numbers, which are supposed to follow a special pattern for the SI controller. They seem to be correct after resetting the 9800, but sometime later they have become wrong, so the code thinks it sees a real MBA out there. I'll have to figure out a way around this problem too. The byte count bug was a known bug when the old 9400 controller was around, and it wasn't fixed in the 9800. Ask about its status in the 9900; I'd be surprised if it was fixed. And SI seems awfully paranoid about giving out circuit diagrams for their stuff, an attitude which I do not like (though other manufacturers have the same problem).