bane@parcvax.UUCP (05/27/87)
I recently spent an interesting evening in the offices of Berkeley Microsystems. I was having trouble getting their board set to run a Quantum Q540 hard disk; the disk would format and run, but with a huge number of bad blocks (3 meg short out of 36). Since I live within 30 minutes drive of them, they told me to come on up with my hardware and they'd get it running. After about two hours of playing with various drives, controllers and interface boards they had laying around, they discovered that the drive was sending out some sort of electronic interference whenever it moved its heads, which the Adaptek was picking up as bad blocks. The BMS folks had suspected this problem with other customers before, but this was the first time they had seen one fail so thoroughly and repeatably. The fix is straightforward, fortunately: DDDDDDDDDDDDDD DDDDDDDDDDDDDD <- Quantum Q540 drive DDDDDDDDDDDDDD D D -------------- <- Shielding (clad PC board or metal plate works fine) Nylon ->S S stand- AAAAAAAAAAAAAA <- Adaptek 4000 controller offs ->S S BBBBBBBBBBBBBB <- BMS 100 interface board I have no connection with BMS other than as an extremely satisfied customer. -- Rene P.S. Bane bane.pa@xerox.ARPA ...!parcvax!bane.UUCP
mjd@doc.ic.ac.uk (Martin J Davies) (05/29/87)
Having seen discussions on the BMS100 ACB4000A combination I thought I would throw in my two cents worth. Overall I am very impressed with both products, the two have been sucessfully interfaced to an 8" Quantum Q2020 (20Mbyte) & Q2010 (10Mbyte) Both these drives are SA1000 but with a bit of coaxing ( a little box that converts the 34 way ACB4000 to a 50 way SA1000) they work very reliably and quickly. I only have one or two gripes and would be interested to hear of ways around them:- 1) I cannot leave any partition space free e.g. if I set up 10Mbye and 5Mbyte the 5Mbyte partion grows to fill the remaining free blocks. This prohibits the use of one or two utilities that rely on 300K of free space to make the drive bootable. 2) I cannot at present connect more than one SCSI devive to the BMS100, berkly say that soon they may have a new revision and a mod to do this. P.S. If anyone has had any joy interfacing tape streamers to the SCSI port I would like to hear. I have an Archive Corp Sidewinder (30MByte) and would dearly love to interface it to my ST * Usual discliamer :- I have no connection etc.etc. ... satisfied customer
pwv@fluke.UUCP (05/30/87)
In article <329@parcvax.Xerox.COM>, bane@parcvax.Xerox.COM (Rene P.S. Bane)
drew the following picture describing a solution to a disk drive problem:
%
% DDDDDDDDDDDDDD
% DDDDDDDDDDDDDD <- Quantum Q540 drive
% DDDDDDDDDDDDDD
% D D
% -------------- <- Shielding (clad PC board or metal plate works fine)
%Nylon->S S
%stand- AAAAAAAAAAAAAA <- Adaptek 4000 controller
%offs ->S S
% BBBBBBBBBBBBBB <- BMS 100 interface board
%
For the shield to be effective, it needs to be electrically connected
somewhere. Was it connected to the disk drive (thru mounting screws?)?
--
Pat Vilbrandt John Fluke Mfg. Co., Inc. Everett, Washington USA
UUCP: { ihnp4!uw-beaver, ucbvax!lbl-csam, allegra, ssc-vax }!fluke!pwv
ARPA: fluke!pwv@uw-beaver.ARPAbane@parcvax.UUCP (06/01/87)
> % DDDDDDDDDDDDDD <- Quantum Q540 drive > % DDDDDDDDDDDDDD > % D D > % -------------- <- Shielding (clad PC board or metal plate works fine) > %Nylon->S S > %stand- AAAAAAAAAAAAAA <- Adaptek 4000 controller > %offs ->S S > % BBBBBBBBBBBBBB <- BMS 100 interface board > % > For the shield to be effective, it needs to be electrically connected > somewhere. Was it connected to the disk drive (thru mounting screws?)? I just took a couple of pieces of copper-clad PC board, drilled holes in them, and put them between the stand-offs for the Adaptek and the metal rails coming down from the Q540. The copper faces away from the Q540, so it isn't connected to anything. The way I understand it from the BMS folk is that the problem must be mostly magnetic, since the shield works whether grounded or not. As long as the posting system is forcing me to, I'd like to compliment whoever decreed that included text must be shorter than new text, and suggest that they relax this restriction for messages shorter than, say, two screens, to keep people like me from having to add ridiculous "fillers" to messages that happen to have 10 lines of included text and 8 lines of reply. Sheesh! -- Rene P.S. Bane bane.pa@xerox.ARPA ...!parcvax!bane.UUCP
toml@xrxns.UUCP (06/03/87)
for the record, i have been using a quantum 540 with the BMS boardset since late january with no shielding and no problems whatsoever. excuse me - i am using shielding - a 6x9" square of 1/4 inch plywood which is part of my "board sandwich". of course this is special high- tech antimagnetic dielectric suppression plywood smuggled at great expense out of the orient. :-) but seriously, no problems, and no shielding. tom love xerox edds leesburg, va 22075 seismo!rochester!rocksanne!xrxns!toml