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August 18, 2017

Fine-tune Friday: SCSI codes, and clean-ups for UDCs and 3000 power supplies

Cleanup-siteI need to clean up COMMAND.PUB.SYS on my 3000. There's a problem with BULDACCT. Is there a utility to help manage the UDC catalog?

Stan Sieler replies:

One option is "PURGE," which ships on all MPE systems :) Of course, that means you have to rebuild the UDC catalog. We recently encountered a site where, somehow, an HFS filename had gotten into COMMAND.PUB.SYS. You can't delete UDC entries with HFS filenames, nor can you add them. I had to edit the file with Debug to change the name into something that could be deleted.

Keven Miller adds:

I believe you want the utility UDCSORT from the CSL, the UDC sorting and reorganization program.

There are so many SCSI types. It's got to be the most confusing four letter acronym. Is there a guide?

Steve Dirickson offers this primer:

SE (single-ended): TTL-level signals referenced to ground; speeds from 5 Mhz to 20 MHz

Differential (HVD): something around +/-12V signals on paired wires (old-timers think “EIA 20mA current loop”); same speeds as SE

LVD (Ultra2): TTL-level differential; 40 MHz clock

Ultra160: same as LVD, but data signals double-clocked, i.e. transfers on both clock transitions like DDR DRAM. LVD and Ultra160 can co-exist on the same bus with SE devices, but will operate in SE mode. HVD doesn’t co-exist with anything else.

Upon arrival this morning my console had locked up. I re-started the unit, but the SCSI drives do not seem to be powering up. The green lights flash for a second after the power is applied, but that is it. The cooling fan does not turn either. The  fan that is built into the supply was making noise last week. I can’t believe the amount of dust inside.

Tom Emerson responded:

This sounds very familiar. I’d say the power supply on the drive cabinet is either going or gone [does the fan ‘not spin’ due to being gunked up with dust and grease, or just ‘no power’?] I’m thinking that the power supply is detecting a problem and shutting down moments after powering up [hence why you see a ‘momentary flicker’].

Denys Beauchemin added:

The dust inside the power supply probably contributed to its early demise. It is a good idea to get a couple of cans of compressed air and clean out the fans and power supplies every once in a while. The electrical current is a magnet for dust bunnies and other such putrid creatures. 

Tom Emerson reminisced:

Years ago at the first shop where I worked we had a Series III and a Series 48. Roughly every 3-6 months an HP technician would stop by our office to perform Preventative Maintenance. Amazingly, we had very few hardware problems with those old beasts. Once we didn't have a tech coming out to do PMs anymore, we had hardware related failures, including a choked-up power supply fan on a disk cabinet.

Finally, Wayne Boyer said"

Any modular power supply like these is relatively easy to service. It is good advice to stock up on spares for older equipment. Just because it’s available somewhere and not too expensive doesn’t mean that you can afford to be down while fussing around with getting a spare shipped in.

The compressed air cans work—but to really do a good job on blowing out computer equipment, you need to use an air compressor and strip the covers off of the equipment. We run our air compressor at 100 PSI. Note that you want to do the blasting outside! Otherwise you will get the dust all over where ever you are working. This is especially important with printers as you get paper dust, excess toner and so forth building up inside the equipment. I try and give our equipment a blow-out once a year or so. Good to do that whenever a system is powered down for some other reason.


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