test-drb May 2005

test-drb@ccmp.vtda.org

248 participants
723 discussions

OT Don't read this (was Re: Altair MBL source)

by dwight.elvey＠amd.com

>From: "Brad Parker" <brad at heeltoe.com> > > >Paul Koning wrote: >> >>I very much doubt it. The story you quoted doesn't seem to have any >>connection with physics as I know it. > >I'm not disagreeing, but I am confused. > >If you inhale a gas which is heavier than air, what happens? > >-brad > Hi You sink? Dwight

19 years, 2 months

Free uVax III, 9-track tape drives, Q-bus SCSI controller, etc.

by shoppa_classiccmp＠trailing-edge.com

Seeing how the demand for Q-bus SCSI controllers is, I would've thought I'd have gotten rid of this by now. But again: Free, for pickup only in the Washington DC area: A DEC H960 (6-foot) rack with a BA213 chassis, KA650 CPU + memory, Ethernet, TK70, Emulex Pertec Formatted tape controller (QT13), and a Q-bus SCSI controller. Also in the rack: Fujitsu M2444 1600/6250 BPI 9-track drive. There's a complete (but disassembled) M2444 in addition for spare parts. A BA23 for Q-bus expansion. The Q-bus extender paddles and cables. A Trimm Industries SCSI enclosure (styled just like the BA23) and associated SCSI cabling. Outside the rack are some miscellaneous Q-bus cards that I've dug up since the last giveaway. I want this system to go to a hobbyist so I'm not selling off the "valuable" cards and sending the rest to the metal recycler. So I'm insisting that it be picked up from my basement just outside Washington DC. Don't worry, you get lots of help de-racking the components and carrying up the steps. But you do need a vehicle that'll hold the rack and components, an empty Minivan or a pickup will do quite nicely. (All but the smallest pickups will hold a 6-foot rack if you unscrew the casters...) Also, you're welcome to take away as many VAX/VMS and Alpha/VMS condists as you want. And I'll probably find some other stuff that I'll want you to take (but you can say no). If you're interested, mail me at my regular off-list E-mail address, "shoppa at trailing-edge.com", or call at 301-767-5917. I'm available for getting it out of the basement most weeknights and most weekends. Tim.

19 years, 2 months

IBM Winchesters

by Saquinn624＠aol.com

O.K- I'm confused. (a) Are the bad IBM drives the ones that say "Frame Electronics" "Manufactured in San Jose, CA, USA" (got several in RS/6ks, etc.- seem to work O.K (they're on topic and still chugging along) but I want to be forewarned Just In Case. (b) are, as discussion indicates, the "Incredibly Dubious Engineering" interface drives from IBM/Hitachi O.K.? I'm looking for decent IDEs as it seems time is running out for some of my drives.

19 years, 2 months

Seven Segment Displays

by ajp166＠bellatlantic.net

> >Subject: Re: Seven Segment Displays > From: ard at p850ug1.demon.co.uk (Tony Duell) > Date: Wed, 04 May 2005 23:30:20 +0100 (BST) > >The name 'minitron' seems to be floating in my brain for some reason... > >They could well be incandescent. I've seen such devices in a 16 pin DIL >package, in a smaller package with 9 socket contacts on the back arranged >like a miniature DE9 connector (those are used in the ICL Temiprinters >for the column display, for example), and in a wire-ended valve-shaped >envelope. I have a bunch of them too. Four are in a counter I made back in 73, the rest are spares for it. Actually they are fairly nice and at about 10MA brighter than leds of the time (I must ahve a dozen MAN-x series LED 7 segments as well). FYI: those things are considered rare as hens teeth as most systems that use them have burnt them out. One series of ARC (used in cessna aircraft) radios had them as they were bright enough for day use and I hear they cost about 100$+ per digit to replace. Allison

19 years, 2 months

OT: EMP and Equipment

by leeedavison＠yahoo.co.uk

> Wow! That is a mother of a resistor! :-) > Must be one of those aluminum clad ones? The traditional type are coated glass tubes about 50mm in diameter. The newer type are some sort of sintered material and around 20mm in diameter. When the new type fail they just burn amd crumble, the older glass type would bubble and run like a small child's nose does. 8^)= Lee. . ___________________________________________________________ Yahoo! Messenger - want a free and easy way to contact your friends online? http://uk.messenger.yahoo.com

19 years, 2 months

Now hard drives too. Re: Modern floppy disk question...

by mamcfadden＠cmh.edu

>Hi > Why doesn't anyone mention Micropolus. On, I think it was >2G drives, we had 100% failure in 2 weeks. >Dwight One of our local companies APS went out of business after the Micropolis debacle. I heard they had hundreds of Micropolis drives they had replaced under warrantee and when Micropolis went under they were stuck with bad drives and no repair, replacement, or money. Mike

19 years, 2 months

Now hard drives too. Re: Modern floppy disk question...

by aek＠bitsavers.org

> Why doesn't anyone mention Micropolus. Because their drives were crap, and they are dead, dead, dead (good riddance) "Never buy a drive from a vendor starting with 'M'" Seagate and Quantum have honorary M's in their names, too. I just made the mistake of buying three 300 gig Seagates. One was DOA, the others are very picky about operating temperature ( I have to run them in open air with the logic board facing up). They also will only run on firewire bridge boards in with a G4 powermac (they hang the system on any of the internal PATA busses). Hitachi 400's worked perfectly (I have 4 running in this machine right now). No doubt one of them will crap out now that I've posted this. The only recent IBM/Hitachi drives I know of that were dogs were 120's made in Hungary (the ones from Thailand are fine).

19 years, 2 months

DEC BA356 termpwr oddity

by witchy＠binarydinosaurs.co.uk

Hi folks, I came across weirdness this morning with an 8-bit BA356 shelf and some TLZ09-VA tape drives....hopefully someone here has seen it before. Basically, said BA356 had an RZ disk of indeterminate size (I didn't look :) and 4 TLZ09s; the shelf has a BA35X-MG 8 bit personality module and is plugged into an Alpha 3000-300LX. All well and good. However, while the TLZ's could be seen at the dead sergeant prompt (>>>) VMS 6.2 was having none of it. On swapping one of the tape drives for another spare all of a sudden the whole shelf came to life and VMS was happy. The only difference between this last drive used and all the others was that this drive had the TERMPWR jumper installed (default config I thought) and so was providing TERMPWR to the backplane. Since the SCSI adapter in the 3000-300LX should have been providing this power and the personality module in the shelf provided termination why should this jumper make so much difference to the bus? It's not a length issue since I've duplicated the setup this afternoon using a DS10 and half metre cables. Also I thought too much TERMPWR was a Bad Thing. Interestingly, swapping the shelf for a blue UltraSCSI BA356 and using an Ultra personality module made the problem vanish and the drives were happy whether there was a TERMPWR jumper installed or not. Since these drives are destined for non-ultra environments do I have to crack them all open and fit the jumpers or is there something I'm missing? Ta! -- adrian/witchy Binary Dinosaurs creator/curator www.binarydinosaurs.co.uk - the UKs biggest home computer collection?

19 years, 2 months

OT: EMP and Equipment

by leeedavison＠yahoo.co.uk

> I've been told (during military service) that the dv/dt > of an EMP is so fast a Faraday cage will saturate and the > eddy currents are so strong it re-launches an EM wave > inside the cage. Not quite. What happens is that the surfaces parallel to the incident wave behave as capacitance and the surfaces perpendicular to the incident wave behave as indictors. The initial pulse sets this LC circuit resonating much like a struck bell and creates it's own internal EM field as the energy dissipates in the resistance. This can be effectively damped by placing low value resistors, 50 to 100 ohms, across surfaces to reduce the Q of the shield and absorb the energy. Similar damping Rs are used in high power Tx equipment to stop parasitic resonance in structural parts. It's not uncommon to see a couple of 700W 68ohm resistors bolted to the anode boiler of an HF output tube. Without them the boiler suffers greatly from burnt supports and melted bolts. Lee. . ___________________________________________________________ How much free photo storage do you get? Store your holiday snaps for FREE with Yahoo! Photos http://uk.photos.yahoo.com

19 years, 2 months

All things ESDI

by drb＠msu.edu

> ESDI was common in high-performance machines and for "large" drives > - 120MB was about the smallest I saw (when 20MB - 40MB was still > common) and ~330MB was typical. I have heard of ~600MB units but > never installed one. I think I handled a 600 in a Novell server once. > It's an Int11 device, just like an ST-506 drive. The BIOS needs > to be configured with the right number of heads, cylinders and > sectors-per-track, tho' picking type 20 or so will usually give you > enough to boot and read the true settings off the drive itself. They > will probably need to be low-level formatted if moving them from > one controller to another. DEBUG and then G=c800:5 is what I dimly > recall for this, tho' in later years I used CheckIt or even SpinRite > to do this. I'm inclined to disagree, though I'm hardly the expert. Specifically, I recall having trouble setting up several ESDI drives in servers. The fix was to tell the machine BIOS the disk didn't exist, then let the ESDI controller BIOS work out geometry. I think on some ESDI controllers, the C800:5 trick did work, though. That was a common disk interface, MFM, ESDI etc. De

19 years, 2 months

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test-drb May 2005