test-drb October 2001

test-drb@ccmp.vtda.org

259 participants
770 discussions

by Antonio.Carlini＠riverstonenet.com

> Can anyone point me to a scan of the DEC TC01 tape > controller? This is the > early dectape controller used with very early PDP8 machines at least. There is a maintenance manual here: http://www.spies.com/~aek/pdf/dec/pdp8/ And docs for a TC01 exerciser are here: http://www.pdp8.net/pdp8docs/maindec-08-ditca-a-d.tif Antonio

22 years, 8 months

Redactron WP

by Antonio.Carlini＠riverstonenet.com

> Redactron dual mag card WP (with one card), schematic, no > printer. Can I assume there's no interest and I can finally > toss something without feeling guilty? and >One gone, one awaiting its fate: T300 dual floppy PC semi-compatible, no monitor (but std >RGB OK), spare KB, 2 sets of 3 manuals, 123 & dBII, diskettes & some tech info; also >service info & schematics for T100. Good for converting 360 to/from 600 Kb diskettes. Hi, If there are no other (or nearer) takers for these items, could I have the tech manuals and schematics (and maybe diskettes?). I'll scan them if there is sufficient interest. Obviously I'll pay for shipping (surface mail). I'm in the UK otherwise I'd be interested in the hw too! Thanks Antonio carlini arcarlini(a)iee.org

22 years, 8 months

Looking for TC01 drawings/manual

by kevin＠xpuppy.freeserve.co.uk

Can anyone point me to a scan of the DEC TC01 tape controller? This is the early dectape controller used with very early PDP8 machines at least. Kevin Murrell -------------

22 years, 8 months

Dark Tower - any internals info out there?

by Antonio.Carlini＠riverstonenet.com

> I am pretty sure TI published a datasheet on the chip. It > gave at least > the pinout and the pin functions, it may have included the > instruction > set. I may hae some data on the chip in old TI databooks, I can check. The only reference within TI's own site (that I can find) is that the chip debuted in 1974. freetradezone has a two page sheet which has little technical information. It does say that software simulators were available for customer use as were hardware simulators. Antonio

22 years, 8 months

IIgs using hard disk 20

by dhquebbeman＠theestopinalgroup.com

> I have a card in my 512 which increases memory and gives a SCSI port. > It's called a MacSnap by Dove computer, dated 1985. It actually consists of > 2 cards. One contains the memory chips aand circuitry and the other has > the SCSI socket and also 2 large chips labelled upper and lower ROMs. I'm > even able to boot off the external HDD. Great product, I used mine with a Cutting Edge 30MB external drive until the drive's piggyback OMTI SCSI <=> MFM adapter went south. Anyone know where I can get one of these tiny adapters? -dq

22 years, 8 months

Unknown IC

by mcguire＠neurotica.com

On October 15, Tony Duell wrote: > > > Ahh, the 74LS181s are ALUs, as is the 'F582. Interesting that they > > >used both. I'm curious...what kind of processor is this? > > > > Am I the only one who finds it a bit perverse that there are 74xxx standa= > > rd > > TTL circuits for such complex functions as ALUs? I thought that the way t= > > Actually, what suprises me is how _simple_ the 74181 gate schematic is > (it's published in most TTL databooks). It doesn't take that long to > understand how it works. > > In terms of the transistor count, I suspect there are TTL chips which are > more complex than the '181. The '181 is even used in the pdp11/04 and /34 if memory serves. Anyone know of any others? -Dave -- Dave McGuire Laurel, MD

22 years, 8 months

Twiggy Find

by jrkeys＠concentric.net

I purchased a plastic bag mixed with new and used 5 1/4 floppy diskettes and inside the middle was one of the famous "Fileware" or Twiggy diskettes with it's sleeve used with the Lisa I. I could not believe my luck as I had just watched one of these go for almost $50 dollars on eBay for just one diskette awhile back. Now I just need to find a twiggy drive or better yet a Lisa I. :-) Yes I went back to the thrift store looking for more disk but no luck. The cost of the package was $1.40 for about 20 diskettes.

22 years, 8 months

ArcNet and the Pursuit of Multiple Topologies

by mythtech＠Mac.com

>When I installed PhoneNet stuff into my mother's all-Mac shop, it >specifically uses the yellow-black pair of standard (US) phone >wiring and the documentation explicitly shows it as such. They >even had a sort-of passive hub for your wiring closet to collate >all the black-yellow pairs for a larger (floor-sized as opposed to >room-sized) network. We had six Macs and one LaserWriter on the same >floor of a smallish retail establishment, so it wasn't a problem. >I can see networks near the edge of their physical spec falling off >a cliff, though. Yeah, phone net was designed with the idea that you would piggy back it over your existing phone wiring... the theory being that a standard house/business would be wired either all serial (one jack to the next) or in a star (all jacks coming back to a central punch block). Following this assumption, it was specifically designed to work over the unused pair (being yellow/black in standard station wiring). All PhoneNet REALLY cares about is having two wires from one box to either the next box, or to a central hub. It need not be twisted pair, and it need not be the yellow/black pair. Although, if you choose to use a different pair, either you need to make sure you wire it to the correct pins on the jack (and thus fake a y/b) or you will have to cut a custom wired flat cord as the boxes all expect the wires to be the outer two wires in an RJ-11. But there is nothing stopping you from using unused pairs in Ethernet and just use a custom flat cord (or break them out into their own jack). The single biggest problem with Phone net that I ran into was it was VERY picky over the wiring being correct. Unlike phones, you could not safely reverse pairs in a serial setup. Also, the fact that it expects there to be either serial wiring, or star wiring falls thru in most phone lines. And even depending on the unused pairs wasn't a surefire idea. In every Phone net system I installed, I was forced to do some degree of rewiring, or correcting the wiring. POTS phones are very forgiving to poor wiring, and many telco installers use that as an excuse to be lazy. In almost all POTS phone setups you will find some degree of "non spec", things like unused pairs not being connected, reversing pairs, mixing star and serial wiring, tapping mid line into a drop to extend for a new jack. Tapping was DEATH to phone net, it was the single worst thing you could do, as it caused things like ghosting (items showing up after they have been removed, or showing up more than once on the network), and random dropouts of networked devices. It also proved hard to track, as you almost had to physically trace every wire, looking for a tap. But all things considered, phone net was a much more econimical way of wiring a localtalk network. True localtalk cables were very expensive compared to cheap 2 pair phone cable, so even with rewiring, it still worked out to be the less expensive way to go. Even today, phone net works as a nice quick and dirty network when all you want is printer sharing. I keep a 25ft retractable cord and phonenet connectors connected to a Localtalk to Ethernet bridge. It lets me connect old Macs to the network (or my Newton) on the fly, and I can set it up anywhere in my office. When I am done, I just unhook the phonenet box, and let go, the retractable cord rewinds and pulls the box back to my hub shelf, where it hangs waiting for my next use. -chris <http://www.mythtech.net>

22 years, 8 months

IIgs using hard disk 20

by dhquebbeman＠theestopinalgroup.com

> BUT... predating that was a "Macintosh Hard Disk 20" that was not scsi. > Rather is was some drive (don't know what kind, but MFM seems sensible > enough) that used a special adaptor board that enabled it to plug into > the disk drive port on a bunch of the older macs. It was all enclosed > (drive, power supply, adaptor board) in one nice zero footprint beige > case (back when beige meant brown, and not grey like "beige" computers of > today). In spite of the now long-extant senility, I seem to recall that these interfaces through the serial port, not the floppy port. Regards, -dq

22 years, 8 months

looking for documentation for 1963 minuteman missile computer

by mcguire＠neurotica.com

On October 16, Gene Buckle wrote: > > According to at least one movie I watched the part that is critical are > > some special triacs so that each charge can be detonated within a fairly > > tight time window. > > Klystron(?) I might be wrong though. I keep thinking it begins with a > "K". For the gun type, all bets are off - it's a _much_ simpler design. That would be "krytron". A Klystron is a microwave oscillator tube. -Dave -- Dave McGuire Laurel, MD

22 years, 8 months

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test-drb October 2001