test-drb December 2010

test-drb@ccmp.vtda.org

154 participants
208 discussions

by cc＠informatik.uni-stuttgart.de

Hi everyone, we've had a look inside our IME 122 calculator and discovered that it is full of SN14xx logic ICs. They are mainly from TI, but there are also some >from Motorola and others. It seems that they have the same function and pinout as the SN74xx parts but there must be a difference since the machine has quite a lot of SN1401 (the SN7401 is a quad open-collector NAND), but there are no pullup resistors anywhere! Some of the types are SN1400, SN1401, SN1474, SN1490; the ALU is made up of SN1482 and SN1483. Anyone knows this series? BTW the supply voltage is 5V. Christian

13 years, 7 months

Uncommon: Intel Paragon on iOffer

by cclist＠sydex.com

Something you don't see every day: http://www.ioffer.com/i/intel-paragon-super-computer-180057571 --Chuck

13 years, 7 months

Need help with Project Northstar/Data I/O System-19/ADM, Terminals (dwight elvey)

by melamy＠earthlink.net

The Northstar mother board uses 8251s which require CTS to be active in order for the usart to transmit. There are jumper headers on the motherboard that allow you to strap them so they are active by default so you can use just a three wire RS232 connection. regards, Steve Thatcher -----Original Message----- >From: "Robert J. Stevens" <trebor77 at execpc.com> >Sent: Dec 18, 2010 11:13 AM >To: cctalk at classiccmp.org >Subject: RE: Need help with Project Northstar/Data I/O System-19/ADM, Terminals (dwight elvey) > >Message: 15 >Date: Sat, 18 Dec 2010 06:46:57 -0800 >From: dwight elvey <dkelvey at hotmail.com>RE: Need help with Project Northstar/Data I/O System-19/ADM Terminals (dwight elvey) >Hi > It is unlikely that there is a problem with the 2708s If the programmer said they >were good, I'd expect them to be fine. > The places I'd look are first the RS232 connection. The fact that the canon >book works on one machine doesn't mean it will work on another. As well >as the data lines, there are handshake wires that need to have the right >levels. > He said that he'd single stepped the code, what were the results of >that? what did it do or not do right?? >Dwight > >It just goes crazy as the Prom was not burnt correctly >Bob > >Turns out that the Problem is that the Data I/O System-19 I am using doesn't want to load the Hex file as INTEL. It will only load a File if it is flagged as BINARY and that doesn't give a proper code Image. I am trying to get a fellow to see if his System-19 will load the file and burn the 2708 Properly then I can get mine Fixed I HOPE. >I also have been Re-Erasing the EPROMs as I go along. >Bob >

13 years, 7 months

Bendix G-15 Diode Tester

by wdonzelli＠gmail.com

The Diode Tester unit for a Bendix G-15 very recently sold on Ebay. I would like to know who won it. Did anyone here? You can reply off list (I can be very discrete) - I have some questions to ask. -- Will

13 years, 7 months

Sports! and Star Trek

by aek＠bitsavers.org

http://www.briancasey.org/artifacts/astro/moon.cgi just as I suspected, Full Moon

13 years, 7 months

Service bureaus (Was: Tek 4051 firmware listing

by jonas＠otter.se

> I've always wondered what the Scandanavians do to differentiate 0 > from O from ?. They don't differentiate 0 from O- Although when I learnt Morse Code (at a Swedish Army facility) together with a group of radio amateurs in the 70s, we were taught to slash the zeroes (contrary to the IBM mainframe people) and write the Es as reversed 3s. And Swedes always cross the 7s. About the letter '?' in Danish and Norwegian, which is written '?' in Swedish (with the r?ck d?ts) and pronounced 'er', it is obviously differentiated from Oh and zero in everyday writing by the slash or dots. What the Danish or Norwegian radio amateurs or mainframe people do to resolve the conflict they might have there, I have no idea. /Jonas

13 years, 7 months

IBM PC-DOS 1.0 question

by rich.cini＠verizon.net

All -- I?m working on a side project to another thing I?m working on and I?m trying to compare code from DOS 1.0 and 1.1. I have the PC-DOS 1.1 files (all including IBMBIO and IBMDOS) but only disk images (Teledisk) for PC-DOS 1.0. Is there an easy way to extract these files from the disk image? Does anyone have these files already extracted that they can send me? I think I can convert the TD0 image to IMD, but the IMD tools seem to work at the track level on the image and not the file level, but any help would be appreciated. Thanks! Rich -- Rich Cini Collector of Classic Computers Build Master and lead engineer, Altair32 Emulator http://www.altair32.com http://www.classiccmp.org/cini

13 years, 7 months

Service bureaus (Was: Tek 4051 firmware listing

by jonas＠otter.se

> And I have a model 33 teletype here, with some provenance claiming an > IBM lineage, that has a slashed-oh between the I and the P keys and an > unslashed-zero next to the 9 key. > > Pressing the slashed-oh, sends 0x4F and pressing the unslashed-zero > sends 0x30... and conversely, it prints an unslashed-zero when 0x30 is > sent to it and it prints a slashed-oh when 0x4F is sent to it... I just borrowed a book from 1974 about JCL by a person who had worked as a systems programmer at IBM. In his coding examples, he consistently puts a slash through the Ohs and leaves the zeroes unslashed. I would assume therefore that that was standard practice for IBM mainframe work at that time. /Jonas

13 years, 7 months

Unknown TI logic series

by tshoppa＠wmata.com

> They are interesting, but no more than weird numbers on semicustom > devices. Motorola does the same thing, with their SC series of parts > (not MC or XC).. I tend to come in on this side too, these funny series are Effectively TI-supplied "house numbers". They may be different than stock SN7400 TTL or whatever DTL in minor or Major ways but that was an agreement between the customer and TI. I've seen the innards of DTL and TTL based calculators, and to think that They would work with rejects or floor sweepings is unreasonable. If Anything I would think that the house-numbered part would have some specs tightened And others loosened to produce something most manufacturable. And isn't That the reason for house numbers to begin with? (e.g. not purely obfuscation) Tim.

13 years, 7 months

Unknown TI logic series

by tshoppa＠wmata.com

> but the speed, temperature range, etc. requirements for a desktop calculator are not that high. I think you (or maybe someone else) may have hit it earlier with the suggestion of fan-out/fan-in requirements and maybe some specializations such as open-collector wired-or with built-in pullups at the receiving end. Later 7400 series chips for specialized functions (e.g. verge of SSI and MSI) had not-really-TTL-compliant inputs and outputs for specialized daisy-chain or low-fanin-load purposes. Look at the BI/RBO pin of a 7447 etc. (It's an input AND an output! Wow!) It's easy to see how this could be applied to some of the "stock" standard logic functions to greatly cut pin counts for a desktop calculator, and I suspect that's what the unique numbers are for. Tim.

13 years, 7 months

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test-drb December 2010