test-drb September 2005

test-drb@ccmp.vtda.org

212 participants
437 discussions

by trag＠io.com

>Date: Sat, 3 Sep 2005 00:17:50 +0100 (BST) >From: ard at p850ug1.demon.co.uk (Tony Duell) >Most, if not all, of the single-bit-wide DRAM chips (4164, 41256, etc) >had separate DIN and DOUT pins. They were not dual-ported, though, you >only had one address bus for both reading and writing. Thank you. I have since noted this on X 1 DRAM datasheets. I had never noticed that before. >You could link these pins together externally, or you could use them >separately. IIRC on the IBM PC, the DIN and DOUT pins are linked on the >RAMs storing data bits, but wired separately on the RAMs storting the >parity bits. What is the point in using them separately? Was it for the case where the destination of a read is different from the source of a write? I could see where that could happen in parity checking. For the data bus though, the source and destination would be the same. For a little while I thought it might be for some odd timing advantage. But since the write data isn't required on the bus until just before the CAS anyway, I don't think the timing idea could be valid. Besides separate IN and Out could only confer a speed advantage in the cases where a Read followed a Write or vice versa. >If you have the machines that are supposed to use these 64 pin SIMMs, can >you not just check to see if DIN and DOUT are linked on the mainboard >with an ohmmeter? I don't have a IIfx or the SIMMs yet. I was exploring the feasibility of the project first. However, I posted a WTB to the austin.forsale news group and got lucky with a fellow who wants to give a IIfx away. So next week I should have hardware to explore. It's nice to avoid shipping when shipping would be greater than the value of a machine. Still, I would like to get my hands on the Apple Hardware Developer Note for the IIfx. It should at least mention whether they were using separate data_in and data_out for some timing related purpose. Of course, if an ohmmeter reveals that In and Out are tied together on the motherboard, then I'll have my answer. Jeff Walther

20 years

Intel MDS Series II IOC question

by dmabry＠mich.com

I think there are some Intel MDS owners here, and even some who use them! ;) Maybe one of you will know this detail. I'm trying to troubleshoot a problem on one I just got, a Series II, model 225. There is a large PC board on the back panel of these beasts called an IOC (Input/Output Controller). It contains an 8080 cpu, some ram, some rom, and basically all the I/O for the machine on the back panel. It is commanded by the system's cpu (a different board plugged into the front multibus chassis) through a couple of I/O ports, if I remember correctly. The IOC board has a three-position switch on the back. One position is "line" and in that position it is connected to the system cpu and does its everyday work of controlling the I/O for the MDS. One position is "local" and in that position I think all it does is echo characters typed on the keyboard to the crt. The third position, "diagnostic" causes it to run some internal confidence test. In that position, if everything is healthy, there are a series of two beeps, a pause, then three beeps after reset. After that there are some choices on the crt that let you run a few different tests from the keyboard. The one I'm working on will beep twice, then pause, then only one beep. Nothing further happens. No characters on the crt (which does have a raster, so at least part of the crt-controller function of the IOC is working), no apparent response to keyboard typeins. My question is this...does anyone know what part of the diagnostic is failing when there are only three beeps instead of five? The documentation I have only says it should beep five times but doesn't say what each beep signifies. It would help narrow down my search for the problem if I know what part of the test is failing. I'd love a disassembly of the firmware of that board, but I've never seen it or any source for it. That would be very helpful. Anyone have such a thing? I don't remember ever seeing anything like that from Intel, but it was a long time ago and I may have just forgotten. I'll be diving into this problem this weekend, but if anyone can help with the above couple of questions that would be wonderful. Thanks in advance! Dave Mabry

20 years

more stuff in Kansas City, 20 new 2400' magtapes, 4 DSSI drives, microvax2000

by mamcfadden＠cmh.edu

4 RF31T DSSI drives with carriers and front panels 2 cases sealed precision magnetics 2400 foot 89 track magtapes microvax 2000 with external disk drive Make me an offer on the microvax 2000. The DSSI drives and tapes are free to whoever pays shiopping. m a m c f a d d e n atatat c m h dotdotdot e d u

20 years

IBM 3725

by gcarrick＠cse.uta.edu

Well, I have a bit of a dilemma and I am seeking advice. (No flames, please.) As so many on this list I abhor seeing things scraped if they are useful. As with much of the older mainframe stuff, however, it is very big, and an isolated unit is not generally useful by itself. So here is my problem. Our museum is a part of a big state university. I go by the surplus department once in a while and see some interesting stuff that I take back to our space and add to our inventory. If it has a residual value on the books then it is transferred to our department. If it is not on the books then I just take it and there is no record of it. In the latter cases I have been known to swap newer stuff for other older stuff we are interested in. Yesterday I went by and there was a nice IBM 3725 front end processor. It is not anything attractive for a museum visitor to look at. It takes up a lot of valuable display space (roughly 2 racks & about 5' tall) for something kind of obscure (for most people) and not at all visually interesting. Now I have no idea what our surplus department generally does with such things. Assuming that there is no actual market for it, I could probably go over there and get it for our museum. Right now I could probably even store it, at least until something more attractive came along. On the other hand, when we get to the point that we are a bona-fide museum, with lots of visitors, I can see raising some much needed cash by parting this thing out. I am sure there are lots of boards and control panels that could be sold individually. I would envision tagging these parts as being a souvenir of the museum, much as I will with punched cards, 8" floppy disks, 5-1/4" disks, etc. I guess a third alternative would be to sell or trade it to somebody on the list for something that is more visually interesting and perhaps smaller. Gil We don't sing because we're happy - We're happy because we sing! mailto:gilcarrick at comcast.net? web page: http://goodtimeschorus.org/ Gil Carrick VP Chapter Development/ Webmaster 1012 Portofino Dr., Arlington, TX, 76012 817-274-2210

20 years

Important: Need to hear from potential VCF 8.0 exhibitors/attendees

by vcf＠siconic.com

I need to hear from people who had planned to attend or exhibit at VCF 8.0 this November, especially if you've already made your flight arrangements. It's important that you respond to me SOON. Please send your replies directly to me. Thanks! -- Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org [ Old computing resources for business || Buy/Sell/Trade Vintage Computers ] [ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]

20 years

DEC Computer Lab

by Watzman＠neo.rr.com

If someone will photocopy these DEC computer lab manuals and send me the photocopies, I will create a PDF file and return the photocopies (if desired). They need to be unbound, and preferably single sided. They do not need to be 8.5" x 11". The better the copy of the copies, the better the PDF file. Barry Watzman Watzman at neo.rr.com

20 years

Clean out of stuff in Kansas City, alphaserver, PDP-11, TEKtronix terminals, AT&T 7300

by mamcfadden＠cmh.edu

Winter is coming and the garage must be cleaned up. Make me an offer and come and pick it up, it's large and heavy. Alphaserver 2100 external DEC TZ87 DEC CRT VRT19-HA DEC CRT VR297-DA several DEC VT220, VT320 terminals several Wyse terminals PDP-11 BA23-A in floor stand TEK 4205 TEK 4209 2 LMSI 1200E 12" Optical Disc Drives AT&T UNIX PC i.e. AT&T 7300 TI Explorer compact chassis labeled on outside as Unisys, inside as T3127 contact Mike m a m c f a d d e n atatat c m h dot dot dot e d u

20 years

Mass Memory Unit from Space Shuttle

by trag＠io.com

>Date: Sat, 3 Sep 2005 19:48:23 -0700 >> I found a pile of these things this morning. They are made by Odetics >>in Anaheim Ca. After I got home with them I realized that they are for the >>space shuttle. Does anyone know anything about them? I THINK they use a >>tape drive inside. I haven't opened one up yet but I saw the remains of a >>tape drive at the same place and I think it was the guts out of one of these. I worked at NASA JSC in the mid-80s. Back then they definitely used tape drives for the mass storage on their flight computer systems. I don't know what they use today, whether they've changed or when any changes may have occured. But back in 84 - 87 they used tape drives. There was a thick (~3") training manual that explained the basic system architecture in passing. If I still have a copy there's not much hope of my finding it, but if I run across it, I'll post. Jeff Walther

20 years

64 pin SIMM (Mac IIFX) Specs?

by trag＠io.com

I am looking for specifications for the 64 pin SIMMs used in the Macintosh IIFX and one or two of the LaserWriters (IINT, IINTX?). I have the pinout from the "Guide to the Macintosh Family Hardware" but could use the physical dimensions, i.e. an engineering drawing. Any special electronic considerations would be nice to know too. I'm thinking about running off a few homebrew boards. One of Apple's old Tech Notes states, "The IIfx has 64-pin SIMMs, which are different from previous Macintosh models. Developers can request mechanical drawings and electrical specifications of the IIfx RAM SIMM modules from DTS. Please send the request with a mailing address and include the words "IIfx SIMM information request" in the title of the electronic mail request or letter to facilitate handling." But since that note was last updated in 1991, I'm guessing that wouldn't work any more. But if one of you sent off for that information way back when, I would love to see it. My main concern is that the pinout lists a separate data pin for data in and data out. So even though they are eight bit SIMMs, there is a Data In [0:7] and Data Out [0:7] in the pin out. It's possible, perhaps likely, that these are simply tied together, but it would be nice to see some confirmation. The chips I've identified on IIfx SIMMs don't appear to be dual ported and I don't see any extra circuitry on the SIMM that could be making an adaptation, but I'm working from JPEGs so far. If this looks feasible I'll actually spring for a IIfx and a few SIMMs to work from. On the other hand, if the SIMMs require some rare dual data ported DRAM chips, then I'll drop the idea. Jeff Walther

20 years

XTs and large hard disks

by ISC277＠CLCILLINOIS.EDU

Hi everyone! I have an old Portable PC that I put a 2MB memory card in, along with an EGA card, sound card, and some other stuff. I'm doing my best to max it out. Anyway, I'm having some trouble with hard disks. I have two hard disk controllers: a Seagate ST02 SCSI/Floppy controller, and a Juko Labs D16-X IDE controller. Now both of these cards work okay, except they recognize some strange sizes for the disks. The only disk that seems to show up correctly is a Quantum LP105S...the others I tried, all bigger than a gig, are either not recognized, or recognized with the wrong size. This is also the case with the IDE controller - everything is recognized at 10MB. I purchased an LBA PRO card for my machine hoping to overcome the large disk size problem, but all it does is freeze the machine...however, if I remove the 8088 and replace it with a NEC V20, I get the banner for the hard disk drive card, and THEN the machine freezes. So my questions are: 1. Does anyone know a good solution for putting a large drive in an XT, while still leaving it an XT? 2. Should I leave the V20 in? I've heard it has compatibility issues with some programs, but I'm not solid on my information. Regards, Julian

20 years

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test-drb September 2005