test-drb October 2007

test-drb@ccmp.vtda.org

228 participants
467 discussions

DOS lives (was: Taken: AT 286 motherboard with mathco)

by dm561＠torfree.net

-------------Original Message(s): Date: Wed, 17 Oct 2007 09:11:33 -0700 From: "Chuck Guzis" <cclist at sydex.com> Subject: Re: Taken: AT 286 motherboard with mathco On 17 Oct 2007 at 9:30, Jim Leonard wrote: > Ethan Dicks wrote: > > I do *not* miss the days of DOS. > > I do, since it was simpler and easier to gain complete access to the > hardware. You can still do so in other operating systems, but DOS+Debug > remains one of my favorite environments to poke around in. Ditto here. Not much of a problem running DOS 7.x for FAT-32 with DOSLFN to give long filename support. With a faster disk, an otherwise unusuable (under WinXP) system can turn in very decent performance. And using a 32-bit DPMI server to run 32-bit command- line applications can turn in very good results indeed--while not putting a wall between the hardware and your applications. A lot of Linux has even been getting bloated enough to adversely affect performanc on many P1 systems, particularly when one of the graphics desktops is involved. Cheers, Chuck -------------Reply: Count me in! Dos7.x on a modern system is sweet; fast, stable as a rock and lots of time-tested *useful* utilities out there as well to make it even better. Hook it up to your network and who could ask for more; now if only there were drivers for some of the newer peripherals... Thanks, BillG! <ducks>. m

17 years, 2 months

yet another logic family?

by rtellason＠verizon.net

I've just encountered some datasheets for parts that I've never heard of before -- 74ABTxxx parts. The lack of a "C" in there would seem to indicate TTL of some sort but looking at the datasheet the power supply current would seem to indicate CMOS of some sort, it's in the uA range. Anybody ever encountered these before? What can you tell me about them if so? I note that packaging seems to be _only_ surface-mount styles. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin

17 years, 2 months

Emailing: Universal Floppy reader, was Re Extracting CDOS and CP-M) files

by lynchaj＠yahoo.com

> Really don't understand all the talks about catweasels secrets, etc. > Just make few boards for the classiccomp group, and be done with the > subject ;-) I suppose--every once in awhile, I run into a very odd format that's not compatible with any of the commodity controllers and am forced to use a Catweasel on it. But 99% of what I see is plain old soft- sectored media, readable on most WD17xx or NEC 765 controllers. Cheers, Chuck -----REPLY----- There has been lots of talk about these universal floppy controller devices and I for one would LOVE to see one done but so far nobody has made one work. The closest thing I have seen is either the external floppy drive and compaticard combination or the parallel port Backpack external floppy drive >from Microsolutions. If anyone actually makes the universal floppy reader, please put me down to buy one as well. However, IMO, the best solution for the universal floppy drive is an old PC with a Catweasel and a 3.5", 5.25", and/or 8" floppy drive. Then just write the software for it. Really, writing software for the Catweasel is really simple and it is 100% open source. The documentation is all available publicly, its supported in Linux, MS-DOS, and/or Windows, the owner/manufacturer is as accomodating as one could possibly hope for (Jens Schoenfeld). There is a developer list and lots of enthusiastic users. The hardware is cheap and readily available. Count me as diehard Catweasel fan! The Catweasel in an old PC is as close to the perfect universal floppy drive reader as far as I can see. What else is needed? More and better software and that is about all. There are Catweasel software available for practically every format imaginable. Most if not all of the soft sector formats are covered by the Tim Mann CW2DMK software. There are reader for many formats such as specialty disks as the Amiga, Atari, Macintosh, Commodore, Nintendo, Apple II, etc. There is software for many of the hard sector formats as well (NorthStar, PTDOS, Data General, and Heath, at least. Vector Graphic is in work). Thanks and best of luck with your project. Really, if anyone does complete a universal floppy reader which is even close to as good as the Catweasel, I will be in line to buy it. Andrew Lynch

17 years, 2 months

MAI cable -anybody want it?

by dm561＠torfree.net

>Date: Wed, 17 Oct 2007 12:21:16 -0700 >From: Marvin Johnston <marvin at west.net> >Subject: VCF on November 4,5 <Snip> >The rational is that I frequently find cables and don't know if they are worth >saving or just scraping out, and I think others would benefit as well. Ugh - scraping out... sounds most unpleasant and not very rational at that... Speaking of cables, I've got one here from a previous life marked MAI Tape. 50-pin 3-row AMP DB??-type male connectors with 34 pins used (11,12,11). Anybody have a use for it before it gets 'scraped'? m

17 years, 2 months

That poor system/36

by ballsandy＠msn.com

Thanks for breaking the good news colin. :D I really hope it goes to a nice home it would be a shame to neglect that big of a system. Hmmm, asides from our two Canadian tire sores (they have something, there are Twinax terminals everywhere!) I really can't think of any place in town that would have an IBM mainframe of any kind. I can see modern servers and lots of them but the closest place I can think of that would hide an IBM would be the lower mainland....or the Okanagan valley. _________________________________________________________________ Have fun while connecting on Messenger! Click here to learn more. http://entertainment.sympatico.msn.ca/WindowsLiveMessenger

17 years, 2 months

FPUs for small computers (Was: What to download for a PDP-8)

by ajp166＠bellatlantic.net

> >Subject: Re: FPUs for small computers (Was: What to download for a PDP-8) > From: "Chuck Guzis" <cclist at sydex.com> > Date: Wed, 17 Oct 2007 10:21:40 -0700 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 17 Oct 2007 at 12:09, Jim Battle wrote: > >> Finally, I recall seeing an article where somebody took a pocket >> calculator chip and essentially poked simulated keystrokes at it and >> then decoded the LED driver output to determine the answer. It was very >> slow, though, so all it saved was the space of the floating point >> library code. > >I remember that one. It may have been an early issue of Byte. I >also wondered at the time if any speed was gained over just running >plain old x80 code. If it's the article as I remember it it was a push for Add/subtract but better for multiply and divide (to 8 digits). An 8080 does a 16x16 multiply in a few milliseconds to compare. In another Byte there was a simple design and explanation of hardware multiply by shift and add. That was capable of high speed. With TTL of the time that was something under 10 microseconds for 16 bits using a 2mhz clock. At that point a 4mhz Z80 takes nearly that much time to load and read it. You can do subtract and shift to implement a divide. Allison

17 years, 2 months

FPUs for small computers (Was: What to download for a PDP-8)

by ajp166＠bellatlantic.net

> >Subject: FPUs for small computers (Was: What to download for a PDP-8) > From: Jim Battle <frustum at pacbell.net> > Date: Wed, 17 Oct 2007 12:09:44 -0500 > To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> > >woodelf wrote: >> Jules Richardson wrote: >> >>> For a math copro to be called as such, does it have to integrate >>> itself with the CPU's instruction set - or does some sort of box of >>> tricks sitting on an I/O port and accessed through normal CPU >>> instructions count? I'm not sure what the correct definition is. >> >> It does tricks, but then with only 8 opcodes defined on the PDP-8 >> what do you expect. >> >>> What do you mean by 'smallest computer' by the way? Smallest in terms >>> of spec? I'm pretty sure some of the 1950's stuff had optional >>> floating point hardware available, although it wouldn't have been >>> physically small :) > >Northstar (of Northstar Horizon fame) sold an S-100 card that had a TTL >FPU on it. It was a microcoded affair (256 words of 40 bits) that >processed a nibble (BCD digit) per clock (4 MHz I believe). You could >also specify how many digits were in the mantissa (2-14, even # digits >only). Only the four basic functions, +-*/, were supported. > >Northstar had a version of BASIC that could use this FPU. As I recall, >you had to specify how many digits of precision you wanted in your >floating point numbers when you ordered BASIC (it wasn't dynamically >specified in the interpreter). > >Others sold S-100 cards that used an AMD FPU chip. This too required >poking data bytes and a command, then waiting for the result to be >computed and then pulling out the result bytes. It wasn't somehow >integrated into the instruction set of the host processor. > >Finally, I recall seeing an article where somebody took a pocket >calculator chip and essentially poked simulated keystrokes at it and >then decoded the LED driver output to determine the answer. It was very >slow, though, so all it saved was the space of the floating point >library code. Actually The article used a CALC chip that was slow on speed but had an interface that was BCD output and convenient for input. A few years back I took a 8742 (8048 with a slave interface) at 11Mhz and programmed it to do 24bit BCD math (+-/*) and it was faster than a calc chip. It was done because I could. Overall it was as fast as z80/4mhz. Allison

17 years, 2 months

IBM 5120 monitor issues

by derschjo＠msu.edu

Well, here I am again soliciting advice from you guys. One of these days I'll be able to answer someone else's question and I'll feel useful :). Anyway. I picked up an IBM 5120 (i.e. the "really big and heavy" (with emphasis on "heavy") variant of the 5100/5110) awhile back that has a few issues and I've just now got enough spare time to take a look at it. Finally got done cleaning out copious amounts of gooey black tar that used to be foam 25 years ago... There are two major issues, the first being the monitor, the second being a ROS error on startup (which I suspect may be quite difficult to solve...) But I'd like to see what I can do about the monitor. The picture exhibits a strange behavior that I can't say I've seen before. The horizontal retrace seems to "fold" over itself in the middle (like the electron gun is doing a "loop" in the center of the screen for each line). I've taken a (terrible) picture of the fault and put it at: http://yahozna.dyndns.org/scratch/5120disp.jpg). The picture's also a bit jumpy. I've tinkered a bit with the various adjustments on the CRT's PCB but it doesn't make any appreciable difference. The monitor is labeled as a "Ball TV 90." I've done a bit of maintenance on old Arcade monitors, mostly of the "cap kit" variety so I know how to be careful around the HV sections, but I'm not much for troubleshooting (yet). Any suggestions on where to start? While I'm at it -- anyone have an archive of software for this thing anywhere? I haven't found much, I'm looking for floppy images (the 5120 has 2 8" drives). Thanks again for the advice... - Josh

17 years, 2 months

That poor system/36

by ballsandy＠msn.com

>Unlike most mini and microcomputers, the mainframe things tend to get >slaughtered off about ten years after introduction. Which is why I feel pity for that system/36. I talked to the guy and while he never mentioned that he will eventually give up and scrap it I have a feeling that after a few years with no bites he might re-think scrapping it. It's currently in a cold storage locker and all that's needed is for someone to contact him and come with a cube van that you must supply. I think he also tole me that they will even help you load it all up and wave you goodbye. :) Okay, how about I cut down to the point: -I'm 17 and have a wicked case of OCD -I like old electronics -I use a 5 1/4" floppy drive on a normal basis -I like things that have blinkenlites and make cool whirring noises -I have passed notes written in hex to a friend in class ("what are you doing at lunch?") Just owning a computer like this would complete my childhood. Yes, I am a very strange person indeed. :P _________________________________________________________________ Express yourself with free Messenger emoticons. Get them today! http://www.freemessengeremoticons.ca/?icid=EMENCA122

17 years, 2 months

VCF on November 4,5

by marvin＠west.net

As usual, I'll be up at VCF this year with quite a bit of stuff to get rid, er, sell :). If anyone who will be there is looking for something, let me know and I can bring it up if I have it ... and it is not too bulky or heavy (unless there is a committment to buy.) As usual, I'll have quite a few books, some computers, and some other not easily found items. I am assuming that there will also be the informal Saturday night dinner at the usual place (can't remember the name, just how to get there.) One thing I've been thinking about for some time is a FAQ on cables and connectors, i.e. something with pictures and what computers, etc. it goes to. As such, I'll have a variety of cables with me that I'll be talking to others about to find out what they go to. Examples would be like the Appletalk cables, cables connecting the Commodore computers to disk drives, etc., video cables, DEC cables, etc. The rational is that I frequently find cables and don't know if they are worth saving or just scraping out, and I think others would benefit as well.

17 years, 2 months

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test-drb October 2007