Someone actually *paid* $20 for one, already. <URL: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=74947&item=5… --jc Randy McLaughlin wrote:

On Sat, 2005-06-04 at 22:16 -0500, Randy McLaughlin wrote: Good grief. I thought that was going to be a drive, not just a floppy!

Due to the categorical-no-exceptions-for-bidders-out-of-usa of this auction, I think it would be great if someone could save this computer and its "in appeareance" huge lot of companion diskettes. http://cgi.ebay.es/ws/eBayISAPI.dll?ViewItem&category=4193&item=520… d=1 Regards Sergio

And, for the same reason than the other auction, perhaps someone would be interested in purchase this machine. Pretty. http://cgi.ebay.es/ws/eBayISAPI.dll?ViewItem&category=1247&item=520… d=1

http://cgi.ebay.es/ws/eBayISAPI.dll?ViewItem&category=1247&item=520… :-)))))) Sergio

From: "Tony Duell" <ard at p850ug1.demon.co.uk> Sent: Sunday, June 05, 2005 4:24 PM Personally I think the basic design of the PC is bad but I've got enough 8" disks that if I could get $20 each I could build a newer better shop to work on my toys I truly love :-} I've always thought computers should be built to maximize performance, IBM not only appear to have ignored that but built down. They took a 5mhz brain dead version of a 16 bit chip and ran it on an 8 bit bus @ 4.77mhz and put a RAM limit of 448mb of RAM. The excuse of running 4.77mhz was for color burst but I never saw a video card that didn't use its own crystal negating the need for the 4.77mhz. In any case the extra $0.50 it might add to a video board versus slowing down a $3000.00 computer doesn't make any sense any way. In the 8088/8086 world I like what others did in the S100 world. They started with the 8088 simply to keep compatible the 8 bit S100 bus, later a 16 bit standard allowed for 8086's. The S100 systems generally ran at the full chip speed (5 or 8 mhz), allowed full 1mb RAM, didn't use 10% of the processor speed to refresh RAM. I produce PDF's that love PC's not because I think they are perfect or I love PC's but simply because after thinking of the problem PDF's are the best choice I have in the world Willy boy created. It reminds me of what is going on in the EU (no I'm not trying and hopefully won't make a big political statement). The problem as reported in the US is that the EU constitution is like Windows I giant agreement that creates so much structure the citizens of Europe are afraid they could lose their individualism. It's a shame we didn't have the sense to just say no to Willy. Please note I have no personal knowledge about the EU constitution, more over "I don't have a dog in that fight". Randy www.s100-manuals.com

Patrick wrote: On the original PC, the limit was less than 640K. It was determined by the DIP switch settings, and there weren't settings that went as high as 640K. To convince the BIOS and DOS to use more memory, you had to run a program that fiddled with the pointers in low memory. Yes, that was the reason. They had a 4x colorburst crystal (14.31818 MHz). They divided by three for the CPU clock, and by four for the colorburst. Eric

And on the IBM PC/AT motherboard. The HMS manuals tells you to adjust it if you get no colour on a composite (NTSC) monitor. -tony

On Sun, 2005-06-05 at 17:45 -0700, Eric Smith wrote: Does that mean that IBM machines running PAL display rates had a slightly different CPU clock frequency as the main crystal would be different? [btw, where did we suddenly get an 8-foot floppy from!?] If the 8088 has an 8 bit bus and the 8086 is 16 bits, is there a good reason why it didn't get named the 80816? I'm assuming that's what the last digit in the number signifies... cheers Jules

I'm looking for an Osborne Executive boot disk image, or even better, a set of distribution disk images. All I've been able to find, so far, is for the Osborne 1. Mike Loewen mloewen at cpumagic.scol.pa.us Old Technology http://ripsaw.cac.psu.edu/~mloewen/Oldtech/

.From: Joe R. <rigdonj at cfl.rr.com> . . No ya didn't.... I did get a tan early OC-1 from you though, and I do/did have a set of Executive disks around here somewhere but no such machine. I'll search if they're not conveniently closer elsewhere. ;) - Mike: dogas at bellsouth.net

Mike Loewen wrote: I've got known good boot disks and a full set of masters that I haven't yet tested. Making images is this week's project. Doc

On Mon, 6 Jun 2005, Randy McLaughlin wrote: ... but the 8' FLOPPY disk could be folded a few dozen times to fit in your pocket

On Mon, 2005-06-06 at 09:55 -0500, Randy McLaughlin wrote: That suddenly made more sense when I realised how keys are laid out on a US keyboard :-) Until that point I thought you'd gone completely insane...

On Mon, 6 Jun 2005, Jules Richardson wrote: USUALLY that its from a typo, or a cultural difference in punctuation. I have a [damaged/unusable] platter that probably came from either a 1401 or an aftermarket drive on a 1620. It is 2 feet in diameter, but seems larger. After I showed it to a class to emphasize Moore's law, I asked them about their recollections of it from a week before - MOST estimated THREE feet, and a few went as high as FOUR! But none of them thought that it was over 5 feet, and certainly not eight. Sorry, but the last digit is NOT bits. It was simply a progression: 8085, 8086, 8087 (FPU for 8086), 8088 (8086 chopped down to be cheap) There does not appear to be any reliable pattern to the intel numbering. There are conflicting accounts for the naming of the 4004, 8008, etc. At least the Pentium name is reasonably documented (to be more easily trademarkable (inspite of the Pentaxium)) -- Grumpy Ol' Fred cisin at xenosoft.com

Randy McLaughlin wrote: You forgot the two REAL biggies: How will we preserve the contents? In what format should this disk be documented? I'll just grab my coat on the way out.... ;) Doc

Oooh, another potential stupid project :-) (I was wondering the other week whether a reliable digital network could be made between two machines out of a couple of paper cups and a piece of string ;)

Well, if you run Moore's Law backwards.... (I haven't done so, these are totally off-the-cuff responses.) Spindle RPM - maybe 30? Drive size - eh. 9 by 12 by 1 (feet), maybe? Spindle motor power - maybe .5 to 1 hp? (ca. 400-750 watts) Capacity - couple dozen kilobytes? Hard sectored - had they even *invented* soft sectoring? Maybe two or four sectors per track? Density - probably near the boundary between TPI and TPF :-) Box of ten - you mean more than ten were made? S-100 - goodness no, we don' need no newfangled high-speed interfaces! /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse at rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

On 7 Jun, 2005, at 00:28, Tony Duell wrote: I made a hacked CGA in order to get the colours from the original Flight Simulator displayed on a CGA monitor, since NTSC monitors were not generally available in Norway at that time. As far as I recall, I found some spare gates which could be used to demultiplex the composite signal into RGB. As you may remember, the FS used programming tricks to make NTSC colour in the monochrome "high resolution" mode. We used it in a running demo to show off the power of the PC! I also fried a monochrome display by trying to run it off a hacked CGA. It was not designed to stand up to the frequency change, even though I could adjust it so that it synched. -- -bv

I thought there was an issue with the very first version of the PC DIOS where it would only use somewhat less than 640K RAM. It most certainly does!. Read the Intel 8284 clock generator data sheet (which explains the divide-by-3), look at the PC motherboard and CGA card schematics. Everyting is derrived from a 14.3... MHz crystal. -tony

Me too... When I got my set of TechRefs, I read through the schematics and ROM listings. About every 30 seconds I would exclaim 'They did WHAT???' Agreed... The original IBM CGA card (and many clones of it) used the 14.3... MHz clock from the motherboard. This was divided by 4 on the CGA card to give the NTSC colour subcarrier anr by 3 on the motherboard to give the processor clock. On the AT motherboard (both the 6 and 8 MHz versions) there's a separate 14.3... MHx oscillator to provide this clock signal. There's a similar oscillator on the expansion unit backplane since the 14.3... MHz signal is not sent through the expansion cable. AFAIK, though, you can't put the CGA card in the expansuon unit (memory accesses to the video address range are not passed to the expansion unit), so I guess IBM though this signal might be used by something else. I can't think of another IBM I/O card that uses it. What makes even less sense to me was missing out the couple of cheap TTL chips (literally) that would have let them have active-low level-triggered interupts on the expansion slots. Uses had IRQ conflicts for ever more.... I once jokingly said that IBM-PC stood for 'Interrupts Being Missed, Polarity Corrupted' :-) Now why Intel sold an interrupt controller with active high inputs is also beyond me, but then again Intel were not known for good designs (I once claimed that there wasn't a single Intel LSI chip without a design misfeature at the time the PC came out...) I try to. I rarely run MS-DOS, the only version of Windows I have is v1.0 for the HP150 (!). OK, I've got M$ BASIC in ROM on some of my 8-bitters, but I don't depend on those (and other BASICs, like BASIC-09, BBC BASIC and HP71 BASIC are much nicer. Heck HP9830 BASIC is nicer than Microsoft's offering). One of the good things about classiccmp (IMHO) is that I can avoid Microsoft here (This has nothing to do with PDF files, there are plenty of tools for creating and reading them on non-Windows machines) -tony

From: "Ethan Dicks" <ethan.dicks at gmail.com> Sent: Monday, June 06, 2005 6:57 PM It was common to just change the crystal to 24Mhz and ignore the 14.3. I used a few CGA cards all had their own clocks. I believe the one I used the most was an MCT 1/3 length card that included composite video on the monochrome pin. It came with a 9 pin to RCA plug. Another I used a lot was an MCT full length card that included 2 serial, 1 lpt, clock, and floppy. It had jumpers to allow PAL on the composite out. I would use this and a hard disk controller for a full system with only two cards. It's been a while but on every system I over-clocked I never had an issue with the CGA but I can't guarantee what cards I used. I used a good variety of video cards but which ones on systems with changed crystals and which ones used a separate oscillator (switchable) I can't swear to. I did use CGA cards on systems without the 14.3Mhz line being valid. I started by changing the crystals but all of the last hacked systems were switchable and left the 14.3Mhz crystal in. Randy www.s100-manuals.com

<snip all> One thing to remember is that the filter caps of an Imsai are much larger than an Altair and the bleed down dime is MUCH longer. Be careful after turning off the computer and don't pull the cards until you are sure the voltage levels have dropped enough to not damage the cards. Randy www.s100-manuals.com

From: <shoppa_classiccmp at trailing-edge.com> Sent: Sunday, June 05, 2005 11:49 AM All of the S100 systems I've dealt with have had the line power exposed somewhere, none would ever pass UL testing. Randy www.s100-manuals.com

From: "Richard A. Cini" <rcini at optonline.net> Sent: Sunday, June 05, 2005 2:25 PM In the 70's it was assumed that you knew what you were doing today a device that is designed to be user serviceable with open line voltages would never pass muster. Imsai built to a high standard but they assumed they customer had basic understanding of electricity. Recently there was a power blackout where I live. I started up my gas generator (5500 watts) and used high quality extension cords to hook up the TV, satellite reciever, and refidgerator, and some lights. My neighbor had a tiny generator (800 watts) he knew nothing about. I helped him get his going and told him to get a good extension cord, I plugged it in and handed him the other end and told him to use that for power. He pointed out that the cord had a female socket and asked how to plug it into the house wiring to power the whole house :) Randy

From: "Ethan Dicks" <ethan.dicks at gmail.com> Sent: Sunday, June 05, 2005 2:54 PM No I explained to him that he didn't have a big enough generator to even run a full sized fridge safely but he could run a couple of lamps and a TV. He was disappointed since he had a fridge & two freezers, I told him to make sure no one opened them and the power came back on in a few hours. I like independence so having a medium sized generator and LP grill & Cajun cooker means I can get a long even though I have an all electric house. It's funny I got the generator through some horse-trading from a buddy a few years ago. It was a millennium generator (when everyone thought everything would turn off in 2000). It had never even had oil put into it before I got it. We have ice storms that can keep power out for days at a time but none since I get the generator. I'd run it for testing but this was the first time I needed to use it for real, it just goes to show if you have a generator the power won't hardly fail :) Randy www.s100-manuals.com

From: "Scott Stevens" <chenmel at earthlink.net> Sent: Monday, June 06, 2005 10:00 PM Luckily mine has a sensor and won't run without oil. My neighbor's generator's gas tank is like a square donut and the spark-plug is accessible through the hole, my generator's spark-plug is offset at an angle through the side. Seems a little stupid having the spark-plug right next to the gas fill cap. I told my neighbor that most generator related injuries come from adding gas to a hot generator and he should be careful. Every year people blow themselves up adding gas to a running generator. My neighbors generator looks like they designed it to get someone hurt. Randy www.s100-manuals.com