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Building a better "old" computer

by dhquebbeman＠theestopinalgroup.com

26 years

Building a better "old" computer

by allisonp＠world.std.com

>Even better.. Today you could use one of the modern chips (pentium) to emulate >the Z80, probably at unheard of speeds, with full access to all the internal >registers (after all the pentium would be keeping those registers in memory >somewhere..) You could and then you have one of the Z80 emulators. >Using original parts we may not be able to make a better computer than then, but >using modern parts, perhaps we can make it smaller and faster, even using a Z80 >memory is denser (and cheaper) today than then, right? <imho> using a standard Z84C010 (cmos 10mhz) and common cache rams I could easily do a z80 1mb 10mhz machine. It's not hard. Use a Z180S00 and 33mhz is possible. With cheap, dense fast static memory most of the old designs get real simple and can go faster. The best example is a proto I've build using a Z84C50 (z80/10mhz with clock + wait state management, 1k ram) in a clone of the amproLB using static ram (eliminates 15 DIPS) making is a fairly bare board. It runs at 8mhz due to limits in the SIO and CTC parts I had. I wanted it to run the same boot and BIOS so I used what I had. If I were to do the latest and greatest I'd go with Z380 as it will run Z80 native and make the IO a z180 slave, then the only limits would eb the how fast can the Z380 go (20mhz is common part and it executes Z80 instructions in about half the clocks). Allison > >Ernest wrote: > >> Based on what the current computer industry knows about building computers, >> would it be possible to build a better Z80 based computer today, using the >> same chips that the builders in, say, 1979 had available? >> >> I heard someone say that the manufacturers did the best they could with what >> they had to work with "back then," and I started to wonder if we could do it >> better today. Has our understanding of how it all works improved enough to >> do it better now, using the same chips, etc.? >> >> Just curious, >> >> Ernest >

26 years

Guy needs help building collection in UK

by vcf＠siconic.com

Can anyone in the UK help this guy out? Reply-to: dh8987mary3(a)netscapeonline.co.uk ---------- Forwarded message ---------- Date: Sun, 25 Jun 2000 05:46:50 -0700 From: DAVID HOLDSWORTH <dh8987mary3(a)netscapeonline.co.uk> Subject: VCF Feedback! i would like to ask if any one in the uk could donate any old computers to my small colection.as i aam dissabled and i love old pc.s computers of any kind .i also collect old radios dating back to 1945 especially valved radios working or not.please help if you can thankss my phone no is 01493 300955 . uk Sellam International Man of Intrigue and Danger ------------------------------------------------------------------------------- Looking for a six in a pile of nines... Coming soon: VCF 4.0! VCF East: Planning in Progress See http://www.vintage.org for details!

26 years

DD disks and HD drives (was: Where can I find...)

by allisonp＠world.std.com

From: Douglas Quebbeman <dhquebbeman(a)theestopinalgroup.com> To: 'classiccmp(a)classiccmp.org' <classiccmp(a)classiccmp.org> Date: Sunday, June 25, 2000 9:56 AM Subject: RE: DD disks and HD drives (was: Where can I find...) >> I do it all the time, no problem. Key thing is while the drives >> are HD capable (TEAC FD55GFV) I happen to have them >> jumpered as required to properly run DD mode. In this >> mode they are plain DD, DS 96 TP! drives. ^^^^^^^^^^ I repeat for the impaired 96 TPI. > >Does setting that jumper cause them to write double-tracks, NO. >then (as ISTR that the HD drives wrote tracks that were >half-width, and someone used to sell a software package Yes, thats the ppoint of using 96TPI drives... to get more tracks. >that wrote an HD-width track, stepped the head, then >wrote an adjacent HD-width track to create pseudo-DD >tracks)? You can but, the reliability of the read data sucks to be blunt. I said that you ccan do this in an earlier post if you needed some special project hack to get you by. I don't as a good 48tpi drive does a far better job and swapping it is no big deal. I used 5.25 96tpi two sided double density for one reason easy to get and use storage space. That mode does 720 or 782k depening on the formatting were an older 48tpi drive will do 360k. Where 1.2mb used funky media, data rates and all that are not easily found on NON-PC systems. Back in the old days using DD on a 96tpi drive was called QD. >Hey, precisely what jumper is that? I ave five different versions of the FD55-GF drives and they are all different. So I did a lot of guessing and tried them until it worked. A manual would have helped. I also ahve a few FD55Fs (also 96tpi DD two sided without ability to do the oddball 1.2mb format). Allison

26 years

Building a better "old" computer

by allisonp＠world.std.com

-----Original Message----- From: Douglas Quebbeman <dhquebbeman(a)theestopinalgroup.com> To: 'classiccmp(a)classiccmp.org' <classiccmp(a)classiccmp.org> Date: Sunday, June 25, 2000 9:55 AM Subject: RE: Building a better "old" computer >You can buy a brand-spanking-new IMSAI 8080 that has 1 meg >of bank-switched static RAM and a 20mHz Z-80 (actually Z-280?) >processor for under US$1000. I'd say that qualifies for an >excellent "old" new computer. First Z280 didn't need bank switch as it had a 24bit MMU. Second if it has Z280 production would be hard as Zilong endof lifed it some 6 years ago. Likely is Z180 or Z380. Allison

26 years

DD disks and HD drives (was: Where can I find...)

by dhquebbeman＠theestopinalgroup.com

> Well you left out all the caveats. > > I do it all the time, no problem. Key thing is while the drives > are HD capable (TEAC FD55GFV) I happen to have them > jumpered as required to properly run DD mode. In this > mode they are plain DD, DS 96 TP! drives. Does setting that jumper cause them to write double-tracks, then (as ISTR that the HD drives wrote tracks that were half-width, and someone used to sell a software package that wrote an HD-width track, stepped the head, then wrote an adjacent HD-width track to create pseudo-DD tracks)? Hey, precisely what jumper is that? -doug q

26 years

OT: Tech Support Fun

by rigdonj＠intellistar.net

> >A woman called the Canon help desk with a problem with her printer. The tech asked her if she was "running it under Windows." The woman responded, "No, my desk is next to the door. But that's a good point. The man sitting in the cubicle next to me is under a window, and his is working fine." >GENIUS GENIUS GENIUS GENIUS GENIUS > >Tech Support: "OK Bob, let's press the control and escape keys at the same time. That brings up a task list in the middle of the screen. Now type the letter 'P' to bring up the Program Manager." >Customer: "I don't have a 'P'." >Tech Support: "On your keyboard, Bob." >Customer: "What do you mean?" >Tech Support: "'P' on your keyboard, Bob." >Customer: "I'm not going to do that!" >GENIUS GENIUS GENIUS GENIUS GENIUS > >Overheard in a computer shop: >Customer: "I'd like a mouse mat, please." >Salesperson: "Certainly sir, we've got a large variety." >Customer: "But will they be compatible with my computer?" >GENIUS GENIUS GENIUS GENIUS GENIUS > >I once received a fax with a note on the bottom to fax the document back to the sender when I was finished with it, because he needed to keep it. >GENIUS GENIUS GENIUS GENIUS GENIUS > >Customer in computer shop: "Can you copy the Internet onto this disk for me?" >GENIUS GENIUS GENIUS GENIUS GENIUS > >I work for a local ISP. Frequently we receive phone calls that start something like this: >Customer: "Hi. Is this the Internet?" >GENIUS GENIUS GENIUS GENIUS GENIUS > >Customer: "So that'll get me connected to the Internet, right?" >Tech Support: "Yeah." >Customer: "And that's the latest version of the Internet, right?" >Tech Support: "Uhh...uh...uh...yeah." >GENIUS GENIUS GENIUS GENIUS GENIUS > >Tech Support: "All right...now double-click on the File Manager icon." >Customer: "That's why I hate this Windows - because of the icons - I'm a Protestant, and I don't believe in icons." >Tech Support: "Well, that's just an industry term sir. I don't believe it was meant to -" Customer: "I don't care about any 'Industry Terms'. I don't believe in icons." >Tech Support: "Well...why don't you click on the 'little picture' of a filing cabinet...is 'little picture' OK?" >Customer: [click] >GENIUS GENIUS GENIUS GENIUS GENIUS > >Customer: "My computer crashed!" >Tech Support: "It crashed?" >Customer: "Yeah, it won't let me play my game." >Tech Support: "All right, hit Control-Alt-Delete to reboot." >Customer: "No, it didn't crash - it crashed." >Tech Support: "Huh?" >Customer: "I crashed my game. That's what I said before. I crashed my spaceship and now it doesn't work." >Tech Support: "Click on 'File,' then 'New Game.'" >Customer: [pause]: "Wow! How'd you learn how to do that?" >GENIUS GENIUS GENIUS GENIUS GENIUS > >Got a call from a woman said that her laser printer was having problems: the bottom half of her printed sheets were coming out blurry. It seemed strange that the printer was smearing only the bottom half. I walked her through the basics, then went over and printed out a test sheet. It printed fine. I asked her to print a sheet, so she sent a job to the printer. As the paper started coming out, she yanked it out and showed it to me. I told her to wait until the paper came out on its own. Problem solved. >GENIUS GENIUS GENIUS GENIUS GENIUS > >I had been doing Tech Support for Hewlett-Packard's DeskJet division for about a month when I had a customer call with a problem I just couldn't solve. She could not print yellow. All the other colors would print fine, which truly baffled me because the only true colors are cyan, magenta, and yellow. For instance, green is a combination of cyan and yellow, but green >printed fine. Every color of the rainbow printed fine except for yellow. I had the customer change ink cartridges. I had the customer delete and reinstall the drivers. Nothing worked. I asked my coworkers for help; they offered no new ideas. After over two hours of troubleshooting, I was about to tell the customer to send the printer in to us for repair when she asked >quietly, "Should I try printing on a piece of white paper instead of this yellow paper?" >GENIUS GENIUS GENIUS GENIUS GENIUS > >A man attempting to set up his new printer called the printer's tech support number, complaining about the error message: "Can't find the printer." On the phone, the man said he even held the printer up in front of the screen, but the computer still couldn't find it. >GENIUS GENIUS GENIUS GENIUS GENIUS > >And another user was all confused about why the cursor always moved in the opposite direction from the movement of the mouse. She also complained that the buttons were difficult to depress. She was very embarrassed when we asked her to rotate the mouse so the tail pointed away from her. >GENIUS GENIUS GENIUS GENIUS GENIUS > >Customer: "Hello? I'm trying to dial in. I installed the software okay, and it dialed fine. I could hear that. Then I could hear the two computers connecting. But then the sound all stopped, so I picked up the phone to see if they were still connected, and I got the message, 'No carrier,' on my screen. What's wrong?" >GENIUS GENIUS GENIUS GENIUS GENIUS > >An unfailingly polite lady called to ask for help with a Windows installation that had gone terribly wrong. >Customer: "I brought my Windows disks from work to install them on my home computer." Training stresses that we are "not the Software Police," so I let the little act of piracy slide. >Tech Support: "Umm-hmm. What happened?" >Customer: "As I put each disk in it turns out they weren't initialized. >Tech Support: "Do you remember the message exactly, ma'am?" >Customer: (proudly) "I wrote it down. 'This is not a Macintosh disk. Would you like to initialize it?" >Tech Support: "Er, what happened next?" >Customer: "After they were initialized, all the disks appeared to be blank. And now I brought them back to work, and I can't read them in the A: drive; the PC wants to format them. And this is our only set of Windows disks for the whole office. Did I do something wrong?" >GENIUS GENIUS GENIUS GENIUS GENIUS > >For a computer programming class, I sat directly across from someone, and our computers were facing away from each other. A few minutes into the class, she got up to leave the room. I reached between our computers and switched the inputs for the keyboards. She came back and started typing and immediately got a distressed look on her face. She called the tutor over and explained that no matter what she typed, nothing would happen. The tutor tried everything. By this time I was hiding behind my monitor and quaking red-faced. I typed, "Leave me alone! They both jumped back as this appeared on their screen. "What the..." the tutor said. I typed, "I said leave me alone!" The kid got real upset. "I didn't do anything to it, I swear!" It was all I could do to keep from laughing out loud. The conversation between them and HAL 2000 went on for an amazing five minutes. > >Me: "Don't touch me!" >Her: "I'm sorry, I didn't mean to hit your keys that hard." >Me: "Who do you think you are anyway?!" Etc. > >Finally, I couldn't contain myself any longer, and fell out of my chair laughing. After they had realized what I had done, they both turned beet red. Funny, I never got more than a C- in that class. >GENIUS GENIUS GENIUS GENIUS GENIUS > >This guy calls in to complain that he gets an "Access Denied" message every time he logs in. It turned out he was typing his username and password in capital letters. >Tech Support: "Ok, let's try once more, but use lower case letters." >Customer: "Uh, I only have capital letters on my keyboard." >GENIUS GENIUS GENIUS GENIUS GENIUS > >Email from a friend: "CanYouFixTheSpaceBarOnMyKeyboard?" >GENIUS GENIUS GENIUS GENIUS GENIUS > >My friend was on duty in the main lab on a quiet afternoon. He noticed a young woman sitting in front of one of the workstations with her arms crossed across her chest, staring at the screen. After about 15 minutes he noticed That she was still in the same position, only now she was impatiently tapping her foot. He asked if she needed help and she replied: "It's about time! I pressed the F1 button over twenty minutes ago!" >

26 years

Building a better "old" computer

by allisonp＠world.std.com

>of "better" that you use. I've recently been fiddling with techniques for >taking what was, back in 1982, considered a pretty good implementation of >the general case of Z80 application, e.g. the Ferguson Big Board, which used >the standard Z80, and NOT the Z80-A which ran at 4 MHz instead of the >standard Z80's 2.5 MHz. I've got a number of these boards so I can test the In 1982 that was a low end example. DECs VT180 was a 4 serial port, 4mhz, no wait states With DD floppy design. It was ment to go in a VT100 so video was not needed. My NS* S100 crate in 1978 was running at 4mhz even. In the z80 world there were those that used Z80 peripherals and live with the limits they imposed and those that went with other parts. What was the limits? Price, they were not cheap and they were SLOW. By 1982 a Z80 not running at at least 4mhz was considered slow and by 1983 that would be 6mhz. Parts existed to do that. >in place of potentially better chips because they did make the design dirt >simple and the supported some features that other devices didn't support, >e.g. Z80 mode-2 interrupts. Mode 2 was supportable without Z80 parts, easy and cheap to do. >the Ferguson BigBoard, i.e four parallel ports four serial ports, local >video and using a parallel keyboard rather than a terminal, using a single >device, i.e. an FPGA or CPLD (take your pick)and one memory IC. When you're >done, you 'll have a CPU that operates at about 25 MHz, a double/single >density FDC, the parallel and serial capabilities and other features of the >Ferguson board. I don't know whether the result will be better. Try a Z180 part at 33mhz, SCC or other all on one chip like the SMC92667 and static ram on a 3x4" board. Takes very little glue to do that. The question goes mroe to price and creative engineering. Allison

26 years

Building a better "old" computer

by allisonp＠world.std.com

>Based on what the current computer industry knows about building computers, >would it be possible to build a better Z80 based computer today, using the >same chips that the builders in, say, 1979 had available? Yes. Though finding the parts would be hard. >I heard someone say that the manufacturers did the best they could with what >they had to work with "back then," and I started to wonder if we could do it >better today. Has our understanding of how it all works improved enough to >do it better now, using the same chips, etc.? For pre micro processor... there were designs that did thig with transistors and later SSI that were way ahead of the pack so the answer was yes and no also. For the z80 case: Yes and no. Some designs the designer was doing the best they could though the parts were more capable. Many cases the goal was to meet a price so that limits you. There were some very capable designs. But, using the same parts you could have done better then assuming the budget (size, power, $$$$) allowed it. Can you do better now using current parts and reusing old z80s, yes. Allison

26 years

RA81 problem :(

by peter＠joules0.demon.co.uk

I haven't used my MicroVAX II in some time, and one of it's RA81s wont spin up. It starts to spin, for about 1 second, and then cuts out and, after pressing the 'fault button' it leaves the fault light on and the 'B' light flashing. According to the RA81 user manual the cause is 'spin error' (I could probably have told _them_ that ;-). Can anyone give me any advice on whether it is possible to resurrect the HDA? If not, I have another drive which has no fans so I can make a good one out of the two but the one which has gone down contains my only copy of VMS. Is it drag in the bearings which is causing it to cut out whilst the motor is accelerating it? If so is it possible to lubricate them without opening up the HDA? -- Regards Pete

26 years

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