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More thoughts on building a Z-80 (64bit!!!)

by allisonp＠world.std.com

< Are z80's still being produced? Yes. <If so, are they the same as the 1980 ones? actually the z80 is 1976 design and yes. The z180 is an enhanced part that is very popular in controls and other embedded uses. <I would think so, since the TI-86 (still in production) uses < a z80. BTW, I guess comparing the multi-Z80 system to a 386 isn't too < fair. It's fair as the z80s were only running at 6MHz. <How much faster is it than 1 z80 running the same program? Not terribly. The actual test only used one. The rest were doing background tasks (printing). Z80 excels at IO and byte oriented tasks. The real advanatge was the system had highly optimized IO channels for everything and the disks had track caching. The other minor advantage is the z80 code used was tight and by time 386s got in PCs code bloat had already set in. FYI: the machine was originally designed to tackle several things more speed from a cpu, Multiprocessing/multitasking and more efficient IO systems. The IO systems part proved to be the key to using one cpu more efficiently. Multiple CPUs had a minor advantage that was offset by fairly complex programming. To this day that system runs but with only one master cpu installed(the other three are spares). Two years later Compupro would come up with the MPX1 combined with their frequent use of DMA to make one of the fastest s100 systems available (for any given cpu). Basically doing the same work I did earlier for myself and proving that multiple CPUs and DMA can be a performance enhancement when applied to the bottlenecks (most tend to occur at the IO level). <Why is everyone making multi-z80 machines, anyway? Partially to capitalize on available software (mountains of it all free) and experince. <Why not 6502 or 6800 or even (gasp!) 8088? Because those were done also. I have a trackstar128, two 6502s. IT has a lot to do with the way the CPUs interface and the ability to interconnect them so they don't fight each other. The 8088 has a selection of bus interface chips that allow for multiple CPUs on the same buss (8289). Also multiple CPUs are a cost/complexity vs performance race and some win better in that contest. Allison

27 years, 10 months

TRS-80 emulators

by SUPRDAVE＠aol.com

i've got slackware 3.0 two disk set somewhere around here i'll let go for $5 In a message dated 10/23/98 8:30:17 AM US Eastern Standard Time, bwish(a)pcfa.org writes: > You could get someone to burn you a CD copy, or find someone willing to > give away their old distribution CD. I was able to get a copy of RedHat > 5.1 burned for $5. I'm sure you could find someone fairly easily who > would do something similar. > > I ran across a web page that listed people with old distribution CD's who > would either give them to you or let you borrow them.

27 years, 10 months

Starting from Scratch (was Re: OT: Modern college educations)

by mtapley＠swri.edu

Chuck McManis wrote: >You guys don't get it. :-) > >You play the game like this: > 1) Scout for a surface deposit of Coal and start mining coal. > 2) Scout for (surface) deposit of iron ore and start mining ore. >... > 15) Using generator create electricity. > 18) Mine tungsten and build lightbulb. > ... >First one to a PDP-8 wins :-) > Oh, I got it. I used to play that game with myself, but with the goal being "First one to match orbits and dock at the space station in polar orbit wins." I could never figure out a workable way to do it in one lifetime. (ObCC: guidance computers were a serious problem. Relays I built, clicking away in the vibration environment induced by a rocket I built? Right....Sequencers? Stable time reference? Oy.) I guess I'd have to start out: 1) Scout for native woman. 2) Establish dynasty. 3) Found school/religion to keep dynasty on task 4) Gosub Chuck's #1) above. ... :-) - Mark ----------------------------------------------------------------------- Large Asteroids headed toward planets inhabited by beings that don't have technology adequate to stop them: Think of it as Evolution in Fast-Forward.

27 years, 10 months

More thoughts on building a Z-80 (64bit!!!)

by maxeskin＠law-smtpdev.hotmail.com

Are z80's still being produced? If so, are they the same as the 1980 ones? I would think so, since the TI-86 (still in production) uses a z80. BTW, I guess comparing the multi-Z80 system to a 386 isn't too fair. How much faster is it than 1 z80 running the same program? Why is everyone making multi-z80 machines, anyway? Why not 6502 or 6800 or even (gasp!) 8088? >< connections is good, soldering them helped a bit but no dice. > >Huh? I have 6 cards, s100 protoboards with about 25-40 pieces of mos and >TTL on them that I wrapped in 1981 still running. Ohmic losses? What were >you doing wrong. Remember #30 is for signals not power! > >< Have data transfers done with DMA, all memory mapped and irq driven >< to knock subCPU as needed to grab data then place it in CPU's lap. >< Leave CPU alone for processing. How about that? > >Those 6 boards built a multi z80 system with DMA and slave processors for >things like IO and disks. It helps but the z80 bus is so busy that it's >very hard to slip inbetween cycles so you steal cpu cycles by holding it >off with BUSRQ/. Z280, z8000 and Z380 use burst mode access to the bus so >that other devices can get in and get a few cycles without holding up the >cpu. Even with slaves you reach a bottleneck between memory management >and overhead to move data around. Still the results with 6mhz z80s were >enough to blow away 386/16 class machine for text oriented applications. > >Allison > > ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com

27 years, 10 months

DEC Hardware

by jrice＠texoma.net

I'm going to look at some DEC hardware, a PDP-11/34 and some VAX equipment. I'm not into DEC's so I thought I'd look at it as possibly a rescue setup. This company is going to want some residual value payment. how much is this stuff worth? It was taken out of service a couple of months ago. I'll try to get a list of what's available. It's located about 60 miles from Dallas. I might want one of the Vax boxes, but I don't want any PDP hardware. Anyone interested? James

27 years, 10 months

128k Mac Schematic needed

by nerdware＠laidbak.com

Hi, group. My 128k Mac went south on me. When I first got it a year ago, it turned on and the screen came up and asked for a floppy. Not having a system disk that old, I just put it in storage until I came across one. Needless to say, next time I turned it on the floppy made funny noises and kept spitting the disk out and no video. Does anyone have a schematic for the little beast so I can get it cooking again? If I have to, I can use my Mac Plus for my history presentations, but I would rather use the original, if possible. Thanks. Paul Braun NerdWare -- The History of the PC and the Nerds who brought it to you. nerdware(a)laidbak.com www.laidbak.com/nerdware

27 years, 10 months

Starting from Scratch (was Re: OT: Modern college educa

by pete＠dunnington.u-net.com

On Oct 23, 14:04, Ethan Dicks wrote: > > Where is my copy of '101 basic games' ? > Mine's at home, but I do happen to have a version I ported to the PET > in 1978 that is sitting right here on my SPARCstation disk. I've got > xpet, and a directory full of my old tapes that I converted to .d64 > emulator disk format. I'd post HAMMURABI.BAS, but I suspect that more > than one person would get annoyed. I'm sure I've seen a copy on one of the Vax sites somewhere. I'm fairly sure I have a copy on one of the hard disks here, too. Somewhere :-) -- Pete Peter Turnbull Dept. of Computer Science University of York

27 years, 10 months

EDSAC celebration?

by dpeschel＠u.washington.edu

This question has been rattling around in my head for some time. Perhaps one of the UK people has the answer. I enjoyed the Manchester Mark I recreation. I saw the programming contest, thought about writing something really fantastic (a small computer language, whatever), looked closer at the architecture of the machine, and changed my mind. It's pretty limited. I was *quite* impressed by the noodle-timer program that won the contest, though. But I always liked the EDSAC much more than the Manchester Mark I (baby or full version). It has a very elegant design and you can get actual work done with it. (Because the Mark I ran a stored program first but was in proto- type stage, I see the EDSAC as the first working modern stored-prgoram computer, followed soon after by the finished Mark I.) And the Initial Orders are STILL one of the most ingenious programs ever. Except I haven't heard anything about an EDSAC recreation, and the 50th anniversary date is coming up! (Is it June 6 1999 or some time in May?) And M. V. Wilkes has remained active in the field, so he might be inclined to do something like this. Is anything planned? If nothing ends up happening, I intend to get an autographed copy of the Wilkes/Wheeler/Gill book. P.S. IMO history shows that British computer designs are often MUCH more sensible than their American contemporaries. They treat the computer as a tool to be used rather than a hunk of hardware with software slapped on later. Too bad history shows that British computer *sales* are LESS successful than their American counterparts. -- Derek

27 years, 10 months

Starting from Scratch (was Re: OT: Modern college educa

by pete＠dunnington.u-net.com

On Oct 23, 20:54, Pete Turnbull wrote: > On Oct 23, 14:04, Ethan Dicks wrote: > > > emulator disk format. I'd post HAMMURABI.BAS, but I suspect that more > > than one person would get annoyed. > > I'm sure I've seen a copy on one of the Vax sites somewhere. I'm fairly > sure I have a copy on one of the hard disks here, too. Somewhere :-) I was right -- I found it, all 118 lines, including comments, along with a pile of other stuff from David Ahl, such as KING.BAS (same idea, but twice as big). Who remembers this one: 1 PRINT "DIRECT YOUR DOG TO ANY OF THE FOLLOWING FILES:" 2 PRINT "KB:--KEYBOARD, LP:--PRINTER, PP:--HIGH SPEED PUNCH" 3 INPUT "WHICH ONE";A$ -- Pete Peter Turnbull Dept. of Computer Science University of York

27 years, 10 months

Starting from Scratch (was Re: OT: Modern college educa

by CLASSICCMP＠trailing-edge.com

>I'm sure I've seen a copy on one of the Vax sites somewhere. It's not "a VAX site", but Hammurabi does appear on the Spring 78 RT-11 SIG tape, and this is available by anonymous ftp from ftp://sunsite.unc.edu/pub/academic/computer-science/history/pdp-11/rt/decus… The top looks like: 100 PRINT "YOU ARE THE RULER OF THE ANCIENT KINGDOM OF SUMERIA." 101 PRINT "YOUR PEOPLE CALL YOU 'HAMURABI THE WISE'. YOUR TASK IS" 102 PRINT "TO DEVELOP A STABLE ECONOMY BY THE WISE MANAGEMENT OF" 103 PRINT "YOUR RESOURCES. YOU WILL BE BESET FROM TIME TO TIME" 104 PRINT "BY NATURAL EVENTS. THE ONLY HELP I CAN GIVE YOU IS THE " 105 PRINT "FACT THAT IT TAKES 2 BUSHELS OF GRAIN AS SEED TO PLANT" 106 PRINT "AN ACRE. MAY YOU JUDGE WELL, ALKNOWING HAMURABI." 107 PRINT "***********HAMURABI IS HERE***********" 110 P=95 (...) > I'm fairly > sure I have a copy on one of the hard disks here, too. Somewhere :-) Heck, I've got my set of 4 8" SSSD floppies straight from Creative Computing with "101 Basic Games" and "More Basic Games". It's fun to fire up the IMSAI, load a game, fix the typos (yes, there are typos in many of the MBASIC sources!), and play a game of blackjack, lunar lander, or Hamurabi! -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology Voice: 301-767-5917 7328 Bradley Blvd Fax: 301-767-5927 Bethesda, MD, USA 20817

27 years, 10 months

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