test-drb April 1999

test-drb@ccmp.vtda.org

170 participants
1190 discussions

What if,... early PCs (was: stepping machanism

by edick＠idcomm.com

Once again, I've concluded it's more efficient to embed my comments in your quoted message. Have a look below, please. Dick -----Original Message----- From: Allison J Parent <allisonp(a)world.std.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Sunday, April 11, 1999 7:25 AM Subject: Re: What if,... early PCs (was: stepping machanism ><You've got two tracks mixed up, I think. True, the Apple II was quite ><plentiful in 80, but not in businesses the way it was in 82-83. I even ha ><several of them with people to man them as well. I hated the Apple but ><loved the 6502. In the meantime, I noted that the RS Model 1 was a piece o ><junk, and, in fact, so much of one that I never bought one, even for ><experimentation, and I had nearly every other sort of box around the shop. > >OK, maybe where you were that was true. However despite the TRS80s >shortfalls (most corrected with mods or outside hardware) I knew of >businesses using them, and I may add same for the apple II. > ><The model 1 was quite common, but the model 1 was in too many pieces to be ><of much interest to most folks. What's more, it was pretty weak-kneed. Th ><model 3 held out hope, though that was later dashed when the model 3 turne ><out to be not much better. > >My slant was the M1 was close but people wanted something more "one box". >The M3 was never more than a blip on the screen because when it hit the >streets there were plenty more choices and all of them deemed (if only >subjectively) better. The principal complaint I heard about the M1 was the principal complaint about the M3. It was a paper tiger until you opened the box and added a bunch of stuff/mods. The same, to lesser extent, perhaps, could be said for the Apple. The Apple was made easy-to-open. The RS boxes were not. >In the business worlds in NY and eastern PA S100 crates were the rule as >most were seen as the business strength machines and the apple/trs80 >as toys. This was by people that didn't care what cpu only that it ran! > ><The initial impact of the PC was to get people to stop buying non-PC's for ><their businesses. They were extremely costly at first, and didn't have a ><few serious problems worked out. People had to mortgage their houses to bu ><one (a basic PC on the gray-market cost nearly $2k). > >Not really. If you were invested in apple then PC was a non-player as >nothing was compatable and you lost your investement going over. For the >z80 crowd (TRS and S100 crates) that was slightly less a concern but >PCs needed to get up to speed with applications first. Keep in mind when >the PC was introduced the only 8086 stuff out there was ISIS based >and mostly as development tools. It was the spread sheets and graphic >programs that caused the great sucking sound of people going PC but, that >would take more time than your indicating. When I saw my first PC in a commercial environment, it was running CP/M-86 because that had the software the business owner was using previously on his Z-80. I often wondered what motivated him to switch. I also saw a couple of people's Apple-II running CP/M-86, and was awed by the fact they'd run an OS that was slower than the previous and better-endowed (with software) CP/M-80 in the same basic environment. >Yes, I remember getting a bonus check becuase of the PC in 82. IT wasn't >for implementing as a useful system it was for FIXing the design. Seems >one of the design bugs was it would only run intel chipsets. IBM really performed only one major service to the microcomputer world: They lent it its own trade name, which was its legitimacy. Having done that, the behemoth was overrun by smaller, more adept innovators. >As to the cost of a PC... equipped as a useful machine that could run >production it was far from $2k! > >Allison >

26 years

Restoring an 8/E

by mbg＠world.std.com

>Thanks Megan! The are great pictures. Thanks... >Can I confirm a couple of things? >That the vents in the cover are offset from the fans in the PSU? so it >goes: ><begin fixed width font> > ----------------- > | + > | + <- cover vents > | + | > + | | > + <- PSU fans | | > + | | > | + | > | + <--+ > | + > ----------------- ><end fixed width font> I can't really tell... I'm not near the machine right now... and the picture is not good enough to figure that out. >And does the cover have a lip over the PSU with holes in the side to >screw into the PSU? I had a hard time seeing the plastic catches that >were discussed here on the list. The cover does have a lip on the PSU side of the case. There are no screw holes, just the latches. On mine, the latches (which are plastic) seem to have been broken off, so that's probably why you don't see them. They're black on black in a lossy photo, so easy to miss... Megan Gentry Former RT-11 Developer +--------------------------------+-------------------------------------+ | Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com | | Unix Support Engineering Group | (home): mbg!world.std.com | | Compaq Computer Corporation | addresses need '@' in place of '!' | | 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ | | Nashua, NH 03062 | "pdp-11 programmer - some assembler | | (603) 884 1055 | required." - mbg | +--------------------------------+-------------------------------------+

26 years

Micropolis 1518/1538 (24MHz) drive problems

by jpero＠cgocable.net

Wait everybody! I have the same old thing that is on that website and these drives that info is based on assumes it's "stock" setup for standard 512byte in peecees applications or like that is compatiable with this settings. I suspected that both drives I have here might be set for specific applications used in nonstandard machines for example RT. I knew of this facts some drives get special mods or special jumper settings. Those are what I need to confirm that my drives are set up properly. This info I'm searching for are not found on the 'net with basic search engines like looksmart.com, go2net.com etc. Wizard

26 years

What if,... early PCs (was: stepping machanism

by edick＠idcomm.com

I agree with your comment about the IBM's. The first PC-clone I bought was an XT based on an 80186. By comparison with other available XT-class machines, it was EXTREMELY fast. It was, in fact, quicker than the initial AT-class IBM's, as it ran at 12 MHz. The '186 and '286 had the same execution unit, hence the same code would run in the same time, if the clocks were at the same speed. The '286 got the fancy MMU, however, while the '186 got the built-in peripherals, which the boot firmware had to relocated out of the way first off. Dick -----Original Message----- From: Allison J Parent <allisonp(a)world.std.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Sunday, April 11, 1999 12:45 PM Subject: Re: What if,... early PCs (was: stepping machanism ><The principal complaint I heard about the M1 was the principal complaint ><about the M3. It was a paper tiger until you opened the box and added a ><bunch of stuff/mods. The same, to lesser extent, perhaps, could be said fo ><the Apple. The Apple was made easy-to-open. The RS boxes were not. > >RS didn't want people opening the box. Since there really wasn't a bus on >it internally to hook up to there was little reason besides the internal >hacks (lowercase, speed ups, control ^key, and tape fixes.). The real >problem is the V1 EI was a total dissaster. Obviously the designer new >nothing about the timing and skew constraints for Dram. the later V2 EI >was far better. > >The other thing was apple sorta supported adding boards to increase >functionality or performance. They were amoung the first to have the >essence of plug and play. That was a very good thing. > ><When I saw my first PC in a commercial environment, it was running CP/M-86 ><because that had the software the business owner was using previously on hi ><Z-80. I often wondered what motivated him to switch. I also saw a couple ><of people's Apple-II running CP/M-86, and was awed by the fact they'd run a ><OS that was slower than the previous and better-endowed (with software) ><CP/M-80 in the same basic environment. > >it wasn't an operating system thing it was programs like databases (DBASE) >and spreadsheets (multiplan and VISICALC) what were the killer apps for >business and they ate RAM big time. The z80 could have banked ram, some >did but there never got to be a concenses on how to do it and support it at >the OS level and then the 16bit cpus wer hyped to solve that "64k barrier". > ><IBM really performed only one major service to the microcomputer world: ><They lent it its own trade name, which was its legitimacy. Having done ><that, the behemoth was overrun by smaller, more adept innovators. > >Absolutly. The Compupro and other 8086 S100 systems were far faster and >could run many more OSs and apps. One outfit held off from PCs until >1993 when it was a leap to 386s. The leap also was from older DBASE to >the then hotter Paradox. Sometimes software drives hardware. > > >Allison >

26 years

What if,... early PCs (was: stepping machanism

by allisonp＠world.std.com

<The principal complaint I heard about the M1 was the principal complaint <about the M3. It was a paper tiger until you opened the box and added a <bunch of stuff/mods. The same, to lesser extent, perhaps, could be said fo <the Apple. The Apple was made easy-to-open. The RS boxes were not. RS didn't want people opening the box. Since there really wasn't a bus on it internally to hook up to there was little reason besides the internal hacks (lowercase, speed ups, control ^key, and tape fixes.). The real problem is the V1 EI was a total dissaster. Obviously the designer new nothing about the timing and skew constraints for Dram. the later V2 EI was far better. The other thing was apple sorta supported adding boards to increase functionality or performance. They were amoung the first to have the essence of plug and play. That was a very good thing. <When I saw my first PC in a commercial environment, it was running CP/M-86 <because that had the software the business owner was using previously on hi <Z-80. I often wondered what motivated him to switch. I also saw a couple <of people's Apple-II running CP/M-86, and was awed by the fact they'd run a <OS that was slower than the previous and better-endowed (with software) <CP/M-80 in the same basic environment. it wasn't an operating system thing it was programs like databases (DBASE) and spreadsheets (multiplan and VISICALC) what were the killer apps for business and they ate RAM big time. The z80 could have banked ram, some did but there never got to be a concenses on how to do it and support it at the OS level and then the 16bit cpus wer hyped to solve that "64k barrier". <IBM really performed only one major service to the microcomputer world: <They lent it its own trade name, which was its legitimacy. Having done <that, the behemoth was overrun by smaller, more adept innovators. Absolutly. The Compupro and other 8086 S100 systems were far faster and could run many more OSs and apps. One outfit held off from PCs until 1993 when it was a leap to 386s. The leap also was from older DBASE to the then hotter Paradox. Sometimes software drives hardware. Allison

26 years

stepping machanism of Apple Disk ][ drive (was Re: Heatkit 51/4 floppies)

by allisonp＠world.std.com

<Z-80, which was enjoying almost universal acceptance as the most widely <applicable and easiest-to-use microprocessor available. Most of the popula I could argue it was or it wasnt. ;) Keep in mind at that time I was doing 8048, 8085, z80, 1802, 6100, sc/mp, TI9900, LSI-11, some 6502 and 6800. That does not include the uCOM4 (NEC 4bit) and uCOM75 (cmos high end 4bit) parts. <statements about it were pretty much on the money. Of course, the evolutio <of the 64K DRAM made its refresh counter more or less useless, but the Only some as a goodly portion still had 128 address row refresh (NEC4164 and About four others). But 64kDrams were really a year out due to price in late 79 being rather high. (then design cycles for new products wer 9-18 months too). <the Apple to accomplish the same thing. Meanwhile, Motorola was making a <BIG mistake, abandoning the amateur and "small" users. Yes! The 6800 if you had the 25$ big book you were an expert if you could read. Later parts did come so cheaply supported. <Since the evolution of the now-popular 'C' and PASCAL compilers for the <8051-core micro's, I believe the popularity of this 25-year-old model has <actually increased. The HLL's and the development of high-speed versions o Yes it has but the code it not as dense as hand written. Then again with the availability of LARGE ROMs/EPROM/EEPROM it may be development timeover code density. <'51-core user. I believe that it's as a consequence of that, that there ar <now compilers for several truly "ugly" architectures, e.g. the PIC/SCENIX Yes they were never a favorite for me but then again I could program them as they looked like the 4bitters I used to work with. <class of processors. There are also VHDL and VERILOG cores for several of <the older architectures, e.g. 650x, available for those who prefer to <"roll-their-own" which are also, though less well, supported with compiler <and other tools. If your need embedded 8051, 6502 and z80 are good choices. <Again, Motorola seems to have been left behind at least with their smaller <MCU's. I guess that's because of their reputation for spurning application <which consume fewer than 100K parts per week. Yep, seen that before. Now the worst thing I've seen was the 8086/8 and its heirs. I really hated writing code for it. The segmentation scheme was one horrid hack. Allison

26 years

stepping machanism of Apple Disk ][ drive (was Re: Heatkit 51/4 floppies)

by allisonp＠world.std.com

<> The point was apparently missed. Of course I can take a cmos z80 and <blow <> that out of the water using a 6 or 8 mhz clock. < <But because of the way the phases are used, a 2MHz 6502/65C02 is running a <roughly the same rate (for comparable operations) as a 4MHz Z80. Yes, the 6502 overlaps the instuction fetch and execute (mini pipeline). The z80 is more classic multi-state machine. In the end the two parts are roughly the same speed for their generation. IE: a 4mhz z80 does basic operations in 1uS and 6502 at 2mhz is about the same. the difference is any is when complex indexing or other tassks are discussed where the z80 has a better instuction set (though slower...more states) the 6502 uses more small instructions(fast but many). In the end they do the same task just different. That supports the only logical conclusion... clock speeds dont count. The full measure is instruction execution time. Which is why I used the PDP-8 example as that machine used 1.4uS core yet it had a fairly high effective speed. Now to extend this to other older cpus there are some out there that were just plain slow or due to their instruction set so awkward as to end up being slow. Allison

26 years

Parting out PDP-8a

by mbg＠world.std.com

>I would also like to lay my hands on a programmer's console. It's one of >the only things (besides hex-high core) that I'm missing. Same here... the 8/A I recently got seems pretty fully loaded (I haven't yet itemized what's in it), but the one thing it doesn't have, and that I really really want is a programmer's console for it... Megan Gentry Former RT-11 Developer +--------------------------------+-------------------------------------+ | Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com | | Unix Support Engineering Group | (home): mbg!world.std.com | | Compaq Computer Corporation | addresses need '@' in place of '!' | | 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ | | Nashua, NH 03062 | "pdp-11 programmer - some assembler | | (603) 884 1055 | required." - mbg | +--------------------------------+-------------------------------------+

26 years

Parting out PDP-8a

by ethan_dicks＠yahoo.com

--- jeff.kaneko(a)juno.com wrote: > Guys: > > I have discovered a PDP-8a in a scrapyard near my workplace. > It has been outside for awhile; but if there are any salvable > parts there, would anyone be interested? But of course. > BTW-- How do I get the front panel off without breaking > anything? Depending on the front panel style, if you see two 1/4" holes, one on either edge, it may take an allen wrench. If the panel has no apparent tool access, it's probably held in place by a pair of ball and socket joints on each side which can get extremely tight if pressed on too hard and left to sit. There are times when I think I'm about to bust the balls right off the backplace, and sometimes I'm right. :-( What's inside? What are you offering? At this point, I could even use a new chassis as I have a full set of a mix of verified working and untested boards (128kW MOS, RL8A, etc). I'm sure that the memory and disk I/O work; I am not certain that my spare DKC8AA is any good. ISTR that about 10 years ago I pulled it and set it aside for acting up. I would also like to lay my hands on a programmer's console. It's one of the only things (besides hex-high core) that I'm missing. -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

26 years

PDP-8/E PSU Debugging (was Q-bus pinout)

by CLASSICCMP＠trailing-edge.com

>>> There should be >>>some plastic catches (or more likely the remains of same) on the PSU. > >>I've found that most half-inch tape seals have latches which are >>quite amenable to being used as replacements for the original plastic >>catches :-). >Tim, >I think I'm going to have to plead ignorant here. What are "half-inch tape >seals"? You know those 2400-foot, 600-foot, and other lengths of half-inch tape that are used in 7-track and 9-track drives? The reels are commonly enclosed in plastic straps with latches; the strap with the latch is the "tape seal". I think "Tape Seal" may actually be a trademark of Wright Line. The latch part usually has a plastic hook extending >from it that you can hang the tape up by on a Wright Line tape stand or cabinet. There are non-Wright-Line tape seals with very different plastic designs that serve the same general purpose, but are specifically designed for auto-loading tape drives. These seem to be more common in IBM shops. -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

26 years

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test-drb April 1999