test-drb

test-drb@ccmp.vtda.org

101090 discussions

homemade computer for fun and experience...

by edick＠idcomm.com

You're right on the money, here. It depends almost entirely on what your goals are or may be. ( Perhaps, like many of us, you don't know, exactly, what your goal(s) at any given time might be.) I try to fool myself into thinking that I do things involving computers and circuits to enhance/extemd my ability to earn a living. Maybe that's true. However, using a task like implementing a current strategy or algorithm on an old piece of hardware tends to extend one's thinking, which is also of benefit to one's ability to earn a living. If I had the task of building a homebrew computer, I could probably fit the whole thing on a single or maybe dual-width VME card. That's not much more area than an S-100 board if you leave out the regulators. The way this would have to come about, is that I'd build a processor<=>memory interface and an interface to a bridge controller for mass storage. If the processor didn't have I/O on board, which most of the ones in which I have interest relating to building a system from scratch do, then a single high-speed link to a system which had conventional resources would come next. Over time, I'd migrate the mass storage interfaces into my computer and leave out the bridge adapter. Likewise the external comm link(S). After that, it's anyone's guess. It depends on what goal(s) I am chasing at the time. 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 04, 1999 5:26 PM Subject: Re: homemade computer for fun and experience... ><I'd thought of that, but if you're not careful, your 'homebrew computer' ><contains ready-built I/O cards only. That's no so educational as building ><them yourself. > >Depends on what your goals are. For me building yet another serial or disk >card is tedious and repetition. I'd rather experiment with advaced software >on old style but enhanced platforms. > ><Sure. But the IIRC, this thread started with somebody wanting to make ><their first homebrew machine. IMHO, this should be a fairly simple ><machine - say a Z80 + maximum of 64K memory. Adding lots more memory, ><MMU, etc can come later. The first machine should be something that is ><likely to work first time. > >No arguement. As a first pass machine static is usually the least painful >to deal with as are simple serial IO. The usual first time builder wants >more than their skills can generally support. > >Allison >

26 years, 8 months

homemade computer for fun and experience...

by edick＠idcomm.com

Well, I'm inclined to agree with you. I've long felt that if one needed to spend time playing games, what was really needed was another job. What's happened over the years, however, is that people, having seen what a computer CAN do as shown in games, etc, have actually found ways to make data easier to interpret, and perhaps to add meaning and emphasis to a presentation, making it more persuasive, if not more informative, by using the graphical capabilities of a computer. As for the terminal vis-a-vie the color graphic display, I find the terminal quite limiting. However, most of the stuff I do is unaffected by these limitations. It's just the drafting work that would be limited, and perhaps the interpretation of the results from the various simulators I use. However, since I've got a farly hot system with which to do the drafting, the CP/M box doesn't really need graphics, does it? If you use a terminal, that's what you've got. There were, for a time, attempts made at graphic terminals. These failed, however, because there weren't standards on which they could base their usage. Consequently, if one didn't have certain hardware, there were limitations on the software he could use. Today, that's not the case, as EVERYONE has a PC clone with at least 1Kx768 pixels in 256 or more colors. EVERYONE has fairly ample resources, comparable, perhaps, to the sum of all the computer resources in the world when I went to college. Today, no one would normally consider a CP/M box for "useful" and essential work. For mental masturbation, speculation about would could, would, or should (note the subjunctive) have been, CP/M works just fine. If you have a construction business, or a medical office, there's no reason why CP/M can't work today every bit as well as it did back 20 or more years ago. However, aside from the notion of operating on an "antique" there's no reason to do so. It does serve to keep one grounded in what has changed over the years and what hasn't. Dick -----Original Message----- From: CLASSICCMP(a)trailing-edge.com <CLASSICCMP(a)trailing-edge.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Sunday, April 04, 1999 12:58 PM Subject: Re: homemade computer for fun and experience... >><ISA cards on a single s-100 board. This would certainly be cheap enough i >><most cases, to warrant such an effort. The software might get to be a >><problem, though. > >>Yes, and therein lies the "problem" for the average user. > >This is why I prefer simple serial console. No software to write, >no memory mapped video to take a chunk out of usable memory, no >memory banking schemes, no dependence on finding monitors of a >particular scan rate or interface. Just a simple I/O port! > >Admittedly, many folks seem to believe that a computer must have >a video generator to be a "computer". My CP/M experience started with >Model 33 Teletypes and blinkenlights front panels, so perhaps I'm the odd man >out here. > >-- > 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, 8 months

homemade computer for fun and experience...

by edick＠idcomm.com

Keep in mind, folks, that some of us remember when there simply weren't computers which we could use. Back when I was a boy, even the US GOV couldn't afford a computer capable of what my smallest simplest Windows9x system is capable. The fact that I don't use it for pure number-crunching is a recognition that there are other things equally deserving of the benefits of advancing technology. If a picture is worth a thousand words, then why type them if it's easier to draw the graphic representation. Moreover, if you have to read my 1000 words (about a page) and then draw yourself a graphic representation to understand and digest it anyway, why not stick to the graphic? A simple graphic can save both ends of a communication time, effort, and embarassment from when there's a miscommunication. If you tend to use your hands when you're explaining something, you probably know what I mean. Dick -----Original Message----- From: jpero(a)cgocable.net <jpero(a)cgocable.net> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Sunday, April 04, 1999 5:03 PM Subject: Re: homemade computer for fun and experience... >Date sent: Sun, 4 Apr 1999 16:23:49 -0600 >Send reply to: classiccmp(a)u.washington.edu >From: "Richard Erlacher" <edick(a)idcomm.com> >To: "Discussion re-collecting of classic computers" <classiccmp(a)u.washington.edu> >Subject: Re: homemade computer for fun and experience... >Originally to: <classiccmp(a)u.washington.edu> > >> Well, I'm inclined to agree with you. I've long felt that if one needed >> to spend time playing games, what was really needed was another job. >> >> What's happened over the years, however, is that people, having seen what >> a computer CAN do as shown in games, etc, have actually found ways to make >> data easier to interpret, and perhaps to add meaning and emphasis to a >> presentation, making it more persuasive, if not more informative, by using >> the graphical capabilities of a computer. > >Beauiful point and to point that out, we're still doing it even way >back from stone and clubs days. Graphics on any media is easier >to understand than stackful of numbers and words even spoken! >Even when I was in elementery and HS school we generate >numbers and words into graphics respentions or vice vesa. That >was in CP/M to 386 days but didn't use computers. > >> >> As for the terminal vis-a-vie the color graphic display, I find the >> terminal quite limiting. However, most of the stuff I do is unaffected by > >Terminal is out because one would have to code so much that you >really made another i/o out of software. I'm at that mental stage >now. Better start in hardware then put bit of homebrew s/w in to >get started. > >> Today, no one would normally consider a CP/M box for "useful" and >> essential work. For mental masturbation, speculation about would could, >> would, or should (note the subjunctive) have been, CP/M works just fine. >> If you have a construction business, or a medical office, there's no >> reason why CP/M can't work today every bit as well as it did back 20 or >> more years ago. However, aside from the notion of operating on an >> "antique" there's no reason to do so. It does serve to keep one grounded >> in what has changed over the years and what hasn't. > >We're still writing characters/numbers and users are using so >powerful computers *because* it's easier for them to see in >graphics form and graphics items to operate at or in to get basic >functions done besides writing and putting numbers in. That eat up >more power just to do that. Crunching numbers and doing massive >moves in graphics, is one thing I accept. And, decent windowing >that does quickly and low on resources requirements does get job >done bit easier that about it as I know so far. > >> Dick >> >Wizard

26 years, 8 months

Lisp, the machine language. Was Re: Hallelujah!

by allisonp＠world.std.com

<Yes, although you could consider "P-code" to be a lower level. It is lower level. <> But why would anyone want something that was microcoded to run Pascal? < <Speed mostly, that and ease of use with compilers. P-code is not Pascal. It's a platform that all Pascal P-compilers grind code to. Speed wise it was slow as the Pcode was interpreted on all but the WD Pascal microengine. Why was it done? In the late 70s Pascal was emerging as a teaching language and it was highly standardized. Most small systems had the resources to run it as native compiled but the authors (UCSD) decided that portable Pcode would allow more platforms to run it as the Pengine was easier to code than a whole compiler. The additional part was the P-system was an integrated system with all the tools (all written in pascal) for editing, compiling and running programs. It was a good teaching environment as it isolated the user form the machine very well. the entire environment was menu driven and integrated. I have a NS* that runs the z80 version. Allison

26 years, 8 months

bringing up an 8f...

by allisonp＠world.std.com

<trouble with it also, but can peal it apart. So basically you're stuck <having to read it using Windows, which quite bluntly strikes me as stupid, I have winders and the problem is I have to buy the dang viewer...Not me. Fortunately having worked with 741, 744 and 7441 power supply and regulators this (740) is not too strange for me. Allison

26 years, 8 months

bringing up an 8f...

by allisonp＠world.std.com

<> OH, "SROCTH" is Some Rare Old Computer To Hack. < <I can name a number of people here who easily have enough clues to keep Clearly I'm not refering to them. <I am, however, a little worried with what happens to some of the machines <sold on E-bay. I suspect that some of them go to people who want them but <haven't a clue how to look after them. That is the exact audience I refer to. <Ouch!. It's bad enough when a fault causes melted PCB traces (Some SMPSUs <suffer from this). This was abuser installed. I've cleaned it up a lot. The current bug fixed in the PS was the chopper shorted and then fried the SCR used for crowbar. We are up again. Now back to the stuck bit. Allison

26 years, 8 months

homemade computer for fun and experience...

by allisonp＠world.std.com

<Admittedly, many folks seem to believe that a computer must have <a video generator to be a "computer". Retrorevisionist PCism. Though a VC8E is a definate computer thing. < My CP/M experience started with <Model 33 Teletypes and blinkenlights front panels, so perhaps I'm the odd m <out here. Same here. It's seems silly for me to recreate the logic and programming of my vt100 when I have a vt100 that works better than any I could put together. There is advantages to useing a PC keyboard and monitor as they already take space on my desk but then again I can provide a serial port and use the PC for a terminal. Allison

26 years, 8 months

homemade computer for fun and experience...

by allisonp＠world.std.com

<>Been there and done that. <>Also, there are no less than two articles on how to go from s100 to ISA. <> <There's a substantial reach from an article to a solid and working circuit <on a board capable of actually supporting the functions. This is The articles actually are descriptions of circuits that do work. <particularly true since, now, the user is required to understand the inner <workings of his own machine as well as those of the card he wishes to use. <Having the usual inkling about ISA is not always sufficient. That was true then. Unlike PCs with plug and pray configuring a s100 system meant you generally had knowledge and documentation or were plain crazy. <><ISA cards on a single s-100 board. This would certainly be cheap enough <><most cases, to warrant such an effort. The software might get to be a <><problem, though. < <Yes, and therein lies the "problem" for the average user. define average user... today that's mom and pop that buy a PC and plug it in. Definatly not the case in 1980. The reality of older computers like the S100, SS50, Multibus types were you had to be a knowledgeable user. Or if that was a problem you went to Apple or TRS80 styled machine where the hardware was generally a fixed and software was the experimental arena. Allison

26 years, 8 months

Lisp, the machine language. Was Re: Hallelujah!

by allisonp＠world.std.com

<C-machines (and I wouldn't class Unix as being one, although Unix would <ran rather well _on_ one) have existed as well. They're machines where <the instruction set is optimised for running C (so things like pointer <indirection, particular loop structures, etc are machine <instructions/operations). the PDP-11 instruction set was the near ideal C machine due to it's available addressing modes. Allison

26 years, 8 months

homemade computer for fun and experience...

by allisonp＠world.std.com

<I'd thought of that, but if you're not careful, your 'homebrew computer' <contains ready-built I/O cards only. That's no so educational as building <them yourself. Depends on what your goals are. For me building yet another serial or disk card is tedious and repetition. I'd rather experiment with advaced software on old style but enhanced platforms. <Sure. But the IIRC, this thread started with somebody wanting to make <their first homebrew machine. IMHO, this should be a fairly simple <machine - say a Z80 + maximum of 64K memory. Adding lots more memory, <MMU, etc can come later. The first machine should be something that is <likely to work first time. No arguement. As a first pass machine static is usually the least painful to deal with as are simple serial IO. The usual first time builder wants more than their skills can generally support. Allison

26 years, 8 months

Lisp, the machine language. Was Re: Hallelujah!

by hhacker＠home.com

>On Sun, 4 Apr 1999, Buck Savage wrote: >>not stored in RAM. Instead, they are stored in ROM. > >AFAIK, they are hard-coded into the CPU (except for PERQ and the like >where they can be altered). ROM conjures up images of little socketed >chips on the motherboard. > >--Max Eskin (max82(a)surfree.com) > Consider the PDP 11/44 in my living room. It is constructed using the AMD 2900 series of bit-slice microprocessor chips. In this case, the microcode is, in fact, stored in ROM chips, each of which is socketed to the motherboard. For some other types of processors, sure, the CPU real estate does carry the code but, the part of the chip that holds the code is ROM. William R. Buckley

26 years, 8 months

Several things

by mark_k＠iname.com

Hi, Several different subjects in one message... Sony 650MB 5.25" MO drive ------------------------- I posted about this drive a couple of week ago. At the time, I thought one of the firmware EPROMs was faulty. (It wasn't. I have backed up all four EPROMs in the drive.) It turned out that the drive lens needed cleaning. Not having a 5.25" head cleaning disk -- these are expensive, I think IBM wants over 50 pounds for one -- I had to disassemble the drive, removing both circuit boards to reveal the lens. After cleaning with a cotton wool bud & isopropyl alcohol and putting the drive back together, it miraculously worked! The surfaces of all the disks were quite dirty. I believe the drive was used in the City of London, and years of pollution left a residue on the surfaces. I don't have a 5.25" MO disk cleaning kit, but luckily it's quite simple to clean 5.25" disks by hand. Briefly, I did this: - wear plastic gloves to avoid getting oil from skin on surface - breath on disk surface and wipe radially with a folded-up kitchen towel - rotate the disk using finger (there is space to do this between the outside of the disc and the casing) and repeat the breath & wipe until the entire surface is cleaned - do the same for the other side Things I learned: - Old MO drives and disks are sometimes available very cheaply, so it's worth looking out for them. - Cleaning the drive lens and disk surfaces can bring performance back to as- new. Dirt impairing performance might be a common reason why a company would get rid of old drives. - You don't need an expensive cleaning kit to clean 5.25" disks. If you're adventurous, you can clean the drive lens without needing to buy a special disk. - The old drives are much slower than modern ones. Performance is about equivalent to a 4.5x CD-ROM drive for reading, with average seek time of 95ms (some modern drives are 20-25ms). If anyone in the UK wants to get rid of an old 5.25" MO drive, especially a 1.3GB unit, please let me know. I'd like to have a backup unit in case my drive breaks down. EPROMs ------ My experience with one of the firmware EPROMs (made by TI) in the Sony drive showed that "not all EPROMs are the same", which is news to me at least. Data in most EPROMs can be dumped by doing this: - drive /OE low - set up address lines - read value on data bus However the TI EPROM didn't like that; doing it that way, even reading multiple times and ANDing the results, gave errors. After changing my program to set up the address lines before driving /OE low, everything went okay. Now I need to re-dump the various EPROMs from other things that I thought were bad. Hopefully at least some will be okay. C= PET VisiCalc EPROM --------------------- The Commodore PET version of the VisiCalc spreadsheet came with a chip that plugged into a socket on the main board. This was probably an EPROM, used for copy-protection. I have an original VisiCalc package, minus this EPROM. Does anyone know where I can download an image of the EPROM from? Nutspinner ---------- Disassembling PCB-mounting D-type connectors is a pain without having a nutspinner for the hexagonal bolt things which typically fix the connector to a panel. What size, number or whatever nutspinner is the right one for this purpose? IBM 3363 WORM drive ------------------- Along with the Sony MO drive, I picked up an IBM model 3363 WORM drive (IBM part number 63X4146). This was made in 1987. The original product announcement can be read on the IBM web site. It uses write-once disks which store about 200MB. Luckily it came with twelve such disks, four of which are still in their wrapping. Anyway, the drive uses some kind of custom interface. It connects to a special ISA or MCA card via a cable with 37-way D connectors at each end. The drive came with two MCA cards, part number 63X4266. I have been unable to test the drive or cards, since I don't have an MCA machine. Does anyone know what the part number of the ISA controller for the 3363 drive was? And where I might get one (cheaply)? The MCA controllers have a firmware (EP)ROM on. One uses a 27C64 EPROM, which I was able to backup without (many) problems. The other uses what I presume is a mask ROM, MN2364DSP; this is made by Matsushita. I can't seem to dump this properly, so its pinout must be somehow different to the 2764 EPROM. Any ideas where I might look to find the pinout for this chip? Regards, -- Mark

26 years, 8 months

RLV11/RL02 ->11/73?

by CLASSICCMP＠trailing-edge.com

>> Generally, a "D" at the front means it's some sort of communications >> option, a "M" means memory, a "K" means CPU, "R" means disk controller, >> a "T" means a tape controller, an "A" means an A/D or D/A converter, >> a "V" means some sort of video-related hardware, and "L" means either >> a line printer or a linear module. I'm sure someone will come up >> with many options that don't quite fit into this scheme :-). >Obvious exceptions without even thinking about it : I don't think they're all obvious exceptions, though some are certainly pushing the definitions to their limits! >DR11-x (parallel interfaces, not really comms) "Yeah but" a very common use of these cards were for interprocessor communications (not necesarily between two -11's.) In any event, a parallel interface is conceptually not much different than a serial one, though certainly by the time you start putting interrupt request and DMA handshaking on the cable you are stretching the boundary of what "comms" is. >KMC11 (soft-microprogrammed version of the DMC11. Not really a processor) DEC felt differently - they really pushed the fact that there was a processor (they call it a "microprocessor", somewhat at odds with the modern interpretation, but it makes historical sense) in there. >KM11 (maintenance card, not a processor) >KW11-x (time clocks, etc) Well, the module designation has to start with some letter, and I think K is more appropriate than anything else here. >KL11 (early version of the DL11, current loop serial at 110 baud) If used as the console interface - as the KL11's usually were - K isn't too inappropriate. >MNCxx (MINC I/O modules, not memory at all) >LPS11 (Lab Peripheral System, not a printer interface) These are, indeed, true exceptions - though I don't think anyone would get too confused and try to use a MINC module in place of memory :-). -- 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, 8 months

homemade computer for fun and experience...

by edick＠idcomm.com

OOPS! I thought you were referring to the ubiquitous "text mode" switch on the back of so many EGA-class monitors, e.g. NEC Multisync-I, of which I've pressed several into service for Win95 with VGA cards. These use analog inputs and really aren't much different from VGA monitors, with the exception of their default horizontal sweep rate. Dick -----Original Message----- From: Tony Duell <ard(a)p850ug1.demon.co.uk> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Sunday, April 04, 1999 4:09 PM Subject: Re: homemade computer for fun and experience... >> >> You're right. The "text" mode was really not a valid construct for VGA > >Eh? Text mode has nothing really to do with the monitor. It means that a >single character cell on the screen is controlled by 2 bytes of memory. >One contains the character code (Ascii + a lot more characters), the >other contains the attributes (foreground/background colours, etc) > >> valuable. The "hardware" text mode with which I'm familiar is simply a >> color killer, which drives the display into a light green on a dark green > >Text mode can be (and is, on CGA and EGA and probably VGA) a colour mode. > >-tony >

26 years, 8 months

bringing up an 8f...

by mbg＠world.std.com

>Things must be dry before power up or electrolisys and other bad things >happen. Pure water is generally harmless. In what way harmless? Even 'pure' water has ions... (or so I've learned in chem class) >Soap, I used one of the standard products that seems to work well on >glasses. You mean something with a surfactant? 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, 8 months

Lisp, the machine language. Was Re: Hallelujah!

by hhacker＠home.com

>> "Buck Savage" <hhacker(a)home.com> wrote: >> > Actually, microcode is not compiled. >> >> All the microcode I've ever written was compiled. Of course, it was >> compiled from special source languages defined for that explicit purpose. >> No one with any sense would write a non-trivial amount of microcode any >> other way. > >All the microcode I've ever written (or seen) was written in a special >_assembly_ language. Or at least I'd class it as that as (a) one 'line' >of microcode corresponded to one microinstruction and (b) the language >statements were pretty close to the hardware definition. > >Here's a PERQ microinstruction : > >R0:=R0+R1, if neq goto(loop); > >The first 'phrase' defines the contents of >X and Y fields (select particular registers) >AMUX, BMUX fields (gate registers to ALU inputs, rather than, say gating >a constant there) >ALU field (do an addition operation) >W field (we want to write it back to a register and not just set the flags) > >The second phrase sets the >Condition field (to select the 'not equal' condition) >Jump field (to do a got and not just a next instruction, say) >SF and Z fields (to define the jump address). > >So the actual machine instruction is pretty close to the higher level >version. OK, some fields (Z in particular) can be set by several >different types of phrase, as the Z field is used for jump addresses and >IO addresses and shifter control and constants and... Yes the assembler >moans if you try to set it in 2 different ways in the same instruction. > >-tony > This is my experience as well. HP 21MX microcode is very similar. I will dig up some examples and post it at a later time. Thanks, Tony, for the examples and the clarification. William R. Buckley

26 years, 8 months

Lisp, the machine language. Was Re: Hallelujah!

by hhacker＠home.com

>On Sun, 4 Apr 1999, Chuck McManis wrote: > >>They are micro-coded to run LISP, sorta like the WD P-Engine machines run >>PASCAL. > >So, an assembly language program for them would look like lisp, as opposed >to MOVs, ADDs, and so forth? And same with Pascal? But why would anyone >want something that was microcoded to run Pascal? Are there any other >languages that have gotten microcoded into a processor? > > --Max Eskin (max82(a)surfree.com) > The value of a high-level language capable machine is that the code can run without the need to invoke language translation. In such cases, the hardware becomes a language interpreter, with the speed of processing dramatically increased. For a well designed system, the speed of processing is actually greater for a Lisp program running on a Lisp machine than it would be for the same Lisp program to run on a non-Lisp machine CISC or RISC processor. William R. Buckley

26 years, 8 months

homemade computer for fun and experience...

by edick＠idcomm.com

You're right. The "text" mode was really not a valid construct for VGA monitors. Many EGA monitors would work just as well as VGA's, which, I guess is a testament to the not so unusual notion that people charge less for a product even though they've spend extra resources to make it less valuable. The "hardware" text mode with which I'm familiar is simply a color killer, which drives the display into a light green on a dark green background. It didn't do anything to the sync. Monitors which work with VGA should be fine. What's required in order to make the VGA look like monochrome, is either to drive all the colors equally or to drive only the green video. It would be much simpler to allow the use of an S-100 adapter to use his old monochrome monitor with either a mono or a Hercules, or whatever other card he desires. His software will have to deal with it anyway, and the hardware for mapping it isn't too complicated to support on an adapter card. Dick -----Original Message----- From: Tony Duell <ard(a)p850ug1.demon.co.uk> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Sunday, April 04, 1999 12:13 PM Subject: Re: homemade computer for fun and experience... >> Fire). One of those little switch boxes would serve just fine. The 8.0 MHz >> Z80 wouldn't be sufficient to drive a VGA, so no need for anything fancy. > >Hmm... Don't VGA cards still have a hardware text mode? That's all you >really need for the Z80 machine, and using it wouldn't be any worse than >using an MDA or CGA card, once it's initialised. > >Of course that means you need to get a VGA card based on a documented >chipset so you do know what to stick in all the registers. The on-board >BIOS is going to be no use at all. > >I've seen a VGA card in a 4.77MHz 8088 machine, and it was usable for >text and point-plotting type graphics. I think a Z80 could manage that as >well. Of course you'd probably need some kind of paging hardware to map >all the VGA's memory space into the Z80 memory map. > >The advantage of using a VGA card is that most people have a VGA monitor >on their desk anyway... > >-tony >

26 years, 8 months

FA: ZWS-0200-97 pair and ZWS-0300-04 Units "SupersPORT" portables on eBay

by rhblake＠bigfoot.com

Not sure if anyone may be interested but I have just posted these two ZDS machines to eBay as well as a GridCase2 (see the other auctions link)

26 years, 8 months

Apple stuff....

by roblwill＠usaor.net

Will do. -- -Jason Willgruber (roblwill(a)usaor.net) ICQ#: 1730318 <http://members.tripod.com/general_1> -----Original Message----- From: Mike Ford <mikeford(a)netwiz.net> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Sunday, April 04, 1999 3:15 AM Subject: Re: Apple stuff.... > >I bought a box full of Apple etc. cables recently, wait a couple days and I >will sort out what I have and put it on my web page. > >http://www.netwiz.net/~mikeford/MacList.html > > >

26 years, 8 months

Several things

by CLASSICCMP＠trailing-edge.com

>C= PET VisiCalc EPROM >--------------------- >The Commodore PET version of the VisiCalc spreadsheet came with a chip that >plugged into a socket on the main board. This was probably an EPROM, used for >copy-protection. I have an original VisiCalc package, minus this EPROM. Does >anyone know where I can download an image of the EPROM from? I'd be interested to know exactly what this chip did. It was never perfectly clear to me that it was used for copy-protection. >Nutspinner >---------- >Disassembling PCB-mounting D-type connectors is a pain without having a >nutspinner for the hexagonal bolt things which typically fix the connector to >a panel. What size, number or whatever nutspinner is the right one for this >purpose? 3/16 inch. -- 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, 8 months

Lisp, the machine language. Was Re: Hallelujah!

by allisonp＠world.std.com

<>They are micro-coded to run LISP, sorta like the WD P-Engine machines run <>PASCAL. < <So, an assembly language program for them would look like lisp, as opposed <to MOVs, ADDs, and so forth? And same with Pascal? But why would anyone <want something that was microcoded to run Pascal? Are there any other <languages that have gotten microcoded into a processor? Pascal was never microcoded, the P-interpreter was microcoded on one system. The difference is significant. The P-engine was a theorhetical stack machine that Pascal would optimally compile to. The idea was everything above the P-engine level would be standard code and only the P-engine would ahve to be rewritten for each different processor (which is why it was on PDP-11, Z80, 6502 to name a few). Allison

26 years, 8 months

homemade computer for fun and experience...

by CLASSICCMP＠trailing-edge.com

><ISA cards on a single s-100 board. This would certainly be cheap enough i ><most cases, to warrant such an effort. The software might get to be a ><problem, though. >Yes, and therein lies the "problem" for the average user. This is why I prefer simple serial console. No software to write, no memory mapped video to take a chunk out of usable memory, no memory banking schemes, no dependence on finding monitors of a particular scan rate or interface. Just a simple I/O port! Admittedly, many folks seem to believe that a computer must have a video generator to be a "computer". My CP/M experience started with Model 33 Teletypes and blinkenlights front panels, so perhaps I'm the odd man out here. -- 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, 8 months

homemade computer for fun and experience...

by edick＠idcomm.com

please see imbedded comments below. 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 04, 1999 11:47 AM Subject: Re: homemade computer for fun and experience... ><have something concrete in mind, too. If one inserts a wire-wrap 62 pin ><(8-bit ISA) connector into a DIN 41612 right-angle socket, such as what on ><finds on a VME wire-wrap board, but of opposite gender, (remembering that ><once sold S-100 wire-wrap boards with a pattern certainly suitable for thi ><purpose, and VME wire-wrap cards as well) one can, indeed, host two 8-bit > >Been there and done that. >Also, there are no less than two articles on how to go from s100 to ISA. > There's a substantial reach from an article to a solid and working circuit on a board capable of actually supporting the functions. This is particularly true since, now, the user is required to understand the inner workings of his own machine as well as those of the card he wishes to use. Having the usual inkling about ISA is not always sufficient. ><ISA cards on a single s-100 board. This would certainly be cheap enough i ><most cases, to warrant such an effort. The software might get to be a ><problem, though. Yes, and therein lies the "problem" for the average user. >What software problem... since s100 cards tend to be all different anyway >it would be the norm that software would have to be created. > >Allison >

26 years, 8 months

RLV11/RL02 ->11/73?

by allisonp＠world.std.com

<I've done it useing a RLV12 board set though. As far as I know it can't b <done with the RLV11 you have. At least I was given to understand that if <you try you'll let out the magic smoke. I'e done it with both using the correct backplanes. As I remember the SMS1000 is a bit strange in the boot deperatment. <If you're wanting to boot off of RL02's then remember that you'll want to <have something with boot roms that support the drives. The only thing I <have that does is a /23+ My 11/73 boots RL02 (both unix V7 and RT11). Allison

26 years, 8 months

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