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Timex Sinclair ZX81 Back On the Market
Eugene Blanchard writes: "You still have the chance to purchase that Timex Sinclair ZX81 computer. Someone has kept a warehouse full of them. I had a few and thought that they would make a pretty good controller board with the Z80 processor. Now let's see if we can load Linux on them! "
Sinclair had probably the most absurd advertising campaign running in the UK. One advert ran that claimed that the ZX81 could run a nuclear powerstation. Hmm wonder if the Russian ever run a modified ZX81 for their nuclear stations... rampack wobble could have a lot to answer for. Sadder still there were companies advertising strip poker games for the ZX80 & 81, could you image that in block graphics Is it true the rumour that the Spectrum/Timex 1000 used failed chips from McDonnel Douglas Fighter Aircraft ?. ps. Anyone remember playing 3D Monster Maze ? Arguably it was one of the first 3D games, hardly wolfenstein or doom but surely it had to be a defing moment in gaming history.
-- Soruk
My mum queued up in WH Smiths (UK newsagent chain) on the day the ZX81 came out to buy one; ready assembled. I must admit that before I saw this article on Slashdot I was confident that only the earlier white ZX80 was supplied in kit form; but seeing the other posts here, especially those mentioning a ten pounds price difference between assembled and kit, does stir some kind of vague memory.
I sold my ZX81 to buy a hard drive for my Atari ST (having gone through a C=64 on the way). Luckily I was recently given a replacement ZX81 complete with 16k wobblepack which now sits proudly on the black and white TV in my computer room (I'm colour blind so quite handily I already had an ancient UHF B&W telly).
My important question is: can you save ZX81 programs to .AU or .WAV files? Or even MP3s?
--
Andrew Oakley - www.aoakley.com
I also used the memory saving techniques on my Spectrum, when memory was tight. Usually this was when the location of the stack was lowered to allow machine-code instructions to be placed where the stack couldn't smash it. One method of saving memory in basic was to assign a constant used more that 3 times to any unused single-character variable. Made the code utterly unreadable, but saved a few precious bytes.
You must not forget that Taco is one that selected this for posting. The other same submissions that does not include's prolinux statements are filtered out to suit Slashdot's bias.
Guilty.
HOLLY: I was in love once -- a Sinclair ZX-81. People said, "No, Holly, she's not for you." She was cheap, she was stupid and she wouldn't load -- well, not for me, anyway.
LISTER: What are you trying to say, Hol?
HOLLY: What I'm saying, Dave, is that it's better to have loved and to have lost than to listen to an album by Olivia Newton-John.
CAT: Why's that?
HOLLY: Anything's better than listening to an album by Olivia Newton-John.
-Red Dwarf, Season 2, Episode 1: "Stasis Leak"
Can you imagine.... ...a beowulf cluster of ZX81s?
(sorry, but it had to be said!)
-- Soruk
I'm sitting in front of my PC here that has 96meg of RAM. If I bought that much in the form of 16k RAM packs like the ZX81 here uses it'd cost me over 130,000 pounds.
I guess 80 pounds for 128meg is a decent price after all.
http://twitter.com/onion2k
I had one. Parsec, Munch Man, Blasto... I even had the Scott Adams Pirate Adventure. How could you not say those games rocked? Oh, and I had the speech synth too... the pinnacle of coolness at the time. It even did digital audio, one game I played (a Frogger clone) used the speech synth to make the frog do a realistic "ribbit, ribbit".
N4st0r, trixx0r h0bb1tz0rz! Th3y st0l3 0ur pr3c10uzz!
I still have the original - complete with it's modifications. It still works!
It was what got me started with computers so I have kept it. A friend also gave me their old ZX81 which is in mint condition.
I also have a Spectrum but I daren't use it often because of their PSU circuits have a design snafu which can fail catastrophically.
I still also have the motherboard to my old IBM PC/XT with a massive 64K on board.
Sigh - nostalgia!
-- The universe began. Life started on a billion worlds...
-- Except on one where stupidity was there first.
The TI99/4 was, I understand, the first 16 bit home computer available to the mass market (predating the IBM PC by about 2 years). The 4A was a fairly simple upgrade.
Zebra Systems is for real, they've sold this stuff for 20 years now. Call them up tomorrow...
The Z80A in the ZX81 (UK version) ran at 3.25MHz. The Z80A in the ZX Spectrum ran at 3.5MHz.
Actually, there are two POKEs... one doubles the access rate to ROM and the other doubles the access rate to RAM. Doubling the RAM rate disabled the video controller's access which also meant disabling the DRAM refresh cycle -- if the cpu stopped accessing memory for more than 4 microseconds, interesting things would happen.
The COCO3 was designed differently and always ran at the full 1.7Mhz clock rate.
Trivia factoid: the 68B09E uses a quadrature clock so it's speed is comprable to that of a 4MHz 8086.
I had an email from Kevin Darling (Date: Wed, 12 Dec 90 07:11:03 GMT) claiming to have heard of a 15MHz version. I cannot find the electronic version; I've only got a printout of it. (After 10 years, the archive is hard to search.)
Hammer of Truth
Woah, the 102 is kind of like... an ANTI palm pilot.
It sure would be fun to carry one of these around as a joke.
--- Cum catapultae proscriptae erunt tum soli proscripti catapultas habebunt
and I think that was the Sinclair's situation as well.
I remember having to add RS-232 buffers to the C64's otherwise perfectly good serial port, and (with the exception of Radio Shack) many of the others failed to provide a usable serial port.
My production Timex model got warm, but not too badly.
Exceeding the recommended torque is not recommended.
Probably much too late for this to get noticed now, but...
Is there an archive of ZX81 software anywhere, possibly in WAV or MP3 format?
The best by far is ftp://ftp.void.jump.org/pub/sinclair/ zx8 1/, part of World of Spectrum. These are generally RAM images, rather than tape images.
Other places worth going are the comp.sys.sinclair newsgroup, and its FAQ (although this is more ZX Spectrum biased. And maintained by me :-)).
Phil
I'll even throw in an LED digital watch and calculator - plus a couple of hundred batteries to get you through the first week.
There are some zx81 emulation sites with game images, so there must be a way to do it : maybe play the audio tape into a sound card ? The encoding is only FSK, like a 300 baud modem.
Imagine a beowulf cluster of these things! ;)
Has anyone tried this???
The cassette recorder leads you get with the ZX-81 (and spectrum) will plug straight into a PC sound card. You can then load and save the stuff as audio files. (And distribute them on Napster (if MP3 compression does not screw things up)).
Also, any ZX-81 hackors out there???
I'd love to see "3D Monster Maze" modified to include a rocket launcher...
"Rex is approaching..."
"Rex has seen you..."
"Run he is right beside you..."
KABOOOM
Offtopic, Inflammatory, Inappropriate, Illegal, or Offensive comments might be moderated up.
Heres a link to a page with details for building your own ZX80/ZX81 from scratch:h tml
http://www.home-micros.freeserve.co.uk/zx80/zx80.
The Game Boy uses a processor similiar to the z80, but it is not a true z80. It is missing all indexing instructions (IX/IY), 16 bit loads, port instructions (IN/OUT), shadow registers, and some other that I'm forgetting. The GB processor also executes instructions differently than the regular z80, making the timings completely different.
Check out this site for more info: www.devrs.comI don't believe it, I got my Uncle to sell a couple of ZX81's for me on a trip to India in the late 80's as there was still a market for them then. I think he got about 50 quid ($75ish) for the two of them!!
Not quite so direct as
10 FRYPROCESSOR
But something that basically did that when executed--probably an assembler instruction.
"I say consider this day seized!" -Hobbes
"Tomorrow we'll seize the day and throttle it!" -Calvin
$100! Now that's inflation.
This sig intentionally left blank.
They were the days...I was working for the local (oz) Sinclair importer; we had to take thousands of ZX80s apart to replace the UHF modulators with VHF (AU Ch 0 and 1) units as the marketers didn't think that the market would spring for new TV's (UHF TV hadn't been around long for us) The computers came to us ready assembled..The cassette interface was a crock..very touchy.
"Never underestimate the power of very stupid people in large groups" seen on someone's blog...
It would have been a common clock, based on a single crystal divided by the custom IC. The problem was probably due to malfunction of the glue or the ROM when overheated. In those days most systems with any amount of display RAM used either Motorola's 6845 for display timing generation (interleaving bus cycles with CPU access); a few did DMA during the whole scan line but this had heavy CPU performance penalty; others were asynchronous with separate display RAM but this was prone to snow during display updates. The really cheap systems with minimal RAM typically generated an interrupt at the horizontal sync and executed a string of NOPs (either via ROM or bus-pulling); video data was then snooped off the RAM while the CPU walked through a dummy address range. ZX81's glue logic did this. Don Lancaster described the principle very early on in his famous TV Typewriter Cookbook. Who did it first I can't remember, but this kind of trick was common in many of the early video games which often used hw or sw in unorthodox ways.
You forgot the best z80 TI calculator of all: the TI-86 :) You are not entirely correct about the calculators memory sizes. Note that all of the calcs have the OS stored in ROM, but the size is not mentioned since this is not changable (except on the two with Flash ROM):
TI-73: 25k RAM, 64k Flash ROM
TI-82: 28k RAM
TI-83: 27k RAM
TI-83+: 24k RAM, 160k Flash ROM
TI-85: 28k RAM
TI-86: 128k RAM (96k user, 16k system, 16k work)
on my way to take the dust off to my Flight Simulator cassette!!
.oo00OO
This is entirely false. The GB uses a CPU that is similiar to the z80. And it only has one. In fact, the Game Boy cannot display individual pixels without special programming. It can only display sprites (up to 40) and tilemaps (up to 256 tiles on the GB, 512 on the GBC).
Now I can relive my high school days.... with a Sinclair. Oh how I wanted one, after my infatuation with the TRS-80 faded....
There is an archive of many sinclair computer programs at ftp://ftp.nvg.unit.no/pub/sinclair, for the ZX81, 48K, Spectrum+, and others.
These are typically in the format of RAM images, rather than as audio files. I know that there are various tools around suitable for the 48K Spectrum for turning these into audio (I'm also writing one of my own), though I don't know if there is anything out there for the ZX81.
Steve.
This will look great on my horse and buggy! Now if only I could find that "fire" invention that everyone was talking about...
Daniel
Ofcourse you can't run anything usefull on it...a Vic 20 on the other hand was a very usefull computer.
In the UK it was sold in assembled form (but you could get it in kit form if you wanted to buy on and have something to do)
I hate to do this to you guys but:
I had the expansion case, 32K, floppy, 300 baud modem, speech synth, Gorilla dot-matrix printer, and the FORTH compiler! Hah!
I had more fun exploring different way to program the thing than writing the programs themselves. The sprites on Extended Basic were great. A friend and I wrong a stupid program called Fred and Ed. The equivilent today would be Itchy and Scratchy. Fred and Ed took turns killing each other. One day I gave Fred a bow and he shot Ed in the head with a great explosion of small red sprites. Early carnage. Too cool.
Anybody ever heard the voice in the Atlanta airport shuttle many years back? The voice sounded _exactly_ like the 99/4a speech synth.
I, too, regret throwing mine away.
-tim
Make sure that before you load it on your penis, you aren't doing any Input/Output or using any "tunneling" protocols.
Ah, but remember that "all the silicon" means 4 chips - the CPU, RAM, ROM and ULA, plus the odd transistor in the (external)power supply and the vidoe modulator. That's the lot. Down from, IIRC, twentysomething chips on a zx80, partly to keep the heat down, partly to keep the cost down, and partly to make it a viable kit for a wide market. This was the machine that really kicked the whole thing off for the UK.
TomV
For crying out loud, it takes one bit in, one bit out, and a couple of transistors & resistors. *presto*, rs-232. There was even one that just plugged into the game paddle port on the Apple II.
And if memory serves, you needed the expansion unit on TRS-80, and even then, it only gave you room for a card for rs232, not the actual port.
Unless, of course, you're talking about much later models . . .
And isn't $99 a bit steep for one of those these days?
hawk
Actually, C9 stands for RET (return) :)
As others pointed out, it hasn't dropped in price much! The kit was $99 when I ordered it.
However, I have slight modifications:
1) I taped the 16kb RamPack down with black duct tape, to eliminate fear of Ram Wobble. People who whine about this are just not inventive.
2) Someone said they thought the ZX-81 was POS and replaced it with a TI99/4a. How appropriate then that I used a scavanged TI99/4a keyboard to replace the original contact keyboard!
Also, I won my first computer contest ever (in KPower magazine), by writing a crossword generation program for the ZX-81. My Prize? A brand new Timex Sinclair 2068, which my parents had also thought to buy for me a week before!! I still have one new in a box.
Therefore I hail the ZX-81, as it started me down the long and happy road of programming.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
FAST
and then SLOW to get the display back. FAST/SLOW was the major difference between a zx80 and an 81, from the programmer's POV. on a zx80, there was only FAST.
TomV
C9 was RET. ED B0 was LDIR. 01 was possibly LD A, x.
I havn't touched any of this for 13 or so years, and even then I used an assembler. My assembler was broken with respect to the IX and IY instructions, causing code to be assembled with the opcodes in the wrong order. By the time I'd noticed this the manufacturers of the assembler had ceased trading!
They used the halt instruction because the ZX81 generated the display by having the CPU execute the display. Resistors in series with the CPU data bus (!) allowed the SCL chip to force a no-op into the CPU after it had successfully latched the display file byte for output to video. At the end of each display line the SCL chip let the CPU see the halt, and it would then sit and wait till an interrupt hit and the CPU began executing the next line of display.
The CPU only got to execute your code during the vertical retrace period, which is why slow mode was so slow.
Regards, your friendly neighbourhood cranq
Regards, your friendly neighbourhood cranq
Quoted from article:
You still have the chance to purchase that Timex Sinclair ZX81 computer... Now let's see if we can load Linux on them!I wanna buy a couple of hundred and make the world's slowest Beowulf cluster!
I wonder if it's possible to underclock 'em, or if that would completely screw up all of the IO timing.
Anyone wanna port the SETI@home client to a Z80?
Uhhh... How do you mount a cassette recorder onto a Linux filesystem?
Fire and Meat. Yummy.
Variants of the Z80 are embedded EVERYWHERE.
Calum
Egads man, it was a joke. One that definately made me smirk as I read it. (Like the other reply to you about the beowulf cluster. ;))
;P
Don't be so serious.
-- www.bteg.com | bleh.n3.net | hac47.dhs.org
the bbc also used to distribute acorn electorn & bbc programs on the teletext system
.oO0Oo.
before I got a bbc I used to sit there and write down the source code on squared paper so i made sure i got every character (they didn't put on screen line break in but ran the contiguously).
I never used any of them but it was a good way to get used to source code.
and red hat think THEY invented open source!!
There are places where the networks are not touching,and there are places where they are-Boeing's Lori Gunter
It's called tokenization-a memory saving technique used by many 8 bit machines for their interpreted BASICs.
Calum
Also speeds up running the code, as keeping it pre-tokenised means the interpreter has a _lot_ less to do. No need to work out what each instruction does, or to check if they're valid.
When you get used to it, it's really rather fast to use.
Greg
(Inside a nuclear plant)
Aaaarrrggh! Run! The canary has mutated!
That is a beautiful link. Please, before you mod me down look at where the link points to.
Impersonating Tycho from Penny Arcade since before there was a PA.
IIRC there is a ZX Spectrum emulator that can convert wav files to its own file format (and vice versa). Don't know about the ZX81 though.
There was a radio programme in the UK that would broadcast BASIC programs that you could record and then load into your spectrum. Internet, who needs it. :-)
Damn, the Speccie was the one and only PC I ever truly understood - I owned a disassembled and commented ROM book - they packed that all into 16K too, with room to spare!
Ahh, nostalgia, it's not what it used to be!
Whoa, that keyboard brings back memories, Membrane-BASIC (tm), not to mention my cassette record as a source of non-volatile memory, what a blast! You could save your programs/data then play them back as audio, very exciting. There was a mag just for this machine, though the name escapes my memory, probably "Sinclair something or other".
Noooo. It came in a white case, with brownish writing with a black or gray outline depending on issue. It also had the distinctive modulator hump. The principle difference between the ZX80 and ZX81 was that the ZX81 could read the RAM to generate a video image while doing other tasks - all interrupt driven - the ZX80 couldn't, so display was suspended during processing, execution, keypresses etc. If you think that's dodgy, you should have seen the fuss at Sinclair Research in the 6 weeks before the Sinclair QL was released. Oh the stories I could tell you!
MP3s would probably not work for storage of anything, as the compression causes a lot of artifatcs that would quite possibly mess up the reading. Then again, this thing could be using 200Hz pulses for a logic 0 and 10Khz pulses for a logic 1, or something to that effect, and MP3 might work then. How exactly did this old computer store data on audio tape?
Only those who dream can grasp reality.
Then what would you do? Leech my lotion? Get access to my soap? Watch my girlfriend shower? :)
As you can see this is a slow friday at work...
Have a productive weekend
no, what are they?
.oO0Oo.
is it for converting tv signals or someting
There are places where the networks are not touching,and there are places where they are-Boeing's Lori Gunter
It's alot more fun than it sounds. Sometimes you get some downright surreal stuff. Sometimes you get a whole conversation, because the machine didn't stop recording when someone picked up the phone. I have one where some old guy is talking to his buddy about how his wife and her friends are eating all the damn food. The next message was from his doctor about his colon operation apointment. Nutty, Man....
I have an old Compaq 386SX notebook. Believe it or not, it runs Windows 3.1 and Thought Communications FaxTalk Messenger and an external voice modem really nicely. Connected to my home LAN through a parallel port LAN adapter, it's been a great answering machine for a couple of years now.
So, of course, you always get the collection of dumbass telephone messages. I save them in a folder on my hard drive and play them every now and then for fun.
I'm seriously considering putting them up on the 'Net as a shrine to stupidity. Do the same, with yours, it'd be a fun site to go to!
For legal reason, tho, I suggest that you get a Tripod free page or something and don't give them any real info about you - that way, if the old owner of the machine happens to find them, they'll have a hard time sending lawyers after you.
<grin>
Fire and Meat. Yummy.
They sell a book on the site - something like "The INS and OUTS of the ZX81" or something. It has a full schematic, as well as interfacing info (or at least that is what the writeup says).
I support the EFF - do you?
Reason is the Path to God - Anon
The sheer number of peolpe who took the "let's put Linux on it" comment seriously absolutely frightens me. I'm sitting here reading some of them and the blood from me having clawed my eyes out is clogging up the keyboard...
:)
Maybe there should be some sort of written and oral exam people have to pass to be able to read Slashdot. Not unlike how a driver should be able to pay attention to the road and the people around him or her, people who read Slashdot should have a good head on their shoulders and a healthy sense of humor -- and be able to detect it when it's there.
It's just really amazing.
Anyways, to keep this on topic: the ZX81 was the first home computer I ever had. Had it hooked up to a nice B&W TV around 1986 or so with it's L337 16k expansion... Don't forget, you can still mess (so to speak) around with it using the MESS emulator...
http://mess.emuverse.com
BytesTemplar.com
I had one given to me several years back - of course, it was already put together. I think before I would spend $100 on one of these, I would buy a PIC stamp kit or something.
But you know how nostalgia is...
I support the EFF - do you?
Reason is the Path to God - Anon
I find it hard to believe what they are asking for these machines. Sure, they are new surplus, possible still in the original boxes, so that has something going for them. And they are arguably worth it as a computer kit. Plus, there is always the nostalgia factor...
I can understand wanting to buy one to learn more about how a computer is actually built - learning about microprocessors, bus interfacing (for RAM, ROM and peripherals), and digital electronics. There aren't many kits out there that would let you do this at that price, and none as simple, I would wager. I find it strange that someone would want to use these as microcontrollers, though - as it would be cheaper to buy Basic Stamps, or for the assembler freak, PICs (and these are real cheap - $5-6 each). Not as much memory, but much more compact.
I am reading a book right now call "Build Your Own Self Programming Robot" (I think that is right) by David L. Heisserman (sp?) - about a building a robot he calls Rodney (he has another book, which I may have the titles mixed up, about a system named Buster - Buster came before Rodney). The systems computer is built around an 8085 microprocessor, and a bit of RAM chips, and a bunch of glue logic. Data is entered into the system via toggle switches - one bank sets the address (12 bits), and the other bank the data (8 bits), then there are toggles for load, reset, and run/program. It is pretty clearly laid out.
I gave thought to actually building this thing, as diagrammed in the book, but after reading about it, I realized that most of such a system could be built using a cheap 486 laptop (which I have one with a busted screen) and the parallel port, plus a little bit of addressing logic on the parallel port. Then some custom coding, and there's Rodney. Still, it was fun reading that 80's robotics book, and realizing how far we have come, yet how so far we have to go (the books author was real optimistic about robots and what they could/should be able to do)...
I support the EFF - do you?
Reason is the Path to God - Anon
EMI? That's sort of unlikely for stuff running at low speeds and for circuits of that size. More likely it's a power supply problem.
Nope. The power supply was stiff and well filtered, and separate for both the motors and CPU. The motors were isolated from the CPU by relays (with the proper reverse EMF blocking diodes). Small DC brush motors put out a *lot* of noise, and apparently the ZX81 was pretty susceptible. The ZX81 put out a *lot* of noise itself, too, especially when I ran it without a case. but the EMI problems I had were there with or without the case.
While I almost certainly say that the Z80 wouldn' handle Linux I can say that the Z80 had several clock versions... Z80 - 2.5 ??? Z80A - 4MHz (as per RadioSpares catalogue) Z80B - 6MHz (ditto...) I believe there was also an 8MHz version. I also have personal experience, having built a Z80 machine of my own when I was 16ish. 4MHz, 16kROM, 32kRAM, and 2 pageable 8k RAM/ROM sections using a 32 character by 6 line display. Ahhh... Those were the days. Elite for the ZX spectrum was a true classic along with JetPac, Sabrewulf and all the Ultim8: Play the Game doohickies. Elgon
I had one - it was my first computer too. It sucked. I remember a programming books with BASIC games for machines machines like this. Some of them would have a little yellow star with "1K" in it, meaning it would fit into the ZX81's RAM. Most of these "1K" listings were about half a page long. Imagine the hours of fun you can have playing a game that fits into half a page of BASIC code. By the time the C64 rolled around, the ZX81 was a waste of plastic, or bakelite or whatever the hell it was made from.
Here's a spectrum emulator that runs in a web browser. It's not a ZX81, so you'll have to make do with the extra power. Now I ask you, $100 (+shipping) for something that would have to be slowed down to run in a web browser?
http://www.spectrum.lovely.net/
Everyone knows that damage is done to the soul by bad motion pictures. -Pope Pius XI
I had one of these and wrote my first original programs on it. Interactivity that was really a series of 'if-then' statements. Whadda ya want, I was 12.
I loved that thing and its dual use monitor (doubled as a portable tv! Creature Features in my own room so I wouldn't get caught).
Now I'm all misty-eyed, but there is NO WAY I'd pay now what I paid then to get a new one.
Right, so you have 1024 bytes of RAM, but part of these are used for storing environment variables.
From (my chemical) memory, the ZX81 Memory map looks like this:
Decimal address 0 to 8191 ROM
Decimal address 8192 to 16383 Copy of ROM (this can be overlaid by a second add-on ROM)
Decimal addres 16384 upward is RAM.
Addresses 16384 to around 16515 (Im' guessing the figurse a bit now...) stored the environment. This means things like the lines at the bottom of the screen that are reserved for editing, the "protected lines". These don't get scrolled or cleared by a CLS command, so you can use them for stuff like status, background. Another address contains the number of TV lines before the picture starts. If you POKE a value into this address, you shift the whole display up (or down). I used this once for an earthquake effect, by vigourously drawing a skyscraper, shaking the screen, then drawing a pile of rubble (OK, I was 12 at the time).
So, you've really got less than 1024 bytes for your program and data! Oh, and the screen is memory mapped into that space, too! You had a choice, limit the amount of screen you used, or limit the size of your program. The screen works like this, each line is mapped as a series of characters, teminated by a newline character. If you never print to the screen, the screen memory stays fixed (perhaps at 1 character, a single newline). If you print
, you're going to gobble up 68 (if I've counted right) bytes of memory including the two newlines.Now, the Basic keywords were part of the character set, so for example the keyword PRINT occupied only one byte. So you could economise by using these basic keywords to print text to the screen. For example, to prompt the user to type a number, you could use the keyword INPUT (1 byte) rather than ENTER (5 bytes, including the space). Big saving.
More memory could be saved by doing numerical operations on the values of strings, rather than on numbers themselves... doing (the value of letter "A" plus the value of letter "B") took up far, far fewer bytes that (64+65).
Then if you programmed directly in machine code, you could do wonderfule things... Two lads from Hull (U.K.) set up a firm called Artic; they managed to cram a game of chess into 1kB!!!!
We used to use these things at school, too. An I/O card plugged into the expansion bus, a few relays, and we could play around making traffic light systems, reading temperatures and light levels, turning on pumps to sprinkle water on the plants...
Those were the days! All you need is a bit of imagination. Oh, and it was small and ran silently, no annoyingly noisy fans and hard drives....
It ran from a 9Volt transformer, too. 700mAmps, I think. You might be able to run it off a PP3 battery...
I was what 14? and i used to sneak out at night to go to a friends house and program the z80 chip for a game we were doing... man so much fun... I am weepy.
Am I the only one that thinks it was a GREAT chip (the Z80) when compared to say the 6502 AppleII had inside?
We used to program an adventure game on ZX81 went pretty far but never released the final game. I remember we used to code with the loads of buffers that came with it and when I switched to 6502 I found it clumsy compared to the Z80.
Too bad it only had 16 k of RAM with the extensions and it was pretty hard to do much of anything and it used to just die on us since our connection to the RAM was screwed.
But what really amazes me now is that we had an expensive AppleII but had more fun programming assembly on the ZX...
I also remember that my parents were surprised that I sneaked out at night (yeah they eventually found out) to go programming all nighters!!! They, I guess, were expecting me to sneak out to go to parties and drink beer and smoke pot but no... we would do it for programming. I guess it was pretty obvious what I would be doing later.
marc
The real mnf999 always posts as anonymous coward
Nice, I'd like one...
But they only ship to USA and Canada so I'm not able to order one.... (on the other hand... for that price... almost $100... just me who thinks thats too much?)
/droid
My dogs like the computers.... They're geek dogs, too.
EMI? That's sort of unlikely for stuff running at low speeds and for circuits of that size. More likely it's a power supply problem.
Engineering for Humanity.
But on the Spectrum it was possible to set every pixel of the screen whereas the ZX81 only allowed to print characters.
On my old coco, there was an address you could POKE (hey, remember POKE?) that would cause an internal relay to throw continuously, thusly burning the whole mess out. We used to do that a lot when visiting the Radio Shack Computer Center (hey, remember Radio Shack Computer Centers?). Ah, the good old days.
Hey, I can't believe nobody else has said this of the ZX81's yet:
CAN YOU IMAGINE A BEOWULF CLUSTER OF THESE???
-Those who dance are considered insane by those who can't hear the music.
God, here I thought I was the only one who had a TI994A. My parents bought me one, and then sent me to a special school on Long Island that taught programming on the TI. I began converting all my choose your own adventure books into programs.. I guess thats why Im here today..
Pen Up.... Pen Down...
There was also a 1K noughts-and-crosses program which I typed in from a magazine, which was practically unbeatable (actually you could beat it but only by playing the most illogical moves possible - but that's another story).
I can top it - I had the RS-232 expansion in mine and a 300 baud modem!
LOL I miss mine... not sure if it's still in an attic or not. I know I've got the cartridges in a box next to my XT. (And oddly enough, I had the phatty supra-l33t disk array, even the word processor for it, the speech synth, and Parsec still owns me... but I didn't have that 3-cartridge-in-one expander! GAH!)
The ZX81 had a 40x25 screen and the memory for this came right out of the 1024 byte RAM. They played tricks to conserve memory; the memory wasn't a flat 40x25 array of bytes, but was stored as a list of variable-length strings of character information, each row starting from the left and ending at the last non-whitespace character on the row.
They had a whole chapter on the zany stuff you could expect as the memory ran out. The sample program to demonstrate this began with this line:
10 DIM A(140)
and it was all downhill from there.
The ZX81 was my first computer - and man, what a wonderful absolute piece of junk it was !
I learnt basic on that damn thing, not to mention 'finger karate' - eventually the keyboard bombed out.
The only use I can see for it now is a paperweight or a door stop
:)
Anyone from the UK remember the trouble they had with the launch of that machine ? - They had like a 4 month delay, I think I waited about 6 months after ordering before getting it.
The Vic20 was a lot better - as my one friend was very keen on pointing out everytime he saw my sorry excuse for a computer.
A slashdotting - you get the stick first and then the carrot !
It's cause they love their precious, precious linux and anything said that even implies the contrary is to be shot down with extreem speed.
Fuck them if they think I'm tring to be a troll.
are you some kind of prevert? cool!
I've archived my old MITS Altair sw eariler this year and found that MP3 worked great with the 88-ACR. It stores data using 2400 and 1850Hz at 300 baud. Dunno about the ZX81 audio format (I bought one of those from these guys before they raised the price to $100 - it was around $40 a couple years ago, heheh. Haven't even built it yet tho).
BTW - saving old computer audio data with a PC sound card, preferably just make an audio CD, is HIGHLY recommended as you won't have any of the tape problems of noise, hiss, drop outs and speed fluctuations, is much more reliable - and those old tapes aren't getting any younger you know. After a time the lube dries up and then you'll have a problem with it squealing and that definitely throws a monkey wrench into loading 8K BASIC.
try { do() || do_not(); } catch (JediException err) { yoda(err); }
i think it was meant as a joke
isn't that what was in the original gameboy?
i seem to remember reading something about the gameboy either containing the z80 or a slightly modified z80.
-barton
Text mode: 32 by 24 - Graphics mode: 64 by 44
Graphics mode was done using characters in the range 128-255 with each combination of quater blocks filled in.
Special Relativity: The person in the other queue thinks yours is moving faster.
I've purchased from Zebra, about a year or 2 ago. The ZX81 was less expensive then ($30) but if the demand is enough I can't see anything wrong with his pricing. I mean has has kept them for a while!
BTW, there is a project out there to build a new ZX/TS version of the Z80 with the latest and greatest technology. I can't find the link but I did backup the notes. Very cool to be able to run a ZX81 at 33MHz with up to 1 Meg of ram (not very useful with the way the ZX's ram addressing was set up).
--
Linux Home Automation - Neil Cherry - ncherry@home.net
http://members.home.net/ncherry (Text only)
http://meltingpot.fortunecity.com/ lig htsey/52 (Graphics)
http://linuxha.sourceforge.net/ (SourceForge)
Neil Cherry - Linux Smart Homes For Dummies
10. You think 16K ram packs are Sexy.
9. The sales man told you it was a laptop.
8. You know a guy who knows a guy that has a couple of old games for sale.
7. It is a dream of yours to port Quake 3 to the Sinclair.
6. Brand loyalty because your watch is "still ticking."
5. A pit bull ate your ZX80.
4. The devil is making you program in BASIC for all the hours you spend playing Frogger.
3. You consider yourself the first Computer Archeologist.
2. You have been locked in ICE since the 80's.
1. Three words "Spite Bill Gates."
Almost right on the screen size. It was 32 columns of 24 lines with the bottom 2 lines reserved for entering/editing program lines and inputting data.
Very good memory on the 1K RAM display file method. If you had the 16K RAM or better, the display was fully padded with spaces and HALT codes. Of course, to do so caused the "boot" time to be longer as it grew the display file one byte at a time. A 1K machine was ready to go instantly when you jacked in the power. However, if a 1K display had several lines padded to different lengths, you had to wait for it to clear it out before getting back to your program listing. And even that was wierd to think about - since it was stored tokenized, it usually took more bytes to display the program than it did to store it, and on a 1K machine, that could mean that a long program might only display a few lines of code at a time when memory got nearly full.
Also, there were all sorts of well known memory saving tricks that relied on the tokenized BASIC. If you needed the value '3', then just saying "LET X = 3" cost you like 10 bytes (or more if memory serves) since there was a byte for each token, a byte for the character '3' and 5 bytes for the floating value of 3 stored hidden along with a 1 byte 'number' token. Well, if you used "LET X = INT PI", then that only used 5 bytes! No number to store - just tokens. "NOT PI" was a 2 byte zero, "SIGN PI" was a 2 byte '1'. In fact 'LET X = VAL "2.3"' was still cheaper than 'LET X = 2.3', especially since you didn't need parenthesis for functions with a simple argument.
The absolute coolest thing about Sinclair BASIC that no other BASIC I ever saw did, was to allow the VAL function to evaluate rather than just convert numeric constants. You could do the following: LET Y = VAL "2 * SIN(X + PI/2)". Basically, an EVAL type function, which allowed for some very powerfull stuff.
[sniff..]
oh well, back to the future...
actually if i remember correctly the zx81 had more like a 40x20 screen without colors at 8 bit a character that would be 800 bytes.
It actually used a neat trick to vary the size of memory used by the screen. So that largish programs could fit into the 1K unexpanded version.
Damn, I'm glad I only use digital answering machines at home! I hate analog tape formats because they have crappy quality, and the hardware is unreliable.
This sounds like more fun than what I like to find at thrift stores, which is old Mac hard disks and Syquest cartridges. One time I found a backup tape from a SCO Unix system, and a tape drive that could read it. Nothing really fun, though.
--
"Open source is good." - Steve Jobs
"Open source is evil." - Microsoft
Anyone remember the Marathon Lambda? It had (as I recall it) the same specs, but was in a somewhat different case. Was it, in fact, just a ZX81 in disguise?
2 Kb RAM and BASIC only on a 40x20 display - I still remember how proud I was when I finished a racing game on it at age 13. Man, that makes me feel old :-)
Black holes are where God divided by zero
http://www.home-micros.fre ese rve.co.uk/zx80/zx80.html
The IPCC has purposely engineered a massive scientific fraud.
My first computer was a ZX80. Totally useless, but fun to play around with. It's still sitting in a closet in my basement.
Its cassette interface was virtually unusable. The wall wart created so much electrical interference that it showed up on the tapes as a loud hum. The machine also overheated badly and had to be run with the top of the case removed.
I upgraded it with the ZX81 ROM and keyboard overlay and the 16k RAM module before I gave up on it.
A couple years later I picked up a TS1000 just to play around with. It was a little more usable and was a fascinating bit of electronic efficiency.
Anyone remember Synch magazine? It was put out by the publisher of Creative Computing and was dedicated to the Sinclair machines. This tells you what a fanatic following these computers had. Lots of ads in the magazine for all kinds of software and odd peripherals.
No sig? Sigh...
/ver someone-31337-like-xeno42 CTCP VERSION reply from someone-31337-like-xeno42: z80-irc-0.01a (z80 4.77MHz) That's WHY!
You can get a real Z80 (in fact its a modified Z180) development kit including C compiler, debugging tools and tons of standard IO for 140$, a kit with ethernet and a full TCP/IP library for 200$. A standalone module comes to $40.
- http://www.rabbitsemiconductor.com
I have one of these and its really cool. The specs are:Oops.
Sorry.
A friend of mine once ran a C64 BBS. He kept his PS in a shallow saucepan, upside-down, in a couple inches of water.
Mail? Put "slashdot" in the subject to pass the spam filters.
I found that once I had bought the TS2040 printer, it's pass through connector created a more stable connection for the RAM pack, and I rarely had a wobble crash after that.
It still had the problem of when I had been coding for many hours and it got very warm, something would go wrong and quietly march through memory and twiddle the bits on about every 40th byte. Inevitably, this either created a display file that was invalid and locked up, or created an invalid program line that you better not touch, or lockup was certain.
Now there's the first version of "liquid cooling technology!"
Actually, I remember during hot summers (with no A/C in our house...crazy), loading and playing games on my C-64 required a fan aimed directly at the external power supply or the machine would tank.
At any rate, if I had the dough, imagine what a RAID would look like with a bunch of Zx80s around. (And yes, you could put Linux on it!!)
------------
--- There is a man in a smiling bag.
Hey, this was my first computer too. And it was more than that, it was a friend. But I'd be damned to hell and back if I'm gonna pay $100 to see my old friend again!!!
The ZX-81's were manufactured in the UK and shipped here for a limited time. But due to the high failure rate, Sinclair had to take up with Timex to raise the quality to an acceptable level. Thus was born the Timex-Sinlair venture and the TS-1000.
Unless you're counting the program counter (PC), stack pointer (SP), and processor status bits (PS) as "registers".
That's how I remember them being referred to in the MOS manual. But, that was a long time ago, my memory could be faulty.
uhm, will they sell me a 70's era tv that has UHF channels still on the "dial"?
I started off with the trs-80 model 1, so while I'd like to own one of these for memory's sake [sic], there's no friggin way I'm paying a c-note for a chip that can't even be given away (the z80).
and I bet you'd have to take steel wool to the pcboard since its probably tarnished beyond all believe from oxidation.
--
--
"It is now safe to switch off your computer."
The ZX81 Support Page has more info about that machine. See also entries in the Open Directory and the Google Web Directory.
You too can live in time when men were men and sheep were scared.
Put together your own computer and watch that BASIC fly. For only 99.95, you can own a piece of history and have a truly 3l337 paperweight. "I built this wrong all by myself."
There was a radio programme in the UK that would broadcast BASIC programs that you could record and then load into your spectrum. Internet, who needs it. :-)
Oh my god! How cool is that? I must have missed that one. Have you got any more details? When was this?
---
As it has always said in my User Bio (not altered for this article), I probably owe my career and geekhood to my ZX81, 16k RAM, and B&W TV that I bought for $210 all told with my paper route money. My folks thought I was nuts at the time, my wife finally convinced me to throw it away in the early '90s, but that machine was how I learned BASIC and Assembler in a neighborhood where no one else had a clue.
And, yes, it was a horrible POS, but I would have been another 5 or more years behind without it, and a more usable machine wouldn't have taught me half as much.
So there!
"You can't get something for nothing." - my grandfather, on the stock market and Reaganomics.
I'm willing to wager that those two lots of kits, after sitting around in a warehouse for who-knows-how-long, will sell out within the next month. And thats too short of a time period for me to get the money and make the decision to actually buy one, which is too bad because they look pretty cool (not that I was around back when they were first on sale, or at least not technologically aware).
The easy BASIC of the TI99/4a got me into computers. You could do text to speech with the speech synth and the Terminal Emulator 2 cartrage. You went into "BASIC" (which the TE2 cart modified in some way) and do something like the following:
:)
10 open #1,(some link to the speech synth, forgot what it was)
20 print #1,"Hello! blah blah blah"
How more easy can you get? you could modify the speech by doing something like this (not sure of the syntax):
30 print #1,"\\50 40"
The first was the pitch, and the second was the rate the tone would drop as it spoke. You out really high/low values and get crazy disorted voices out of it. Good for making prank phone calls.
I even had the PE box (extra 32k,disk drive,rs-232,cool blinking lights), but the stupid extra thick cable always kept falling out of the bus port. The Extended basic cart let you do hardware based sprites, which looked way cooler than moving a character block by block.
Games? Parsec, of course. Remember trying to re-fuel by hitting '3' and steering in the narrow tunnel? Had most of the Atarisoft games, Tunnels of Doom, some infocom games (HHGG, still have the "Don't Panic" button), and other stuff. I used TI-Writer to do all my high school papers, and had to send escape codes directly to the printer to do underlining (good thing TI-Writer supported that trick). Even had TI-LOGO, that let me play with simple recursion. Of course, by the time I got all this stuff, it was dirt cheap.
when you can load games from a casette tape!
I still remember putting a carton of milk on the back of a ZX80 to keep it cool...
SLOW could be simulated in software on the ZX80. It took about 400 :->) but it worked
bytes of code (half the default size of the RAM
well enough. There was even a commercial game released that used
it...
http://www.geocities.com/Athens/7374/Parsec.gif
I need an emulator...
-----------
end communication
From what I understand, it is perfectly legal to take someone's trash and distribute it how you want, especially in this situation. A) They knew their voice was being recorded, and they gave permission by talking to the answering machine. Otherwise, they would have hung up. B) The machine's original owner gave the tape, freely, to a third party, to do with as they see fit. Incidentally, the same is prety much true of people's trash in general. You take an item, put it outside and entrust it to a third party. The third party might be liable for damages incurred because of negligence, but the person who gets the item from the third party should be perfectly legally scot-free. -Ryan
Now let's see if we can load linux on them!
Ugh, must EVERY story mention Linux? I mean, I know we like Linux and everything, but mentioning putting it on a 4.77MHz Z80 just makes me feel sick.
What would be an otherwise excellent nerdy retrocomputing story is tarnished by the ObLinux mention. Can't people just appreciate this stuff for what it is?
I'll say it again, ugh.
Quidquid latine dictum sit, altum viditur.
It's been said before, but $99.99 for one of these things Plus Shipping. God knows what they'd charge me for overseas on top. Jesus, I can get a calculator with more memory and a better processor for less than that! and I wouldn't have to put a glass of cold water on the back to stop it overheating...
Oh that were the days! The most incredible thing I ever saw on a ZX81 was some weird form of "High Resolution Graphics", still black and white and somewhat fuzzy but it worked just through a software hack. If I remember correctly they used the content of the ROM to dynamically change the char sets to the needed bits. There were even one or two commercial games that used this technique. Oh boy!!!!
's me fa-a-a-vorite devo song by a long shot. listen to the intro sometime w/ headphones.
Devo was certainly years/decades (centuries?) ahead of their time. I think the public may finally be 'ready' for that level of aural majesty in about 10-15 years. Just as I'm becoming a grandfather?!
:)Fudboy
:)Fudboy
I guess I'm only a Fudboy, looking for that real Transmeta
Just remember how little you can squeeze in there. Your program and data have to fit in 1024 bytes... unless you get the memory pack.
A PC 80x25 character screen is 2000 characters.
I bought one of these at a garage sale for $15CDN when I was in gradeschool. It was so cool.
I think that exhausts all I have to say about the machine.
"Anybody who pays $99.95 for these is -- excuse me -- a fucking moron."
:)
If it wasn't for morons, Ebay would not exist.
Thank god for Goodwill and Value Village, it's where I get most of my clothes. Got a SGI/Cray T-shirt there for $1.00.
And now, as a service to the Bored Slashdot Reader...
The best thing to do at a Goodwill is this:
1. go to a goodwill
2. look for some used answering machines
3. take the tapes out
4. take them to the checkout, the chasier will just make up some price
5. most people NEVER erase the tape before giving it to goodwill, so now you can go home and listen to peoples messages.
It's alot more fun than it sounds. Sometimes you get some downright surreal stuff. Sometimes you get a whole conversation, because the machine didn't stop recording when someone picked up the phone. I have one where some old guy is talking to his buddy about how his wife and her friends are eating all the damn food. The next message was from his doctor about his colon operation apointment. Nutty, Man....
The TI-83, the most popular one, retails for about $100, but is smaller, uses only 4 AAA batteries, has a serial port, and can be carried around in a pocket to show off your geekiness. Still, you could use the Sinclair ZX81 as sort of a base station, or one with an AC adapter and TV out. But never underestimate the utility of a programmable Z80 graphing calculator.
Tell me what makes you so afraid
Of all those people you say you hate
Hey, I've still got my "fat" 4032 packed up in the basement along with a 8050 floppy drive. When is the Linux/FreeBSD crowd going to get their act together and do a port to some serious 1 MHz hardware ?
In Soviet Russia, the Beowulf cluster imagines you!
I remember the ZX-80 (white case, 1K RAM) being sold as a kit, but I could of swore that the ZX-81 was sold already assembled here in the US. The Sinclair ZX-81 was obviously before they cut the distibution deal with Timex.
Can anyone shed some light on this bit of computer history trivia?
I thought you could not actually put Linux on anything below a 386...
--AP
Oh man, that's UPN where I live. There goes Moesha...
-josh
Wow, this was the computer that started it all for me. My parents purchased one for me when I was the grand old age of eleven, and I guess it all went downhill from there :) I still remember purchasing the 16K RAM pack for it a couple of months later, and being completely frustrated at the fact that if you pressed the keyboard too hard the RAM pack edge connector would flex and cause the machine to crash. I tell you, it's amazing what a liberal application of epoxy resin can fix :)
Anyway, enough of my misty-eyed reminiscing and on to my real comment:
Has anyone ever over-clocked one of these babies? I'd love to see how fast some psychopath could get one going with some extreme refrigeration / cryogenics thrown in!
--
The gift of death metal does not smile on the good looking.
... er, oh, forget it.
I want to delete my account but Slashdot doesn't allow it.
I am glad that someone had the foresights to keep warehouse full of the Sinclair computer. There are things that are old but still VERY INTRIGUINGLY USEFUL, and that Sinclair computer is just one of them.
I dunno if it is practical or not to get Linux to run on the Sinclair, but as you know, there are zealots amongst us that will get Linux to run on anything !
In another note: Apple hauled out all their LISA stockpile to the dump site !! Yes, BRAND NEW, NEVER USED computer, warehouse-load, straight to the dump site !
My only wish is that someone is still keeping a warehouse (or two, or three...) full of the LISA computer.
I think someone will get Linux to run on LISA too, if someone is keeping a warehouse fill with LISA.
Muchas Gracias, Señor Edward Snowden !
Now hiring experienced client- & server-side developers
-- @rjamestaylor on Ello
I remember ordering and building my Sinclair back before Timex became involved and it became the ZX81. Wow, what a memory trip it is to think about putting together that thing... I can almost smell the 60/40 now.
Unfortunately, I never got to do much programming on mine... it had a temperature problem. After a few minutes of running, the TV would lose horizontal sync. Turned out that my ROM chip ran way too hot, and as it warmed up the TV signal went out of sync. Sinclair must have saved money on components by interleaving the sync of the ROM with the video generator, instead of having separate clocks for each. My girlfriend's techhead brother figured this out for me -- never would have discovered it on my own.
We solved the problem by keeping a piece of ice on the ROM chip, in a little plastic bag. Every so often, when the ice had melted, I'd have change the bag for one with a fresh piece of ice. Talk about your cooling problems -- and I wasn't even overclocking!
--Jim
The damn RAM pack was the worst POS I ever saw. After a few hours plucking away at assembly language, one false wobble would make the whole thing crash (hmmm, is there a RAM pack in WindowsÉ heheh).
:) I'm not kidding - the join between my ZX81 and 16K RAM pack looked like Ridley Scott's Alien had built a nest around it!
It things like this that epoxy resin was invented for
--
The gift of death metal does not smile on the good looking.
Anybody ever heard the voice in the Atlanta airport shuttle many years back? The voice sounded _exactly_ like the 99/4a speech synth.
I allways wanted to hack that (the airport shuttle, not the 99/4a) to say 'By your command'.
Now hiring experienced client- & server-side developers
-- @rjamestaylor on Ello
The answer? To be an Uber Geek. Why hack a palm pilot? Why write a web server in postscript? Why turn a tall building into a tetris game? Because its challenging and some people like that kind of challenge. Now go back to your little complacent windows world and keep telling yourself that you really aren't a lemming and that you do lead an intersting life.
"What are the three words guaranteed to humiliate men everywhere?
In Republican America phones tap you.
Amstrad (aka Schneider in Germany) built a lot of computer with a Z80, running at 4MHz instead of 3.75 in the ZX81 iirc. I have an Amstrad CPC6128, 128Kb ram, colors, sound, 3" floppy drive integrated, etc. This is the machine who killed the C=64 in Europe.
--
"Science will win because it works." - Stephen Hawking
Did you manage to calculate the total power budget for your circuit? Switching relays take up a lot of current as well.
By well filtered I hope you did add 0.1uf ceramic caps in close proximity to the Vcc and Gnd pins of your logic chips. Tantalum (not electrolytic) 4.7uF along the power rails. Oscillators should be well ground and the clock lines as close to the clock pin on the processor as possible.
Engineering for Humanity.
On cassette tape. A visicalc clone (spead sheet) and a couple games. (life, a maze game etc..)
I had the zxx100 which looks identical. I liked it but the lack of a space bar and a very stange keyboard/.entry system. Each key had about 4 symbols and basic commands, depending on input mode it would do different things.
Ah the nostalga.
Who in their right mind would pay $99 for a Z80? I bought my Timex Sinclair WITH the 16K ram module for $33!
Jeez, just because it's old, doesn't mean it's worth anything. I've got an old pair of underwear for sale; only $50! Any takers?
"That which is does. That which does can. That which can won't"
~Any apparent grammatical or typographic errors are caused by defects in your display device.
A Z80 plus a MC68000 - killer box for 1979, eh?
Dang, there's enough CPU there to run... dare I say it...
Nahh. No need.
Yeah, right. The Zilog Z80 was the first Intel PC processor spoof, and is the same exact processor which is in the TI-82, 83, 84, 85, and 86 graphing calculators. Now those models take an incredibly long time to draw a circle with a resolution of 5 degrees (about 30 to 50 seconds; I own a TI-89 now [10MHz 68000], so I don't exactly remember). Can you imagine how long it would take to have the 8-bit SCSI card do a hard disk scan?
In short, if you want a geezer for Linux, I'd recommend hunting for an old Dell OptiPlex; those usually have some good chipsets in them (I found an old XM 590 with the Intel Neptune chipset, popped in the Pentium OverDrive, squeezed in RedHat, and it worked; probably a hell of a lot better than that Z80 fossil of your affection).
"Ancillary does not mean you get to rule the world." --U.S. Circuit Judge Harry Edwards, speaking to the FCC's lawyer
Sinclair BASIC stored all numeric literals in binary form, requiring 6 bytes. Amazingly inefficient for a 1K machine, hence all the tricks to avoid putting numeric literals in BASIC code - things like INT PI = 3, PI/PI = 1, NOT PI = 0, and so on. Line numbers were an exception, stored as 16-bit integers.
Numbers are stored as ASCII 14, followed by 5 bytes of binary representation. Numbers are expressed as m * 2^e, where m, the mantissa lies between 0.5 and 1.0 (not including 1.0), and e is the exponent.
The 32-bit mantissa always has a leading bit of 1 (since it's at least 0.5). Store this number in bytes 2-5 of the binary representation. The leading bit (which we know is 1) becomes the sign - 0 for positive, 1 for negative. As for the exponent, e + 128 is stored as byte 1 of the binary representation.
All pretty complex, and there is an optimisation for numbers between -65535 and +65535, but that still takes 6 bytes to store in BASIC.
The thing worked, and the 6502 still is the hallmark of 8bit CPU design to me. Z80 is sort of ... ugly.
Yeah, all those extra registers hanging off everywhere truly screwed the aesthetics into the ground. The 6502, with it's sleek and aerodynamic 6 register design, really set the style for future processors.
(BTW, I'm not harassing you - anyone who owns a 2001 is cool in my book. Didn't that thing show up on Battlestar Ponderosa on a regular basis? Or maybe I'm thinking of Buck Rogers... with Erin Gray in spandex it was hard to concentrate on the background...)
I don't mean only the PCB schematic, but the actual wiring.
Does anyone know whether such schematic exists at all somewhere?
Thanks!
Sigged!
a lot of folks are going to wax nostalgic over this here machine, but I'm gonna have to disagree. This was my first computer. I recieved it IIRC around Oct 1982, and I was stunned at how crappy a machine this was. I was 9-10 years old, personal computers were an utterly and completely brand new phenomenon, but I could immediately sense the uselessness and cheapness of this machine.
My dad, who bought it for me, had previously engineered some of the first networked cash register systems in the mid 70's (for the Burger Chef chain of fast food resturants), he was/is a primordial hax0r, but even he couldn't get into this dog. But he could understand my dismay, so he got me a TI994a.
I would love to get a bevvy of brand new TI99 parts, maybe even c64 or some '086's, but I can't quite bring myself to embrace this amazing find.
just my $.0200251
:)Fudboy
:)Fudboy
I guess I'm only a Fudboy, looking for that real Transmeta
The thing worked, and the 6502 still is the hallmark of 8bit CPU design to me. Z80 is sort of ... ugly. Sort of like Pentium, only slower.
Of course, the VIC was a real stupid thing to do marketing wise: it looked like a toy, but had more features than their business machine.
My next computer was an Atari ST, 'cause I couldn't afford a Mac.
To this date it is beyond me why 808x won out.
Bert Driehuis -- All I asked was a friggin' rotatin' chair. Throw me a bone here, people.
There are so many better micro controlers out there these days, why would anyone fool with one of these old things? The Basic Stamp is an older example that can run for hours off a 9V battery (SWAG time, this is a low estimate bassed on personal experiance, poster is too lazy to check out real power consumption). It comes with an easy DOS bases programer that uses your PC as a display and it's ports to talk to it. Stand alone displays are available. Hell, if you are in love with Z80's go get a new eZ80.
Man, and I thought some of the other Slashdot stories were old. This one should get a medal or something.
-atrowe: Card-carrying Mensa member. I have no toleranse for stupidity.
Unless you're counting the program counter (PC), stack pointer (SP), and processor status bits (PS) as "registers". I do not, since they're hardly useful for storing data.
I love this testimonial:
.." send me four more kits, I'm using them as controllers for a project"
from a NASA engineer
Oh boy, here we go again...
WWJD -- What Would Jimi Do?
WWJD -- What Would Jimi Do?
(Smash amp, burn guitar, take home the groupies)
Oh man, why should you want to use Linux on a Z80? It's waaaaaaaaaaaaaaaay too heavy and bloated and slow for that. Besides, you'd have to rewrite most of it too, since the Z80 is no 32-bit CPU.
Just make an OS in Z80 assembly, like people do for Texas Instruments calculators. Check out ticalc for instance.
ZX81 For Sale
(and others)
D
----
Anyone wanna try Dunking one of these in flourinert and see if ya can't push her up to 500MHz?
I am allowed to criticize you: you are not allowed to criticize me. Sorry, that's just how things are.
I have a 16k ram module so if anyone deperately needs to upgrade their $100 ZX81 let me know, it might still work :)
Of those to whom much is given, much is required.
I agree the concept of loading linux onto a zx81 is pointless bordering on perverse the fact that there's a good reason why the zx81 has the OS that it does and that's because it has like 1k of memory and the only externals it has to deal with are a casetteplayer and a TV. I have Linux on my PC because It helps me get the most out of it Linux on a ZX81 would not be any kind of improvement, in fact I suspect it would be impossible unless you added extra hardware or were prepared to spend a lot of time forwarding and rewinding the tape machine.
I was just mentioning to someone today that I remember when 64K was a lot of memory, and here someone dumps a real blast from the past in my lap that had only *1K*. Now, you can do a lot in 1K with Z-80 machine code, but then again, you have to program in Z-80 machine code.
.. C3 xx xx and CD xx xx->C9 being my favorites ..
And as if that ain't scary enough, I still remember a few Z80 opcodes
73 de N5VB (ex-KD5BIV) AR SK
I haven't come across a utility that will do it through the sound card. There are plans around somewhere that would interface into the lpt1 port and read it using bit twiddling.
The programs were stored in two parts. The first part would be a header, after that a pause, then the program.
Steve's Computer Service, Hobbs, NM
Clock Speeds: 3.5 MHz - Introduced: 1981
Text mode: 32 by 24 - Graphics mode: 64 by 44
Interfaces: TV, Earphone, Microphone, Expansion Bus
Loaded programs via tape, of course. This computer was sold as a build-it-yourself and pre-built. Came with 2k ram on it, and you could clip on a 16k module to actually do something productive with it. The keyboard sucks, its a membrane that you basically have to hammer to type something.
I'd laugh quite a bit if someone could make linux run on this. Didn't linus start programming linux on a Sinclair QL (much later sinclair, with a motorola 68k chip in it)?
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As a side note, I put together a website about the big brother to this computer (this was released in kit form in 1981), the Timex Sinclair 2068 (released in 1983)...
If you like some retro computing, head out to http://www.unixville.com/2068
Also check http://www.obsoletecomputermuseum.org/ for LOTS of retroputing stuff...
Come on man, it's all linux these days. I plan on loading linux on the digital clock in my car.
Timex Hmmm....Now all you need to do is hook up a Cuecat and mabye you can scan in some code :)
"Science is like sex: sometimes something useful comes out, but that is not the reason we are doing it" Richard Feynman
Nope.
My 8086 can run elks, but that's only because it has 640kb of ram. This computer, on the other hand, has only a few kb. It's not going to work.
I never had a ZX81, I had the TS2068, very similar but with more memory and colour. Very nice computer at the time, light years ahead of the competition back then, but a trifle out of date right now I fear. Still, a fun thing to play with. The system used the high ascii characters to represent basic keywords and one used keyboard shortcuts to input them, which was actually a very handy feature once you got used to it. And of course you could use basic commands to load and execute Z80 machine code for your most commonly called functions, allowing for some very fast programs. The peripherals were interesting too, there were endless loop tape drives for instance, that actually were pretty comparable to the much more expensive hard drives available in the day - high seek times, of course ;^) but linear read/write functions were blindingly fast for the day.
This wouldn't be a bad machine at all for someone that wants to learn Z80 machine code (NOT assembler) - anyone out there working on embedded systems with that particular chip? But as for putting Linux on it, forget that right off, the Z80 has, what, 64k of address space if memory serves. No way you can run any sort of *nix on that - this isn't segment:offset, it's just one segment, period. Still, if you are clever and don't mind a little work, you can do some pretty amazing things in 64k. ;^)
Anyone got info on the actual hardware behind it? I'd be interested in knowing how much trouble it would be to replace the ROMs with EPROMs, make it work with python or something like that instead of basic, maybe rewire it with an LCD display too... you might could make a really cool PDA or something out of one of these...
=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Friends don't let friends enable ecmascript.
Which reminds me of a pop quiz I've wanted to take out for years... Who are the knights that say Nu, which processor did they use, and why is it a good thing that some opcodes have a printable ASCII representation?
Bert Driehuis -- All I asked was a friggin' rotatin' chair. Throw me a bone here, people.
I plan on loading linux on my penis, maybe that stupid bird will stop crashing.
Only the State obtains its revenue by coercion. - Murray Rothbard
Has any one actually purchased one of these? I'd love to have one but i'm afraid it might be a scam. Sounds to good to be true. (but i hope it is)
Coder's Stone: The programming language quick ref for iPad
I have a Coco2, which is oodles faster than the Sinclair, and it uses the Motorola 68B09E processor at 0.89Mhz. With one POKE you can double the clock to 1.7 Mhz. So I doubt that the Sinclair be even One Megahertz
Wow i did't relize how OLD that processor is... I've been programming in ASM on my TI-86 calc which has a 6 mhz Z80 processor in it... That Processor is OLDER than I am !!! WOW
This chip is a definite classic. Has any instruction set been in use as long? Indeed, before IBM jumped into the microcomputer market, Z80-based systems were the standard for desktop business computing. And probably the most popular config was an Apple ][ with a Z80 coprocessor board. (I once nearly bought the Microsoft version of this one!) If Apple had known how to exploit its dominance in this market, history would be very different.
I just went to the Zilog web site to see what they were up to, and found the latest Z80 product: an embedded web server!
__________
I've just installed linux on my bodylotion box and I am creaming it all over my body.
Seriously, we had a TS1000, 16k ram pack and the printer. We had to get a new tape recorder for it becuase ours couldn't save right. I remember the screeen display when it saved or loaded. The TV would just go to hash and when the picture came back, it was done. BTW, it wasn't UHF ch 33 it was VHF 2 or 3. Ah, the joys of trying to program in BASIC, remember those preprinted statements on the keys? I think it was shift-4 to get a Print statement. Used to have a heck of a time trying to run Flight Simulator, not so much the running but the playing. It used to have two modes, Fast and Slow. Fast used to slow down the refresh of the screen to let the CPU concentrate all of it's 1 mHz on actual processing. The printer ran on 24VDC and was thermal. Printed on rolls of 6 inch wide paper. Odd blue print on waxy white paper. Plugged into the expansion slot. Had to be really careful that the ventilation slots were kept clear cause it tended to catch fire. We didn't have a word processor for it, so I remember writing my Christmas list as a bunch of Print statements in Basic. Hey lay off, what did you expect from a nine year old.
Title says it all... run Linux? I think it has 1k of memory unless you get the memory pack which gives you a whopping 16k, and make sure you don't jiggle it or the system will crash.
If you want really neat hack value, try building one of these puppies from scratch. Perhaps somebody could make a really nice high-res scan of the mainboard of this thing. I seriously doubt if the board is multilayered; you could probably build an equivilent machine yourself on a breadboard. It was a cheap POS when it was new; even paying rat shack's inflated prices for components you could probably build one for
Why is it that the proponents of "one nation under God" are so eager to get rid of "liberty and justice for all"?
.. but way too expensive, I guess the company doesnt wanna lose money, and is betting on nostalgia to sell these things.. Oh well, their choice. I'm not old enough to have been around back then, my first computer was an old (even then!!) Zenith 8088 that I got around '89. Alas, what ever happened to Zenith?
Shit adds up at the bottom...
I still have my Timex Sinclair, that we bought in 1982. It sports the following:
- 2KB RAM
- 150bps cassette interface
- 16KB RAM Pack
- 32 column printer
The damn RAM pack was the worst POS I ever saw. After a few hours plucking away at assembly language, one false wobble would make the whole thing crash (hmmm, is there a RAM pack in WindowsÉ heheh).
I also remember doing some BASIC on it. The computer would refresh the entire line you were typing at every character. For the first 32 characters this was fine, but after 2-3 lines, typing became utterly sloy, hence the "Fast" button.
In any case, this gem got me started on computers. I still have the original box and booklet. History in the making!!
The Z80A (as used in the ZX Spectrum) was 2Mhz, and the Z80B was 4Mhz. I remember articles about trying to get a ZX Spectrum to accept a Z80B... the first overclocking ever?
I remember the cost difference to get an assembled model was about £10 (UK).
It's 50/50. I know it was the guy who wrote the submission who suggested Linux, but sometimes it just feels like you have to mention Linux to get a story accepted these days. Would this story have been posted if it didn't have the Linux bit? Ordinarily, I'd say of course, but the way /. has been going lately, I'm not so sure.
Quidquid latine dictum sit, altum viditur.
I had a few and thought that they would make a pretty good controller board with the Z80 processor.
I did a project in high school (~1985) trying to use a ZX81 as a controller for a robot. It worked, kinda. Very susceptible to emi, especially the sort that small DC motors put off. It used technology that was "good" for the time, which translated to today's technology, means "slow and power hungry."
Other than the "vintage-cool" factor, as a controller, you can do a whole lot more with a modern microcontroller. More I/O, similar amount of memory, much more in terms of MIPS/W. You do lose the video display and the ability to program it in BASIC.
The ZX81 was a great hack. The ability to implement a GUI (it did output to a TV) and an interpreter with that little amount of processing horsepower, RAM and ROM is a pretty impressive feat, especially keeping it relatively cheap.
I think that we could all learn something from the ZX81- it is amazing how far you can stretch your resources when you don't have many. The real power of such knowledge is knowing when it is appropriate to use it.
Imagine what your "uptime" will be?
Corporate Gadfly
Jonathan Archer: the most beaten up Enterprise captain in Star Trek history
The Timex Sinclair was my very first computer from my childhood. Its like seeing an old friend.
:)
Though I'm sure as hell not paying $100 for one nowadays!
VENI! VIDI! VICI!
I still remember ...
AAAAAAAAARRRRRRRGGGGGGGGHHHHHHHHH!
The only instruction worth using in Z80 machine code on the ZX81 was C9 (EXIT).
Anyone else here ever use the HEXLD program (Ah.. THERE was a MAN's text editor)
- BASIC in an 8KB ROM.
- 2KB RAM on board
- Expandable to 16KB RAM with a "backpack"
- Expandable to 54KB RAM max with some mods.
- A 40 key keyboard with multiple shift modes to get all of the characters and BASIC keywords.
- Cassette interface for program loading and storing.
- A low cost thermal printer.
This was not a serious machine; it had major shortcomings. But the price was right.The keyboards were very troublesome. The thin ribbon connector often cracked from the heat and aging, disabling the membrane keyboard. With a little experimentation you could still "pick" it with wire ties. ;-)
The cassette interface was flakey too. They recommended a mono portable cassette recorder, run from batteries. The volume level had to be "just right."
The memory backpack was troublesome as well - it wiggled too much, breaking the connection to the card edge connector on the back of the machine.
Entering programs on this machine was truly unique - you didn't type the word "PRINT". You pressed "P", and depending on where you were on the line, the BASIC interpreter knew if you were going to enter a keyword ("PRINT"), or if you wanted the letter "P". Sorry, uppercase only.
It was amazing was assembly language programmers could do with this thing. I fondly remember the Flight Simulator, which fit on a 16KB machine. There were programmers toolkits on cassette, and other little applications. Data storage was a serious problem though.
Is there an archive of ZX81 software anywhere, possibly in WAV or MP3 format? I still have my cassettes, but after 16 years of disuse I doubt that they are readable.
Mike
PS: Search on google - there are several projects out there for emulators.
The ZX-81 was a classic for learning assembler.
mirrors here, here and here
cya, Andrew...
This is my sig, exciting huh!
New -- in the box. My father gave it to me before I went off to college. He even bought me the 16k add-on pack from eBay :)
I am considering handing in one of my coding assignments for computer science on a casette.... just to see the look on my TA's face.
Question: Does anyone know how to dump files from the sinclair 1000 to a PC? I don't have the machine here in my room (so I can't check) but I don't remember any ports other than the video-out.
coding is life
Hemos isn't the one who suggested Linux on this thing... Eugene Blanchard did.
Just making sure you ain't slamming the fine folks at Slashdot (there's my suck-up comment)
D.
Now go back to your little complacent windows world and keep telling yourself that you really aren't a lemming and that you do lead an intersting life.
oh the sweet blessed irony!
"Smart companies save money by deploying MySQL instead of Oracle." - slashdot post
I got my Sinclair free from a friend a few months ago. I'm holding it for posterity... to show my kids what got me into computers. Heck, I don't even have kids yet... they'll appreciate it anyway.
My better memories of early computing is my cousin first saw it advertised in Popular Mechanics. He sold enough of my grandfather's tomatoes on the street to buy one in a few days. He had a plan.
It was cool, too. Biorythms and the flight simulator bring back memories. He had the 16k rampack. After a long while the thing would wear out the TV though....
way cool
would only be because you were overclocking the piss out of it. At stock clock speeds the machine didn't have a cooling problem.
By 1985, Z80 family machinery achieved, I believe, something like 12 or 16 MHz. It may go faster now.
If you took all the silicon (memory chips, maybe a logic gate or array) out of the board and replaced them with modern production, you could crank it a LOT faster than standard. Fast Z80s kept up with 8088s. Linux will fit on neither.
Exceeding the recommended torque is not recommended.
In the last two years, I've seen dozens of these things hogging space at hamfests around the U.S.. I still have yet to see one bring $15.00, much less $100.00. You can find Amigas for far less money. Nice try, guys. Now if they have a warehouse full of TRS-80 Model 16 systems, they might really have something (a Z80 plus a MC68000 - killer box for 1979, eh?) :)
Out of order? Fuck! Even in the future nothing works! - Dark Helmet (Rick Moranis) "Spaceballs"
Try to tell kids today that successful programming included a thick rubberband and a soldering iron and they won't belive ya'. Put the kit togther in a couple of hours. Ah Sweet memories, not of that 16k expander tho...
Ah, I would love to get a ZX80, but alas, they are rare. I do have a ZX81 and a QL, they are some of my favourites of my computer collection, along with the Amiga 1000 and Sparcstartion 1+.
We used to do that on the ZX spectrum. The RAM contained a pointer to the adress of the bitmaps for the char set. Normally this pointed into the ROM, but you could set it to point into the RAM, and do your own font (as much as 8*8 pixels allows the concept of "font") or draw little aliens and move them around the screen by writing basic or ASM.
Back in the day....
My Karma: ran over your Dogma
StrawberryFrog
I never used a Timex, Started with a Vic-20, then a c64,c128, Amiga2000HD, Watched Amiga fall, lost interst in computers and faith in the world, got PC, still no interst / faith.
I want my Amiga back
Fear the government that fears your guns. Fear the government that fears your computers. Remove them from my email.
I make a hobby out of going to surplus stores and picking up surplus hardware real cheap. I've got all sorts of crufty old stuff, none for over 15 dollars. They were selling VIC-20s and C-64s for $50. This is way too expensive, and even though it'd be a nice little piece of hardware to have, it's too expensive and not worth the price they're asking.
Let me put it this way. I picked up a drawing tablet that works with mouse protocol for $15. I picked up a much more recent, in fact, brand new, microcontroller-based device that only needs reprogramming for $5.
That price is outrageous. Wake me when they sell them for $10.
If you can't figure out how to mail me, don't.
For linux tips: http://www.linuxtipsblog.com
How reliable do you guys think this is ? From the web-site...
Site last updated:
Nov 29, 1999
The site also seems to be a part of the normal user accounts provided to an ISP user.
20 GOTO 10
RUN
Out of memory error