I still have mine!
It still works greats.
Two words to get fellow owners nostalgic:
Gawd bless ya Clive and all who sail in yer.
Tomorrow, 5 March 2011, marks the 30th anniversary of the arrival of the machine that did more to awaken ordinary Britons to the possibilities offered by home computing: the Sinclair ZX81. While its successor, the Sinclair Spectrum, got the nation playing computer games, the ZX81 was the tipping point that turned the home …
I added one to my collection of "antique" computers a couple of years back. I was at the tip and they had one in the electronics recycling area, fully boxed, in really good nic. I spoke to one of the rubbish-nazis, sorry, Civic Amenity Centre Employees, and he gladly accepted two quid for it.
No collection of old computers is complete without a ZX81. The BBC master + music 500 still kicks it's ass though.
I was gifted an old '81 a few years ago, it had already had a "real" keyboard (kingston?) added in a bigger case, and the ram pack connected with good old fashioned solder!
My BBC I've had for almost 30 years is still with me. PSU upgraded to switch mode model from it's original linear jobby. Board upgraded from model A to B with all the trimming. Solidisk sideways RAM, CPU upgraded to 65C02, and of course the Music 500 you mention... And it all still works! How on earth that happened after the number of soldering iron adventures I had inside that case in my teenage years I do not know!
I never did manage to make head nor tail of composing with the Music 500 though!
And it still works! I lent it to my cousin many moons ago and I got it back as a wedding present at my wedding. It had the wanted effect of turning me red with embarrassment. The only thing missing was the wobbly ram pack. 30 years on from getting it and I am still making a good living out of learning how to PEEK and POKE :)
A truely legendary computer.
I can't believe how far we've come in just 30 years. IT's fine to understand Moores theorum academically, but to look at a ZX81 and then look at a modern super gaming rig is just mind blowing!
Just think though, without this (and of course others liek the VIC20) we'd have no UK games industry to speak of.
Not even that... Look at a ZX81 and then look at the mobile phone in your hand!
I've been doing some work with microcontrollers recently, and even those £3 chips have 32k of EEPROM, 2K of RAM and run at 16Mhz! It does amuse me no end, but the tight assembler programming habits I picked up from years of 2Mhz 6502 coding on my BBC micro has stood me in good stead.
The original Spectrum 48K got me started on computers at a very tender age, mucking around in BASIC. I've now got three of them, a ZX81, the very same 48K (still working) and a Spectrum plus, with the solid keyboard. Think I'll dig out the ZX81 tomorrow and hook it into a big widescreen TV in honour of its birthday. I owe a lot to those little black blocks with the gigantic overheating power bricks.
so they say... Well, after all those years I'm still wondering (i.e. if I could be bothered) what the ZX81 was about (yes, I owned one and probably still do). You can't really compare the two but the TI-59 calculator turned out to be much more practical and I even used it till the 90s.
I still have my ZX81 and Spectrum kicking around, my later mother got me the ZX81 as she could see that computers would be the future.
I remember my ram pack wobble and my first ribbon cable as well, plus the Thermal printer.
Nothing better than using that sodding keyboard to manually type in games programmes from the magazines for hours on end, only for the ram pack to wobble before you saved it.
Just caught that on the Beeb the other day (missed it first time around). As they had the Chris Curry character say, "If we'd stuck together then we could have been the British IBM".
It's amazing to me how Clive Sinclair and Alan Sugar are acclaimed as visionaries. They were (and are) nothing of the kind. They were just lucky in happening to release the right product at the right time, pure and simple. The fact that both men subsequently ran their companies into the ground with a long series of crap decisions makes that pretty damn clear. The only reason AMS is a millionaire today is that he offloaded some of his money to other people to invest - everything he personally touched turned to shit in pretty short order.
I'm not sure anyone's claimed Alan Sugar as a visionary. There's loads of tales of his early days and some of the interesting bodges used to make Amstrad products 'better' - but that's a separate post.
As for Sinclair - yes, he was lucky, but he was in a market where there were hundreds of other people trying to be as lucky, and failing. It's easy to forget in these days of near-two party OS politics, that alongside the ZX81 and Spectrum were devices from Jupiter Cantab, Oric, Tandy, Commodore, Newbrain, Dragon, Elan, Atari, MSX and a dozen others - each completely unique and incompatible.
Sinclair's skill at the time was getting more bang for less buck than virtually any of his competitors. He pushed components beyond their limits, made use of quirks in their specs and pulled together innovative technologies to deliver something unique. It was a scattergun approach that had as many failures as successes, but before commoditisation removed much of the advantage, he was putting home computers into the home. There has to be huge credit to the teams that worked on the machines - from Rob Dickinson's wonderful industrial design through to the FPGA and OS that ran inside.
Of course the industry changed massively and that shook Sinclair, Acorn and most of the others back down to nothing. I'm not sure that makes them less significant, nor necessarily less visionary. Very few technology companies have survived from those early days to present times, and even those have had disastrous moments alongside the successes.
It's a huge pity that these days we're so risk averse and so keen to ridicule people who're willing to try something different that we have trouble producing such exciting technology. Hold an iPad in one hand and a ZX81 in the other and think what could have been.
@"I'm not sure that makes them less significant, nor necessarily less visionary."
Another very significant aspect of the ZX81 (along with the ZX80 and the ZX Spectrum) is that Sinclair Research computers were the first computers available to so many people. That in turn spawned the UK games industry, which has for almost the past 3 decades, been able to compete at a world level in a multi-billion dollar per year global industry. That is a massive legacy that none can ever take away from the work of Sinclair Research Ltd. Their computers were hugely influential in starting the careers of so many programmers. Sure they moved onto so many other platforms but Sinclair computers were the first computer for so many programmers.
I have so many memories of the ZX81 and of that amazingly inspiring & enthusiastic time. It really did feel like the future was happening now kind of moment in time.
Happy Birthday ZX81!
It was not called FPGA, although the technology was similar. The real name was a ULA, or Uncommitted Logic Array, which was a bleading edge technology in 1980/81, invented by Ferranti, a British company.
The ZX81, Spectrum and BBC Micro all had ULA's in them, to consolidate the function of dozens of 7400 TTL chips into a single large chip.
Unfortunately, the technology was still immature, and the production problems that Ferranti had were a large part of the shipping problems for all of the systems mentioned. I waited for nearly 6 months to get my BBC model B that had been ordered as soon as Acorn would take orders.
By the time later systems came along, it was possible to have your own design of chip fabricated moderately cheaply, so the ULA died an ignominious death
My fault, yes of course it was a ULA rather than FPGA.
And yes, I do know about ARM. I've been lucky enough (!) to work with Chris Curry, Sophie Wilson and some of the Sinclair crowd - as others have said there are plenty of stories about the things they got up to. The BBC4 doc was a great dramatisation, if it took a few liberties for the sake of pulling the various strands into a coherent story.
... in my case in 1982, when I got a ZX-81. Many a happy hour was spent punching type-ins from Sinclair Programs magazine ... though I never had a RAM pack wobble because I didn't have the Sinclair RAM pack. My RAM pack was the Centronics 16K, which was laid out to fit the shape of the computer's rear and came with a velcro patch to hold the far end in place.
My big brother bought one of the kit versions with his birthday money and savings from his paper round. A week after he bought it they dropped the price on the pre-built verion to be the same as the kit version, oh how I laughed.
Then after assembling it with the help of a neighbour with a soldering iron, it didn't work, I laughed more.
It got sent back to the factory, where it was tested and it turned that several of the components were duds, so they sent back a fully built one.
So all the effort, grief and waiting to try to save a few pounds, which didn't really happen either. Still makes me smile.
...and put it together with the help of my brother who was an electronic engineer (conveniently).
Worked first time. Then I added an aftermarkey 16k RAM pack as it was cheaper than the Sinclair one (drive to London to buy it from a shop). Later I put it all in an ugly oblong plastic case with a keyboard on it, which I bought just before the company in question went bust. It took me several lengthy phone calls to harass them into sending it to me but it was worth it!
I spent many a happy hour playing games from a small company in Portsmouth (where I live) called Automata who produced early software for it and later the Spectrum.... anyone remember Pimania, the treasure hunt game? I was so close to cracking that one..... turned up on the right day but went to Greenwich instead of Hurstmonceux.
Ah those were the days - 3D Monster Maze anyone?
I had the pleasure of working for Jim Westwood in my previous job at Amino Communications. (He is still working for them).
Some of his stories of what they did in the 'Good Old Days' were truly amazing.
I was happy to see his cameo role in the BBC TV "Micro Men" film , made everyone at work laugh. (That and the picture of him on Planet Sinclair showing him when he was 34).
I really wish the BBC would release Micro Men on DVD. Every few months for about two years I've tried to see if its going to be released and still they don't. :(
Its a shame Micro Men wasn't longer, so it could show more background than mostly just the creation of the ZX Spectrum vs the BBC B, so maybe show more about the ZX80 & ZX81 (and Atom), but anyway, it was pure unending nostalgia from start to finish. A real joy to watch. :)
Please BBC, release Micro Men on DVD! :)
30 years... wow, I feel old! :)
I spent probably thousands of hours on my ZX81, learning BASIC and Z-80 machine code (didn't get a proper assembler until the Speccy came along).
It's a shame kids today don't have that immediate access to a programming environment. Lots of fun to be had once you get your head around variables, reading keyboard characters using INKEY$ and moving things around using PRINT AT and SCROLL.
"It's a shame kids today don't have that immediate access to a programming environment. Lots of fun to be had once you get your head around variables, reading keyboard characters using INKEY$ and moving things around using PRINT AT and SCROLL."
The bit that is lacking is resources to teach it at such a simple level. Most JS tutorials either assume prior programming knowledge and jump straight in to talking about objects and anonymous functions, or are aimed at designers so focus on DOM and HTML interaction. I haven't seen anything aimed at using it as an introduction to general programming.
I haven't seen anything aimed at using it as an introduction to general programming.
Everybody has access to dozens of totally free well documented programming languages today. Free C compilers, Free Python, Java, C++, you name it. And a bunch of more off beat graphical programming languages. Not to mention pretty good game creation kits bundled with many games. If you go looking, one problem you will not have, is a shortage of options. There has never been such good resources for even a lone teenager to learn how to program.
Problem is.. We also have access to pretty much every program or game we could want. How many kids even think that writing a program might be possible? .. And lets be honest. A GUI based program is not going to be nearly as easy as bashing out a few lines of BASIC to get a black square to move across the screen. Unprecedented access, unprecedented availability of help, but the least motivation ever. Sad really.
Back when I had a ZX81, I had little choice but to type in programs. Not a lot available for the 1K machines. And as I had to save up for the cassette deck too, I spend the first month or more typing everything in if I wanted to use the program. No way you could avoid learning a little something in such an environment. And just about every kid with a ZX81 was also a dabbler in programming at the very least.
You wanted to do something with the computer back then, you paged through the stack of magazines you kept under the bed(Not that kind of magazine... ), and hoped someone wrote an article on how to do it, or you figured it out yourself.
Now.. If you want something, just type it into Google and you get a whole slew of pretty much any program for pretty much any OS..
About the only hope is for kids to get interested in cell phone app programming. But to be honest, even that is a long shot, and again, a temporary thing. Give it a few more years, and the simple cell phone apps will be as complex and demanding as the PC apps are today.
Are you sure it was a MK14? Many universities used a KIM-1 (produced by Commodore, at least at the end), which was a similar product but used a MOSTEK 6502 rather than the Nat. Semi SC/MP which is what I believe was in the MK14.
I remember having to write a sine-wave generator on a KIM-1, and I managed to get a higher resolution wave than everyone else by having a lookup table with just 1/4 of the whole cycle in the lookup table, whereas everybody else had at least a half cycle (and some of them stupidly coded the whole cycle). Fitting it into 512 BYTES was a real challenge. But then I also managed to write a simple lunar lander on the Sinclair Cambridge programmable calculator in just 32 program steps!
Though you can still get kids into programming if you show them Scratch (scratch.mit.edu) which is a drag and drop programming language which lets you do graphics, animations and sound very easily and teaches you the fundamentals of program design. Say it quietly and you can even use it to do message passing and parallel processing (of a kind).
Sooner or later they'll hit the limits of Scratch, but by then they might be hooked enough to go on to a more powerful language like Alice.
And kids today have LEGO Mindstorms which really is far too good for them.
My ZX81 is gathering dust in a box in my parents' attic I think. I think my RAM pack gave up the ghost but will have to dig it out and see if it still works. Ours came from a family friend who had departed these shores (for Paraguay as memory serves), I wasn't really into computers so I barely prodded it at the time. Missed opportunity!
I had a look on eBay to see if they're exchanging hands for any kind of money. A basic unit without any of the gubbings seems to fetch around £30 going up to c.£100 depending on additional kit and publications. Wonder whether to punt it now or wait until the Chinese get a taste for computer nostalgia.
Paris, because she has a RAM pack slot too (sorry!)
I started my programming career (I'm at my office PC typing this whilst working as a developer for a major ecommerce company, thanks Uncle Clive) when I bought a 2nd hand ZX80 in 1981 when I was 16. I soon followed it with a 2nd hand ZX81 and loved them both.
My weirdest/'most inventive' use of the ZX81 was when a friend and I soldered electrical block connectors (the plastic blocks with the screws for fixing mains cables together) via a ribbon cable to the 81's keyboard matrix solder points on the board. That meant that a virtual external key could be created by connecting a switch to the block connectors and using INKEY$ to detect it in BASIC. I then took my classical guitar, covered the frets in a matrix of aluminium foil, taped wire in all the right places and used the strings as a conductor via the bridge, connected the wires to the ZX81, programmed it to make suitably pitched beeps based on the incoming INKEY$ detection and bingo, one very primitive and early digital guitar!
Those were the days!
Ill raise a glass to a old friend tomorrow, we'll fire up my zx81 and 16k rampack and play mazogs on the big projector for a laugh. Ive already introduced my 6yo to basic on it in the past, although we mostly use a emulator running on a xbox out of respect for fragile aging hardware.
j shifted p shifted p day it is ;)
What was really the spirit of the age was opening the thing up to add stuff. I remember a book called the explorers guide to the zx81 touting adding ram over the udg roms so you could have definable ascii, currah keyboards (although we rolled our own from a ancient industrial keyboard that we had to make the matrix to suit ourselves, being poor) and lots of other general vandal soldering activities. In fact my current zx81 was picked up a few years ago pristine because my original had long since died spewing kynar hookup from multiple places in the quest for comprehension and tinkery. Its spirit of mad hardware hackery lived on, they can't teach that with a degree ;)
Although out of the box, the ZX81 did not have sound, there were a number of third party add-ons that gave you sound.
I had a Quicksilver board that had an AY8910 on it, feeding a secondary modulator to add sound to the TV signal.
Quicksilver also had a number of other accessories including a high resolution graphics board and a programmable character board. You needed an interface board that sat between the ZX81 and the RAM pack, which provided two interface slots for the add-ons. Ugly as sin, and made the RAM pack wobble problem different, but as I added an external keyboard to mine, complete with power switch and reset button, I did not have to touch my ZX81 at all.
As I've said before on these forums, my ZX81 actually had 18K of memory, the 16K RAM Pack, the 1K of internal static memory re-mapped to a different address when the RAM Pack was plugged in, and another 1K of static RAM on the ULA side of the data bus isolating resistors to hold programmable characters that were accessible by changing the contents of the Z80's I register, which was used to hold the base address of the character generation table, normally in the ROM. Happy days!
You could control the value of the output cassette port directly with a poke or machine code. Idealy machine code for ability to change the pitch up and down - could get a good octave and a half out of it. It was capable albiet very limited due to the way it would save your works of wonder to tape or inted load them back up. I also managed to get the same resolution highres(sic) graphics that the spectrum did by rewritting the display control code, ok it was realy slow and not colour but hey I did it. Best part was you could then point to your own block of memory and have UDG's instead of an alphabet and it would actualy run slightly faster than normal as it was running from RAM and not ROM. But you needed to have the wobbly attached to pull that trick.
Nice first machine, went for the Oric after that instead of the Spectrum as it had that technical appeal and a 6502 after that I went Atari ST though I do think I missed out on the whole Amiga area, but we all make mistakes. I know COBOL I'm allowed, OK.
Actually, they were not thermal at all. The paper was covered with aluminium, which conducted electricity, and was 'written' by a wire that passed a current through the paper as it wizzed round on a rubber belt. Where the 'spark' hit the paper, the aluminium vaporized, letting the black paper below show through. Crude, noisy, and completely incompatible with listening to the radio. That is why the 'paper' was silver with black print, and also why you got a new high power supply for the ZX81 if you bought the printer.
I believe that they were not allowed to sell the printer in the US, because (surprise, surprise) it contravened the US electrical interference regulations.
This was an example of innovative thinking that made Britain good at creating ideas, but pretty crap at exploiting them!
Sorry, but the ZX81 did not contain dedicated video circuitry to prevent the bounce. Instead, it had two modes, "fast" and "slow". In fast mode, it was just like the ZX80, and bounced just as much. In slow mode, it gave priority to maintaining the display, so everything you tried to do went even more like molasses than normal for the day.
For maximum fun, tap out a long line of gibberish BASIC in slow mode, then try to backspace across it. Be aware that you will need something to keep the spiders from building webs on you while you wait for each character to be erased. For even more fun, set this up on one you find in a shop. (This was a common affliction of Timex-Sinclair 1000s (the American name for the same thing) found in US stores.)
Steve the Cynic
Fact failure #
Posted Friday 4th March 2011 13:44 GMT
Sorry, but the ZX81 did not contain dedicated video circuitry to prevent the bounce. Instead, it had two modes, "fast" and "slow ..
iirc, video was handled by a ULA and the Z80 cpu, as in the ULA forced the data bus low and fed NO OP opcodes to the CPU, the CPU then reading the character bitmaps from ROM back to the ULA.
9. ZX81 character display timing
... in 'fast' mode it had considerably more raw processing power than the BBC Computer.
I remember hand compiling assembly language and sticking the byte values into DATA statements in BASIC. These then had to be POKEd into a REM statement at the beginning of a BASIC program. Typing RAND USR <number I can't remember> then ran the machine code for you. Later there was the ZXAS assembler which made the whole process easier. Amazing what could be done in 1k let alone 16k. Which looking back gives you a whole different perspective on the slowness of a 256MB PC!
Anybody else remember 3D Monster Maze? Given the limited (64x48 black/grey/white) graphics it played surprisingly well. Basically just being chased round a maze by a dinosaur but, wow, in your own living room, controlling something on TV?
Although I am in danger of resurrecting a long dead argument, I dispute that the ZX81 had more compute power than the BBC micro.
Although the BEEB's CPU only ran at 2MHz, whereas the ZX81 ran at 3.75MHz, the BEEB's CPU was a 6502 that executed most machine instructions in a single clock tick, whereas the Z80 in the ZX81 averaged four clock ticks per instruction, and some of them required up to 13.
This was the subject of endless controversy between Sinclair/Amstrad owners and BEEB/Apple/VIC20/C64 owners at the time.
In general, the Z80 instruction set was more advanced that the 6502, containing more instructions, more addressing modes, and even some proto 16 bit arithmetic instructions (by treating pairs of 8 bit registers as a 16 bit register). The 6502 contained enough instructions to do what was required though, and was considerably easier to program (the bible of both processors, written by Rodney Zak, "Programming the Z80" was at least twice as fat as his "Programming the 6502", and had smaller print to boot). This made the debate a forerunner of the CICS vs. RISC argument, which hinged around similar concepts.
Remember, though, that BBC BASIC was blindingly fast for the time, and it remained the fastest BASIC available well into the advent of 16 bit micros, as documented by PCW's BASIC benchmark that they ran on all the systems that they reviewed.
And the BBC micro had a built in assembler, and a means of passing arguments between BASIC and your machine code, and also documented all of the OS I/O, sound and graphics calls that you could make from your machine code. And of course, the display in the BBC was totally hardware driven, freeing the CPU up to run your programs.
I used to write both Z80 code on a ZX81 and Spectrum, and 6502 on a BBC, and believe me, 6502 was easier, and for basic data manipulation, faster.
The BBC Micro IMO set the gold standard for home computers until the IBM PC came along. With its phenomenal graphics, superb firmware, real keyboard and better looks it trumped the ZX81 and all else.
The ZX80 and ZX81 do deserve praise for being an important step on the road, the ZX81 was a marvel for its time, in minimising the electronics into just a few chips, and was significantly cheaper than the BBC so it can never be a fair comparison between the two. Unfortunately it suffered from 'could have been far better' (*) which plagued Sinclair in near everything he did but he was a giant upon whose shoulders everyone has stood.
On what's inside; I was a Motorola 6800 man myself; and would place that higher than the 6502 but lower than Z80 in terms of architectural niceness. It's a shame the 6800 never got into the mainstream (I used the SWTPC which wasn't cheap and not a games machine), the Dragon with its 6809 should have become the king but failed to take off.
(*) I've still got my Sinclair Scientific calculator. Yes, the one which uses Reverse Polish Notation., has no "=" key. Unsurprisingly everyone who 'stole it' when at school brought it back :-)
Surely the 6502 takes two cycles to do the most basic operations, in practical terms? It's one cycle to read in the op code, and then a second to perform the thing. I think part of the reason the 6502 gets a bum rap in general is that it accesses RAM every single cycle, whether it needs to or not (or, if you prefer, doesn't properly indicate its intent), whereas the z80 accesses RAM only as required — and that tends to be more infrequent due to the more complicated instruction set.
So as soon as you put a 6502 into a system where RAM is clocked at a similar speed to the CPU but shared with video circuitry, it gets seriously hobbled. Comparing the Electron to the slightly later Amstrad CPC is instructive: the former hands at least 50% of its RAM cycles to the video circuits, causing the CPU to run at half rated speed; the latter hands 75% of its RAM cycles to the video circuits but the CPU continues to run at (per empirical observations, usually passed around as a rule of thumb) around 82% of its rated speed.
Obviously the BBC Micro gets around that by coupling a 2Mhz CPU to 4Mhz RAM, interleaving video and processor accesses, so it's not a relevant concern. I just think it's something that likely affected the tone of the debate.
The real proof is in the pudding. Elite is clearly faster on the BBC than the ZX Spectrum, but that's partly because the Spectrum does a software frame copy, lacking page flipping in the 48k machine. I, Of the Mask, Starstrike 2 and Carrier Command (asll solid 3d polygon pushers with good real time frame rates) on the Spectrum side are probably more impressive than Revs on the BBC, but the market was so much larger and most of those Spectrum titles are sufficiently later that they're probably as much a result of the greater amount of interested talent and various lessons already learnt.
I sooooo wanted a Spectrum, but in their wisdom my folks bought me a Mattel Aquarius instead :-( To this day I'm still not quite sure how from my christmas list, they managed to arrive at the word "Aquarius" from "Spectrum Spectrum Spectrum Spectrum Spectrum".
30 odd years later I've still never met another person who had one.
I had one!!! (years later, 2nd hand from a car boot even then...)
trying to create my own awesome graphics - as 8 year old it consisted of scanlining my own rectangles and triangles, making up a rubbish version of the Jurassic park logo
don't get me started about the film trailer i tried to do...
Never be ashamed! 16 colours, sound, rubber keyboard... I loved mine!
Although I remember playing the Grand Prix' game that came with it... hmmm.
I used to type all the programs from the flipchart book that came with it... concentric circles!
My dream of recreating Mr Do! on it failed however...
I was doing vacation jobs at Acornsoft at the time, and I remember the slogan that Acorn's marketing people didn't dare to use was "We've sold nearly as many computers as Sinclair has faulty ones". Sinclair sold about four times as many as Acorn, but about a quarter of them were returned as faulty. Rumour had it that the returned ones were marked with a green sticker internally, and re-sold on the assumption that it was just that the user couldn't get them working. Any returned ones which already had a green sticker were assumed to be genuinely faulty.
Started at the age of 10 with an '81, followed by a ZX-Spectrum (the "big" one, 48K) a year later which I then used for six years.
This thing started my IT career and radically changed my life and those of many others. In a parallel universe someone else would have made the first popular UK low-cost machine, but Sir Clive actually did it in ours. Bravo.
As a youngster I had the Australian spin-off of the ZX-81 - the Z300. Sold by Dick Smith Electronics (The Australian equivalent of Maplins) it also was a Z80 based machine with a keyboard which looked exactly like the ZX-81.
16K ram and a dubious tape drive for storage. If you wanted to try out a program from a computing magazine, you had to methodically 'POKE' machine code instructions into memory via the BASIC interface. Get even one wrong and you'd wasted an hour or more of painstaking hard work.
I had the three dead ones up the wall, flying ducks style.
I sprayed the last one gloss white, very posh.
Also I had the Memotech 64KB memory upgrade with the beautiful anodised extruded aluminium case that hugged the back of the ZX81 and NEVER WOBBLED.
3D Monster Maze was utterly terrifying.
I had a ZX-81 and wobbling rampack. and could only dream of getting the non wobbling memotech thingy.
Lots of badgering of my dad only resulted in "go get a job ya lazy bum" "but daaaaaaad its 1981 , there are no jobs"
Later on the only mometech product I got was an MTX512( who had 1 of those?) Brilliant machine, excellent quality, built to last , shame about the marketing.
Still got my one... sitting in the drawer next to me. and it works
As for the Zx81...... lost somewhere between here and my parents home...or lost forever
had a ZX81, and we used to go round to his house to watch him programme it or run a game on it. How sad is that? He became our acknowledged genius about technology for a while.
He quickly decided the ZX81 keyboard was too crappy and the memory pack too unreliable so he moved on to a Beeb and I got a TRS80 model 1. With a '5.25 floppy disc'. Remember them?
And we never looked back.
The thing with the ZX81 design I always thought is it looks stylish and small but is tethered at one end to the mains and at the other to a TV, making the smallness a bit pointless.
Ah, happy memories indeed! I fondly remember 3D Monster Maze with its T-Rex made up of a jumble of ASCII characters and blocks. Surely the natural fore-runner to Duke Nukem 3D and all FPS games since.
I'll raise a glass tomorrow to my long gone ZX81, strapped to a placemat with rubber bands with an empty fag packet stuffed under the 16K RAM pack to stop it wobbling. Probably one of my big brothers packets of Craven "A"s, but that's a whole different memory lane! :-)
Paris, cos err... something to do with being strapped down with rubber bands? That'll do!
A quick search online shows the Retail Prices Index was 78.3 in 1981 - in 2010 it was 228.4.
That makes the £49 equivalent to £143 at today's prices - or the £69 pre built for about £201.
Memories - lots of them and glad to see so many of 'us' still around - also lmao at the 'old arguments' about who's was best resurfacing after all these years :D
It is great to see so many positive stories about the ZX81 and such enthusiasm for it in what were the very early days of home computing.
I had my first ZX81 at the age of 13 in 1982 - purchased from my brother, so he could buy a Spectrum. I too had everything screwed to a board, to stop the ram pack wobble - but then I needed something, as it had to be balanced (together with the TV) on top of my bed!
I eventually moved it into a case with a full sized keyboard, but then sold that and moved onto the Sinclair QL which was still my main machine until about 2002 when I bought my first PC!
I still support the old Sinclair computers and have daily contact with other users. Over the last few years, we have brought replacement keyboard membranes for the ZX81 to the market, and the 30th Anniversary will also see the launch of the ZXPander - a modern interface to provide both additional memory and the ability to LOAD / SAVE instantly from SD memory cards.
A lot of new software has been written over the past couple of years, much of it using hi-res graphics on the ZX81 (something that was not really achieved until about 1983/4) - see www.rwapsoftware.co.uk/zx81/zx81_software.html
The discussion forums at http://www.rwapservices.co.uk/ZX80_ZX81/forums/ are also very active, with plenty of ideas floating around and development occurring as a result.
I wonder how many people will be looking back at Windows based PCs and celebrating their 30th anniversary..... Bet no-one will be looking back in 2030 at the 30th anniversary of WIndows ME / 2000 - that's for certain!
The ZX80 and ZX81 achieved their small size, low component count and price due to much of the necessary logic circuitry being provided by a single Ferranti ULA (Uncomitted Logic Array) on each machine. The ULA had a whole load of gates which were not connected until the final stage of manufacture - the interconnection of gates could then be determined by the customer, in this case, Sinclair.
Ferranti have long since gone but it is nice to remember that Britain produced some significant innovations.
The ZX80 had 21 ICs inside but no ULA - the ZX81 had just four; the custom ULA in the ZX81 combined 18 generic TTL ICs from the ZX80 into a single package. The ZX80 ran hot because of all the circuitry inside and there wasn't much room internally due to all those chips, but the ZX81 was a lot cooler.
The ZX range and all the UK home computing explosion of the early 80s was at a pivotal point for the UK - it is often seen as the birth of home computing but at the same time it was the beginning of the end for many UK "hi-tech" businesses; from then an increasing amount was outsourced overseas.
The ZX81 is still used as a classic computer design in some US colleges in particular because it splits the four basic sections of a computer across the four ICs - RAM, ROM, CPU and the ULA handling the interface jobs. It's highly optimised and that demand from the colleges keeps the kit price high - in US terms, it's about the same $price as it was 30 years ago, at least on the sticker and without taking inflation into account (in the UK, kits currently fetch about £100, which is more than it cost in the beginning).
Steve the cynic is basically right, there was no dedicated video circuitry. There wasn't an FPGA either, there was a custom logic chip (made by Ferranti?) which replaced a bunch of standard logic chips that the ZX80 had, reducing the chip count from I believe 21 to 4 (or 5 on some units). There was some sort of hardware modification in the logic chip to allow slow mode, that would not work on a ZX80 with the ZX81 rom upgrade.
The video was generated with the help of the DRAM refresh cycle built into the Z80 microprocessor, this wasn't needed as the computer used static ram (1x 1K or 2x 512byte).
The refresh cycle was set up by sortware at the start of each scanline to generate addresses to read the screen data, the logic chip kept the Z80 executing NOPs (No OPeration instructions) for the duration of each line by basically shorting the data lines to ground.
Lots of use and abuse of the components, but they made a working computer system using just 4 chips all the way back then, and it was affordable. Within its rather tight limits (it was cheap) it was a very capable little machine.
You didn't mention the manual. The manual was awesome, it started right at the start (it had to, most owners would never have used a computer before), introduced more concepts as you read through, working up to documenting many of the inner workings. My favourite page is where it introduces the concept of variables by using the rapidly increasing price of eggs!
My First ever computer. Badgered my dad for one for ages in the run up to christmas. First computer I ever owned/programmed/tinkered with.
This was the computer that launched my interest into all thing computers and gadgets and ultimately launch me in a career in I.T.
Still got a couple in my collection along with one of every Spectrum Model (including the resonably rare 16k Spectrum (fully boxed)).
I also had an Acorn electron and then a BBC model B. Those were the days...........
Of cours these days I still run emulators to play the old games for these computers and tinker with programming.
I shall lift as pint or two tonight in celebration.
Christmas 1981 what a great moment for a 11 year old.
After 6 months hanging around in WHSmiiths staring at it and begging my parents.
Ah I can still vividly remember the absolute thrill and joy as I pulled the polystyrene packaging from the cardboard sleeve. Looking at the pictures, I can still remember the smell of it for heavens sake!
Then Christmas day spent typing in the first programs from the manual. Something about the price of oranges I seem to remember.
What a major pivot point in my life. 30 Years on and I've got kids of my own and we're living a great life style. In no small way, thanks to that little black box.
Sir Clive and everyone involved - Thanks from the bottom of my heart!
ps I have a 4 year old daughter who is teaching her two year old sister how to play cartoons on our old iphone. I wonder if they will have similar memories?
It did indeed. The CPU did everything, so if you could tie it up doing something else, it wouldn't have time to do the screen.
The ZX80's screen used to flicker when you pressed buttons, purely because it was being distracted having to process the keyboard input.
The PET was a bit expensive for the home market, but I do have fond memories of them (and one in the attic). First computer I ever programmed in machine code. Still got my Rodnay Zaks' programming books on the shelf.
Somewhere I should still have the sound interface I made for the PET... By connecting onto the 6522's serial shift register.
..software designer who cut his teeth on a ZX81 (and thermal printer and 16K ram pack). Moved on to a BBC B after saving up my paper-round money.
Lots of sitting in my bedroom typing in programs from magazines. And playing Elite. Then learning to program and decided that this was what I wanted to do for a living.
And I do. Marvellous.
Good old ZX81, couldn't have done it without you.
I marked this occasion by buying a mug from eBay which has a picture of the keyboard on it, should cause some comments in the office.
I had one of these as my second computer (first was the bat + ball console), it was fantastic but wasn't it mono? Or maybe I was using it on a B/W TV? Don't really remember.
Apparently you can still buy the kits for this - but only with the US PSU.
Would be interesting to see if you can write a networking stack for it or something...
Great article, by the way.
Back in 1980/81 we still had the ability to try and create something like this. We succeeded. The wobbly ram pack for Sinclair was no worse than the wobbly one on the Commodore - I had both at different stages. The games industry and software engineering that resulted has seen the country make far more money than Sinclair could have predicted.
I tried to create something (not on such a grand scale) last year to be told I couldn't possibly expect investment to develop it in the UK, and certainly not to make it here. This was not just one isolated investor but many different ones. In the end I decided that if I couldn't do it here I wouldn't do it at all.
Britain will never be great again unless we find some banks/investors with the balls to invest (preferably at a sensible cost) in the UK.
When I were a mere whippet,my boss used to drive me (as a BT apprentice, I wasn't allowed to drive) to Gaydon, one of the first 'X' exchanges.
We always knew there had been problems, because as the door was opened, this nasty 'printer smell' would be obvious. The stronger the smell, the bigger the problem.
Now, if you want 'smelly' without the 'ruby mellie' try working with a TI 'Silent-700' all day. "Silent, but deadly" springs to mind.
Having said that, page 1 of the article shows a Sinclair MK14. I cut my teeth on that*. I'd seriously love another.
*No, I had wire-cutters. Well, actually my toenail clippers. Or, used me mam's teeth when she was asleep....I reckoned the water in the glass killed static.
I remember the Spectrum power pack recall.
It was taking so long to receive the replacement I rung them up to complain. I thought it was very good service from Sinclair when I received a new power pack the next day.
A week later I recieved another one.
Subsequently when I ordered from Sinclair I received 2 of everything I ordered. Of coarse I never abused this faulty part of the Sinclair system..........
When I was 16 I wanted a ZX Spectrum - all my friends had them - but couldn't afford one, so I saved up my pennies and got a ZX81 instead.
I spent countless hours working my way through the manual, writing 1k games, or typing in listings from magazines. I saved up and bought a Memotek 16k rampack (fastened with velcro and much sturdier and elegant than the wobble-prone sinclair job) and then spent even more hours playing 3D monster maze and 3D defender from J.K.Greye software.
As has been said, the manual was excellent. A complete tutorial in how to use the computer and program it. It helped me learn to program, which meant I was ahead of the entire class in Computer Studies at school.
Later I got a C64, and sold the ZX81 for £25 to pay for it which I regret. Luckily a few years later I bought a battered second hand one from a school kid for a fiver, and I still have it today. It still works, though the 16k Sinclair Rampack is faulty.
The ZX81 was my gateway into computing, and I've worked with computers ever since, eventually getting into game development, so I owe Clive Sinclair a debt of gratitude. Even though I graduated to other computers like the C64, Amiga, and PC, I still have a soft spot for the ZX81 and Spectrum.
Nifty bit of soldering to get that fitted with sockets*. Certainly my version didn't have plated-through holes. U used maplin's socket-on-a-strip concept, so I could solder both sides...
Like practically every story I've heard, almost every MK14 owner regrets selling theirs. (I gave one away to a broke enthusiastic apprentice we had). Useless? Well, I got it to display MSF's fast-code time display (fast-code now discontinued).
*That crystal looks like it's been in the wars. Which reminds me - the SC/MP was feted at 4 meg. but the crystal, IIRC, was a TV decoder part, (4,43Meg?) so some 10% faster than the chip was specc'd. So, I guess Sir Clive was the first mass-overclocker...
Although I admire its specs I've never been too impressed by ZX81 because I think Spectrum was the real blast... I'm still planning to get one on eBay.
Wasn't Spectrum way more successful commercially as well?
ZX Spectrum, with its rubber keys etc - my first machine, that probably put me on this track. :) As I grew up in then-Commie Hungary the COCOM-list made it impossible for us to buy one there so we had to go to Vienna to get one. I was around 12-13 years old I think when my parents asked us if we want a computer or a new video recorder and I remember telling my 7-8 years old brother 'we can watch movies on a computer'... so we went for the Spectrum and boy, it was a great call! Of course, almost everybody told me I am stupid and should have gone for the new VCR instead but what do they know? ;)
Sinclair BASIC was fun especially on Spectrum, better than on ZX81, obviously.
All that tech in so few chips. There was nothing quite like it at the time. Still got my original, with the ZX printer and a 3rd party wobble-free RAM pack.
Built up a large collection but it's all gone to a museum. Kept my Sinclairs though, including a couple of ZX81s in Fuller cases. Full-travel keys. U Jelly? Picked up the US version of the printer along the way too.
Have the Hi-Res software package somewhere. Maplin did a hardware version in the days when you could get any of half a dozen electronics magazines in WHS. We have lost a route into tech for the young courtesy of surface mount devices, patent laws, copyright and sealed boxes.
Did everyone start out with Toni Baker's intro?
There was a colour convertor, but I've never seen one working.
The ZX96 is worth a look.
Best Christmas present a small boy could have in 1981.
Happy birthday little guy.
I bought a Mk 14 and did some machine code programming. I even modified the thing to use a UV erasable EPROM to save my code. The whole thing was interesting, but I couldn't really say the results were useful!
So I waited a bit, and bought an early Osborne 01. This had CP/M, floppy disks, dBASE II, the BDS C compiler, Wordstar and a 300 baud (!!!) modem........almost modern really.
Seventy nicker in '81 is now 220 quid, apparently. For which you can still get a small slow computer with crap screen resolution...
I managed to sell mine (with RAMpack) for fifty quid, just before it became worthless. Didn't buy another machine with my own money for *years*. Got interested in girls and motorbikes instead, IIRC.
Geekdom didn't reclaim me until the late 80s.
I still use 1980s kit every time I use my computer - IBM Model M keyboard, 1989.
You were my first computer, you gave me a spark which lit a fire and gave me the wonderful career I now have. I wish, like many of the more foresighted and prudent people here, that I'd kept you in a box in the attic, but sadly I can't even recall what I did with you. Sure you had your faults, but you also helped to create a whole new generation of coders and IT luminaries that would have otherwise never realised their potential. I'll be raising a glass to you this weekend you can be sure of that.
I picked potatoes and harassed my dad incessantly until he caved and chipped in 20 quid he didn't really have to buy the ZX80 kit, and I breathlessly soldered it together over a weekend on the kitchen table.
The wonder and satisfaction as it fired up for the first time and worked perfectly, then the countless hours sitting bleary-eyed through entire nights making (I thought) amazing programs on that flickering screen, is closer to magical in my mind than any sterile, disposable iDevice could ever hope to be.
Thanks, Sir Clive!
Apparently there was a way to upgrade your ZX80 almoust to an ZX81. You got a plastic keyboard overlay and floating point math. However no slow-mode.
Well that little machine was where I had my first experiences in programming on. I also calculated some homework on it.
What we'd now need would be an equally clever BASIC on a microcontroller. Unfortunately current attempts either need an external compiler, or are limited to fixed line length. A single chip home computer would be a great teaching aid.
I have 1987 Acorn User with review of Acorn's ARM based Archimedes. Also later issue featuring RIscOS.
As many ARM licensed cores shipped per day as x86 from Intel in a Month, or more.
MS win2008 will run on ARM.
MS winCE/WinPhone/WinMobile/win7Phone runs on ARM. MS for some years now has only really supported ARM for WinCE/Phone family.
ARM also runs
Hands down this article and the subsequent comments from it form the best thing the Reg has ever done, thanks to the zx80 I got hooked I to IT and have worked all over the world owing it all to the accessibility of those hobbyist machines, the problem with newer machines is that they have no 'tinker' value nor create any interest in looking under the hood
Get yourselves a handful of 18F PICs (http://www.microchip.com/) and a programmer. It's easy to set one up to do all sorts of jobs and hook it up to a PC via a serial or serial/USB converter. One of mine is providing me with info about my house (temperatures etc.) via a small server program on my fileserver even though I'm 800 miles away in Switzerland.
Another is emulating a serial port chip on my homebrew FORTH 6809 system.
Cheap, robust, versatile and available in 0.1" pin spacings so PCBs can be made using laser printers by printing the mirror image onto photo paper, ironing that onto clean copper board, soaking off the paper and etching the board.
After building a Nascom 1 1k computer in 1978 my children got the bug and we ordered a BBC B computer as soon as they were announced. This had a real keyboard and enabled assembly language programming. Soon we had a family business with both my schoolboy sons writing games in their bedroom and publishing them through Micropower and AMX, culminating in the highly successful AMX Super Art. program used in many UK schools. Both sons went on to successful careers in computing.
I remember studying an electronics course at the local night school, the end-result of which was to be the building of our very own ZX81 from the Sinclair-supplied kits. We paid our money*, built beepy wossnames out of 555 multivibrators, waited and waited and (as best I know) the kits never actually arrived...
I still get flashbacks when I smell a waft of flux-smoke...
*Well, I paid my parents' money. I was far too young to have much of my own...
I too started my computing career on a MK14 - taught me all the basics about microprocessors at a pocket money affordable price. Chemist is quite right about modern microcontrollers offering the same experience, plus quite a bit more. You can combine the two - I've built a MK14 real-time emulator running on one. See the front page shot on http://mymk14.co.uk. I prototyped on PIC, but I've moved to AVR, as it offers enough memory to emulate a fully expanded (640 byte RAM!) MK14, and also comes with GNU C if needed. Happy days!
Never had a ZX-81, but my Dad did get a ZX-80 when they came out. I cut my programming teeth on that, later moving on to an Acorn Electron. I got to use the ZX-81s, Spectrums, and BBC Micros at school.
Many happy memories typing in stuff from magazines and creating my own code too. :)
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