[HN Gopher] March 5, 1981: Timex Sinclair ZX81 Launched (2018)
___________________________________________________________________
March 5, 1981: Timex Sinclair ZX81 Launched (2018)
Author : rcarmo
Score : 99 points
Date : 2022-03-05 11:08 UTC (11 hours ago)
(HTM) web link (dayintechhistory.com)
(TXT) w3m dump (dayintechhistory.com)
| jonathanstrange wrote:
| I loved mine and learned BASIC with it. Unfortunately the RAM
| expansion had this undesirable auto-reset feature. If I only had
| known that the defect RAM expansion could be fixed with a bit of
| tape...
| qiqitori wrote:
| I recently replaced a broken DRAM chip on one of those!
| https://blog.qiqitori.com/2022/02/testing-a-zx81-ram-pack-wi...
| (this is more about finding which one is the broken one than
| about the actual replacement)
|
| The one I had doesn't seem very wobbly though. Maybe there is
| some variation between production runs etc.?
| bencollier49 wrote:
| Or a bit of blu-tack, in the shape of a runner bean...
| louthy wrote:
| Nice reference there! Micro Men really is a great docu-drama,
| it really feels like it captures the time very well.
|
| As my first computer was a BBC Micro, it really struck a
| chord. It's great seeing the specs for the (yet to be built)
| ARM chip on the board in the Acorn office, and it's also
| awesome that Sophie Wilson playing the barmaid too!
|
| For those that haven't seen it, it's definitely worth a watch
| [1]
|
| [1] https://youtu.be/XXBxV6-zamM
| unfocussed_mike wrote:
| An absolutely brilliant bit of creative work, indeed.
|
| Nothing else has ever really conveyed that Clive Sinclair
| wasn't a sort of little professorial boffin the way the
| British press portrayed him; he was very business-focussed
| and evidently had quite a presence.
|
| (Common to the almost concurrent misportrayal of John Major
| as a small, retiring, grey man)
| bcl wrote:
| Mine had the unfortunate 'let out the magic smoke' feature :/
| Which fortunately led to the upgrade to an Atari 800 :)
| Zenst wrote:
| Ah yes, the RAM pack wobble. Was common as heck upon the
| original Sinclair expansion. There was however 3rd party RAM
| upgrades and those in comparision proved less prone to such
| wobble and with that regard, I was pretty alright with the one
| I setteled upon. But such PCB edge connectors were common then,
| less so these days.
| jeffreygoesto wrote:
| I had the Memopack 16k and it even fitted the
| "High"Resolution graphics pack on top. But then I also
| soldered a flat cable to an external keyboard which was much
| nicer to type on an did not wiggle the whole stack with every
| key stroke.
| nonrandomstring wrote:
| My ZX81 had audio.
|
| The ZX81 was so badly shielded with its thin plastic case it
| would make nearby radios go crazy. You could tune a MW radio off-
| station, put it close to the computer and listen to code
| executing. It made different sounds depending on what loops it
| was in. That was how I was able to make "computer music" in 1981,
| by poking little "machine code" routines into RAM and running
| them to make "songs" come out the radio.
| camillomiller wrote:
| This website is a clickbait website full of ads. I'm really
| surprised to see such a low quality publication raise to the
| first position on hacker news. Ads are all over the page and make
| it impossible to even find the actual article in all that mess.
| Horrible.
| JasonFruit wrote:
| On a complete side note, I grew up in Wisconsin, live there now,
| and have never heard anyone refer to another Wisconsinite as a
| "Sconnie". I think it's purely a marketing thing. "Sconnie Geek
| Nation," indeed!
| readingnews wrote:
| Heh, I have one of those, and the extra parts in the original
| boxes. I bet they are worth nothing still!!
| FollowingTheDao wrote:
| Oh my, the memories!
|
| I remember sitting on a big swivel chair late into the night in
| front of a 13" black and white TV writing programs and
| attempting, mostly in vain, to save them to a cassette tape.
|
| At 15 I should have been out chasing girls instead but what can
| ya do...
| sharken wrote:
| That's the wonder of the internet.
|
| While i cannot say i was a first mover with the ZX81, many
| hours was spent typing in hex codes on the ZX Spectrum in the
| hope that a great game would appear.
|
| Odd to think that the ZX81 is now some 40 years old.
| shever73 wrote:
| It seems like only yesterday! The Speccy itself is 40 years
| old on 23rd April this year.
| sharken wrote:
| Unreal! And the C64 turns 40 next year.
| tyingq wrote:
| I had a C64, and couldn't type terribly well, so typing in those
| programs listings from magazines without a typo was a frustrating
| cycle that made the end result more satisfying when it finally
| ran. I have to imagine that was more intense with the shite
| keyboard on these things.
| unfocussed_mike wrote:
| > I have to imagine that was more intense with the shite
| keyboard on these things.
|
| Yes and no. Yes, because the keys were not great, obviously.
|
| And no, because the ZX81 and the later Spectrum had a massively
| clever optimisation.
|
| A big chunk of the lexer and parser was implemented in a way
| that was kind of coupled to the keyboard driver.
|
| So you never typed out GOTO/GOSUB etc., in full.
|
| In fact you _could not_ type out a BASIC keyword in full; the
| keyboard would not let you. At the points where your program
| could syntactically accept a BASIC keyword, the keys went into
| keyword mode and would not produce letters at all.
|
| So pressing G or H at that point would not get you a letter,
| but GOTO or GOSUB.
|
| This was unusual then and is unheard of now. But it helped make
| some aspects of coding much more kinaesthetic. And it ended up
| being quite quick to key in listings, especially if you
| replaced the keyboard with an aftermarket unit.
| russfink wrote:
| I would even call that a sort of primitive IDE - it only let
| you enter valid commands like 10 GOTO 20 instead of 10
| xhehcbehsjsjdheh
| unfocussed_mike wrote:
| Yes in a sense it is.
|
| You could say its modern equivalent is the MIT LLK research
| group's design for visual block structure in Scratch, where
| you cannot assemble control flow in ways that cannot be
| parsed, and the quasi-physicality of it teaches you as you
| go.
|
| A tangentially-related story:
|
| When I was a kid I asked my chemistry teacher if a
| particular chemical bond could happen in ordinary
| circumstances.
|
| _(I can 't remember for sure but I imagine I asked about
| carbon-carbon triple-bonds, not least because it must be a
| common question and he was ready with the answer.)_
|
| His response -- which obviously elides some details! -- was
| to ask me to try to represent it using the balls-and-
| springs chemical models. Which you can't really do ;-)
|
| I am reminded of these things, really regularly, when I
| design any app or website a person has to interact with.
| It's possible to design useful tools that are also implicit
| teachers -- where designs communicate possibility and
| limitations without overburdening the user with detail.
| tyingq wrote:
| Ah, that's clever. Though the bulk of the typing was the
| "DATA" lines that got POKEd.
| Doctor_Fegg wrote:
| No DATA statements in ZX81 BASIC though! That came in with
| the Spectrum.
| unfocussed_mike wrote:
| Yeah, nobody liked keying in the DATA lines!
| unfocussed_mike wrote:
| Footnote: I guess the ZX80 did this too, judging by the photo
| at Wikipedia.
|
| https://en.wikipedia.org/wiki/ZX80
|
| I don't think I've ever seen one of these outside a display
| case, though.
| dcminter wrote:
| Oh my god so much. One learned a weird technique of sort of
| wiping ones finger tip firmly across the keypad.
|
| Slightly ameliorated by the fact that one usually used a single
| keypress to enter Basic keywords (e.g. J, symbol shift, P P for
| LOAD "" to put it into cassette loading mode).
|
| It made the notorious ZX Spectrum "dead flesh" keyboard seem
| quite luxurious in comparison.
| unfocussed_mike wrote:
| This article makes two important errors, unless I am much
| mistaken. [0]
|
| First: the ZX81 was not a "Timex Sinclair" product on the day of
| its launch because Timex didn't get a licence to manufacture it
| in the USA until the following year.
|
| Second: Sinclair Research was never (again, unless someone can
| correct me) a "Timex Corporation"!
|
| If it had been, it wouldn't have gone conclusively bust and been
| given a new life by Grumpy St Alan of Sugar, the brave champion
| of British national technology pride.
|
| "Timex Sinclair" was the US licensing venture (not the maker).
|
| Timex pulling out of that deal (because the Spectrum was
| understandably too British in spirit to easily flog to a market
| that had birthed the Apple II and where the C64 was cheaper) is
| arguably the start of Sinclair's slow-building battle against the
| tide.
|
| --
|
| [0] Important in the sense that I, as a Brit of a certain age,
| must correct them in the interests of a kind of battered and
| timeworn national pride.
|
| I would put these corrections in comments on the original
| article, but that would mean having a Disqus account, and in my
| experience that ultimately means encounters with trolls.
| helsinkiandrew wrote:
| Timex Sinclair was a joint venture to market the ZX81 in the
| US. I don't remember Timex ever being used in the UK at the
| time?
|
| https://en.wikipedia.org/wiki/Timex_Sinclair
| unfocussed_mike wrote:
| > I don't remember Timex ever being used in the UK at the
| time?
|
| No, indeed it wasn't -- perhaps my initial comment wasn't
| clear. (Some of that might be the latent British rage of the
| overlooked)
|
| I've amended a bit.
|
| (In fact I doubt the Timex Sinclair devices even worked here,
| and vice versa, hence the need for a manufacturing deal that
| dealt with needing NTSC and 60hz power etc.)
| scoot wrote:
| NTSC just needed a different modulator; and the ZX81 used a
| simple transformer/bridge rectifier/smoothing capacitor
| brick to convert to 9v DC, with a regulator in the computer
| to convert down to 5v, so 60Hz wouldn't have been an issue,
| although the mains power connector is obviously different.
|
| So, there's nothing special about a machine for the US
| market that _required_ it to be manufactured there.
| Presumably it was commercially preferable to do so.
|
| You're correct though that a US model wouldn't work in the
| UK without modification, and vice versa.
| krallja wrote:
| It also claims that "the Z80 CPU at 3.25 MHz was actually
| faster than the Apple II processor (1.08 MHz)." This is,
| pedantically, true, in that the oscillator is ringing faster.
| However, the 6502 completes more work per clock cycle than the
| Z80 does. A single-byte instruction (such as "increment the A
| register") takes 2 clock cycles on 6502, 4 cycles on the Z80.
| More complicated instructions can take up to 7 cycles on the
| 6502 and 20+ on the Z80. The estimate I use is that a 6502 is
| approximately 3x faster clock-for-clock than a Z80.
|
| Also, the Apple II CPU didn't spend 70% of its time drawing the
| screen! It had separate video hardware that transparently
| interleaved with the unused back half of the CPU clock cycle.
| The ZX81 was tricked into "executing" sequential screen-memory
| addresses in a very tight loop by falsifying its data bus with
| a NOP instruction. Fancier computers would use dedicated DMA
| hardware. Not Sinclair!
| unfocussed_mike wrote:
| Right. They were really simplified, and up against US
| economies of scale that meant less simple machines could be
| made at competitive prices.
|
| I think Timex's main projection was that the Sinclair
| machines would be affordable over the long term. But I guess
| in the USA, the competition became cheaper much faster than
| they expected.
|
| Over in the UK, as well as more expensive imported Commodore
| machines, the native competition included the _very
| expensive_ BBC Model B and its cousin the Acorn Electron, the
| beloved and excellent Dragon 32, the quite inexpensive
| Jupiter Ace (think ZX81 /Spectrum but running FORTH
| natively!), and Tangerine's Oric-1, which was adorable, and
| as with the Amstrad CPC sold well in France, expanding its
| market size a bit.
|
| The Spectrum 48K did well against them on price-performance,
| though the Oric-1 was often cheaper and is arguably the
| better device.
|
| In the USA, much larger economies of scale meant that the C64
| was more affordable, and for cheaper machines the Spectrum
| was up against the VIC-20 and Atari 400, and even Mattel
| wanted a chunk of the low-end in that same period of time
| with the Aquarius (which is similarly simple Z80 stuff).
| TMWNN wrote:
| >I think Timex's main projection was that the Sinclair
| machines would be affordable over the long term. But I
| guess in the USA, the competition became cheaper much
| faster than they expected.
|
| The competition became cheaper much faster than _anyone_
| expected.
|
| The Timex Sinclair 1000's introduction in the US in 1982
| caused the US home computer industry to believe that they
| had to enter the sub-$100 market. Tandy introduced the
| MC-10 (<https://en.wikipedia.org/wiki/TRS-80_MC-10>) as a
| cut-down version of its Color Computer, and TI designed the
| 99/2 as a cut-down version of its 99/4A. Two unexpected
| things happened:
|
| * Americans, more wealthy than Britons or Europeans, viewed
| $99 computers as toys.
|
| * Commodore's Jack Tramiel began a massive price war that
| drove the retail price of existing, more capable home
| computers down to $99. In 1983 the Commodore VIC-20 and TI
| 99/4A reached the $99 price point. TI thus never introduced
| the 99/2 despite having it ready for production.
|
| The VIC-20 and 99/4A received substantial third-party
| support; the Timex Sinclair 1000 and MC-10 did not, and
| quickly disappeared from the market.
| krallja wrote:
| BTW, the Jupiter Ace and ZX81 both have excellent iOS
| emulators, written by Kevin Palser.
| unfocussed_mike wrote:
| Ahh, nice.
|
| The Jupiter Ace is one of the great _" someone really
| made that a product?"_ things, lost to history. It had a
| flimsy shell and bad keys from what I remember reading,
| but it's amazing it became a product at all.
|
| There's a lot more of this stuff going on again in the
| microcontroller world; perhaps partly out of
| reminiscence.
| opinali wrote:
| I'm not sure about this simple comparison of 6502 vs. Z80.
| Sure the Z80 instructions had higher latencies in clocks, but
| it also had more registers so you could write the same code
| with fewer memory load/stores and it had a 16-bit ALU. It
| also had a fair offering of complex instructions that, while
| very high-latency, should be faster than the equivalent
| sequence of simpler instructions and also helped with code
| density which was critical in systems with a max of 64KB (see
| https://web.eece.maine.edu/~vweaver/papers/iccd09/iccd09_den.
| ..).
|
| For one data point in performance, theultimatebenchmark.org
| has some Forth benchmarks that apparently show a 4GHz Z80
| beating the 6502 by 2X (best scores for each: mc-CP/M Z80
| 4Mhz / FIG-Forth 1.1 / Fib2 = 1m19s, Apple II 1Mhz / Apple
| GraForth / Fib2 = 2m19s).
|
| Disclaimer: biased, veteran Z80 / ZX Spectrum programmer ;)
| shever73 wrote:
| Absolutely correct. Thank you for typing it out in such an
| eloquent, yet curmudgeonly, fashion. It saved me from having to
| do it!
| shever73 wrote:
| Although, Timex (technically) was the manufacturer. The ZX
| Spectrum, at least, was built in the Timex factory in Dundee
| [0]
|
| [0] https://www.bbc.co.uk/news/business-29122873
| ZeroGravitas wrote:
| And some trace the history of Grand Theft Auto and Lemmings
| back to this factory and the local boom in computers it
| produced, with one of the Rockstar North founders working in
| the Timex factory before creating his first game:
| https://www.nostalgianerd.com/from-dma-to-gta-the-story-
| of-d...
| rwmj wrote:
| Also - https://www.youtube.com/watch?v=RbAVNKdk9gA
| unfocussed_mike wrote:
| Yes -- though this was under contract, I guess.
|
| (Like how the Raspberry Pi is manufactured under contract by
| Sony in Wales)
| shever73 wrote:
| Yes, exactly. The article is still very wrong.
| zabzonk wrote:
| Timex did manufacture the ZX81 in the UK at their Dundee
| factory:
|
| https://www.thecourier.co.uk/fp/past-times/2030845/dundee-wa...
| iam-TJ wrote:
| I've still got the original Sinclair ZX81 bought in March 1981
| (but not delivered until 1st week of June 1981 due to demand) and
| it still works, even with its wobbly 16KiB RAM Pack!
|
| Much fun was had programming in machine language by looking up
| op-codes in Rodney Zak's "Programming the Z80" and counting the
| clock cycles to figure out the most efficient set of op-codes. As
| I recall the fastest op-code requires 4 clock cycles but some
| instructions would need more than 10 so much performance could be
| gained by knowing and optimising. This was before there was a Z80
| assembler available so the hex of those op-codes had to be typed
| and POKEd into memory from the BASIC interpreter.
|
| A side-note - don't forget the ZX81 was preceded by the Sinclair
| ZX80 in 1980 [0].
| Jaruzel wrote:
| FYI, the retro community have developed an internal 16Kb
| 'daughter board' so you can finally ditch that unreliable
| wobbly ram pack.
|
| Also, there's a 'composite mod' which replaces the RF
| modulator, and gives you rock solid composite image on modern
| TVs.
| scoot wrote:
| Modern TVs don't have a composite input. :)
| rbanffy wrote:
| It's a shame they didn't have SCART output.
| LeoPanthera wrote:
| I don't think that's actually true. Even my shiny new Sony
| 4K HDR TV, bought literally this year, has a single
| composite input.
|
| It's certainly being phased out, but it's not gone yet.
| chkas wrote:
| I would like to refer to this great book that taught me
| programming.
|
| [Sinclair ZX81 BASIC
| Programming](http://otremolet.free.fr/otnet/otzx/zx81/basic-
| progr/)
| open-source-ux wrote:
| " _The Sinclair ZX81 only had 1 kB RAM with option to upgrade to
| 16 kB._ "
|
| If you're wondering "what can you do in 1kb of RAM?", how about a
| complete computer game of chess? The YouTube channel _Nostalgia
| Nerd_ compares the 1981 '1K ZX Chess' program with a more modern
| chess engine. How do they stack up?
|
| _A game of Chess: 1981 1KB Computer vs. Modern PC_
| https://www.youtube.com/watch?v=R3By_rdwxSg
| rwmj wrote:
| David Given, who posts on here sometimes, did a great video
| about the process of coding a game on an unexpanded ZX81:
| http://cowlark.com/2018-09-26-zx81-programming/index.html
| russfink wrote:
| Yes, and it is our lot that decries software bloat. We know
| what can be done with K bytes, why do we need K * K * K to
| simply boot?
| retrac wrote:
| Ever written anything in assembly? We trade cycles and bytes
| for programmer convenience. Assembly code heavily optimized
| for size will do things that are absolutely horrifying from a
| maintenance or general "architectural cleanliness" angle.
| Terribleness you might encounter:
|
| * Reading instructions as constants because the values you
| need happen to already be in the code.
|
| * Self-modification, including writing variables as constants
| into the instruction stream, generating instructions at run-
| time, and reusing code space as data space for one-once code.
|
| * Using bits in the opcodes to store data, since a single
| bitflip doesn't affect the interpretation of some
| instructions. E.g. on the Z80 if Z and C are both always 1 at
| a particular point, you can use either jrz (0010 1000) _or_
| jrc (0011 1000) and use the 5th bit in that instruction as a
| flag. Free storage!
|
| I do find this sort of thing fun. As a hobby. I wouldn't want
| to write an air traffic control system that way.
| KingOfCoders wrote:
| Encountered the ZX at the same time as a Vic20, liked that it was
| more colorful, but was astonished about the bad keyboard compared
| to the Vic20.
| dcminter wrote:
| You're thinking of the ZX Spectrum (colour, hence the name)
| rather than the monochrome ZX81.
|
| Edit: If you thought the Speccy's keyboard was bad then you
| would have been astounded by how much worse it was on the '81.
| KingOfCoders wrote:
| Yes you are right, the Spectrum had the rainbow over the
| keyboard compared to the boring color of the keyboard of the
| Vic20.
| krallja wrote:
| The ZX81 had only two colors: black and white.
| lupin_sansei wrote:
| 3! You could make grey using the checkboard box character
| thing.
| lupin_sansei wrote:
| I was super impressed how they got high resolution graphics out
| of the ZX81 which only has characters not a user programmable
| bitmapped display
|
| https://retrocomputing.stackexchange.com/questions/6134/how-...
|
| https://youtu.be/iW8QoL4NYkU
| rbanffy wrote:
| These are really impressive "misuses" of the technology
| available. _VERY_ impressive.
| SigmundA wrote:
| Ah yes my first computer, still have it in the garage, keep
| wanting to spend some time and see if I can get it to boot again.
|
| My Dad built it from a kit, can still remember him spending all
| night soldering it. Literally set the direction of my
| life/career.
|
| We didn't have any permanent storage at first, so I would type
| basic programs in by hand like games from magazines and play
| them, then it was lost on power cycle, so if I felt like playing
| I had to retype, talk about learning programming through
| repetition.
|
| Eventually we got an audio cassette recorder working which took
| like 10-20 minutes to save and load a small basic program, was
| torture. Eventually upgraded to C64 but still needed audio
| cassettes for a while the 5 1/4" floppy drive was much more than
| the computer itself but when we finally got it felt like the
| future being able to quickly load and save programs!
| YZF wrote:
| I also still have mine somewhere. With the 16KB expansion
| pack...
|
| Nah, it was a lot less than 10-20 minutes. Quick research says
| ~300bps so a 1KB program should save/load at about 27 seconds.
| [deleted]
| rwmj wrote:
| Don't just plug it in! The power supply and voltage regulator
| are notorious for going bad, and on the ZX81 they can fry the
| RAM chips (which are hard to get and even harder to desolder
| and replace). Watch some reputable online videos about
| restoring this computer first.
| 300bps wrote:
| Commodore 64 power supplies fail similarly.
|
| The voltage regulator on the 5V line fails causing higher
| voltage to be fed to the motherboard potentially frying every
| chip on the board.
|
| https://retrogamestart.com/answers/replace-c64-power-
| supply-...
| russfink wrote:
| Took my TS 1000 out about THIRTY years ago - plastic membrane
| keyboard leads cracked with age, could no longer type (arguably
| only a minor loss compared to when the keyboard was working :-)
| rwmj wrote:
| Not sure about the US variant, but UK keyboard membrane
| replacements are available: https://zxrenew.co.uk/Keyboard-
| Membranes-c20672681
| pauldavis wrote:
| My ZX81 memory: I took the T to the Sinclair administrative
| office in Boston to buy a super-early one with cash money.
|
| I had pre-flighted the transaction by phone, but it was still a
| strange thing for the office to do a retail transaction - I think
| my change came out of the postage money drawer. The machine was
| handed over in brown corrugate, without shiny shelf-ready
| packaging.
|
| Many hours of programming and experimentation ensued.
| mellosouls wrote:
| Arguably the most important computer in British history with
| respect to enabling access to the general public rather than
| niche segments and tech enthusiasts.
|
| Important also as the predecessor of the monster that was the
| adored Speccy, and it's competitors from Commodore etc.
|
| At least in the UK, this is where the home computer began.
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(page generated 2022-03-05 23:00 UTC)