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Good articleZX81 has been listed as one of the Engineering and technology good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it.
Did You KnowOn this day... Article milestones
January 30, 2011Featured article candidateNot promoted
August 24, 2012Good article nomineeListed
Did You Know A fact from this article appeared on Wikipedia's Main Page in the "Did you know?" column on January 7, 2011.
The text of the entry was: Did you know ... that users of the Sinclair ZX81 (pictured), a British home computer of the early 1980s, balanced cartons of cold milk on top of the case to stop it from overheating?
On this day... Facts from this article were featured on Wikipedia's Main Page in the "On this day..." column on March 5, 2011, March 5, 2014, March 5, 2018, and March 5, 2021.
Current status: Good article


I've changed the table to reflect the market position in the UK in June 1981, the time when the ZX81 was available to buy. The IBM PC, Dragon and Tandy Color Computer were not available at that time, I've put in some kit computers that were widely available in the UK instead. (talk) 02:33, 4 December 2020 (UTC)Reply[reply]

Just to add some other points. I was going to add the Acorn Atom - after all they are the great Cambridge rivals to Sinclair - but firstly I didn't know how to describe the BASIC in the table, its a mixture of TinyBASIC and assembly code (MS Level 0.5 ?), secondly anyone actually ordering an Atom in June 1981 was unlikely to actually receive one in 1981, so I don't know if that can be counted as an available system.
Well I've added the Atom now, I'm not sure if the table is getting too big ? (talk) 01:20, 31 January 2021 (UTC).Reply[reply]
There is also the Nascom but I couldn't find much info on the system pricewise for June 1981 and its a bit neither here nor there, not as cheap as the Tangerine system, nor as widespread as the Ohio Scientific, which was one of the most popular systems in the 1970s, you used to see them in universities and laboratories all over the place - but who remembers them now ?
The MicroTan and Compukit didn't include a power supply - but then neither did the ZX81, that cost another ₤15, although by June Sinclair was giving up on that idea because of all the returns because of incompatible power supplies. The Apple II was the real outlier, there wasn't a cassette interface availble by then, you had to buy a disk drive and a controller, and the full 48k because 32k was taken up by ProDos. You couldn't just plug it into the telly either, it had RF but only for NTSC, you had to buy a PAL RF card which cost almost as much as a Taiwanese composite video monitor - a total Apple system cost almost as much as a brand new car.
Oh, another thing. The TI and the TRS-80 had restricted BASIC - there were no POKE or PEEK commands meaning that only very simple BASIC programs could be written. TRS-80 Level II BASIC cost a cool ₤150 extra - three times the price of a ZX81 ! The TRS-80 was a fairly low cost system in the US, but Tandy's foreign prices were crazy. (talk) 03:59, 29 January 2021 (UTC)Reply[reply]

A few thoughts...[edit]

As a former ZX81 owner, I think this is a pretty good article overall, but a couple of things did come to mind:

  • I'm wary of appearing insular with this one, but there does seem to be a bit of an American slant in places, which seems odd as the ZX81 was primarily a British machine. Firstly, I think it would be much better if the main photo was of an actual ZX81 rather than a TS1000 (though the latter could certainly be retained to illustrate this variant), since although the outward differences are small they are there (brand name, "DELETE" key instead of the ZX81's "RUBOUT"). Secondly several peripheral prices are given in USD only, also odd for an article about a British machine.
  • You're right! A real ZX81 image is quite better, and I just happened to find one on Commons for once. I think the Timex image is better fit in the actuall Timex Sinclair 1000 article, so Im going to fix that soon. --AndersL 19:32, 29 November 2005 (UTC)Reply[reply]
  • There's a bit of confusion about RAM packs. Quite early in the article there's a reference to a Memopak (made by Memotech), yet there's no attempt to explain what a Memopak is, which might lead readers to assume that it was a brand name for the RAM pack pictured (Sinclair's own effort), which is in fact of a completely different appearance. (I always found Memopaks to be less "wobbly" than Sinclair ones in any case.) Finally, a few other companies - DK'tronics was one, IIRC - sold RAM packs too.

I also wonder whether at least one of the authors has been reading The Explorers Guide to the ZX81, since quite a number of the things mentioned here are also mentioned there! :) Loganberry (Talk) 15:06, 26 October 2005 (UTC)Reply[reply]

The ZX81 was marketed in the U.S. Why do you say it is a "British machine"? Mirror Vax 23:04, 26 October 2005 (UTC)Reply[reply]
For exactly the same reason I consider the VIC-20, which was widely marketed in the UK, to be an American machine. After all, you can buy Jaguars in America, and the company is owned by Ford, but that doesn't stop a Jaguar being a British car. Besides, I don't have a problem with US prices being quoted for peripherals - but since this is an international encyclopedia, not a US one, I do have a problem with only US prices being quoted, and I was hoping someone would know the sterling prices and include them in this article. Loganberry (Talk) 15:52, 27 October 2005 (UTC)Reply[reply]
The machine was designed in Britain by a British company started by a particularly famous British entrepreneur. I think that makes it pretty British :-) Richard W.M. Jones 19:21, 27 October 2005 (UTC)Reply[reply]

The machine was third rate, poorly designed, and supplied by a company whose customer service was appalling. How could it possibly be anything other than British?! —Preceding unsigned comment added by (talk) 12:19, 4 September 2008 (UTC)Reply[reply]

Very true, but you need to understand Britain in those days to understand why. The ZX81 was able to bring computing to the masses because it was designed down to a price (and was in fact a very elegant design in those terms, not a "poor" design at all). Britain had been struggling under a disastrous socialist/keynesian economic experiment since the war, and the masses of the people, teh proleteriat, were genuinely poor and could not afford the kind of computers (and other goods) americans could afford at the time. The middle class- in Britain, this translates generally to people who get an income from the government, such as bureaucrats, teachers, BBC employees and so on- got a computer especially designed for them a little later- a high spec, high cost machine with the BBC name attached. The rest of us had what we could afford, the ZX81 and then the ZX Spectrum. Cheap, shoddy british goods existed in order to be affordable to the cheap, shoddy british working class. (talk) 13:05, 2 December 2009 (UTC)Reply[reply]
A the time of its introduction - 1981 - the ZX81 had no competition at it's price range, all the other microcomputers available in the UK were far more expensive than the £69.95 of the Sinclair machine, or required kit-building and soldering skills as well as prior computer knowledge, these included the Acorn Atom, Tangerine Microtan 65, Research Machines 380Z, TRS-80, Video Genie, NASCOM, Atari 400 & 800, the Commodore PET, and the Apple II, the latter two and the RML 380Z costing serious money such that they were only found in businesses and institutions. — Preceding unsigned comment added by (talk) 20:29, 5 March 2014 (UTC)Reply[reply]

A call to ZX81 tape owners[edit]

Does anybody have a tape cover of the 3D Monster Maze game, preferrably the original (J.K.Greye Software as opposed to the New Generation Software republishing)? It would look great for the infobox there. You're welcome to improve the article in any other way you can think of, too. TIA, BACbKA 22:08, 17 December 2005 (UTC)Reply[reply]

P.S. Just got a helping hand from the c.s.sinclair group, will upload the scan myself now. BACbKA 22:37, 17 December 2005 (UTC)Reply[reply]

Images at Sinclair ZX81[edit]

I have followed the 16KB RAM expansion pack image link, and it looks like the file suffered as follows:

  1. somebody posted it as a public-domain work to the English wikipedia
  2. subsequently it was moved over to commons
  3. thereafter the original en: upload was removed (since it was not a GFDL image, noone cared about the history)
  4. then the PD tag became obsolete, and an explicit reference to whoever uploaded it originally and why it had been public domain back then (own photo? another PD source?) is needed by the commons

Bottom line: this fine image is being threatened by the local copyright police any moment now :-) will the original uploader please step forward ASAP? Thanks, --BACbKA 12:01, 25 February 2006 (UTC)Reply[reply]

  • I have updated the copyright - I thought I'd been through all my images, obviously missed this one because someone moved it. -- Jbattersby 12:57, 25 February 2006 (UTC)Reply[reply]

Thank you very much! --BACbKA 14:31, 25 February 2006 (UTC)Reply[reply]

Merge proposal[edit]

I have proposed a merge of Timex Sinclair 1000 into this article because IMHO they are fundamentally the same machine; the Timex model has more RAM, a different modulator, more shielding and some minor cosmetic differences, but for all that they are essentially the same.

It's not that the TS1000 is not important enough to warrant its own article; rather that I feel that the two machines would benefit from being placed in context instead of being artificially separated. Fourohfour 12:49, 18 March 2006 (UTC)Reply[reply]

Sounds very sensible to me. Cheers --Pak21 13:05, 18 March 2006 (UTC)Reply[reply]

What about TS1500? --BACbKA 18:10, 18 March 2006 (UTC)Reply[reply]

Merge that in as well :-) Cheers --Pak21 18:47, 18 March 2006 (UTC)Reply[reply]

All right, since both the TS articles cited above are stubs essentially (yes, I know the TS1000 isn't marked as such), I agree with the merge proposal. If the relevant sections in here grow too much, it'll be always possible to split them off again. --BACbKA 22:53, 18 March 2006 (UTC)Reply[reply]

I agree. Kialari 15:08, 27 March 2006 (UTC)Reply[reply]

I think that TS1000 should remain a seperate article. In the US, the TS1000 was the one that was famous and widely sold, not the ZX81. If people want to find out about the ZX81 and the differences, they can always click on the link to it. Vivaldi 06:40, 4 April 2006 (UTC)Reply[reply]

I'm undecided about this. Clearly the TS1000 is a variant of the ZX81 rather than vice versa, so if there is a merged article it should go here - with, of course, a redirect from Timex Sinclair 1000. Having said that, the Dragon 32/64 is very similar to the Tandy Color Computer, yet has a full article of its own. And Pentagon (computer) has a separate stub article, despite being a Spectrum clone.

I think that if TS1000 is merged into ZX81, for consistency's sake the Pentagon (and other clones) should be merged into ZX Spectrum... but the Spectrum article is 30K long already, which is a good argument for keeping the clones on separate pages. And if we do that, then consistency would demand that TS1000 is not merged with ZX81! Loganberry (Talk) 13:13, 4 April 2006 (UTC)Reply[reply]

I think the difference there is that the Pentagon article could say a lot more about the machine than it already does, whereas there's not really anything else that can be added to the TS1000 article than is already there. Cheers --Pak21 13:29, 4 April 2006 (UTC)Reply[reply]
The Dragon 32 was not entirely compatible with the Tandy, although there were very major similarities. It was also marketed by an entirely separate company with its own history.
By contrast, the differences between the ZX81 and TS1000 were secondary or peripheral; shielding, more memory, NTSC output. They by a company closely involved with the ZX81 already and had Sinclair's name on them.
Timex Sinclair warrants its own article, but this computer? In all honesty, I agree that there is little more to say that would not belong in the main article.
I see what you're (Loganberry) saying about consistency, but splitting due to length is a perfectly valid thing to do for practical reasons (both editing *and* reading). Consistency demands that either the Spectrum article grows to a horrible length or that all computers marketed differently get their own article....
Should Laser 200 be split into separate articles for "Texet TX8000" and "Dick Smith VZ200" simply for this reason? In all honesty, I think that would be a very counterproductive thing to do.
Fourohfour 18:26, 4 April 2006 (UTC)Reply[reply]
I disagree. They're different machines,
I should point out this is a circular argument; we're basically discussing whether or not they're different machines, so you can't assert that they're different machines and use that for support. :)
made in different countries
Many computers, consoles, cars, etc. belonging to the same range have been manufactured in several different countries; e.g. the ZX Spectrum was originally manufactured in Scotland and (IIRC) later made in China. More significantly, many of the "same" version of many products have been manufactured in different places, often simultaneously.
by different companies,
Well, the ZX81 was (mainly IIRC) made by Timex, so that point's debatable.
sold under different names in different packaging.
Different packaging? Well, that's true; not sure if it's that big a deal.
Yes, they differed mainly only in specification (e.g. amount of RAM as standard, type of TV modulator and case design)
It should be noted that other machines (e.g. the Atari 800) came in NTSC/PAL variants, and with varying amounts of RAM. Even the case design issue is only internal and relates to the shielding. Variations of such (or greater) significance have occurred over the lifetime of other computers such as the Commodore 64.
but the same is true of myriads of PC-compatibles, but they are not all lumped together. They're different - but closely-related - machines. Keep 'em separated. And I'm not just saying this because (AFAICR) I'm the author of the TS1000, TS1500 & Laser 200 articles! Liam Proven 12:04, 8 May 2006 (UTC)Reply[reply]
The *vast* majority of PC compatibles do not warrant (and have not got) separate articles.
My main concern is that I cannot see any great benefit to having two separate articles; a lot of the information is going to be pointlessly duplicated, and if it isn't it will end up being a stubby article which refers to the 'main' ZX81 article. In which case, why have it separate at all when it would be better placed in the more encompassing and illuminating context of a single article? Fourohfour 19:36, 14 May 2006 (UTC)Reply[reply]

I disagree with the merge proposal. Both articles are good at present. To combine them only gives the possibility of confusion between the two very similar iterations. In addition both are very clearly linked to each other early on in the text. The situation seems perfectly good as it is.HappyVR 19:46, 14 May 2006 (UTC) If only for the sake of clarity, please do not merge these two articles.HappyVR 19:49, 14 May 2006 (UTC)Reply[reply]

I also disagree with the merge proposal. The US 'Syntax' magazine published programs for the prototype BASIC in Dec 1980 and a considerable number of ZX81s were sold in America prior to the production of the TS-1000. The TS-1500 came at the end of 1984 at the same time as the TS-2068. Timex were aware that they had goofed with the ROMs and managed to keep the lid on this for over 20 years. I became suspicious after reading a TS-1500 review in 'Syntax' and imported a machine to the UK in order to confirm that Timex had implemented the Logan/O'Hara division correction without testing it. A lot of books were pulped. This would be out of place in a ZX81/TS-1000 article.

The TS-1500 comes with its own skeletons which should not be allowed to impinge on the status of two Classics.

Popiy Popiy 01:21, 19 June 2006 (UTC)Reply[reply]

In response to HappyVR; you said "the possibility of confusion between the two very similar iterations".... in other words, they *are* similar!
Popiy; I don't mean to be rude, but why does the fact that the original ZX81 was sold in North America prior to the TS-1000 justify separate articles? To clear up confusion? On the contrary, separate articles means either (a) inevitable duplication since the two machines are fundamentally the same, or (b) the minor article will end up constantly referring back to the parent article, making it hard to read.
There is no reason that having a separate article (as opposed to "merely" a distinct section) would make this clearer. It comes down to the quality of the writing.
The minor differences in the ROMs are just that; this happens with lots of computers and computer-based products. For example, the Atari 800XL came with at least two slightly different BASIC ROMs, but no-one would dream of using that as justification for separate articles.
Fourohfour 13:08, 24 June 2006 (UTC)Reply[reply]
I had not realized that the same discussion served both merger proposals. To me it seems fine to merge the ZX81 and TS-1000 articles as they are essentially the same machine. The TS-1500 article is less important as the machine was launched as Timex pulled out in January 1984. The recently discovered facts about the machine are only important due to the lack of any previous coverage. For instance, the various ROMS of the ZX81 received coverage at the time but not the TS-1500 ROM. A single sentence for the TS-1500 would suffice if it was merged with the ZX81.
--Popiy 18:11, 3 September 2006 (UTC)Reply[reply] 
I'm against any merger that would dilute the prominence of the ZX81 in this article - after all it' an importrant part of British cultural history. I suspect a certain amount of geographical bias may be at play here. Artw 00:42, 9 July 2006 (UTC)Reply[reply]
Given that the merged article would be titled "Sinclair ZX81", I don't think that's very likely. BTW, I live in Britain. Fourohfour 11:10, 16 July 2006 (UTC)Reply[reply]

A few factual errors[edit]

There are a number of factual errors in this article.

1. The ZX81/TS1000 clock speed is 3.25MHz, not 3.5MHz as stated in the article (It uses a nominal 6.5MHz ceramic resonator, divided by 2).

2. The article states that the ZX81 contained a single 4118 (1k*8bit) RAM Chip. Actually, a large proportion of the ZX81s made used a pair of 2114 (1k*4bit)RAM chips instead. The PCB was designed so either could be mounted.

3. Further into the article, it states that in SLOW mode, user programs are only executed during the time the electron beam moves from the bottom to the top of the screen (The vertical retrace). This is incorrect. On the ZX81, in SLOW mode, user programs execute in the white top and bottom borders, not the vertical retrace.

4. In the section titled "Integrated Circuits", it "A15 is used for display purposes (see below), and the upper 32K memory area is therefore unusable for code execution, it can still be used to store data (such as BASIC programs) however." It does not state though, that in the default configuration (i.e. without a RAM Pack >16k), the upper 32k contains a shadow of the lower 32k. Hence, the previous sentence refering to 16/8 shadows is not strictly correct.

--MikeWynne 23:44, 25 April 2006 (UTC)Reply[reply]

Then edit and fix them! Edrigu 20:26, 26 April 2006 (UTC)Reply[reply]

ZX printer - well built and safe to use...[edit]

Wondereing if this is worth mentioning - if you touched the metallised paper whilst the zx printer was operating - under certain conditions (no rubber boots) - you got electricuted - I remember - it happened to me...HappyVR 12:29, 7 May 2006 (UTC)Reply[reply]

Ha ha.... I've never heard that one before, but it's pretty interesting. Still, unless there's a reputable online source confirming it, it counts as original research and shouldn't go in. Sorry :-( Fourohfour 12:22, 3 November 2006 (UTC)Reply[reply]

It certainly is true, and if you look at how the ZX Printer worked its fairly obvious too. The ZX Printer only printed on special paper which had a thin layer of metal foil laminated onto it. The printer basically generated sufficient voltage to allow the print head to arc and burn holes in the foil, and these holes formed the dot matrix that formed the characters. Therefore, as each dot was printed the foil became momentarily electrically "live" until the arc occurred, so if you touched the paper the potential would discharge through your finger. It wasn't enough to harm you, but it certainly made you jump. —Preceding unsigned comment added by (talk) 12:11, 23 December 2008 (UTC)Reply[reply]

Merge resolution[edit]

As this page is one of the last on Merge since March 2006, I'm making a command decision. Sinclair 1500 was merged into Sinclair 1000, but since Sinclair 1000 now has a good bit of material, I'm NOT merging it to ZX81. If someone disagrees they can re-post the merge. Alba 19:41, 4 October 2006 (UTC)Reply[reply]

It seems okay to me now. The only objection I would have would be if more material were added and it ended up duplicating the ZX81 article (in other words, unique non-overlapping material is what counts). Anyway, that's not the case at present. Fourohfour 12:19, 3 November 2006 (UTC)Reply[reply]

Size and weight?[edit]

What are the physical dimentions of the computer? // Liftarn (talk)

How slow?[edit]

In the fast and slow section, it says that a 1-1000 for loop takes 19 seconds to execute, but it is unclear whether this is measured in fast or slow mode. Given the speed of contemporary Basics I'd guess it is slow mode. Can someone who knows please clarify the main article? Drhex (talk) 12:05, 29 April 2008 (UTC)Reply[reply]

Square root bug[edit]

There's a good ref for this here. Letdorf (talk) 14:41, 25 November 2008 (UTC).Reply[reply]

That reference suggests that it was a ROM issue which was corrected at some point. If that's the case, the issue probably belongs in the "reception" section, as does the cover-up. Chris Cunningham (not at work) - talk 14:49, 25 November 2008 (UTC)Reply[reply]

Significant reworking[edit]

I've begun to rework this article into an accessible form which follows our guidelines for article content. For now, this has necessitated removing about 50% of the content, which was an excessively detailed overview of the hardware to the point of reading like a professional runbook. I don't disagree that this stuff might have value, but when it is the main focus of the article (to the detriment of general details about the machine's impact in the market, its influence on later products, what it was used for and how it affected Sinclair) the article isn't doing its job. The material is in the page history if someone wants to take it and make a sub-article dealing with low-level technical details. Chris Cunningham (not at work) - talk 14:49, 25 November 2008 (UTC)Reply[reply]

ZX Printer Merger proposal[edit]

I am proposing to merge ZX Printer into this article. There doesn't seem to be enough material on it to warrant its own article and has a Wikipedia:Notability issue due lack of sources. --Macrowiz (talk) 15:38, 25 November 2008 (UTC)Reply[reply]

I don't think a merge is appropriate here. The printer worked with the Spectrum as well. If it's going to be merged anywhere, a good target is back into spark printer, from whence it came. I think it might be able to stand alone if good references are found though. Chris Cunningham (not at work) - talk 15:39, 25 November 2008 (UTC)Reply[reply]
I agree that spark printer is a better target since it worked w/ other computers. --Macrowiz (talk) 15:46, 25 November 2008 (UTC)Reply[reply]
This is still a stub article! The ZX Printer wasn't exclusive to the ZX81 and was a very common peripheral for ZX81 and ZX Spectrum users. Other Sinclair peripherals, like the ZX Interface 1 and ZX Interface 2 have had their own articles for some time now. The Spark printer article is about a particular printing technology; the ZX Printer is a notable example of a printer using this technology. IMHO, these topics can stand alone. Letdorf (talk) 15:54, 25 November 2008 (UTC).Reply[reply]
The sources recently added are definitely an improvement and establish at least some notability in my view. Proposal withdrawn. --Macrowiz (talk) 17:52, 25 November 2008 (UTC). Please also note WP:NOTINHERITED and WP:WAX. --Macrowiz (talk) 18:06, 25 November 2008 (UTC)Reply[reply]


I can remember several adverts for ZX81 ROM swaps that improved speed. One that I was interested in (but never had the courage to swap the ROM at the time) was a ROM with a FORTH 'operating system' on it. The advert promised much faster operation and of course the FORTH language which tends to suite computers with few resources. Would such unofficial add-ons or upgrades be appropriate for the ZX81 page? —Preceding unsigned comment added by (talk) 18:25, 14 November 2009 (UTC)Reply[reply]

Might be related to the Jupiter Ace which should probably be mentioned in the article. (talk) 03:11, 19 June 2011 (UTC)Reply[reply]

Featured article nomination[edit]

I have nominated this article for consideration as a possible featured article - I hope to have it on the Wikipedia home page on 5 March 2011, the 30th anniversary of the ZX81's launch. Please leave your comments at Wikipedia:Featured article candidates/ZX81/archive1. Thank you. Prioryman (talk) 21:00, 10 January 2011 (UTC)Reply[reply]

Comparisons between ZX81 and other computing devices[edit]

I'm somewhat conflicted over this section - I think it's a good idea, yet the list prices are all in dollars, which goes against the UK English article, and most of the other listed machines are primarily American as well.

Does anybody else have any thoughts? a_man_alone (talk) 12:54, 23 February 2011 (UTC)Reply[reply]

I added that section for two reasons. First, even in the UK, the ZX81's principal competitors were imported American machines, and priced in dollars. Sinclair Research itself cited American competitors (notably the TRS-80) as the ZX81's closest rivals. Second, although the article is written in UK English, we mustn't forget the fact that the US played a very big role in the ZX81's story - from Timex producing it to the hundreds of thousands of ZX81s sold in the US. The comparison table helps to show the relative merits of the ZX81 against its nearest competitors in the US market, which helps to explain why it had as big an impact as it did. Prioryman (talk) 23:24, 26 February 2011 (UTC)Reply[reply]
This is an interesting point, the currency issue. But I also have a problem with this section; Firstly, why is a phone listed for comparison rather then a more common computing device like a laptop or desktop model eg. something like the Asus EEE, a modern 'budget' device more comparable to this system. And why is a price listed for the Iphone that only seems to be relevant when signing a long term repayment contract with a US phone provider? Wouldn't an outright price for a computing device be more relevant for comparison. Furthermore, why is there no column for release dates? Isn't this an important tool for people comparing the specifications / costs?--Senor Freebie (talk) 03:20, 5 March 2011 (UTC)Reply[reply]
And why is the BBC Micro omitted? —Preceding unsigned comment added by (talk) 07:41, 11 March 2011 (UTC)Reply[reply]
The BBC Micro came after the ZX81. All of the computers listed were competitors of the ZX81 at the time of its launch - they were already on the market, and they were what Sinclair was trying to compete with when the ZX81 was designed. Prioryman (talk) 08:09, 11 March 2011 (UTC)Reply[reply]

Number of units sold[edit]

The infobox claims "More than 1.5 million", citing the Sinclair website. But this interview states "the ZX81 which replaced it cost £69.95 and sold 250,000". Any ideas, anyone? The ZX81 was certainly less popular than the Spectrum, which claims "many millions of units". Any ideas, anyone? --Trevj (talk) 11:23, 23 May 2011 (UTC)Reply[reply]

The Guardian article is certainly wrong. WHSmith sold over 350,000 ZX81s in the UK alone in a single year. I would definitely be inclined to trust the manufacturer's website more than a newspaper's! Prioryman (talk) 14:24, 23 May 2011 (UTC)Reply[reply]
Pants. I suppose that means the ZX80 figure could be wrong too. It's not good when newspapers don't check their facts. --Trevj (talk) 14:51, 23 May 2011 (UTC)Reply[reply]
I'm afraid it's definitely wrong. The 50,000 unit figure refers to only the first year's sales. The ZX80 sold about 100,000 units in total. I'll add a source to that effect to the ZX80 article. Prioryman (talk) 15:43, 23 May 2011 (UTC)Reply[reply]
Face-smile.svg Thank you --Trevj (talk) 18:52, 23 May 2011 (UTC)Reply[reply]

iphone 4[edit]

I'd like to get rid of the iphone 4 from the comparison table. I removed it a couple weeks ago but someone put it back. I don't think we need a modern computer in the table. It comes across as patronizing the reader in my opinion, like putting a comparison of a modern jet aircraft into the article about the 1930's DC-3. If we do have to have a modern computer I suggest the OLPC XO-1 instead of the iphone. While it's a little bit behind the times by now, it's closer to the ZX81's form factor and intended applications, and it's a FOSS design intended for hacking, avoiding turning yet more of Wikipedia into marketing for slick media consumption devices. (talk) 08:19, 17 June 2011 (UTC)Reply[reply]

I'd like to keep the iPhone in the comparison table. I think we need a modern gadget (not necessarily a computer) in the table for exactly that - a comparison. Although I do have issues over the use of dollars in the pricing structure, I think that it's best to see how times have changed - what you got then, and what you get now. The iPhone is pretty much a perfect example of that. This is not about slick marketing, but a comparison of devices old and new.
The trouble with using something like the OLPC XO-1 - which I'd never heard of - is exactly that. Never heard of it. The comparison needs to be a ubiquitous device that everybody knows about - much as the ZX81 was in its day. Even people who didn't have one, or knew little about computers knew about the ZX81 - much as these days even people who don't have an iPhone (such as myself, for example,) know of the device. a_man_alone (talk) 09:43, 17 June 2011 (UTC)Reply[reply]
I don't see why it's necessary to show that times have changed: we all already know that times have changed, which is why I find the inclusion patronizing. I don't see any comparison with a modern car in the Ford Model T article--so why do we need something like that here? Perhaps you can explain. I see a mostly-good article about a historical computer that says how many kb of memory it has, its cpu speed in mhz, etc, which is fine. We all know what those terms mean and we know how many megabytes a modern computer has, and we don't need to be told what we already know. As for the XO-1, it's basically a netbook of a few years ago (it spawned the netbook genre that started with the Asus EEE PC). We could describe it that way if it helps; or else just say something like "2011-era netbook computer" without naming a specific model (they are all similar anyway). Using a phone instead of a computer really doesn't come across very well IMO.

I had the alternative idea of looking for a current Sinclair product, but it looks like the company was sold to Amstrad in the 1990's. Amstrad is still around but is no longer making computers. (talk) 10:26, 17 June 2011 (UTC)Reply[reply]

I disagree. In fact, I think you have a good idea there - comparing old with the new - I think it would be fascinating to compare the Grandfather of modern cars to one of its n-th generation offspring. The engine section alone is good reading, comparing a 2.9 20hp four cylinder engine against the current Duratec models. a_man_alone (talk) 10:40, 17 June 2011 (UTC)Reply[reply]
Does anybody else have a view about this? My guess is that putting something about the Kuga into the Model T article wouldn't go over too well there, but I could be wrong. (talk) 12:05, 17 June 2011 (UTC)Reply[reply]
Digressing a bit now, but the Kuga was the first model that came into mind because there happened to be one parked across the road from me as I was typing. It could be the latest American Ford as well, but my knowledge of non-European models is lacking. a_man_alone (talk) 13:32, 17 June 2011 (UTC)Reply[reply]
I think the iPhone should be removed. It doesn't show that times have changed because there are no dates given with the items in the table. To evaluate the iPhone against these we would have to look at other modern computers, size, battery consumption, portability. It's completely inappropriate for the table. — Preceding unsigned comment added by (talk) 12:19, 19 August 2011 (UTC)Reply[reply]

I've asked for outside comment at WP:3O.[1] (talk) 19:34, 18 June 2011 (UTC)Reply[reply]

Third Opinion[edit]

Question: Do any reliable sources suggest a comparison between the iphone 4 and whatever computer/phones are compared in the disputed table? If not, then the table is original research and must be removed. See WP:RS and WP:OR.Wikifan12345 (talk) 23:23, 18 June 2011 (UTC)Reply[reply]

There were tons of published comparisons between the ZX81 and other 1970's-1980's computers at the time when those computers were being made, so there's not any issue about the comparison between the ZX81 and other computers of its era. Including the iphone 4 is more anachronistic. FWIW, nobody is disputing the factual accuracy of the comparison (it's just observation, not "research"). IMO it's ok to interpret NOR a bit loosely in a situation like that, which leaves an editorial question of whether the comparison helps the article. I myself think the table is better off without the iphone 4, but was asking what others think. As stated above, I wouldn't have minded as much if the "modern" device was something closer to the ZX81 in function and spirit. (talk) 01:41, 19 June 2011 (UTC)Reply[reply]

I removed the iPhone from the comparison table and will remove it again in a few days. The comparison does not make sense, as this is an article about a single early 80's computer (not about the history of computers), the iPhone is not even a home computer, and the iPhone costs three times as much. If you wish to retain it in the article, please discuss your rationale here with something other than "it is also a computing device". Muad (talk) 08:41, 30 November 2011 (UTC)Reply[reply]

The cost of the iPhone is, in real terms, comparable to that of the ZX81 when it was launched. Strictly speaking I suppose the closest modern comparator to a ZX81 would be a cheap netbook, but are there any netbooks that are sufficiently iconic to serve as a modern comparison? Prioryman (talk) 22:53, 30 November 2011 (UTC)Reply[reply]
(Actually, after adjusting for inflation, the iPhone is still two and a half times more expensive.) You're right, a cheap netbook would be a better comparison, but the point is there should be no comparison to modern hardware. It makes no sense, as this article is about the ZX81, not the advancement of electronics since the 1980s. Muad (talk) 10:20, 2 December 2011 (UTC)Reply[reply]

Aphex Twin Sound[edit]

Should we add that bit about how young Aphex Twin created a sound with the ZX81? Conkern65 (talk) 16:33, 2 December 2011 (UTC)Reply[reply]

News reports[edit]

I came here to leave a note about ZX81: Small black box of computing desire in the news in 2011. But I see it's already included in #News reports. I know these are all valid refs but shouldn't they be either

  1. Included as inline citations; or
  2. Moved out of Article space (e.g. here on the Talk page?

-- Trevj (talk) 10:12, 6 February 2012 (UTC)Reply[reply]

NTSC version[edit]

The article claims that the NTSC version of the ZX81/TS100 computers had a different RF modulator and a different ULA. The modulator is indeed different (VHF instead of UHF) but is there any source for the claimed ULA difference? As there's no chroma and no sound, the only difference in the video signal is the number of lines (525 vs. 625) and that is controlled by firmware as this is an extreme bare-bones machine that does some ugly, kludgy things like SLOW mode and executing video memory as programme code. Some ZX81 kits in Canada (distributed at the time by Gladstone Electronics in Toronto for $C150 or $C200 assembled, in 1981 dollars) were the UK version with jumpers on the board configured to indicate NTSC 525-lines to the ULA but use the UK-style UHF RF modulator (there were differences in modulator pinout as the VHF NTSC modulator was switchable between two channels). The UK modulator will work on NTSC UHF 35 or so as there is no colour or sound - so PAL vs. NTSC is reduced to 625 vs. 525 line video as the sole remaining difference. (talk) 17:17, 6 September 2012 (UTC)Reply[reply]

Why removal of ZX81 1K hires link?[edit]

In tribute to 30 years of ZX81 Dr Beep tried coding a game in 1K RAM with hires. This ended in 2012 in 10 games together.

Never in history was a game coded in hires in just 1K of memory.

This alone makes it part of the history of the ZX81.

In the meantime the Dr has coded 10 new hires games in just 1K. — Preceding unsigned comment added by (talk) 21:36, 29 August 2013 (UTC)Reply[reply]

15kB/16kB RAM packs[edit]

There is a statement in the "Features" section of the article that states "Early versions of the external RAM cartridge contained 15 kB of memory using an assortment of memory chips, while later versions contained 16 kB of chips but the lowest addressed kilobyte was disabled."

I have no references to this other than personal memory and the ZX81 circuit diagram and the referenced articles, but my ZX81 RAM pack, ordered in June 1981 and in my hands in July that year had 16kB of memory, and matched the description in the Personal Computer World review written by David Tebbutt referenced as [95] in the article. This was the first review published as far as I know, so must have been an early system. Additionally, my experience showed that rather than the bottom 1KB of the RAM pack being disabled, when it was plugged in, the RAM pack disabled the internal 1KB of memory by connecting the NOT RAM CS pin (pin 8) of the 2114 internal memory chips (or pins 18 and 20 of the 4118), which was on track 2A of the edge connector to the 5V line in the RAM pack. This arrangement can be seen in the scan of ZX81 circuit diagram and the scan of ZX81 16kB RAM pack circuit diagram (sorry, probably neither of these are sufficiently authorititive as a Wikipedia link).

Rather than just editing the article, I wanted to see whether anybody else had any comments on the change. — Preceding unsigned comment added by Gatherp (talkcontribs) 17:52, 16 January 2014 (UTC)Reply[reply]

Moving part![edit]

The USA version of the ZX81 has indeed a channel selector switch on the bottom. You can easily verify this for yourself by grabbing your USA-release ZX81 and flipping it over.

See for a photo of the bottom of the USA version.

Thanks. Sukiari (talk) 02:44, 3 January 2015 (UTC)Reply[reply]

Ref: " The machine had no power switch or any moving parts (with the exception of a channel selector switch present only on early "ZX81 USA" models which pre-dated the Timex-Sinclair 1000)"

I have a Timex Model 1000 with the channel selector switch, so that statement is not correct and I have revised it.

Nkendrick (talk) 18:17, 22 August 2015 (UTC)Reply[reply]

only 15kb RAM?[edit]

Edited from FaceBook, plot only to 22 lines. What = about 1kb RAM not working? mine OK. 3¼ or 3½ MHz? USA 1s'd 2kb RAM. Also USA 1s'd +1 resistor, which goes to pin of chip to give less top border, so as to fit display to screen, I think the chips =. PAL & NTSC = colour encoding, the fact that 1's 25, & other 30 pictures/2nd & N° of lines = what matters here. (talk) 11:54, 18 May 2015 (UTC)Reply[reply]

List of other computers[edit]

In fact the very 1st Atari 800 Computers were shipped with 8 or 16 KB memory, expandable to 48 KB. After initial release, the 800 came standard with 48 KB memory. That= normally 48 (the comparable 400'd less).

Some time ref' to pixels = block graphics as on PET & ZX81, & not the N° of pixels used by full line of letters. Pixels for VIC20 =@ start-up, it can do little better. (talk) 12:20, 18 May 2015 (UTC)Reply[reply]


This entire article was using "kB" to indicate memory sizes, which is factually wrong, since kB is defined as 1000 bytes. Computers of this era used 1024-byte kilobytes, so all storage references have been corrected to "KB". Clayhalliwell (talk) 18:25, 21 July 2015 (UTC)Reply[reply]

On BBC mention of Sinclair incompetence: To be Censured?[edit]

This were the detailed text added, to the section The BBC affair:

This incompetence was fairly obvious: The ZX80 being a video board that only worked as a computer 1/5 of the time. An hack Clive Sinclair found interesting, though it would mean unnecessarily having 1/5 of a computer. The video generation circuit would be as cheaper the circuits that were needed to keep the hack going. With the ZX81 the ULA would drop the prices while solving the most visible aspects of the hack involved. The comparison BBC made of work/price ratio was not noticed.

Also changed the reference to Sinclair as an inventor, a popular mis-conception, being and entrepreneur.

This is a difficulty Wikipedia suffers, when items are controlled by people who's not inside a subject, but 'believe' to be. Or is just a fan of a subject, blind with it. Or just what is more common, getting a sense of possession instead of correctness.

A lot of pages do have biased information, sometimes misleading, sometimes plain wrong information. In the case of the ZX-80/81, there is enough information as blueprints, technical information and discussion, also more or less popular media publications clarifying a point.

But nothing is more damaging than censorship to keep an hype or worse, a belief. The reaction is simple: Simple erasure, with a sort of justification. Have seen that years ago, needing a decade to get the information right. Some items will take more than a decade, whatever they are or whatever the field.

Wikipedia is damaged from the inside, with pretensions to 'judge' what one is unable to evaluate (due to technical inability, or to emotional attachment). As a result, wikipedia is considered unreliable as a reference. Even if usually useful...

These may be harsh words, may they need to be stated. Knowledge and Information are not just a matter of fashion, 'belief' nor "printed opinion to reference". The actual functioning of wikipedia may be a reason (for too many)... not to maintain it with contributions.

Factor-h (talk) 17:43, 6 March 2016 (UTC)Reply[reply]

The trouble is that your text, whether in article or talk page, is just incomprehensible. It's almost impossible to ascertain what you mean, and even where it is possible, your text is at odds with what the sources say. Even if you are correct - which has by no means been ascertained yet - then your text cannot stay because it falls so far short of fluent general English that it, and it alone, would be enough to bring Wikiepdia's reliability into disrepute. Wikipedia is fully aware of its own shortcomings, and even has an article about it - whether that article is reliable though is of course up for debate. Chaheel Riens (talk) 17:55, 6 March 2016 (UTC)Reply[reply]
  1. You are changing "inventor" to "entrepreneur". This is probably more accurate, but the trouble is that this is a direct quote, and the quote said "inventor".
  2. You say that content is easily sourced. Yet you haven't sourced it. That means it's unsourced.
  3. The wording of the added paragraph is effectively unreadable, the English is so poor. I'm sorry, but this is the English language Wikipedia and content added has to meet basic language standards. This doesn't, and it's so unreadable that it's impractical to copy edit it and improve it.
Andy Dingley (talk) 18:05, 6 March 2016 (UTC)Reply[reply]


Is it a perspective? Here's another, to consider: — Preceding unsigned comment added by Factor-h (talkcontribs) 16:38, 7 March 2016 (UTC)Reply[reply]

  1. Actually there were 2 references to inventor, one being a quote the other didn't look like one. Quote of opinions are not valid, and should be marked with """ so the text may not be misleading.
  2. There are plenty of sources of the several types mentioned. For time reasons they are added later, if a sentence is not obvious enough. There's no need to fill information with spurious references. Most references seen being references to opinions unreferenced. Or text simply being public belief presented as fact (example: "Tape drives" entry, which was erroneous and misleading, based on public view. Now corrected)
  3. When a sentence is poorly written (which is easy to happen when editing a text mixed with raw code and references) then there's a chance to correct the poor English to a better one. Exception being it relates to information hard to grasp. This was not the case.

Corrections being needed, erasing is not correcting. If the subject is demanding, contacting the contributer is not only fair but seems the wise thing to do. Unfortunately the ZX-81 gave rise to it's own folklore, some even mention a cult (no references, sorry, not now).

Would agree it's difficult to deal with opinions and beliefs in an open database. Discretion and wiseness are in order. This being a reminder, as we all should contribute to a common goal: Information that is Informative, yet not misleading. (P.S. Also knowing it not to be knowledge, much less wisdom).

Factor-h (talk) 15:55, 7 March 2016 (UTC)Reply[reply]

External links modified[edit]

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Past tense?[edit]

Why is this article introduced in the past-tense? Do none exist any longer? I was under the impression that so long as a product still exists in any form, we are to use the present-tense, like for the NES.  Supuhstar *  05:09, 4 February 2018 (UTC)Reply[reply]

@Supuhstar: You're right; MOS:TENSE dictates present tense for everything except historical action. I've adjusted the lead. — Hugh (talk) 01:10, 5 March 2018 (UTC)Reply[reply]