Best Use For A Timex/Sinclair 100 / Sinclair ZX-81

[John_L]

After an exhausting search, I've finally found a best case use scenario for this vintage computer...

 

 

[jaybird3rd]

Wow, that's an old one! If I knew you were looking for a use for the ZX81, I could have saved you some time and effort in your search; I was hearing jokes to that effect by the mid-80s.

 

But seriously, I will admit that the ZX81/TS1000 hasn't held up especially well. I had some fun with mine back in the day, and it had a historically important role as one of the first ultra-low-budget entry-level computers, but I haven't been tempted to hook mine up again in quite a long time.

[John_L]

Yeah, i think it's place in history has got to be that it was the first sub $100 computer, which was quite an accomplishment. Unfortunately, to get there, they had to cut out so much, it wound up not being a competitive unit, and within a year or two, C64's and Color Computers were breaking $200, which people were more than willing to spend to get so much more computer. Same thing killed Radio Shack's MC-10, which was a direct response to the Sinclair. I thought the photo was funny because the actual size and shape of the unit lends itself to actually work quite well as a doorstop. What makes it so ironic that useless equipment is often referred to as a doorstop!

 

I don't know much about the innards of the unit, but I do know it had a Z80, which is a great, very powerful chip. As a matter of fact, modern x86 chips have more in common with a Z80 than they do with the intel -8080 and 8088 chips. In other words, Intel took a que from the Z80 as their development line continued. Other than that, I don't know much about the internal hardware. I do seem to remember reading that it had but 5 chips in it, which was few compared to the typical 50 or so on other systems. I think it's biggest drawback was the keyboard, or lack there of. I imagine someone out there somewhere down the link has hacked a proper keyboard onto the unit... if not, it would be cool to do. Of course, an emulator will do that...

 

If there's one thing I've learned about the 2600 it's that often times less can be more. Might be interesting to see what possible if one were to learn the system inside and out and see what sort of hacks to improve the system could be done.

[carlsson]

In the past few years, there has been a number of hardware enhancements and expansions for the ZX-81, including a video chip with improved picture, sound and joystick/mouse interfaces, memory card readers of course etc. Most of them are rather pricy, so you got to be a bit of a hardcore '81 user to invest in those, but then again it holds true for most new hardware for vintage systems.

 

Keyboard replacements, both DIY and commercial solutions, have been around since the beginning of the ZX-81 so that is far from unheard of. Many also decided to integrate memory expansion into the case while doing the modding, some even improving the power distribution.

[jaybird3rd]

Yes, the ZX81 used a Z80 and a PLA to keep the chip count to a minimum. A very minimalist design, but also very flexible. I remember seeing a few hardware projects for the ZX81 in books and magazines, and they're still being designed today.

 

The budget-priced, entry-level market that the ZX81 was created for was quickly taken over by higher-end machines as they came down in price (or were handed down by upgrading users). The Mattel Aquarius was probably the last machine that specifically targeted that market: even though it was a more capable computer than the ZX81, it had certain things in common with it (Z80 processor, skimpy RAM, cut-rate keyboard, etc), but by the time it shipped in 1983, much better machines were available at the same price point. That's one reason it was such a short-lived system.

[TPA5]

My dad had a ZX-81, and I'll be honest perhaps it's just nostalgia but I like the machine. Sure, it was hellacious to type on that keyboard, and yeah it wasn't the fastest and was soon eclipsed by other systems, but I liked it. Sadly, it vanished somewhere along the line and all he could find from it was some literature he had and that was it. If I ever got the chance t own a ZX-81 for a reasonable price again, I'd be all over it.

[MarkO]

 

<< SNIP >>

 

I don't know much about the innards of the unit, but I do know it had a Z80, which is a great, very powerful chip. As a matter of fact, modern x86 chips have more in common with a Z80 than they do with the intel -8080 and 8088 chips. In other words, Intel took a que from the Z80 as their development line continued. Other than that, I don't know much about the internal hardware. I do seem to remember reading that it had but 5 chips in it, which was few compared to the typical 50 or so on other systems. I think it's biggest drawback was the keyboard, or lack there of. I imagine someone out there somewhere down the link has hacked a proper keyboard onto the unit... if not, it would be cool to do. Of course, an emulator will do that...

 

<< SNIP >>

 

The Sinclair ZX81 was my first home Computer ( I used the Apple ][+ at High School, so it was my first computer ), my Dad and I built it from a Kit, ( $99.00 ( USD ) IIRC, $149.00 ( USD ) Pre-Assembled ) from an ad in Popular Science. As usual, there was two or three parts left over... Resistors IIRC... ( Ask me if you haven't heard a "left over parts" Joke... )

 

The Circuit Board in 1981 was designed for 4 or 5 ICs. The Z80, the ULA ( IIRC ), the ROM ( 8K ) and either One, 1K RAM or Two 512 Byte RAMs. The Timex-Sinclair came with 2K of RAM, but I haven't opened any of them to see how their were packaged.. I believe they were a Single 2K RAM.

 

My Uncle that made the Joystick for the Sinclair, game me all of his "stash" when he was cleaning up a decade ago..

 

I have Eight ZX-81/TS-1000, Eight 16K RAM Packs and one Memotech 64K RAM Pack, and I can only find the White Thermal Printer, right now.. I have one with the Silver Thermal Paper too... One of the ZX-81/TS-1000s is in a Metal Case with an actual keyboard..

[John_L]

I remember the Pop Sci adds, and I remember wanting one back then, then the ZX81 assembled unit was released, and about that time, the deal with Timex was announced, but by then I was into the CoCo and went that route instead, also I had picked up a Model I 16k unit w/o the expansion interface, so I never did get into the Sinclair. I pic I posted was done just for fun, but in a few responses it's produced alot of info about it I didn't know about such as the keyboard mods carlsson mentioned.

 

I think the idea of adding the RAM internally would have been a cool while doing the keyboard mods, especially if it was able to be done while leaving the expansion slot open.

 

I've been playing around with the BASIC interpreter through the MESS emulator, and I think one of the things that held it back from doing better was the goofy non-standard implementation of BASIC, but I think overall the internal design was pretty good considering the price, and the poor BASIC wouldn't be a drawback to the serious hobbyist, but for the average user, it would have been difficult to work with.

 

Thanks to everyone for sharing all the info!

[+save2600]

I bet they'd make a great toilet float!

 

I still have (its on display in my computer/gaming room actually) the original Timex brochure I took from a variety store called Petranek's BITD. "The first computer you can really afford"... Umm, by the time I saw that joke of a computer for $99, already had bought a used TI-99.

[Omega-TI]

ZX-81 SKEET SHOOTING!

Replace the clay pigeons with ZX-81's!

Graphic edited: by John_L

Edited July 16, 2014 by --- Ω ---

[BassGuitari]

The Timex is neat for what it is. It's a fun thing to tinker with but not something you'd want to be forced to use. It still kills me how much productivity software was released for it, and that some people actually used it (like my dad!).

It does have quite a few halfway decent games (some could even qualify as "good"), but the keyboard ruins many would-be excellent titles. I will say it does Space Invaders-type games pretty well, though, or other games requiring only two or three key input. The potential for Roguelikes and text adventures is there as well.

[JamesD]

...

I've been playing around with the BASIC interpreter through the MESS emulator, and I think one of the things that held it back from doing better was the goofy non-standard implementation of BASIC, but I think overall the internal design was pretty good considering the price, and the poor BASIC wouldn't be a drawback to the serious hobbyist, but for the average user, it would have been difficult to work with.

...

I've pretty much always thought that what people wanted was something like the TRS-80 Model I and it fell short of expectations.

I realize there are some fans of these machines but I found one at a yard sale for $5 within a year of it's release.

[Ed in SoDak]

I made good use of mine, I think I paid $50 for it with the 16k and some program cassettes. I kept watch for closeouts and bought a good assortment of books and tapes before they disappeared from the dealer shelves.

 

I wrote a programmable timer for it to use in my photo darkroom. Soldered connections and a hacked-on TI keyboard made it much more reliable and useful.

 

At least a few mourned its passing, judging by this article reprint. Interesting reading.

 

 

 

 

 

 

Edited July 16, 2014 by Ed in SoDak

[John_L]

I've pretty much always thought that what people wanted was something like the TRS-80 Model I and it fell short of expectations.

 

Yep, which is really strange because Tandy Corporation was a very conservative manufacturer. Radio Shack managers would report to upper management what people were asking for and NO ONE was asking for a computer. It was typical for Tandy to wait until customers were asking for a product in large numbers before investing in creating a new product and bringing it to market. Lewis Cornfeld was an ad exec for Tandy, and was the one who talked John Roach into making a computer. He was put in charge of making a computer and had no clue about what they were or how the worked, but, he did have enough knowledge to know RAM was important, so he approached a chip maker wanting 4k chips instead of two, but they were much more expensive. He would up striking a deal by asking "how many 4k chips do I have to buy to get them at the 2k price....". He also was involved in defining much of what became the Model I, and, he obviously hired the right people to design and built it because despite being the first, it was one of the best designed computers of the era.

 

Also, even a base model 4k unit was $600 bucks, a far cry from the cost of the sub $100 Timex.

 

Not that I'm a huge Microsoft fan, and felt Microsoft made much of their way by being followers who borrowed, copied, and stole their way through the 80's and 90s, in the early days, they were quite the leaders as they wrote the BASIC interpreter for the Model I/II/III line, the color computers (1,2 and part of 3), the C64 and Apple. Those leaders of the industry from '77 until the early 90's when everything went away except PC's and a few Macs all had Microsoft BASIC in them. Machines like the Sinclair units, TI-99, and scores of others who wrote their own seemingly intentionally different BASIC interpreters suffered and died off.

 

The Sinclair BASIC was especially bad with that stupid "mode" cursor that kept changing to a different letter of the alphabet making trying to operate the computer a real pain.

[carlsson]

Both the ZX-81 and the ZX Spectrum were touted to be easy to program as all the keywords were there, only a few keypresses away and you never risked a PRONT or a NXT. Of course the real reason was to save on ROM space. Most of the lexical parser could be omitted as all the keywords would be correctly tokenized already when input. Perhaps the savings are not that huge though, some 0.5 - 1K of code, but everything counts when price is an issue.

 

A number of other home computers instead combined the shortkey method with traditional input, e.g. Acorn Electron, Sord M5, VTech Laser 2001 to name a few from my personal collection and there would be more of those. Obviously Commodore introduced abbreviated commands like N + Shift-E or GO + Shift S, beyond the ? for PRINT that most Microsoft dialects appear to have, but it would not be foolproof in the same way.

 

Anyway, I don't think it was the choice to license Microsoft Basic or grow your own that mainly determined each manufacturer's destiny. Texas Instruments made their own mistakes and in the end may not have been much interested in the home computing branch. Sinclair was run by someone more interested in new inventions and small vehicles, and so on. Acorn itself may only have lasted a bit into the 90's, but the ARM extention is flourishing today. Whether its success can be credited to BBC Basic - blazing fast and powerful, ported to multiple systems - or other factors is disputable though...

[John_L]

Well, you're 100 percent correct that the forced use of short key for basic statements like PRINT was to cut down the code size. They were trying to squeeze the equivalent of a "level 2" basic into the space of a Level I basic. But forced short key isn't what really bugs me about it. It's that freakish ever-changing-to-yet-another-alphabetic-character of a cursor. Cursors are cursors, and characters are characters. A cursor can be an underline, or an inverted space (block character), it can blink, or not, but the two biggest no no's you could possibly do is A) Let it be an alphabetic character, or B, change. TS 1000 did BOTH. A cursor's job is to indicate where the next character will appear on the display, not to indicate what "mode" you're in, I don't know much about how it works, but what I've figured out just dicking around with an emulator is that "L" means you're in basic statement input mode, and "G" means Graphics mode, and K means whatever letter you type will actually appear on the screen mode, aka, string input mode.

 

They honestly could have indicated the mode by say, changing the border color to indicate the mode or something else. That way, the cursor could have been, well, a cursor, and not a cursor/mode indicator. Also, the problem with short keys is that you have to memorize a bunch of different functions for the same key depending on the mode you're in.

 

I think you're being generous saying that it saved as much as 1k, there's about 300 characters in the keyword set (for the lookup table), and the routines for checking and tokenizing are probably about 20 to 30 bytes each, and both could use the same keyword table, so well under 1/2 kilobyte. If they were looking to keep things light, they could have shelved "Let" the most useless function of any programming language ever of all time.

 

Programming is difficult enough as it is without having to continuously remember what key does what, or to glance down at the keyboard to figure out what key to hit or track modes.

[bkrownd]

In about 1983 my dad got me a TS-1500 and himself a TS-2068 on clearance. I also got of one of the cash-register style TS-2040 thermal printers. By that time I had already used the Apple ][ at school for a few years, so the TS-1500 was little more than an odd and frustrating toy to me. It mostly gathered dust on a shelf. The rubber keyboard was abysmal, and entering programs from magazines required typing on that thing for what seemed like an eternity, only to find out in the end there was a typo in the big binary data block that was really hard to proofread).

 

Sync(?) magazine was still produced for some months after I got the TS-1500. I was always intrigued by the variety of odd peripherals advertised in there. Some of them were normal keyboards and printers that would turn the Timex Sinclair into something more closely resembling other computers. Others were weird modules that did various arcane things. I ordered a homebrew style word processing program advertised in the magazine, which could print odd fonts and characters, superscript, subscript, etc.

[Tickled_Pink]

Whatever you think of the ZX81 and its capabilities, it was the raspberry pi of its time. It was designed with an ultra low price point in mind and, to get more computers into the home and get people coding. In all 3 respects it was a success. The ZX81 and Spectrum kick started the UK software industry.

[Ed in SoDak]

Maybe it was because it was my first computer, or perhaps I had more brain cells back then, but I had no problem learning the odd syntax of the Timex. When I got my TI99/4A, I recall being frustrated at having to type in all those commands letter by letter.

-Ed

[Omega-TI]

 

At least a few mourned its passing, judging by this article reprint. Interesting reading.

 

 

 

Nice article. I made it into a .PDF file for you. It's easier to download and print this way too.

Rise & Fall - Timex.pdf

[John_L]

Whatever you think of the ZX81 and its capabilities, it was the raspberry pi of its time. It was designed with an ultra low price point in mind and, to get more computers into the home and get people coding. In all 3 respects it was a success. The ZX81 and Spectrum kick started the UK software industry.

 

Actually, I'm pretty impressed with what it can do considering what it has under the hood compared to say a C64, Apple ][, or TRS-80 Color Computer. The big drawbacks being the keyboard, and the poorly written 8K ROM BASIC. Internally though, it's an impressive machine considering the number of chips under the hood. When home computers came about, they were a bit expensive. The first home computer, the TRS-80 "Model I" was an extremely well made machine, and sold incredibly well considering it's $600 price point, which was about 4 1/2 percent of the median household income at the time ($13, 572). It was like spending $2400 in today's dollar.

 

Conversely, the Timex Sinclair 1000 was $100 in 1982, which was about .005 percent of the median household income of $20171, which was like spending $250 in today's dollar. A nearly 10 fold decrease in price over the Model I in 5 years. The goal at that point was to put out a home computer at the cheapest possible price point. At that point in time, the industry was still trying to flesh out the best price point for a computer, so there was alot of experimentation with price vs functionality. Moore's law was adjusted in 1975 to "# of transistors on a chip doubling every 18 months", So at that time, the technology was so in flux that the chips for devices like the C64, Color Computer, Apple, etc were dropping like a rock, and the competition was tight, so with newer chips claiming the premium price points, existing chips were pushed down in price. So, instead of competing with the higher priced ~$500 C64 and Color computer, both of those machines dropped from $500 to about $200 by 1982. It's the closing of that gap caused by ever dropping prices of the chips used in the machines combined with motherboard revisions the companies made to further reduce the cost of manufacture that caused the buying public to opt for the $200 C64s and CoCos. Even Radio Shack's attempt at competing with Sinclair with the TRS-80 MC-10 ($119.00 at launch) died a flaming death right about the same time that Timex folded here in the US.

 

I totally get why it was a popular machine for it's time, why it had a big following of folks who loved it, and why it's still a popular vintage unit. I just started the thread as a joke, I have no ill feelings towards folks who owed, or still own one. It was just posted in fun... kinda like this:

[Omega-TI]

 

I totally get why it was a popular machine for it's time, why it had a big following of folks who loved it, and why it's still a popular vintage unit. I just started the thread as a joke, I have no ill feelings towards folks who owed, or still own one. It was just posted in fun... kinda like this:

 

 

I hear ya! By todays standards ALL the old boxes pale in comparison to our modern machines, but as Yoda say's "The NOSTALGIA is strong with these old units." My ultimate goal is to actually have a BONAFIDE use for mine, other than a game machine.

 

BTW - Nice photoshopping of the graphic!

 

P.S. I 'borrowed' your improved version of the image and replaced the earlier version.

[John_L]

BTW - Nice photoshopping of the graphic!

 

P.S. I 'borrowed' your improved version of the image and replaced the earlier version.

 

No problem... I'm pretty handy with Photoshop and couldn't resist...!

[MarkO]

The Timex is neat for what it is. It's a fun thing to tinker with but not something you'd want to be forced to use. It still kills me how much productivity software was released for it, and that some people actually used it (like my dad!).

I had a Pac-Man like game for it... Actually played quite nice... I believe that is what my Uncle made the Joy Stick to play Arcade Games like Pac-Man.

 

It does have quite a few halfway decent games (some could even qualify as "good"), but the keyboard ruins many would-be excellent titles. I will say it does Space Invaders-type games pretty well, though, or other games requiring only two or three key input. The potential for Roguelikes and text adventures is there as well.

There were quite a few After Market keyboards.. I will pull out my Sinclairs and take some pictures...

[MarkO]

Well, you're 100 percent correct that the forced use of short key for basic statements like PRINT was to cut down the code size. They were trying to squeeze the equivalent of a "level 2" basic into the space of a Level I basic. But forced short key isn't what really bugs me about it. It's that freakish ever-changing-to-yet-another-alphabetic-character of a cursor. Cursors are cursors, and characters are characters. A cursor can be an underline, or an inverted space (block character), it can blink, or not, but the two biggest no no's you could possibly do is A) Let it be an alphabetic character, or B, change. TS 1000 did BOTH. A cursor's job is to indicate where the next character will appear on the display, not to indicate what "mode" you're in, I don't know much about how it works, but what I've figured out just dicking around with an emulator is that "L" means you're in basic statement input mode, and "G" means Graphics mode, and K means whatever letter you type will actually appear on the screen mode, aka, string input mode.

I was 16 years old when we got our ZX-81, and I found the BASIC quite easy to pick up, even after Apple Integer BASIC and AppleSoft BASIC. Take a look at a ZX-81/TS-1000 keyboard

 

If you look at the Primary BASIC Keywords ( above the Letter ) on each Key, some are real obvious, like "R" and RUN, "I" and INPUT, "P" and PRINT, "S" and SAVE, "D" and DIM, "F" and FOR, "G" GOTO, "L" and LET, "N" and NEXT.

 

Because of so many BASIC Commands starting with the Same Letters, there are conflicts, but Quite Obvious second choice letters were, "E" and REM, "O" and POKE.

 

In most ALL CASES, the BASIC Keyword is on a key, Close to the First Letter of the Keyword, such as:

"R" and REM, RUN, RAND, RETURN

"I" and IF, INPUT

"P" and POKE, PRINT

"G" and GOTO, GOSUB

"L" and LOAD, LIST, LET

"C" and COPY, CLEAR, CONT, CLS

 

The Secondary Keywords ( below the Letter ) like Math Functions, are mostly grouped around the "Q" <-> "T" <-> "H" <-> "A" keys, String Functions from "Y" <-> "I" <-> "K" <-> "J".

 

The rest obviously got fitted in where they could...

 

Still the Groupings of the related Keywords, made remembering them quite easy..

 

Even Applesoft didn't have something like INKEY$, the Sinclair being my Third BASIC, I learned had it, which was much more obvious that Reading a Memory Location on the Apple ][ and looping until it changed...

 

They honestly could have indicated the mode by say, changing the border color to indicate the mode or something else. That way, the cursor could have been, well, a cursor, and not a cursor/mode indicator. Also, the problem with short keys is that you have to memorize a bunch of different functions for the same key depending on the mode you're in.

True, but it didn't take me long to get them... Once through the Manual and I had it down....

 

I think you're being generous saying that it saved as much as 1k, there's about 300 characters in the keyword set (for the lookup table), and the routines for checking and tokenizing are probably about 20 to 30 bytes each, and both could use the same keyword table, so well under 1/2 kilobyte. If they were looking to keep things light, they could have shelved "Let" the most useless function of any programming language ever of all time.

 

Programming is difficult enough as it is without having to continuously remember what key does what, or to glance down at the keyboard to figure out what key to hit or track modes.

I don't think that the Single Key entry saved much space, at least none in the Stored Programs... Every BASIC I have seen Tokenizes the Keywords into a Byte or Two... What the Sinclair did was Reduce Keystrokes while entering Programs, because of the Barely Sufficient Keyboard.. I am not a Touch Typists, but I could enter programs just about as fast on the ZX-81 as an Apple ][. Maybe faster...

 

MarkO