Zx81plus34 - Revision history

Mahjongg: /* what now? */

2019-09-29T15:31:19Z

what now?

← Older revision		Revision as of 15:31, 29 September 2019
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	===what now?===		===what now?===
	[[File:Preview_ZX14_with_keyboard.jpg\|thumb\|right\|800px\|An early preview of the complete ZX14 system, including keyboard. A larger and newer versions can be seen on the new ZX15 project page, here: [https://revspace.nl/ZX15_ZX81_clone]]]		[[File:Preview_ZX14_with_keyboard.jpg\|thumb\|right\|800px\|An early preview of the complete ZX14 system, including keyboard. A larger and newer versions can be seen on the new ZX15 project page, here: [https://revspace.nl/ZX15_ZX81_clone]]]
	Zoom forward for some 34 years, and its ~~2015~~. Some people, heavy into computers, still remember their first love, the ZX81. But off course the ZX81 is no longer of this time. Now its the time of the Arduino's and the raspberry PI.		Zoom forward for some 35 years, and its 2016. Some people, heavy into computers, still remember their first love, the ZX81. But off course the ZX81 is no longer of this time. Now its the time of the Arduino's and the raspberry PI.
	Still there is something to say for the old ZX-81, it at least was so simple you could learn to understand (and love) '''all''' its intricacies of design, and it was a fully self contained thing, not relying on anything else.		Still there is something to say for the old ZX-81, it at least was so simple you could learn to understand (and love) '''all''' its intricacies of design, and it was a fully self contained thing, not relying on anything else.

Mahjongg: /* what to do? creating the first home computer is what he did! */

2019-09-29T15:30:25Z

what to do? creating the first home computer is what he did!

← Older revision		Revision as of 15:30, 29 September 2019
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	However, for his earlier system the ZX80 his new hardware designer (Jim Westwood) had drawn inspiration from a famous early computer book, (Don Lancaster's "TV Typewriter Cookbook") [https://en.wikipedia.org/wiki/TV_Typewriter#TV_Typewriter_Cookbook] that described how with a micro controller and a tiny bit of hard and software you could create a video signal. And Jim had come up with his own similar scheme that would only use as much memory as there were characters on the screen. But his solution could either compute, or draw a screen, not both. All it could do while creating video was to sense a key press.		However, for his earlier system the ZX80 his new hardware designer (Jim Westwood) had drawn inspiration from a famous early computer book, (Don Lancaster's "TV Typewriter Cookbook") [https://en.wikipedia.org/wiki/TV_Typewriter#TV_Typewriter_Cookbook] that described how with a micro controller and a tiny bit of hard and software you could create a video signal. And Jim had come up with his own similar scheme that would only use as much memory as there were characters on the screen. But his solution could either compute, or draw a screen, not both. All it could do while creating video was to sense a key press.

	Clive Sinclair ~~realized~~ that this wasn't what people wanted, they wanted pictures that would move on the screen, its what all the competing devices could do. And a capability that all computer games needed, except for a very few ones, like computer chess.		After the ZX80 was released Clive Sinclair realised that this wasn't what people wanted, they wanted pictures that would move on the screen, its what all the competing devices could do. And a capability that all computer games needed, except for a very few ones, like computer chess.

	Also, although the ZX80 was very simple, he wanted to further limit the number of components so it could be made cheaper. His aim was the "magical limit" of one hundred pound, not for a kit but for a ready build device.		Also, although the ZX80 was very simple, he wanted to further limit the number of components so it could be made even cheaper. His aim was the "magical limit" of one hundred pound, not for a kit but for a ready build device.
	His famous reasoning went "if you can sell it for a hundred pound, people will buy it even if they have absolutely no idea what to do with it".		His famous reasoning went "if you can sell it for a hundred pound, people will impulse buy it even if they have absolutely no idea what to do with it".
	It also had to look much slicker than his previous efforts, and had to have a less primitive BASIC programming language. So he sent Jim "back to the drawing board", and hired an industrial designer called Rick Dickinson for the new look.		It also had to look much slicker than his previous efforts, and had to have a less primitive BASIC programming language. So he sent Jim "back to the drawing board", and hired an industrial designer called Rick Dickinson for the new look.

	What Jim, and Rick came up with was a truly amazing piece of work, that fulfilled all Sinclair's wishes. And so the ZX-81 was born, and as it name implies, it was launched in may 1981.		What Jim, and Rick came up with was a truly amazing piece of work, that fulfilled all Sinclair's wishes. And so the ZX-81 was born, and as it name implies, it was launched in may 1981.
	It was not only sold by mail order, but actually could be bought in shops too. It was an immediate and large success, in the Netherlands even famous audio designers and shop-chain Bang & Olufsen (B&O) sold it (as the "beocomp"). It was what actually triggered the Home Computer Market, at least in Europe. In the end at least 1000.000 were sold, and it lead to it's successors like the famous Sinclair Spectrum, (with thanks for the case and keyboard design leaned from the TIMEX TS1500, one of the many ZX81 clones).		It was not only sold by mail order, but actually could be bought in main-street shops too. It was an immediate and large success, in the Netherlands even famous audio designers and shop-chain Bang & Olufsen (B&O) sold it (as the "beocomp"). It was what actually triggered the Home Computer Market, at least in Europe. In the end at least 1000.000 were sold, and it lead to it's successors like the famous Sinclair Spectrum, (with thanks for the case and keyboard design leaned from the TIMEX TS1500, one of the many ZX81 clones).

	===what now?===		===what now?===

Mahjongg: /* what now? */

2019-07-30T22:23:23Z

what now?

← Older revision		Revision as of 22:23, 30 July 2019
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	Early 2014 I endeavored to design my own "modern version" of the ZX-81, with all the improvements I could think off, and using modern techniques and components, I initially called my effort the ZX14, as both a tribute to the ZX80/81 and the MK14 that came before it.		Early 2014 I endeavored to design my own "modern version" of the ZX-81, with all the improvements I could think off, and using modern techniques and components, I initially called my effort the ZX14, as both a tribute to the ZX80/81 and the MK14 that came before it.

	In mid April 2014 when I initially wrote this I already had finished the Schematic, and was starting to design the PCB for it, which I then gambled would fit on a 10 x 10 cm dual sided PCB. I tried that because a 10 x 10 cm PCB is often the largest size that ~~extremely~~ cheap (Chinese) PCB manufacturers can handle. Also, I was planning to use a standard Eurocard sized perfboard with 1/10" raster for the hand wired keyboard, using cheap 6x6mm buttons for keys.		In mid April 2014 when I initially wrote this I already had finished the Schematic, and was starting to design the PCB for it, which I then gambled would fit on a 10 x 10 cm dual sided PCB. I tried that because a 10 x 10 cm PCB is often the largest size that cheap (Chinese) PCB manufacturers can handle extremely cheaply, as in adding one centimeter to the size (10 x 11 cm) will double the price! Also, I was planning to use a standard Eurocard sized perfboard with 1/10" raster for the hand wired keyboard, using cheap 6x6mm buttons for keys.

	However during early summer of 2014 I had an accident and spent several weeks in hospital because of a bad leg wound, then had to stay at home, (with help). For more than three months I could not drive to RevSpace to work on the ZX14. That was why it became early 2015 before the layout was finished. I also found out that both ZX14 and ZX15 are Yamaha motorcycles. That is why I decided to rename the prototype ZX81+34.		However during early summer of 2014 I had an accident and spent several weeks in hospital because of a bad leg wound, then had to stay at home, (with help). For more than three months I could not drive to RevSpace to work on the ZX14. That was why it became early 2015 before the layout was finished. I also found out that both ZX14 and ZX15 are Yamaha motorcycles. That is why I decided to rename the prototype ZX81+34.

Mahjongg: /* what to do? creating the first home computer is what he did! */

2019-07-30T22:16:44Z

what to do? creating the first home computer is what he did!

← Older revision		Revision as of 22:16, 30 July 2019
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	After some brainstorming he decided that computers were the future. Not the hobbyist toys he considered that his earlier machine was, but a real computer for the masses, a "Home computer". But at the time these new kind of computers were very expensive!		After some brainstorming he decided that computers were the future. Not the hobbyist toys he considered that his earlier machine was, but a real computer for the masses, a "Home computer". But at the time these new kind of computers were very expensive!
	A typical home/personal computer, like an Apple ][, was thousands of pounds, but even the cheaper and more limited machines, like the UK101, were still many hundred of pounds. ~~Specifically this~~ was partly true, because computer memory chips were very expensive. Chips amounting to 4 Kilobyte of memory still went for something like a hundred pound, and with much less memory you could only create a "MK14" type of computer. The MK14 had just a quarter a Kilobyte of memory, yes just 256 Bytes of RAM, and one half kilobyte of ROM! It also used a hexadecimal keypad, and a tiny calculator display for a screen, (borrowed from his calculator projects, which used 3mm high digits with lenses before them to make them look bigger). This made it unattractive for anyone but computer hackers.		A typical home/personal computer, like an Apple ][, was thousands of pounds, but even the cheaper and more limited machines, like the UK101, were still many hundred of pounds. This was partly true, because computer memory chips were very expensive. Chips amounting to 4 Kilobyte of memory still went for something like a hundred pound, and with much less memory you could only create a "MK14" type of computer. The MK14 had just a quarter a Kilobyte of memory, yes just 256 Bytes of RAM, and one half kilobyte of ROM! It also used a hexadecimal keypad, and a tiny calculator display for a screen, (borrowed from his calculator projects, which used 3mm high digits with lenses before them to make them look bigger). This made it unattractive for anyone but computer hackers.

	Any kind of system that would be able to drive a TV screen, would need at least a byte for each screen location, and a typical (useable) screen of 32x24 characters or so would thus quickly used a large part of a kilobyte (768 bytes).		Any kind of system that would be able to drive a TV screen, would need at least a byte for each screen location, and a typical (useable) screen of 32x24 characters or so would thus quickly used a large part of a kilobyte (768 bytes).

Mahjongg: /* what to do? creating the first home computer is what he did! */

2019-07-30T22:15:55Z

what to do? creating the first home computer is what he did!

← Older revision		Revision as of 22:15, 30 July 2019
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	===what to do? creating the first home computer is what he did!===		===what to do? creating the first home computer is what he did!===

	After some brainstorming he decided that computers were the future. Not the hobbyist toys he considered that his earlier ~~machines were~~, but a real computer for the masses, a "Home computer". But at the time these new kind of computers were very expensive!		After some brainstorming he decided that computers were the future. Not the hobbyist toys he considered that his earlier machine was, but a real computer for the masses, a "Home computer". But at the time these new kind of computers were very expensive!
	A typical home/personal computer, like an Apple ][, was thousands of pounds, but even the cheaper and more limited machines, like the UK101, were still many hundred of pounds. Specifically this was partly true, because computer memory chips were very expensive. Chips amounting to 4 Kilobyte of memory still went for something like a hundred pound, and with much less memory you could only create a "MK14" type of computer. The MK14 had just a quarter a Kilobyte of memory, yes just 256 Bytes of RAM, and one half kilobyte of ROM! It also used a hexadecimal keypad, and a tiny calculator display for a screen, (borrowed from his calculator projects, which used 3mm high digits with lenses before them to make them look bigger). This made it unattractive for anyone but computer hackers.		A typical home/personal computer, like an Apple ][, was thousands of pounds, but even the cheaper and more limited machines, like the UK101, were still many hundred of pounds. Specifically this was partly true, because computer memory chips were very expensive. Chips amounting to 4 Kilobyte of memory still went for something like a hundred pound, and with much less memory you could only create a "MK14" type of computer. The MK14 had just a quarter a Kilobyte of memory, yes just 256 Bytes of RAM, and one half kilobyte of ROM! It also used a hexadecimal keypad, and a tiny calculator display for a screen, (borrowed from his calculator projects, which used 3mm high digits with lenses before them to make them look bigger). This made it unattractive for anyone but computer hackers.

Mahjongg: /* Its working ! */

2016-11-02T23:54:13Z

Its working !

← Older revision		Revision as of 23:54, 2 November 2016
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	On Saturday February 27, 2016, I first had a TV picture from my clone!		On Saturday February 27, 2016, I first had a TV picture from my clone!

	read more about the effort to get it working here: [ZX81PLUS34_ZX81_clone#28_February_2016_It.27s_alive.21]		read more about the effort to get it working here: [https://revspace.nl/ZX81PLUS34_ZX81_clone#28_February_2016_It.27s_alive.21]

Mahjongg: /* Its working ! */

2016-11-02T23:53:19Z

Its working !

← Older revision		Revision as of 23:53, 2 November 2016
Line 63:		Line 63:
	On Saturday February 27, 2016, I first had a TV picture from my clone!		On Saturday February 27, 2016, I first had a TV picture from my clone!

	read more about the effort to get it working here: [~~https://revspace~~.~~nl/ZX81plus34_ZX81_clone~~]		read more about the effort to get it working here: [ZX81PLUS34_ZX81_clone#28_February_2016_It.27s_alive.21]

Mahjongg: /* Its working ! */

2016-11-02T23:51:51Z

Its working !

← Older revision		Revision as of 23:51, 2 November 2016
Line 63:		Line 63:
	On Saturday February 27, 2016, I first had a TV picture from my clone!		On Saturday February 27, 2016, I first had a TV picture from my clone!

	read more about the effort to get it working here: [https://revspace.nl/~~ZX81+34_ZX81_clone~~]		read more about the effort to get it working here: [https://revspace.nl/ZX81plus34_ZX81_clone]

Mahjongg: /* The ZX81+34 ZX81 Clone, and how it came to be */

2016-11-02T23:51:11Z

The ZX81+34 ZX81 Clone, and how it came to be

← Older revision		Revision as of 23:51, 2 November 2016
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	==The ZX81+34 ZX81 Clone, and how it came to be==		==The ZX81+34 ZX81 Clone, and how it came to be==

	Main article about the ZX81+35 is here [https://revspace.nl/~~ZX81PLUS34 ZX81 clone~~]		Main article about the ZX81+35 is here [https://revspace.nl/ZX81PLUS34_ZX81_clone]

	In 1980 one Clive Sinclair from Camebridge in the UK, started to sell a very small simple and cheap computer kit by mail order, he called it the ZX80, (because of the year it was launched, the Z80 CPU it used and because "ZX" sounded mysterious) it met with limited success, he sold about 10.000 of them to "computer hacker" types.		In 1980 one Clive Sinclair from Camebridge in the UK, started to sell a very small simple and cheap computer kit by mail order, he called it the ZX80, (because of the year it was launched, the Z80 CPU it used and because "ZX" sounded mysterious) it met with limited success, he sold about 10.000 of them to "computer hacker" types.

Mahjongg: /* The ZX81+34 ZX81 Clone, and how it came to be */

2016-11-02T23:45:01Z

The ZX81+34 ZX81 Clone, and how it came to be

← Older revision		Revision as of 23:45, 2 November 2016
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	==The ZX81+34 ZX81 Clone, and how it came to be==		==The ZX81+34 ZX81 Clone, and how it came to be==

	Main article about the ZX81+35 is here [https://revspace.nl/~~ZX81plus34_ZX81_clone~~]		Main article about the ZX81+35 is here [https://revspace.nl/ZX81PLUS34 ZX81 clone]

	In 1980 one Clive Sinclair from Camebridge in the UK, started to sell a very small simple and cheap computer kit by mail order, he called it the ZX80, (because of the year it was launched, the Z80 CPU it used and because "ZX" sounded mysterious) it met with limited success, he sold about 10.000 of them to "computer hacker" types.		In 1980 one Clive Sinclair from Camebridge in the UK, started to sell a very small simple and cheap computer kit by mail order, he called it the ZX80, (because of the year it was launched, the Z80 CPU it used and because "ZX" sounded mysterious) it met with limited success, he sold about 10.000 of them to "computer hacker" types.