BEEP VAL

[ZXDunny]

"ok, we need to make an upgraded ZX81. What can we get for the same cost as the '81 cost when it was launched?"

"We can add colour. We could use full or empty RGB channels to get 8 colours, and probably a halfbright by setting an extra bit."

"No interesting colours like the commodores then?"

"Not if you don't want to spend any money."

"Ok, that'll do then. We'll call it a 'Spectrum' and they'll love it. What else?"

"We could get a full 64k of RAM?"

"With a 16k ROM?"

"No, that would cost more, we'd need some sort of paging"

"Bugger that, let's launch it as 48k. It's still more than 1kb. And we could launch two models, and charge more. What else?"

"Sound?"

"Can we do sound? What's the minimum we could go for?"

"A piezo buzzer that we can toggle on and off. We could add it to the graphics chip. But there are better chips out there for sound."

"f*** 'em. A buzzer will be plenty good enough, it's not like anyone will make music with it, this is a glorified calculator like the last one.
Hmm. That graphics chip. What else can we cram in there?"

"Tape loading? We could use it to listen to the tape. Oh, and we could use it to read the keyboard too."

"Do it. Just keep the cost at a minimum. We're not going to make any money if this thing costs £300."

[AndyC]

... they didn't even get all the Interface 1 code into the ROM as they had originally planned.

Interesting. I never header about this. What ROM are we refering here to?

The BASIC ROM, it was originally supposed to contain all the microdrive code, but it wasn't ready it time and so got dropped for a slightly hacky solution in the Interface 1

They had been producing a new model on a yearly basis, they could always do things better in the "ZX83" - the Speccy was never envisioned as staying around even half as long as it did.

Fair enough. However I'm not satisfied with the 128k either.

The.128 design wasn't really a Sinclair thing, it was a Spanish spin off (Investronica?) that stemmed from rules at the time which applied additional taxes on computers with less than 64K (they were seen as entertainment items). They threw in a few extras to make it a bit more appealing, but it was a quick and dirty upgrade. Not quite as cheap a solution as Amstrad, who made a CPC472 by just soldering and unconnected 8K of RAM inside a standard 464 to solve the same problem!

[Seven.FFF]

"Tape loading? We could use it to listen to the tape. Oh, and we could use it to read the keyboard too."

Expanding on my earlier observation that the ULA beeper circuit is the same circuit that outputs the tape MIC signal... it's almost certainly similar to the ZX81 tape circuit too. It's not like Altwasser invented it from scratch for the Spectrum.

I'm veering into conjecture here, but he already had the ZX81 circuit, was aware of it's reliability issues, fixed those in a minimum viable way, then bingo, free buzzer feature too! Job done, with the absolute minimum of work.

[Seven.FFF]

My theory is that the ZXs should appeal to hackers. And to gamers, i.e hackers who do games. So hackers it is. They like things which are transparent, pushed to the limit and extendable.

That may be what we'd all like to be true, but the reality is different. Many of the decisions they made make it much harder for hackers, and edge connector hardware designers

[1bvl109]

But it would have pushed up costs. Adding any extra hardware would have pushed up manufacturing costs.

As would have better software.

So, don't add it, just make the machine flexible enough to be able to add it later. Then sell it. Maybe you need a few lines more on the edge connector. And here's your ULA+ for a nice steep price. How about a 128/256/1024 RAM pack?

Alternatively just bring out an early successor which can do this. Going incompatible where you need to. We have lots of revisions of the board already.

So it was never going to happen. This was a computer done as cheap as possible but still, as has been pointed out, a recognisably better ZX81.

You have to pay for recognizable better however.

And besides, Sinclair didn't add anything. We can't go back and change it so there's no real point to this.

I don't mean, repeat don't mean to bugger the old man. He had to organize a company. I never did such a thing. I have some basic understand of electronics 40 years ago. This is it.

Of course hope goes on forever and maybe somebody somewhere is sitting down with a Z80e thinking what would be needed to make a cheap as dirt successor.

[1bvl109]

That may be what we'd all like to be true, but the reality is different.

You caught me with my pants down, Mr. Feuerbach.

Many of the decisions they made make it much harder for hackers, and edge connector hardware designers

Doubtlessly. But were they "After careful consideration we'd rather not"-, "We don't give a sh*t"- or "We have no time to even considerate this"-decisions? Or what else was the consideration behind the decision?

[1bvl109]

"We could get a full 64k of RAM?"

"With a 16k ROM?"

"No, that would cost more, we'd need some sort of paging"

"Bugger that, let's launch it as 48k. It's still more than 1kb."

I especially like that.

But we would also be able to bring out revisions of the ROM on tape. And sell memory extensions as we did with the 81! And bring out hardware extensions with new custom ROM routines! Of course there will be competition, e.g. like the race for the lowest price for the 16k RAM for the ZX81, but we will always have an edge, knowing the design already and therefore being first to the market.

[ZXDunny]

Having 64k RAM with the ROM on a media was a thing with the Amiga 1000 - Kickstart up to 1.3 came on floppy disk to be written to the "ROM" (which I use in quotes there as it was only semi-permanent; it survived a soft reboot but not a power-down). The thing was it only took a few seconds to read and you were good to go. I upgraded my kickstart a couple of times that way as I went from 1.0 to 1.3.

But for a Speccy? 16kb of tape took a while to load. Having to do that every time you booted up would be a real PITA. And as the Speccy had no soft-reset system (which would have cost more to put in - witness the 48k+'s reset switch that literally cut the power, grounding the CPU - minimal cost) the ROM would have to be re-loaded after every game you played.

It's unlikely that as attractive as a full 64kb was making it work just was either too expensive or too unfriendly to the user.

[1024MAK]

Hmm, I think something got lost, now what was it?

Ahh yes, Sir Clive Sinclair set the specifications. As the owner of the company he was responsible for deciding what features were in and which were dropped.

And you do know that Clive aimed the ZX Spectrum at the educational market and the hobbyist market. It was never intended to be a games machine.

From the limited information available, I get the impression that the ZX Spectrum ULA was the most complex ULA that Ferranti has made at the time. So it may already have been pushing the limits...

Oh, and by the way, Sinclair expected the 16K byte ZX Spectrum to be the most popular, not the 48K byte model. The 16K byte ZX Spectrum was upgradable internally or externally, hence 32K byte RAM packs do exist.

Mark

[1024MAK]

And as the Speccy had no soft-reset system (which would have cost more to put in - witness the 48k+'s reset switch that literally cut the power, grounding the CPU - minimal cost) the ROM would have to be re-loaded after every game you played.

Err, the ZX Spectrum+ reset button is connected to the existing resistor/capacitor ‘power on’ reset circuit that in turn connects to the Z80 /RESET pin. Nothing wrong with that. The only cheap bit being no proper PCB connector.

Mark

[1bvl109]

But for a Speccy? 16kb of tape took a while to load. Having to do that every time you booted up would be a real PITA.

If you don't like waiting and love the ROM so much, as to use it every day, we have a ROM to sell them. Or a microdrive.

And as the Speccy had no soft-reset system (which would have cost more to put in - witness the 48k+'s reset switch that literally cut the power, grounding the CPU - minimal cost) the ROM would have to be re-loaded after every game you played.

That's up to the programmer, whether he would give his user a magic SYSREQ or if he likes to use the shinny aditional 16k. We wash our hands of it.

It's unlikely that as attractive as a full 64kb was making it work just was either too expensive or too unfriendly to the user.

Now is this the glorious land of capitalism or not? We're gona take them for a ride and make them loving it, begging for it!
They are loading 48k on the slower and less reliable 81. They'll load 64k games and love us.

[ZXDunny]

But for a Speccy? 16kb of tape took a while to load. Having to do that every time you booted up would be a real PITA.

If you don't like waiting and love the ROM so much, as to use it every day, we have a ROM to sell them. Or a microdrive.

And as the Speccy had no soft-reset system (which would have cost more to put in - witness the 48k+'s reset switch that literally cut the power, grounding the CPU - minimal cost) the ROM would have to be re-loaded after every game you played.

That's up to the programmer, whether he would give his user a magic SYSREQ or if he likes to use the shinny aditional 16k. We wash our hands of it.

It's unlikely that as attractive as a full 64kb was making it work just was either too expensive or too unfriendly to the user.

Now is this the glorious land of capitalism or not? We're gona take them for a ride and make them loving it, begging for it!
They are loading 48k on the slower and less reliable 81. They'll load 64k games and love us.

Who was loading 48k of data on a ZX81?

[1bvl109]

Hmm, I think something got lost, now what was it?

Ahh yes, Sir Clive Sinclair set the specifications. As the owner of the company he was responsible for deciding what features were in and which were dropped.

And as such unsusceptible in every aspect to the lure of gold?

And you do know that Clive aimed the ZX Spectrum at the educational market and the hobbyist market. It was never intended to be a games machine.

So...?

From the limited information available, I get the impression that the ZX Spectrum ULA was the most complex ULA that Ferranti has made at the time. So it may already have been pushing the limits...

We can leave this at we don't know, if you want to. I just don't like to jump from "This was El Ceapos Computer!" and "There could have been restriction in the ULA" to "It didn't fit". I'll think this over, of someone say from Ferranti, Amstrad or Sinclair/Cambridge Research talks.
of course,

Oh, and by the way, Sinclair expected the 16K byte ZX Spectrum to be the most popular, not the 48K byte model. The 16K byte ZX Spectrum was upgradable internally or externally, hence 32K byte RAM packs do exist.

This doesn't contradict to expect people who want even more.

I also don't see any second thoughts, as the numbers came in.

[1bvl109]

Who was loading 48k of data on a ZX81?

E.g. I knew someone who did the housekeeping of his business (a small electronics shop) with a 64 Memopak, with self written programs. He also sold them with quite some success. He used some of this speedloaders which had a hardware add on and recommended it to his costumers.

The most reliable recorder I had was actually a stereo boombox.

[ZXDunny]

Who was loading 48k of data on a ZX81?

E.g. I knew someone who did the housekeeping of his business (a small electronics shop) with a 64 Memopak, with self written programs. He also sold them with quite some success. He used some of this speedloaders which had a hardware add on and recommended it to his costumers.

The most reliable recorder I had was actually a stereo boombox.

Yes, I am aware of memory expansions, but they weren't commonly owned by non-enthusiasts - I certainly never came across them, but read about them in the magazines of the time. The point was that if you were poor you had a 1Kb ZX81, if you were well-off financially you might have had a 16K ZX81.

So very few people had more than that - so there was very little comparison between loading times on a ZX81 (which typically loaded less data) and a Spectrum.

[alban lusitanae]

When your post gains a life of its own. So beautiful

[1bvl109]

So beautiful

It's called post kidnapping or postnapping. We'll see, who's laughing, when the ransom demand reaches you.

In totally unrelated news: Is there a bitcoin client for the Spectrum?

I had my grandniece (3) code one, but she keeps complaining that my assembler IDE is quirky.