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erasmo0 24th Nov 2020 10:31 pm

Hello all...The Sinclair QL are two types or only one?

Were the electronics similar to the Amiga_Commodore?!

Radio Wrangler 25th Nov 2020 10:17 am

Re: QL_Sinclair
The Sinclair QL used a Motorola MC68000 series microprocessor, essentially a 16 bit CPU but a model with with the external busses thinned down to 8 bits to cheapen the memory required. Sinclair advertised it as a 16 bit machine, but it was one with an 8-bit bottleneck.

The Commodore Amiga computers are a different design and use MC68000 family models with full 16 bit buses for the memory.

The QL launched (eventually it got out) with Sinclair's 'microdrive' tape cartridge as a cheaper alternative to a floppy drive. It was a bit of a disaster.

This same microdrive was also used in the ICL one-per-desk microcomputer/terminal thing. ICL re-engineered the thing to try to make it more reliable, but their whole effort was overtaken by the progress at other companies and the rise of the IBM PC as a standard.

Sinclair generated huge amounts of disappointment with the QL. It looked like they were still designing the thing while they were taking sales orders.

The QL was a forwards looking and innovative machine, but it was spoiled just enough and in many ways to disappoint people. THe mismatch between promises and delivery being the worst.


SiriusHardware 26th Nov 2020 9:56 am

Re: QL_Sinclair
I was a diehard Sinclair fan but the QL was the first Sinclair machine I did not buy, mainly because of their determination to persist with the Microdrive which was never very reliable when I was a spectrum 'power user'.

I defected to the Amiga's rival, the Atari ST.

Phil__G 26th Nov 2020 10:31 am

Re: QL_Sinclair
BT used the ICL One Per Desk extensively when I was on IT support, it combined telephony and computing on one unit. Actually the BT version was called a "Tonto" :)
I remember once we had to decommission a BT building which had been empty for years prior to sale. One office was locked but we forced the door and on the desk was an OPD still switched on and with a spreadsheet open on the screen, still running after all that time. It was a good machine, the drives were its weak point. The rule was to save everything twice using two separate tapes.

Richard_FM 26th Nov 2020 10:42 am

Re: QL_Sinclair
I heard the Microdrive was launched when I was still on the bench, and this meant it was rushed into production before Sinclair had been able to run any long term tests. This meant thermal expansion caused the drive to give trouble, something that should have been sorted out long before it was given the go-ahead.

As mentioned above the QL had the potential to be a decent computer but there seemed to be too many compromises in the design.

barrymagrec 26th Nov 2020 11:18 am

Re: QL_Sinclair

Originally Posted by Richard_FM (Post 1314502)
As mentioned above the QL had the potential to be a decent computer but there seemed to be too many compromises in the design.

That was the story of Sinclair.

Dave Moll 26th Nov 2020 11:45 am

Re: QL_Sinclair
I have ZX80s, ZX81s and various Spectra, but the QL is one Sinclair computer I've never acquired.

electronicskip 26th Nov 2020 12:00 pm

Re: QL_Sinclair
Ive had a couple of QLs over the years and indeed a forum member had a non working example from me a few years back, but mostly i have Spectrum 48ks +2s and +3 with disc drive.
Also have Amiga 500s and a rareish 1200 unit too.
Most get used on a regular basis .

Phil__G 26th Nov 2020 12:04 pm

Re: QL_Sinclair
Do I remember correctly that a microdrive tape was like an 8-track cartridge, ie continuous and spooling from the centre of the coil back onto the outside of the coil?

SiriusHardware 26th Nov 2020 12:42 pm

Re: QL_Sinclair
Yes, a mini 8-track is exactly how I always describe their appearance although I think they only had two tracks.

Anyway, to answer the OP's question properly, the QL is one of the later models made by Sinclair in the UK, referred to as the 'Sinclair QL' or sometimes just the 'QL'. The letters 'QL' may have stood for 'Quantum Leap'.

Craig Sawyers 26th Nov 2020 12:52 pm

Re: QL_Sinclair
A friend bought a QL when they first came out. He wrote a quick test programme to do a simple calculation that he could check with a calculator. The answers were different, not by much - but different.

The test programme used root(2). So he changed it to find root(2.00001) and the answer was bang on.

Basically, commonly used constants, e, pi, root(2) etc were stored in ROM, and the guy (probably with Sinclair breathing down his neck) put in a slightly wrong value for root(2).

Entering not quite an integer argument made the machine do the calculation instead of using the ROM value.


chriswood1900 26th Nov 2020 1:18 pm

Re: QL_Sinclair

Originally Posted by SiriusHardware (Post 1314545)
Sinclair in the UK, referred to as the 'Sinclair QL' or sometimes just the 'QL'. The letters 'QL' may have stood for 'Quantum Leap'.

They forgot to mention it was a Quantum Leap Backwards!

merlinmaxwell 26th Nov 2020 1:35 pm

Re: QL_Sinclair
I was working for him when it was launched, a floppy drive was in the offing but never got there. I had one of the prototypes on my bench, it worked quite well, dear Rick Dickinson was a close neighbour (6 doors or so away) of mine then too. Amstrad bought him out at that time, OK Amstrad did good marketing but the products were mainstream rather than cutting edge in the end.

Happy days, Sinclair did an awful lot of stuff, working for him was fun and stimulating. Free canteen (restaurant really) and free bar, Greene King IPA always on tap. Afternoons were left for walking about and chatting to other engineers if you wanted to, I am sure more work got done then than the mornings.

bluepilot 26th Nov 2020 1:38 pm

Re: QL_Sinclair

Originally Posted by SiriusHardware (Post 1314545)
The letters 'QL' may have stood for 'Quantum Leap'.

What people seem to forget is that in physics a quantum is the minimum amount of any physical entity. A quantum leap is therefore the smallest leap possible. I suppose that means the QL was an infinitesimal amount better than what went before.

Cobaltblue 26th Nov 2020 2:08 pm

Re: QL_Sinclair
Before the Mods start deleting posts please stay on topic.


Mike T

Phil__G 26th Nov 2020 2:39 pm

Re: QL_Sinclair
I don't see any 'off topic' posts ???

Station X 26th Nov 2020 2:43 pm

Re: QL_Sinclair
Time to close this thread.

Station X 26th Nov 2020 9:24 pm

Re: QL_Sinclair
Thread reopened. Please stay on topic. Read the first post before putting fingers to keyboard. Thank you.

Slothie 26th Nov 2020 10:59 pm

Re: QL_Sinclair
The only real similarity between the Amiga/ST and the QL was the processors were 68000 variants. The QL had a 68008 processor which had an external 8 bit bus wheras the Amiga used a 68000 with external 16 bit address bus. The 68000 architecture was 32 bit, so each instruction or memory transfer required 2 memory cycles on the 68000 and four on the 68008 - which was part of the cause of its performance problems. However the main thing that deterred buyers were long shipping delays and poor reliability of the early production models. The last revision released were actually far better quality - the problems with the microdrives were largely cured by Sinclair outsourcing manufacture to Samsung - but by then the reputational damage had been done, the business community (The QLs intended market) had its eyes on the IBM PC, and the Amiga had been released and was more attractive to the wider gaming public due to its sound and graphics being considered superior.

The ICL One-per-desk machine used a lot of the QL design and ASICS, being a collaboration between Sinclair, ICL and BT, I haven't seen anything confirming if they were software compatible or not.

Andrew2 27th Nov 2020 1:02 pm

Re: QL_Sinclair
Ah, the thread is opened again! I'll post what I had laboriously typed out yesterday before realising the thread was closed...

An interesting story from 'The Sinclair Story' (Rodney Dale 1985) concerns the usual 'launched before it was ready' tendency at Sinclair Research.
Apparently the operating system and the BASIC interpreter were meant to live together on two 16k ROM chips, but it was found (at the last minute, natch) that the code could not be squeezed into such a small memory. It would go into 48k, but as there were only two ROM sockets it would require a 16k and a 32k.

32k ROMs were not available (?) and getting them made would have delayed things further, so the decision was made to use three 16k chips. Trouble was there was nowhere to plug a third chip!

Dangling it on the end of a cable and tucking it in some available space inside the machine was deemed risky from a review perspective, as any reviewer worth his salt would almost certainly have whipped the top off the new QL to see the innards, so it was decided to plug the extra ROM into the rear socket designed for a future 'applications' cartridge. And that's the way the machine was launched.

That's what it says here, anyway. Whether a later revision of the QL PCB squeezed in an extra 16k ROM I don't know, but it would have been a good move.

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