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Sinclair QL and compatible computers

o  The Sinclair QL:

Inside QL

The Sinclair QL ("QL" stands for "Quantum Leap") was released in 1984. The basic model got a 8 MHz 68008 processor, 128 Kb of RAM, 48 Kb of ROM, two "microdrives" (looped tape cartridges with 100 Kb storage capacity) units and a 512x256 pixels screen in 4 colours or 256x256 in 8 colours+flash mode.

Its operating system is the QDOS, a single user preemptive multitasking system (the QL was the first personal computer in the world with a multitasking OS !).

Many add-ons were or are still available for the QL. Here are the most significative ones (in my opinion !):

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o  The Thor 8/20/21/XVI:

Thor computers were built by CST and took over the QL when Sinclair Research Ltd was bought by Amstrad. The Thors 8, 20 and 21 were based on the original QL motherboard surrounded with, depending on the Thor model, one or two 3"1/2 floppy disk units and one SCSI hard disk (RODIME 20 or 40 Mb), the whole thing being encased into a proper metal case. Thor 20 and 21 got a 68020 in place of the 68008.

The Thor XVI was a new machine (new motherboard with 16 bits data bus, 512 Kb of RAM expandable to 3 Mb, 128 Kb of ROM) with a 8 MHz 68000 as the main processor, one or two floppy disk units and one optional SCSI RODIME hard disk (20 or 40 Mb).

The Thors' operating system is ARGOS.

The Thor computers are no more in production.

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o  The QXL card:

QXL photo

This is a standard 8/16 bits ISA card for IBM PC compatible computers. It got a 20 MHz (QXL) or 25 MHz (QXL 2) 68EC040 and 2 to 8 Mb of RAM.

"Miracle Systems" idea was simply to use the hardware of a (vulgar) PC to serve a (magnificent) 68040 in order to run a QDOS compatible operating system (SMSQ or SMSQ/E).

The result is quite good, even if we can have some regrets about the design of the QXL to PC interface (just one 8 or 16 bits I/O address) that slows down the exchanges between the QXL and the fast peripherals (mostly screen and hard disks). The QXL supports the QL (512x256), VGA (640x480), SVGA (800x600) and (new !) XVGA (1024x768) video modes with 4, 8 or (new !) 65536 colours thanks to the new GD 2 (Graphic Driver level 2).

I personally got two QXL cards (turbo ones using full blown 68040 with 33.333 MHz (=20 Mips) and 35 MHz (=21 Mips) clocks !).

The QXL is no more in production.

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o  The Q40 and Q60 cards:

Q40 photo

These card are available with three (!) operating systems: SMSQ/E (with 65536 colours graphic modes support), QDOS "Classic" (a QDOS derivative used in the QL emulator for Amiga) and... Linux !

Here are the cards specifications:

The Q40 was sold by TF services and Q Branch.

Only a very small number of Q60 cards have been produced.

I acquired myslef one Q60 back in 2001 (68060RC at 66MHz, 80Mb EDO RAM, picture here): at the time being its speed was... impressive (130 BogoMips, 84460 Dhrystones/48 VAXMips)...

Follow this link for even more details about these magnificient cards.

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o  The emulators:

What I call a "QL emulator" is a software that allows to run a QDOS compatible system on a computer that does not get the original (in the full acceptation of the word !) Sinclair QL architecture.

This being stated, there are two categories of emulators in the QL world:

The emulators pertaining to the first category are:

The emulators pertaining to the second category are:

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(c) 1996, Thierry Godefroy. No warranty or whatsoever is given regarding the accuracy of the information contained in these Web pages.
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