3 ms·

There are no strings to pull. The company was sold to Symantec back in the late 90s, I believe, and he retired (for the most part). At that point, he no longer

There are no strings to pull. The company was sold to Symantec back in the late 90s, I believe, and he retired (for the most part). At that point, he no longer had the source code. Symantec eventually closed it down. Given the state of things like version control back then, I would be surprised if anybody has that source. If I thought I could get it, I'd have asked for it loooong ago :)

accrual 5y ago
Thanks for trying. You're a hero of open source.
a-dub 5y ago
amusingly, it looks like it actually was proposed 20 years ago, but now all the links are dead : / https://slashdot.org/story/02/01/27/1950244/desqviewx-night-of-the-living-dead-codebases https://slashdot.org/story/02/01/27/1950244/desqviewx-night-...
- chipx86 5y ago
  That's a shame :/ Looks like I commented on that thread way back then. And I think my comment there was at least mostly correct. I was always under the impression that much of the core of the product, the interesting bits, was done in assembly, or a layer on top of assembly (they used something called SYMPL in the DESQ and DESQview eras, but I'm not sure about DESQview/X). This would have been for performance and memory constraints. I'll have to call and get clarification on all that. I might be mistaken. In the later years, Quarterdeck transitioned to building DOS and Windows applications like CleanSweep. That was the era when Symantec bought them. I always got the impression that DESQview wasn't really an interest of theirs. It would be interesting to know what they would have done with the source in that era.
  - a-dub 5y ago
    LOL cheers to continuity. device=qemm.sys next up: xtree!
jll29 5y ago
That's a shame - like so many other closed source systems, acquisitions followed by sun-setting and all that hard (and smart) work eventually gone! It's impressive that this software is long deceased and still people hold it dear - that's QUALITY, hard to find in today's world of half-baked, half-finished things designed to fail as soon as they're out of warranty. On the technical side I wonder how the pre-emptive multi-tasking was realised without a MMU, i.e. pre-386? I heard QMX also had that, but it seems tricky to provide that in a stable manner without memory protection.
- kragen 5y ago
  Preemptive multitasking is easy; you just hook the timer interrupt and switch stacks in the interrupt handler. The only tricky part is ensuring that your task queues are modified in such a way that an interrupt at the wrong time can't crash the system. But it's true that, without memory protection, a bug in one program can corrupt all the other programs, too. The 286 did have memory protection, FWIW, and arguably an on-chip MMU: https://en.wikipedia.org/wiki/Intel_80286#Protected_mode https://en.wikipedia.org/wiki/Intel_80286#Protected_mode https://retrocomputing.stackexchange.com/questions/7683/how-do-you-put-a-286-in-protected-mode https://retrocomputing.stackexchange.com/questions/7683/how-... http://www.rcollins.org/articles/pmbasics/tspec_a1_doc.html http://www.rcollins.org/articles/pmbasics/tspec_a1_doc.html EUMEL and Oberon handled this by implementing memory protection in the compiler, but obviously that doesn't help with existing MS-DOS applications unless your compiler's source language is 8086 machine code. That's more or less the approach VMWare and QEMU used to virtualize non-virtualizable hardware. Not sure about Soft-ICE. Also, btw, the 80386 came out in 01985, and DESQview/X came out 7 years later, in 01992.

accrual 5y ago

Thanks for trying. You're a hero of open source.

a-dub 5y ago

amusingly, it looks like it actually was proposed 20 years ago, but now all the links are dead : / https://slashdot.org/story/02/01/27/1950244/desqviewx-night-of-the-living-dead-codebases https://slashdot.org/story/02/01/27/1950244/desqviewx-night-...

chipx86 5y ago
That's a shame :/ Looks like I commented on that thread way back then. And I think my comment there was at least mostly correct. I was always under the impression that much of the core of the product, the interesting bits, was done in assembly, or a layer on top of assembly (they used something called SYMPL in the DESQ and DESQview eras, but I'm not sure about DESQview/X). This would have been for performance and memory constraints. I'll have to call and get clarification on all that. I might be mistaken. In the later years, Quarterdeck transitioned to building DOS and Windows applications like CleanSweep. That was the era when Symantec bought them. I always got the impression that DESQview wasn't really an interest of theirs. It would be interesting to know what they would have done with the source in that era.
- a-dub 5y ago
  LOL cheers to continuity. device=qemm.sys next up: xtree!

jll29 5y ago

That's a shame - like so many other closed source systems, acquisitions followed by sun-setting and all that hard (and smart) work eventually gone! It's impressive that this software is long deceased and still people hold it dear - that's QUALITY, hard to find in today's world of half-baked, half-finished things designed to fail as soon as they're out of warranty. On the technical side I wonder how the pre-emptive multi-tasking was realised without a MMU, i.e. pre-386? I heard QMX also had that, but it seems tricky to provide that in a stable manner without memory protection.

kragen 5y ago
Preemptive multitasking is easy; you just hook the timer interrupt and switch stacks in the interrupt handler. The only tricky part is ensuring that your task queues are modified in such a way that an interrupt at the wrong time can't crash the system. But it's true that, without memory protection, a bug in one program can corrupt all the other programs, too. The 286 did have memory protection, FWIW, and arguably an on-chip MMU: https://en.wikipedia.org/wiki/Intel_80286#Protected_mode https://en.wikipedia.org/wiki/Intel_80286#Protected_mode https://retrocomputing.stackexchange.com/questions/7683/how-do-you-put-a-286-in-protected-mode https://retrocomputing.stackexchange.com/questions/7683/how-... http://www.rcollins.org/articles/pmbasics/tspec_a1_doc.html http://www.rcollins.org/articles/pmbasics/tspec_a1_doc.html EUMEL and Oberon handled this by implementing memory protection in the compiler, but obviously that doesn't help with existing MS-DOS applications unless your compiler's source language is 8086 machine code. That's more or less the approach VMWare and QEMU used to virtualize non-virtualizable hardware. Not sure about Soft-ICE. Also, btw, the 80386 came out in 01985, and DESQview/X came out 7 years later, in 01992.