Timeline for How did DoubleDOS work?
Current License: CC BY-SA 3.0
17 events
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| Dec 5 at 12:41 | comment | added | Michael | I remember Desqview... | |
| Jan 30, 2018 at 18:23 | comment | added | Rui F Ribeiro | Well, TSRs were the most used well behaved technology, but not only that. In fact TSRs only appeared in DOS 2.x or 3.x, if memory does not fail me. You could modify directly the memory allocation structures of DOS and leave code behind, or even write code in the MBR that was installed before DOS booting. At some point I write both of those. Some ROM routines also often wrote in the secondary set of Z80 registers, for instance in the ZX Spectrum. I use Deskview for a while, but by that time was already hooked into using SCO V at home. | |
| Jan 30, 2018 at 3:07 | history | edited | jwzumwalt | CC BY-SA 3.0 |
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| Jan 29, 2018 at 14:10 | comment | added | No'am Newman | IIRC, the author's name was Tom Swan, not Timothy. I learnt a great deal from him, but not how to write a multi-tasking OS. | |
| Jan 28, 2018 at 21:47 | comment | added | Raffzahn | Well, non the less there was never a taskswitcher called DoubleDOS for the Z80. Also, Gates didn't have to plagiarize CP/M, as that job was done by Seattle Computer Product. Not a secret as buying a licence for QDOS as it was called then is part of the official history. I'm somewhat puzzled what kind o 'PCDOS' you might have had on your Sourcerers (also got on back then) or other 8 Bit machines, as PC-DOS was never available for the Z80. it's a 8086 design from the very first version (as QDOS). | |
| Jan 28, 2018 at 21:05 | comment | added | jwzumwalt | I never owned a TRS-80. I had several home-brew S-100 and several Exidy Sorcerer's which ran QDOS (CPM) and PC-DOS. PC-DOS on Z-80's was very common and very easy to export. All you had to do was reassign your hardware ports to the software BIOS interrupt calls. Which is the same thing Bill Gates did to Gary Kildall's QDOS CPM. CPM was exactly the same as DOS including 22 identical interrupt calls with the exact register same vars doing the same thing. I think Gates plagiarized CPM in 3-4 days. It didn't take long for IBM to settle with Kildall. Once folks knew how, it could be done in a day. | |
| Jan 28, 2018 at 19:17 | comment | added | Raffzahn | Erm, you might mix something up here. DouebleDOS on the Z80, or more specific for the TRS-80 was a modified TRS-DOS as supplied by percom for their double density controler board. There is no relation to the PC product in question. In fact, DoubleDOS is such an easy idea for a name, that it also has been used for an Apple add on that allowed a cold boot of DOS 3.2 (13 sector) or DOS3.3 (16 sector) and later with the flip of a switch. I wouldn't be surprised if many more companies had used that name. | |
| Jan 28, 2018 at 18:46 | history | edited | jwzumwalt | CC BY-SA 3.0 |
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| Jan 28, 2018 at 18:37 | history | edited | jwzumwalt | CC BY-SA 3.0 |
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| Jan 28, 2018 at 18:23 | history | edited | jwzumwalt | CC BY-SA 3.0 |
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| Jan 28, 2018 at 18:13 | history | edited | jwzumwalt | CC BY-SA 3.0 |
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| Jan 28, 2018 at 18:04 | history | edited | jwzumwalt | CC BY-SA 3.0 |
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| Jan 28, 2018 at 13:23 | history | edited | jwzumwalt | CC BY-SA 3.0 |
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| Jan 28, 2018 at 13:17 | history | edited | jwzumwalt | CC BY-SA 3.0 |
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| Jan 28, 2018 at 12:25 | history | edited | jwzumwalt | CC BY-SA 3.0 |
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| Jan 28, 2018 at 12:18 | review | First posts | |||
| Jan 28, 2018 at 14:21 | |||||
| Jan 28, 2018 at 12:15 | history | answered | jwzumwalt | CC BY-SA 3.0 |