Timeline for What limited the use of the 6809 CPU in personal computers?
Current License: CC BY-SA 4.0
41 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Sep 5, 2022 at 9:48 | history | protected | Raffzahn | ||
| Sep 5, 2022 at 4:55 | answer | added | Bob J | timeline score: 2 | |
| Aug 11, 2022 at 15:37 | answer | added | Maury Markowitz | timeline score: 3 | |
| Aug 8, 2022 at 4:54 | answer | added | Benjamin Scherrey | timeline score: 5 | |
| Jul 25, 2021 at 18:16 | comment | added | supercat | @RichF: An instruction like "lda 1234,pcr" would be inherently relocatable, but take four bytes and nine cycles to execute. An "lda 1234" that was patched by a loader would not be relocatable once patched, but would take three bytes and execute in five cycles. The performance penalty of making code fully relocatable may have been less than on other microprocessors, but was still significant. | |
| Jul 25, 2021 at 16:13 | answer | added | Ken F Lantz | timeline score: 2 | |
| Jul 24, 2021 at 14:39 | comment | added | RichF | @supercat to the best of my knowledge, 6809 os-9 languages are written to compile position independent code. The loader simply transfers the code from disk without patching anything. There may be languages or compiler switches to modify this behavior, but for the most part positional independence was just expected behavior. | |
| Jul 23, 2021 at 14:41 | comment | added | supercat | @RichF: Did OS-9 use a patching loader, or simply exploit the fact that code could use register-relative addressing? | |
| Jul 23, 2021 at 6:18 | comment | added | RichF | @supercat The high-end operating system OS-9 (the real one, not the Apple one that stole the name) did exactly that. As far as I know, everything written to run on it was position-independent by design. | |
| Jul 22, 2021 at 20:36 | comment | added | supercat | @PatrickSchlüter: I often find myself looking back on 1970s-1980s dev tools and thinking they should have better supported the creation of self-relocating programs, at least for relocation on 256-byte boundaries. On something like the Apple II, an I/O card driver running patched code from RAM near the top of the address space could be much more efficient than one which has to determine which slot it's running from before processing each character. | |
| Oct 16, 2020 at 9:07 | comment | added | Patrick Schlüter | Short routines could also be made position independent on 6502. It was even required on Apple II for ROM code read from slots if you wanted the card be slot independant. Of course for routines longer than a page, it was not possible without code patching for JSR and JMP instructions. | |
| Jun 18, 2020 at 8:29 | history | edited | CommunityBot | Commonmark migration | |
| Feb 17, 2020 at 13:19 | comment | added | John Dallman | @Tommy: The Dragon and the CoCo are based on the same reference design by Motorola, which was published to show how the support chips could be used together. They also both got their BASIC from Microsoft, who had little reason to make them different. | |
| Jul 23, 2019 at 13:31 | comment | added | cjs | IIRC, the 6809 did not have an "especially fast" interrupt system. To the 6800's regular IRQ it added added "fast" interrupts (FIRQ), but these were still a bit slower than the 6502. Both FIRQ and 6502 IRQ were so much faster than 6800/6809 IRQ because they pushed a just the PC and condition code registers on to the stack, whereas 6800/6809 IRQ pushed all the registers. | |
| Jan 28, 2019 at 16:33 | answer | added | Jeremy Holloway | timeline score: 4 | |
| Nov 23, 2018 at 10:55 | answer | added | jonathanjo | timeline score: 4 | |
| Nov 2, 2018 at 0:31 | history | edited | Raffzahn | CC BY-SA 4.0 | doubleintention removed |
| S Nov 1, 2018 at 20:17 | history | suggested | Desty | CC BY-SA 4.0 | fix accidentally inverted concluding sentence |
| Nov 1, 2018 at 17:30 | review | Suggested edits | |||
| S Nov 1, 2018 at 20:17 | |||||
| Aug 1, 2018 at 4:34 | answer | added | Steve J | timeline score: 2 | |
| Jun 18, 2018 at 13:07 | answer | added | scruss | timeline score: 5 | |
| Apr 3, 2018 at 20:02 | comment | added | Steve Jones | @TonyM Yes, of course, but I meant PIC, in that it could move around in memory at runtime. It was a dynamic process, so you could get it to move around at will, not via a linker, etc. It was a hacker toolkit for the ZX Spectrum, so it had to be able to move around in memory, depending which game you were investigating. There was no reduction in execution speed, as it was all machine code. Happy days 8^) | |
| Apr 3, 2018 at 10:21 | comment | added | TonyM | @SteveJones, supporting PIC means having addressing modes that make it very easy to write PIC with little reduction in execution speed. PIC works with the run-time PC address. That's not the Z80 by any stretch of the imagination :-) Practically all CPUs can have utilities written to relocate their code, that's what linkers do and what DOS/Windows did when loading EXEs. | |
| Feb 21, 2018 at 4:00 | comment | added | RichF | @tinstaafl I never worked for Radio Shack, but from what I saw they supported the CoCo until the days of 8-bit computing were coming to an end. They sold the CoCo for 11 years (1980 - 1991), and it had 3 major revisions during its life. Perhaps the third generation was a bit under-designed to make the Tandy 1000 more competitive, but even that machine (a better PCjr clone) was considered more of a home system than business. | |
| Feb 21, 2018 at 3:32 | comment | added | tinstaafl | @RichF - Mind you it did matter a lot to Radio Shack and led to them dropping the CoCo completely | |
| Feb 20, 2018 at 7:31 | comment | added | RichF | @tinstaafl For home computers this would have been a small factor, with the computers on the shelf in stores like Target and Sears. The sales folks generally didn't know a lot, and it didn't matter to them if you bought a computer or a microwave oven. In the "old days" (early to mid-80s), the general chains didn't sell a lot (if any) of business systems. They might encourage you to add a printer, though. | |
| Feb 20, 2018 at 3:55 | comment | added | tinstaafl | Another thing that I don't see mentioned, is dollars and cents.A salesman working on commission would rather spend the time selling the more expensive compatible, that wouldn't require as much hand holding. | |
| Feb 19, 2018 at 18:17 | comment | added | Chris Stratton | In comparing to the Z80, you have to consider that most Z80 based systems were treated by at least application software as being 8080's - the hardware design became simpler, but software efforts could continue an already proven and supported heritage. | |
| Feb 19, 2018 at 15:12 | vote | accept | RichF | ||
| Feb 19, 2018 at 15:05 | comment | added | Steve Jones | As an aside, the Z80 did support position-independent code. I wrote and sold a hacker tookit in Z80 assembly in the 1980's that was position-independent and could easily move itself around in memory (self-relocating). | |
| Feb 19, 2018 at 11:31 | answer | added | Raffzahn | timeline score: 55 | |
| Feb 19, 2018 at 11:07 | comment | added | dim | Indeed, the Thomson machines have mainly been sold in France (but had a great deal of success there due to a govt project bringing computers in schools), and a few neighboring countries. Anyway, the 6809 has probably been used a lot in lesser-known computers like these. There was a (French again) company called Goupil, as well, who made a computer who had several processor options, one of which was 6809. | |
| Feb 19, 2018 at 10:01 | comment | added | Chenmunka♦ | It was used in a large number of industrial microcomputers and quite a few office micros. OS/9 was one of the best real-time OSs around at the time - and still in use. | |
| Feb 19, 2018 at 9:50 | comment | added | Ralf Kleberhoff | The following is not exactly an answer to your question, but might be of interest. There was a real-time multi-tasking operating system "OS-9" that started with a 6809 version (what gave it its name) and became quite successfull later when ported to the 68000 family. Personally, I only used OS-9/68000, so I have to guess a little what the predecessor looked like. OS-9 as a real-time OS needed low interrupt response times, so the 6809 probably was a good match. The OS made use of position-independent, reentrant code, by having the software organized in "modules" containing code and read-only da | |
| Feb 19, 2018 at 7:01 | comment | added | No'am Newman | The very first prototype Mac built by Burrell Smith used a 6809, which makes me wonder now where it came from. Wasn't it used in a laser printer? | |
| Feb 19, 2018 at 5:46 | comment | added | RichF | @dim and Tommy, thanks for the info. I had heard of the Dragon, but I didn't think of it when writing my question. The Thomson machines must have gotten very little press in the USA. Europe and Australia seemed to be more flexible in accepting more of a variety of machines. Even American-designed machines such as the Exidy Sorcerer and Commodore Amiga got a good deal of respect. | |
| Feb 19, 2018 at 5:17 | comment | added | dim | It was used a lot. By french company Thomson, at least. They sold a lot of computers (MO5, TO7) all using the 6809. Thet were cheap, and found a way in a lot of homes and schools. | |
| Feb 19, 2018 at 0:57 | comment | added | Thorbjørn Ravn Andersen | "Couldn't run CP/M" was not helping. | |
| Feb 18, 2018 at 23:02 | comment | added | Tommy | The Dragon 32/64 also; almost exactly like the CoCo but I think because both are based on the support chips provided directly by Motorola (and, especially, the 6847) rather than because the one is based on the other. | |
| Feb 18, 2018 at 22:36 | answer | added | Jules | timeline score: 32 | |
| Feb 18, 2018 at 22:19 | history | asked | RichF | CC BY-SA 3.0 |