SymbOS MSX multitasking operating system - help needed!

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By Grauw

Enlighted (6173)

Grauw's picture

15-09-2017, 19:34

On turboR the primary mapper is always the internal RAM, because it is much faster. On all other MSX computers it picks either the first or the largest memory it finds.

Looks like SymbOS only supports one mapper? In that case, all the extra memory from the 4M external mapper and the 512K in the MFR is ignored. It would be better if it supported secondary mappers as well, even if it is slower (but still faster than Z80)…

Also despite that, one would think 72K free should be enough to run the console application…

Either way, try booting the MFR with the “4” key pressed. This function of Nextor should force the largest mapper to be selected…

By Vampier

Prophet (2104)

Vampier's picture

16-09-2017, 00:43

Thanks Grauw.. that works Smile

By edoz

Paragon (1933)

edoz's picture

16-09-2017, 01:43

Grauw is right here. SymbOS takes the biggest mapper by default. It's supports up till 1024 because of compatibility with other z80 systems. If i understand it right applications reserves memory in 16k blocks. This because of swapping in the multitasking environment. So if your application is 46k big it still takes 48k. This means, when starting a new application you need free blocks of 16k. (not segmented) The turbo-r is the only exception, only internal faster memory is used. SymbOS 3 has the advanced/extended desktop which takes some memory. On a 256k system you are able to start the advanced/extended desktop but the downside of that is that you have less memory left to run applications. In such cases you could disable this feature which saves memory. It helps also to disable the background as well or exit the widgets, If you have 512 or more you don't have such problems. If you use a 128k system the extended desktop is disabled by default. So, yes, when you own a turbo-r ST, it is a bit sad because the 256k. Wink

But it seems that your GT is having less memory than it has on real hardware Wink so make it 512 and you are fine!

By edoz

Paragon (1933)

edoz's picture

16-09-2017, 03:02

Of course if a application is for example 8k and still fits in a block of 16k were only 2k is used it will put such application in such a 16k block. If an application quits it will free the memory in that block. But can only be reused if the memory fits for the new application. So even if you have more memory free than the application needs it doesn't say it will fit. A application could be a maximum of 63 k big for code execution. In such case you need free blocks of 16k . To be clear applications still can use as many 16k blocks for data area as need. (as long the code area fits in 63k)

In my example above, (i was not able to edit it anymore) I say that an application of 46 takes 48. This not true. It takes 46 but it requires 3 blocks of 16k.. The 2 k is still free but it will only fit for a program which will fit in the 2k.

So your CMD was not running because there was no room to fit somewhere in memory despite you had it Wink

By Vampier

Prophet (2104)

Vampier's picture

16-09-2017, 08:49

thanks edoz Smile It did this emulated but it works fine... too bad openMSX doesn't emulate the tcp/ip stack (pretty hard to do this cross platform)

By edoz

Paragon (1933)

edoz's picture

17-09-2017, 19:34

Ok good! Yes, which network things are much cooler Wink

By edoz

Paragon (1933)

edoz's picture

19-09-2017, 11:14

Haha.. this was fun, Yesterday i received a MSX 1 Big smile and i was able to run SymbOS on this machine Wink
Never did this on real hardware Big smile Only in OpenMSX .. probably the first time it runs on a real MSX 1 machine Big smile Big smile







By Grauw

Enlighted (6173)

Grauw's picture

19-09-2017, 13:11

Nice-looking machine!

edoz wrote:

The turbo-r is the only exception, only internal faster memory is used.

Well, this is a SymbOS restriction, one which I think would be good if it was lifted. Being able to run a program slightly more slowly on turboR, or with some extra context switching overhead, is still better than not being able to run it at all.

By NYYRIKKI

Enlighted (4699)

NYYRIKKI's picture

19-09-2017, 13:32

edoz wrote:

Haha.. this was fun, Yesterday i received a MSX 1 Big smile and i was able to run SymbOS on this machine Wink
Never did this on real hardware Big smile Only in OpenMSX .. probably the first time it runs on a real MSX 1 machine Big smile Big smile

Time flies. I just realized that this has been on my todo list for 7 years! I'm glad you did it.

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