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DOS with lowest LOMEM?


Cybernoid

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It can vary in many cases due to the number of drives you have allocated, and how many files are allowed to be open at a time.

 

So, in theory you could have a 1 drive DOS with 1 file open allowance which uses somewhat less RAM than another which has 4 drives and 7 files allowable.

 

Aren't there a number of Read-Only DOSes around - taking out the logic for write means you can also strip most of the file system handling away as well. It would be pretty easy to get a RO-DOS well under 1K including it's buffers and workspace.

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All,

 

Do you know which dos which still allows disk accesses to use that has the lowest LOMEM value?

 

And, what is that LOMEM value?

 

And, where can I find an ATR image of said dos...?

 

Thanks,

C

 

Check out this similar thread:

http://www.atariage.com/forums/index.php?showtopic=116288

 

Looks like SpartaDos X is the lowest of any "regular" Dos (by a bunch). Not sure about the new "Real Dos."

 

-Larry

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I meant this. A pretty short program that makes use of the native I/O routines, that can be erased following program load. There's no footprint left behind if you are trying to squeeze every last bit of memory free for a large standalone Basic program (besides the variable names...which could be changed to match the program's).

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Afaik,

there is a DOS 2 compatible DOS called "DOS 2 XL", which is not the same as DOS XL. Most of DOS 2 XL hides in the RAM under the OS... Alas, I do not know its memlo... -Andreas Koch.

 

It looks like DOS XL MEMLO is 0x0794 and the DOS 2.Xa is 0x1c7c.

 

I am liking DOX XL right now... :)

 

I checked SpartaDos 1.1, its MEMLO is 0x2300, SpartaDos 2.3 is 0x0dbe.

 

I am also trying a menu program called radmenu. It has a MEMLO of 0x0700... allows read only to disk...

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But then,

you can simply load Turbo Basic 3.2q by Tom Hunt which does not use RAM under the OS ROM... (this TB has some restrictions of course)... Besides, DOS 2 XL works only in single and enhanced density, it is written for the XL/XE computers, whereas DOS 2 XA should also work on the 400/800 computers... Hm, who gave me these two DOS versions ?!? The author himself, but I forgot who it was and have not used that DOS more than once... -Andreas Koch.

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But then,

you can simply load Turbo Basic 3.2q by Tom Hunt which does not use RAM under the OS ROM... (this TB has some restrictions of course)... Besides, DOS 2 XL works only in single and enhanced density, it is written for the XL/XE computers, whereas DOS 2 XA should also work on the 400/800 computers... Hm, who gave me these two DOS versions ?!? The author himself, but I forgot who it was and have not used that DOS more than once... -Andreas Koch.

 

I was thinking along the lines of Sparta dos 2.3, but Sparta dosX would be very low as well

At least SpartadosX will work on an 800, even better if the 800 has an axlon compatiable ramdisk :)

 

James

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But then,

you can simply load Turbo Basic 3.2q by Tom Hunt which does not use RAM under the OS ROM... (this TB has some restrictions of course)... Besides, DOS 2 XL works only in single and enhanced density, it is written for the XL/XE computers, whereas DOS 2 XA should also work on the 400/800 computers... Hm, who gave me these two DOS versions ?!? The author himself, but I forgot who it was and have not used that DOS more than once... -Andreas Koch.

 

 

The Author would be Thomas Richter, the author of the Atari++ Emulator, which contains DOS 2 XL.

http://www.math.tu-berlin.de/~thor/atari++/

 

Carsten

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But then,

you can simply load Turbo Basic 3.2q by Tom Hunt which does not use RAM under the OS ROM... (this TB has some restrictions of course)... Besides, DOS 2 XL works only in single and enhanced density, it is written for the XL/XE computers, whereas DOS 2 XA should also work on the 400/800 computers... Hm, who gave me these two DOS versions ?!? The author himself, but I forgot who it was and have not used that DOS more than once... -Andreas Koch.

 

 

The Author would be Thomas Richter, the author of the Atari++ Emulator, which contains DOS 2 XL.

http://www.math.tu-berlin.de/~thor/atari++/

 

Carsten

 

Yes, and the emulator manual file has a nice section that explains many features of this dos. That is the only doc file I have ever seen for it.

Perhaps there is a German language file. (?)

 

BTW, using ? PEEK(128) + 256*PEEK(129), I get a LOMEM value of $794 (1940 decimal). That's impressively low. I also need to check OSS Dos XL when hidden under a Super Cartridge. IIRC, it was also quite low, and didn't interfere with the ram-under-rom.

 

-Larry

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I was thinking along the lines of Sparta dos 2.3, but Sparta dosX would be very low as well

At least SpartadosX will work on an 800, even better if the 800 has an axlon compatiable ramdisk :)

 

But on a 48k 800 it won't be low on MEMLO, rather contrary. :) With Axlon, though, it should be as low as on an expanded 130XE, yes.

 

Other DOS-es load either to main memory or to the RAM under the OS, like DOS XE or SpartaDOS or whatever. The superiority of the SpartaDOS X is that it can occupy whatever memory you want: the main one, or the one under the OS, or the 130XE/Axlon banks.

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Another quick note about Dos 2 XL -- after using this dos for a bit moving files around, I noticed that it does not appear to be compatible with Happy Drives nor high speed SIO as implemented with the Black Box drivers. In order to prevent errors, my Happy Drive had to be set to "UnHappy" and (with the Controller present) set to "SLOW MODE."

 

It *appears* to use the same VTOC/FMS structure as MyDos 4.X as regards ED disks (unlike Dos 2.5 and IIRC, SuperDos. If you are a MyDos user, that's "a good thing." When you format a MyDos ED disk, a directory check shows 1027 free sectors. When you format a disk using Dos 2 XL, it automatically writes out its dos file and a disk title name, and then shows 963 free sectors; however, MyDos correctly recognizes the disk as having 963 free sectors. I would still treat any data movement between MyDos and Dos 2 XL with caution.

 

This dos certainly has some interesting features!

 

-Larry

Edited by Larry
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But then,

you can simply load Turbo Basic 3.2q by Tom Hunt which does not use RAM under the OS ROM... (this TB has some restrictions of course)... Besides, DOS 2 XL works only in single and enhanced density, it is written for the XL/XE computers, whereas DOS 2 XA should also work on the 400/800 computers... Hm, who gave me these two DOS versions ?!? The author himself, but I forgot who it was and have not used that DOS more than once... -Andreas Koch.

 

 

The Author would be Thomas Richter, the author of the Atari++ Emulator, which contains DOS 2 XL.

http://www.math.tu-berlin.de/~thor/atari++/

 

Carsten

 

Yes, and the emulator manual file has a nice section that explains many features of this dos. That is the only doc file I have ever seen for it.

Perhaps there is a German language file. (?)

 

BTW, using ? PEEK(128) + 256*PEEK(129), I get a LOMEM value of $794 (1940 decimal). That's impressively low. I also need to check OSS Dos XL when hidden under a Super Cartridge. IIRC, it was also quite low, and didn't interfere with the ram-under-rom.

 

-Larry

 

OSS XL cannot do magic either, it has to go somewhere (-:

 

Probably time to cleanup the "DOS"-ology a bit:

 

The DOS that comes with Atari++ is a derivative of DOS 2.XL, called DOS 2.++. It is ROM based, i.e. would go into the operating system ROM of a "real" Atari and uses there the

space otherwise required for the parallel port and tape support not in the emulator. DOS 2.++ uses the same disk layout as 2.XL, but not the RAM under ROM, and has a very low

memory foot print (but not quite as low as 2.XL). Clearly, it cooperates with TurboBasic.

 

DOS 2.XL is quite a bit older than 2.++ (by ten years) and its predicessor. It is *almost* identical to 2.XL, lacks only some minor features, namely reading of DOS 2.5 files that lie

beyond the 720 sector boundary. I might also have fixed some bugs in 2.++. 2.XL is entirely disk based, but it requires no "DOS.SYS" file as it places itself in the sectors otherwise

unavailable. Its layout is backwards compatible to 2.0S, i.e. 2++ and 2.XL can write to 2.0S disks fine without destroying the VTOC. 2.XL cannot bootstrap TurboBasic.

 

There is another variant, DOS 2.XA, which is again disk and ram-based, otherwise compatible to 2.XL and thus able to load turbo basic. It is otherwise identical, probably contains

more bugs than 2.XL since its even older.

 

The VTOC layout is "almost" DOS 2.0S, except that the the additional bytes reserved under 2.0S are also used for allocating data. Unlike other "963 sectors" DOS variants it is

safe to write to DOS 2.0S disks, i.e. the "first VTOC byte" is at the same position as it was in DOS 2.0S.

 

For emulator usage, 2.++ is your best bet as it comes with the emulator, doesn't take disk space and is feature-rich. The sources, if you care, are on the Atari++ home page.

 

No, neither of them is aware of any "Happy" or "fast SIO" extensions since I never owned one of those.

 

So long,

Thomas

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All,

 

Do you know which dos which still allows disk accesses to use that has the lowest LOMEM value?

 

And, what is that LOMEM value?

 

And, where can I find an ATR image of said dos...?

 

Thanks,

C

 

Have you looked at micro spartados?

 

From the doc file:

Micro-SpartaDOS 2.2 uses only SIO

($E459) or a High speed SIO for disk

access, so it need not any DOS.

While selecting a file, it uses

memory area $2000-$28FF for program,

and $2900-MEMTOP for buffers, new

filenames etc.

While loading a program, MSDOS uses

only area $700-MEMLO. The MEMLO

values are these:

 

Standard SIO: $A00

XF 551: $A35

Speedy 1050: $A00+SIO length (=?)

 

 

msdos33.zipMSDOS.TXT

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Have you looked at micro spartados?

 

msdos33.zip

 

Hmmm, I cannot seem to get this ATR to boot.

 

Yea, I don't think it's bootable the way it is. I used it to make my ATR of the Crownland EXE file. I think I just extracted the msdos.com file and put it on a Sparta formated disk. The documentation should help. Looks like the image is a MyDos single density image.

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Yep,

Micro-Sparta-DOS in its function is the same as e.g. Nano-DOS, Micro-DOS, Pico-DOS, MyPicoDOs, etc. - just a gamedos to load ML (*.EXE,*.COM,*.XEX) files. None of these are real DOSses, afaik none of them allow to read e.g. a Directory (Error 130 should appear) or to load multi-load-files... But these gamedos versions are fine for single-load files, especially games and demos that overwrite DOS...

 

Otherwise said:

- you have a game or demo that is a single-load file, overwrites DOS, but does not require any DOS functions...

=> use a gamedos

- you have a game or demo or application that is a multi-load-file, or requires DOS functions or...

=> use a real DOS

(of course for some files you can use both DOS and/or gamedos)

 

-Andreas Koch.

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Yep,

Micro-Sparta-DOS in its function is the same as e.g. Nano-DOS, Micro-DOS, Pico-DOS, MyPicoDOs, etc. - just a gamedos to load ML (*.EXE,*.COM,*.XEX) files. None of these are real DOSses, afaik none of them allow to read e.g. a Directory (Error 130 should appear) or to load multi-load-files... But these gamedos versions are fine for single-load files, especially games and demos that overwrite DOS...

 

Otherwise said:

- you have a game or demo that is a single-load file, overwrites DOS, but does not require any DOS functions...

=> use a gamedos

- you have a game or demo or application that is a multi-load-file, or requires DOS functions or...

=> use a real DOS

(of course for some files you can use both DOS and/or gamedos)

 

-Andreas Koch.

 

 

Yeah, thanks Andreas for the clarification. This is what I figured. I have some files that require loading from disk after the main program has loaded. These files will not work with a gamedos.

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Yep,

Micro-Sparta-DOS in its function is the same as e.g. Nano-DOS, Micro-DOS, Pico-DOS, MyPicoDOs, etc. - just a gamedos to load ML (*.EXE,*.COM,*.XEX) files. None of these are real DOSses, afaik none of them allow to read e.g. a Directory (Error 130 should appear) or to load multi-load-files... But these gamedos versions are fine for single-load files, especially games and demos that overwrite DOS...

 

Otherwise said:

- you have a game or demo that is a single-load file, overwrites DOS, but does not require any DOS functions...

=> use a gamedos

- you have a game or demo or application that is a multi-load-file, or requires DOS functions or...

=> use a real DOS

(of course for some files you can use both DOS and/or gamedos)

 

-Andreas Koch.

 

 

Yep, I appreciate the clarification too.

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