DOS 3 Disk Image

[Rybags]

Could have been worse. At least it's not like some, where you had to run Validation tools/commands to recover space from deleted files.

[carmel_andrews]

Looks like we have unearthed the entire Dos 3 fan club, since no one went with my suggestion of the 'Burning DOS 3' ceremony

[+kheller2]

I don't recall DOS 3 having any bugs... in any case, it wasn't in general use long enough for people to work out if anything didn't work as it should.

 

IMO, DOS 3 is in the same bucket as Basic A and B - should be kept offline to prevent people possibly using it and having the bad experience associated with each product.

 

DOS 3 had bugs. In fact, there is a note included with some manuals that tell you how to verify if you have a good or bad copy of DOS 3.

[Bryan]

I wonder if DOS 3 can use more than one sector for the FAT. It seems ridiculous to go to this much trouble to design a DOS from the ground up and then limit it to floppies.

 

This has got me thinking about what the ultimate DOS for the Atari would be- If you could throw out all compatibility issues and just write what you'd really want.

[drac030]

This has got me thinking about what the ultimate DOS for the Atari would be- If you could throw out all compatibility issues and just write what you'd really want.

 

SpartaDOS X?

 

Also DOS XE look pretty good, except its annoying UI and lack of documentation.

[thorfdbg]

I wonder if DOS 3 can use more than one sector for the FAT. It seems ridiculous to go to this much trouble to design a DOS from the ground up and then limit it to floppies.

No, it really can't. There's only one buffer allocated per drive for the FAT...

 

The good part about DOS 3 is that it was able to POINT and NOTE by byte-offsets, unlike DOS 2.xx, where the cludgy sector link made this impossible. That is, DOS 2 really didn't allow "random access" unless you created an additional table containing sector/byte offsets.

 

The general design of DOS 3 would have been fine, would they have avoided to merge as many as eight sectors of the precious 1050 drive space into one block. Unfortunately, this would have made the FAT larger than one sector, thus would have required either more buffering, or a smarter buffer handling.

 

At the other extreme, with one sector per block, the "sector links" of DOS 2 would be the FAT, which would then 16 sectors large.

 

So long,

Thomas

[+CharlieChaplin]

This has got me thinking about what the ultimate DOS for the Atari would be- If you could throw out all compatibility issues and just write what you'd really want.

 

SpartaDOS X?

 

Also DOS XE look pretty good, except its annoying UI and lack of documentation.

 

Well, the early XF551 drives were shipped with DOS 2.5 (nice, max. 130k usable on a 360k drive!), but later Atari changed this and shipped the XF551 drives with DOS XE and manuals (for the XF551 and DOS XE!) - so documentation for DOS XE was + is available directly from Atari. Or do you mean "deeper" programmer / programming information for DOS XE ?!? Afaik, Diamond GOS 2 or 3 supported DOS XE, so there must have been some more information available...

 

DOS XE was a good idea, but with an awful "DUP" consisting of three menus. Next there were very strange separate converter programs (one for DOS 2 and one for DOS 3 files, but one had to use strange device letters, not D: for diskette, like we were used to for several years). And err, remember that annoying "press Return for Menu" from DOS 2 or DOS 2.5, well in DOS XE every step or comand you made was replied with "press START to continue, or press SELECT to abort" which was very awkward (not only for formatting or deleting, really with every command!). Last not least the format option was targeted at certain floppy drives, namely 90k for the Atari 810, 130k for the Atari 1050, 180k for third party and 360k for the XF551. I had several PAL XF551 drives (with patched "PAL-OS" on an eprom, patched by Atari!) and none of them could use the 360k format of DOS XE, since they were not detected as being XF551 drives (maybe the format option in DOS XE looked for a USA drive with original "NTSC-ROM"; well NTSC-ROM is incorrect here, as well as PAL-OS above, but you know what I mean)... and so on and so on... -Andreas Koch.

Edited February 15, 2009 by CharlieChaplin

[Fletch]

My first 1050 came with DOS 3 and I rather liked it. In fact, I had a few .exe files on a dos 2 disk that simply refused to load. I used the convert 2 to 3 utility on that disk and the programs ran just fine. I have no idea why and 25 years later I really don't care

 

But I honestly thought DOS 3 was fine. I probably have about 20 copies of it to be honest. I bought a huge lot of "blank disks" from B&C a few years back and a sizable portion of those disks were DOS 3.

[_The Doctor__]

I always thought Dos 3 had the ever increasing size issue where if you load and save a program too many times it's size kept getting padded and increased it's % of disk used for nothing or some such issue I do not know if it effected copying.

I know there is some reason why we ditched it. Our user group ended up using sparta dos, mydos, dos 2.5, and dos xl/xe respectively

 

My first 1050 came with DOS 3 and I rather liked it. In fact, I had a few .exe files on a dos 2 disk that simply refused to load. I used the convert 2 to 3 utility on that disk and the programs ran just fine. I have no idea why and 25 years later I really don't care

 

But I honestly thought DOS 3 was fine. I probably have about 20 copies of it to be honest. I bought a huge lot of "blank disks" from B&C a few years back and a sizable portion of those disks were DOS 3.

Edited February 15, 2009 by _The Doctor__

[Bryan]

I always thought Dos 3 had the ever increasing size issue where if you load and save a program too many times it's size kept getting padded and increased it's % of disk used for nothing or some such issue I do not know if it effected copying.

I know there is some reason why we ditched it. Our user group ended up using sparta dos, mydos, dos 2.5, and dos xl/xe respectively

 

Atari BASIC Rev B has that problem. Every time a program is loaded and saved it grows. The solution is to LIST it to disk and reload it.

[1050]

I remember reading a blurb about the formating power of DOS 3 VS any other Atari DOS in that if you had a funky disk that would not format for you as a last attempt before round filing the floppy, you might try a DOS 3 format on it. And it worked! Don't ask me how or why, it might have just been happenstance but it's worked for me often like that.

 

IIRC the article was written by Paul Alhart in AIM and it caused more than a little outright laughter and ridicule in the group when it was read aloud. But at home alone, I at least tried it and found it to be good advice. Otherwise I have no use for DOS 3, except to keep it alive.

[Rybags]

Don't know about that.

 

The drive performs the format, DOS only puts the bare essentials of the filing system there.

But, IIRC, DOS 2.x and probably any other number of DOSes don't use the bad sector list that the disk drive provides them.

 

It is possible to just flag those sectors as in-use (so long as they're not vital to the boot program or directory structure), and still have a useable floppy, so maybe it does that.

[drac030]

Or do you mean "deeper" programmer / programming information for DOS XE ?!?

 

I mainly mean the details about the filesystem, but any other deepre info, if any is relevant, would be welcome too. I found none so far.

 

The DOS XE is exceptional among all DOS-es signed by Atari because it is their first DOS, that is not minimalistic: even if its dedicated for XF551, its filesystem is not limited to 360K. It would be good to know, though, how to build it on a larger disk.

 

awful "DUP"

 

This is what I call "annoying UI". Yes, the DUP is awful, and (buzz) "press START to continue", even before loading a program, is just stupid. Or the stupid thing is that this can't be switched off.

[Bryan]

I was reading an article by Eric Clausen on the various DOSes in Antic and came across this confusing section:

 

Those of you with 810 drives need not despair, this DOS is for you too. Although you will not be able to use the enhanced density feature, you can boot DOS 2.5 disks that were formatted and written in single density on 1050 drives. The way that DOS 2.5 handles this is to "hide" files from the 810 drive that cross over sector 720, which is normally the last DOS 2.0 sector. If you completely fill a DOS 2.5 disk (1010 sectors) on a 1050 and then check the disk directory at some point you will see files listed like this:

FILE1.BAS 025

<FILE2.BAS> 025

 

This tells you FILE1.BAS is entirely contained within the first 720 disk sectors and can therefore be accessed by an 810 drive. The file(s) with the "< >" characters around them are NOT accessible with an 810 drive because they are physically located where the 810 drive can't read them. So if you have an 810 and ask your friend with a 1050 to copy some of his files, make sure the files you want don't have <> around them!

 

Now, according to this you can use a DOS 2.5 disk as long as it's in single density and is an enhanced density disk not using sectors beyond 720. This is a contradiction. Too bad the editors didn't catch it.

[Urchlay]

Now, according to this you can use a DOS 2.5 disk as long as it's in single density and is an enhanced density disk not using sectors beyond 720. This is a contradiction. Too bad the editors didn't catch it.

 

Yep, self-contradiction...

 

From what I remember, ED disks can't be read at all on an 810. The only use for those <> around the filenames was to let you know which files on a DOS 2.5 disk would be unusable if you booted DOS 2.0S, on a 1050 drive and tried to read the DOS 2.5 disk. I also remember writing a utility to turn off the uses-extra-sectors bits in the directory, so Fenders 3-sector loader could see & load those files (normally it would ignore them).

 

One other weirdness I remember about DOS 2.5: I had one particular drive that DOS 2.5 would always report "999+ free sectors" in the directory of any ED disk after the drive had been running a while (it got pretty hot compared to my other 1050). I never understood how this could happen: the entire directory would show, and look fine, and reading files worked fine. I can't imagine anything that could be caused by the drive overheating that would result in the dir showing 999+ free sectors, yet not affect anything else. I'd expect an overheated drive to maybe quit reading anything, or maybe return garbage data for all reads... never did figure it out.

[Bryan]

Yep, self-contradiction...

 

From what I remember, ED disks can't be read at all on an 810.

 

Right. It requires that the controller be in MFM (DD) mode which the 810 doesn't support.

 

The only use for those <> around the filenames was to let you know which files on a DOS 2.5 disk would be unusable if you booted DOS 2.0S, on a 1050 drive and tried to read the DOS 2.5 disk.

 

Yup. The disks were semi-compatible with DOSes that didn't know about ED mode.

[carmel_andrews]

wasnt' there a version of the 810 rom that did 'selective formatting' (a'la super archiver alike)...the so called 'E'Rom

[Rybags]

The DOS 2.5 Sectors Free reporting had a bug.

 

If you tried getting a directory of a corrupted or non-DOS disk, it would often subsequently report 999+ Free Sectors on any disk you did a directory on.

 

Pressing Reset would usually fix it.

 

And, yes, the <FILENAMEs> going above Sector 720 wouldn't be readable by older DOSes. Fairly sure DOS 2.0 would generate an error if you tried to read a file that spanned past that point.

[+bf2k+]

I vaguely remember a 'patched' DOS for 1050's that camer after DOS 3 but preceded DOS 2.5. I do remember applying this patch to some version of DOS 2 (I think) but most of the details of this escape my memory... it was 25 years ago or more. The patch could have been in Antic or Analog maybe or downloaded from somewhere...

 

Does anyone else remember this?

[Rybags]

I think Compute! might have ran it.

 

It allowed use of the extra sectors but I don't think it maintained proper compatability, either with normal DOS 2.0s or DOS 2.5.

 

IIRC, it just extended the normal VTOC sector allocation bitmap within the same sector (360), as opposed to DOS 2.5 which put it at 721 (?) which ensured better backward compatability if you happened to use older DOSes to try and read the disk.

[sup8pdct]

I think antic ran an artical similar to this (maybe the same) It changed the vtoc table so it wouldn't be write compatiable with normal dos 2, ie moved the bytes for the votc lower down and added to the end. This was done to get enough room to fit all the extra sectors on the vtoc.

Dos 2.5 uses sector 1024 for the 2nd vtoc sector of a possiable 1040 on the disk.

 

James

 

I think Compute! might have ran it.

 

It allowed use of the extra sectors but I don't think it maintained proper compatability, either with normal DOS 2.0s or DOS 2.5.

 

IIRC, it just extended the normal VTOC sector allocation bitmap within the same sector (360), as opposed to DOS 2.5 which put it at 721 (?) which ensured better backward compatability if you happened to use older DOSes to try and read the disk.

[sup8pdct]

It is a shame that no other atari (or 3rd party) dos used the bad sector list the drive provides. How many 3rd party drives (including rom upgrades) provide a bad sector list?

 

James

 

I remember reading a blurb about the formating power of DOS 3 VS any other Atari DOS in that if you had a funky disk that would not format for you as a last attempt before round filing the floppy, you might try a DOS 3 format on it. And it worked! Don't ask me how or why, it might have just been happenstance but it's worked for me often like that.

 

IIRC the article was written by Paul Alhart in AIM and it caused more than a little outright laughter and ridicule in the group when it was read aloud. But at home alone, I at least tried it and found it to be good advice. Otherwise I have no use for DOS 3, except to keep it alive.

[Rybags]

It's entirely possible to write a program to do the format and use the bad sector info.

 

The thing with bad sectors is that if you have one, chances are others on the same track might start to drop out too.

Even in the old days, 80 cents a floppy or whatever, was "cheap" enough such that you'd just chuck the bad ones out.

[flashjazzcat]

Been reading through this old topic because I'm looking for some docs for DOS 3. For reasons I can't fathom, I want to know more about why my word processor won't work properly with it. Is there a memory map anywhere for DOS 3?

 

Anyway, expanding on points raised above: I always thought DOS XE had potential, and I too would have liked more info on disk structure, FMS, and system calls. It would probably have been a nice DOS if the front end was completely redesigned.

 

I also agree that it's a shame that DOS 3, 4, and DOS-XE (the latter because it was released far too late) failed to break the trend of the terrible diasy-chain DOS 1/2.0/2.5 file system. Even MyDOS - which I admire in every other way - perpetuates it, and across hard disk partitions at that.

[drac030]

There is a topic on DOS XE here, with complete info on FS structure and many internals, including why DOS XE, after all, turns over to be utter crap.

 

DOS 3 FS is limited to 256k. DOS 4 FS is limited to 384k. Both are wasteful: DOS 3 uses a 1k logical sector, and DOS 4 - a 1.5k logical sector (1 byte file takes 1.5k on the disk).

 

DOS XE FS is limited to 16 MB, but the implementation sucks to such extent that it makes no sense to use it (the DOS XE) with floppies bigger than 360k anyway.

 

Vaporware at its finest. Ok, DOS 3 was officially released, so it isn't real vaporware...