Formats and DOS

[1050]

6 hours ago, drac030 said:

Two very popular DOS-es: SpartaDOS and MyDOS are perfectly able to handle 1440k disks, if you still want to do that, I can tell you, what is the PERCOM block parameters SpartaDOS X sends to the floppy drive when requesting a 1440k format.

Please do, I'm all ears. In fact, I'm stuck right here writing the easy to use MyDOS floppy format tool Andreas (CharlieChaplin) is looking for. I don't have a 1.4 meg system set up to read a percom block from but need that data to fold into the oddly used DRVDEF table at 0x07CC which is done by O Change Config menu selection normally. If the DRVDEF table contains the correct information for the drive doing the format, MyDOS will in fact format it and build the proper matching VTOC for it. Currently the only way to do that is via the O Change Config menu. Reading a Percom block from the drive won't do it with MyDOS because of the format bug where the DRVDEF values are written out as a Percom block to the drive FIRST, and even if that fails, a format is attempted without ever correcting the DRVDEF table. As if error checking isn't an option that should exist? Thus writing a percom block to a drive will never work for a subsequent format done on that drive. And this is supposed to be the way it is supposed to work in the land of Atari as I understand it. But it doesn't work at all with MyDOS unless you go manual and use O Change Config first.

 

I'm thinking there is no need to bother with 2,880 k since there are no floppies nor drives available? Even brand new way back when, they didn't work but a couple of times and the drive got returned for defective. Which quickly ran stores out of stock and had angry customers demanding their full money back. Some got their money, most didn't because it was an industry wide hemorrhage of zero drives that could be made to work even for a dozen floppies. They are listed as existing, but today none actually do. AND we don't have a current floppy controller that is capable anyway. Unless I'm wrong in my research, please correct me. Anyone? And TIA for everything.

[archeocomp]

Not sure what you mean by "current". Are there any? PC8477B is capable of 1Mb rates. As is 82077 Intel. WD37C65C is another option.

Edited June 2, 2020 by archeocomp

[drac030]

13 hours ago, 1050 said:

Please do

$50, $xx, $00, $24, $01, $04, $01, $00, $FF, $00, $00, $00 = 80 tracks, 36 sectors per track, 2 sides, MFM, 256 bytes per sector

 

$xx is the step rate value received previously from the drive.

 

This *reportedly* works with HDI (I cannot check it myself).

 

 

[+CharlieChaplin]

Yes, I would not bother with 2880k, since no-one really uses this format (and I also do not know anyone that owns a drive or diskettes capable of this format). If the MyDOS format tool does 90k, 130k, 180k, 360k, 720k and 1440k this is more than enough - but hopefully it does not only format but also write a DIR and VTOC in MyDOS style. Think I have mentioned it various times, that such a format tool only requires 2-3 questions:

 

1) drive number (1-8)

2) choose format: A) 90k   B) 130k   C) 180k

                            D) 360k  E) 720k   F) 1440k

 

(I would choose letters, because they are not next to each other -in a row- like the numbers and it is less likely hitting a wrong letter than hitting a wrong number)

 

3) Press Return to format drive x

(Alternatively: Press "Y" to format drive x)

 

(And question 3 is optional, I think, it could also be left out and the tool could start formatting after question 2 is answered)...

 

Looking forward to see such a formatting tool for MyDOS. This would make the formatting process under MyDOS much easier and faster (then one must no longer use options O and P to format a diskette).

 

[+Larry]

Hi Lee-

I'm interested in what you come up with, although I have only standard floppies up to 720 kb. The 1.44 HD disks did not work very well with a floppy board.  The Floppy Board HD disks had 256 byte sectors, and 5760 gross sectors per disk (IIRC). And, as mentioned, they had to be formatted with the Black Box floppy formatter.  Typically, I'd lose about one or two  files per disk after several months. Not quite reliable, even with good drives and disks. 

[drac030]

56 minutes ago, Larry said:

Typically, I'd lose about one or two  files per disk after several months

I remember something similar on Falcon030: the computer was equipped with a HD floppy disk drive and everything was working fine with the standard 1.44 MB format: 2 sides, 80 tracks, 18 sectors per track, 512 bytes each sector. But the number of sectors per track was tunable and the maximum, as I remember it, was 22 sectors per track (giving 1760 KB per 80-track diskette, and the Epson drive my Falcon had also allowed up to 82 tracks, to it was yet slightly more).

 

But these floppies were behaving as you say, i.e. everything was OK initially, but after some - and not so long - time the reading errors started to occur. So it seems to me that this effect is caused not so by the data density itself or by the unreliability of the controller, but rather by the too high number of sectors per track. What is the precise mechanism behind this, I can only guess.

 

[Mathy]

Hello guys

 

The only time I had problems with a 1.44 MB disk (on the FloppyBoard) was when the flat cable developed a loose contact and the drive started to format the disk spontaneously because of that.  I fixed that by soldering a 3.5" drive connector onto the FloppyBoard.  This made it possible to use a strain relieve on the flat cable.

 

Sincerely

 

Mathy

[+CharlieChaplin]

So here is version 3 and also the last update for this overview (with lots of tables). I removed the 2880k (extra high density) format, since it is hard to find any disk drives or diskettes that work with that format. Furthermore I corrected some typos and changed the height of the tables and the fontsize (from 12 to 14). So there you have it, the rest is up to you... ;-)

 

 

Formats_and_DOS_v3.zip