Format programs for PC / Atari ST

[rcgldr]

In addition to the attached file, here is a link to zip of format programs

 

http://rcgldr.net/atarist/astfmt.zip

 

From FMTRDME.TXT;

 

PC and Atari ST format programs

 

All of these format programs use track skewing to speed up sequential

reads or writes, from 2 revolutions per track to about 1 1/3 revolutions

per track. Track skewing rotates the sector positions on each track so

that after a track step, sector 1 will be in position for the next

read or write operation.

 

FMT.EXE - MSDOS format program.

- Runs from real MSDOS only, not from a Virtual PC.

- Floppy drive A means drive 1.

- Floppy drive B means drive 2.

- FMT will prompt user to switch floppy before formatting.

- Floppy type 4 for single sided Atari ST floppy 360K

- type 4 is a "hidden" option, but it works

- Floppy type 7 for double sided Atari ST floppy 720K

- Floppy type 8 is actually 2.88 MB, but untested.

 

FMT.TOS - Atari ST format program - not PC compatible

- allows both 9 and 10 sector per track formatting

 

FMTI.TOS - Atari ST format program - PC compatible

 

Single sided 3.5 inch 360K floppies will only work with real MSDOS

or Atari ST.

 

Double sided 3.5 inch 720K floppies will work with real MSDOS,

Virtual PC MSDOS, Windows, or Atari ST.

 

Most PC default write sector commands write too many gap bytes after

writing a sector for the 10 sector per track format to work. It's

also possible that PC operating systems don't handle that format.

This is why the format programs don't include a PC compatible

10 sector per track format.

astfmt.zip

Edited July 5, 2018 by rcgldr

[ParanoidLittleMan]

Sorry, but I have some corrections: 360 KB format - so single sided works fine under Windows 7 - I just used it yesterday. And I know that it works in XP too. What works not really is 10 sectors/track. Or 20 in case of HD floppy.

But there is SW for Windows what can work with it too. Even TOS at 1.04 produces 'PC compatible' format . I think that there may be some errors in your parameters if 360K works not in Win.

[rcgldr]

I can reproduce the single sided floppy issue on a system with an Intel D975XBX motherboard, running Windows XP. From Windows XP, it reports "drive not formatted". From Virtual PC 2007 with MSDOS 6.22 installed, it gets "general failure reading drive A:". If I boot from a MSDOS 6.22 floppy, the single sided floppy works. The Intel D975XBX motherboard doesn't support dual floppy drives either, only drive A can be accessed, even with real mode low level direct access of the floppy controller, which is what FMT.EXE does. (Side note, the way that PC setup the control signals requires floppy drives be configured as drive 2, using a twisted subset of the cable in order to access drive A, and the non twisted cable in order to access drive B).

Edited July 5, 2018 by rcgldr

[Goochman]

I always used the DoubleClick formatter for all my density/PC compat needs. Worked perfectly back in the day.

[rcgldr]

I always used the DoubleClick formatter for all my density/PC compat needs. Worked perfectly back in the day.

The point of FMT.EXE, FMT,TOS, and FMTI.TOS was to speed up sequential read / write times with track skewing. I'm not familiar with the DoubleClick formatter, so I don't know if it included track skewing.

[ijor]

There were all many formatting programs with all sort of options. Fast track skew (initially coined as twisted, IIRC), and even an extra header that speed ups TOS seek with verify command. Most were PC compatible, some have the option to just rewrite the boot sector for PC compatibility.

 

Regarding single sided disk on Windows. I seem to remember it doesn't work, but I'm not really sure and It might depend on the Bios setting. Not sure that testing with Virtual PC is conclusive. It might be an issue of the disk image handling not detecting the right geometry. And remember virtualization is not emulation, is not supposed to be 100% compatible.

[rcgldr]

There were all many formatting programs with all sort of options. Fast track skew (initially coined as twisted, IIRC), and even an extra header that speed ups TOS seek with verify command. Most were PC compatible, some have the option to just rewrite the boot sector for PC compatibility.

 

Regarding single sided disk on Windows. I seem to remember it doesn't work, but I'm not really sure and It might depend on the Bios setting. Not sure that testing with Virtual PC is conclusive. It might be an issue of the disk image handling not detecting the right geometry. And remember virtualization is not emulation, is not supposed to be 100% compatible.

Current hard drives still use track skewing, but not interleaving.

 

http://www.pcguide.com/ref/hdd/geom/tracksSkew-c.html

 

That article is out of date though. Cylinders no longer line up, since the initial track servo layout is done by high precision equipment one surface at a time, and there may be a 3 or more track offset between surfaces. Due to the track offset issue, most current hard drives will step all the way across a surface before changing heads. This results in more variation in transfer rates since the inner tracks are moving at a slower rate (while density remains nearly constant across the entire surface of a disk). Average transfer rates can be improved by only using the outer cylinders of a drive , called "destroking", which trades off capacity for faster average transfer rate.

 

> Virtual PC 2007

 

My reason for testing with Virtual PC was to test if it was an issue between MSDOS 6.22 (which I have on the Virtual PC) or Windows XP. I have a newer multi-boot system, Win XP Pro, XP X64 Pro, Win 7 Pro 64 bit, Win 10 Pro 64 bit, but it doesn't have a floppy controller (Intel DP67BG motherboard with 3770K 3.5ghz cpu). As posted above, booting a MSDOS 6.22 floppy on the older D975XBX works with single sided drives (I use a ramdisk with the floppy boot to avoid flipping floppies).

Edited July 5, 2018 by rcgldr

[ParanoidLittleMan]

OK, because you asked for it: here would be more interesting to talk about Atari related things. And little about handling Atari floppies on PC. I don't think that BIOS setting have influence on how Win. accessing floppy. It uses own, very limited code for it, what changed by time - in bad direction. Little overview (pretty much old, but nothing relevant changed since) of work with floppies in diverse Win versions: http://atari.8bitchip.info/FloppyMistery.php

With my FloImg can see exactly what is skew factor - with Scan Floppy function. I used recently single sided format just for reliability with very old disks.

 

And now: Atari talk : Skew is present too when format with TOS 2.06 Desktop format . I know 'little' about this things, since my first serious SW was floppy copy program combined with RAMdisk - ideal for single drive config. - 1987 .

Then I seen that with fast code you can read 9 sectors/track floppies without skew without extra rotation - so max speed. In case of 10 sec/track skew of 1 is enough with fast code. Ah, and I called it then 'spiral formatting' . However, TOS code is not the fastest one, and there is verify flag on for step - for better reliability, so for most popular 10 sec/tr. formats skew factor 2 is needed. With my little later program Tracc (Trackcopy) can see skew - when select question mark in Sector/Track box.

Basically all better formatting SW for Atari used skew, and there is plenty of them. Fastcopy Pro is/was most popular, but it had it's flaws too.

Floppies are now just a headache - really too old, too unreliable. Now, using images for old SW what is made to run only from floppies is the right way. Similar is even with much newer CD, DVD - not much in use now.

When you can buy 32 GB Flash storage for some 15-20 Euros, price of about 1 Euro for writable DVD is not much attractive. Dimensions, need for writer are against disks.

Edited July 6, 2018 by ParanoidLittleMan