Writing Atari ST programs onto floppies with PC
There is two situation, which require different approach and tools.
First is writing of files onto floppies from some directory on PC or some CD/DVD.
In such case simple copy of files on floppy with Windows Explorer, Total Commander or Norton Commander in DOS is the way. What causes troubles is the floppy format.
Atari ST and PC use very similar floppy formats, but not same, and it causes confusion and problems.
General advice is this: format floppy on PC to 720KB, and it will be perfectly usable on Atari ST, any TOS version. Win XP offers not such format in Explorer, but it can be done in command prompt. Type: format a: /t:80 /n:9 and you will get 720KB floppy usable on all Ataris (except those rares with single sided floppy).
Other way is to format floppy on Atari. But I recommend to use only specialized format programs which have PC compatible formats in list.
Use always DD (marked often as 1MB) floppies. HD ones may work after covering hole, but it is not so reliable.
On Atari ST, floppy formats of 800, 820KB were very popular. Unfortunately, modern Windows as XP, 2K and Vista can not work with such floppies (as Windows 95 did).
Worst is that such floppies usually are accepted by system, but reading or writing on them will result in corrupted files.
Second situation: floppy image files.
As name says, they are exact 'images' of complete floppies, with all files and same structure as disks from which they are copied. 2 formats are most popular - ST and MSA.
Most of available ST and MSA images are images of diverse, so called 'menu disks' - floppies with more programs, usually games, and some fancy menu for starting desired title(s).
For writing such disks onto floppies special programs are required - it is the only way.
For DOS, best is MAKEDISK - it handles almost all formats (except hyperformat, 880KB floppies, but it is not programs fault, because PC's hardware can not write 11 sectors/track). Usage is simple, there is help in executable.
In currently most popular Windows XP Floimg is required tool - it overrides limitations of XP's floppy driver by using special kernel mode driver (by Simon Owen).
Get it here: http://www.ppest.org/atari/floimgd.php
There is manual about usage, so I will not go here in details about it.
Program has options for writing files directly onto Atari format floppies (800K, 1600K, etc.)- by using same spec. driver).
There is couple other image writing program for PC, but I don't recommend them - DOS ones are not so versatile and easy to use as Makedisk. Most of Windows programs are obsolete, and can not write usual image files correct under Win XP.
Conclusion: 720KB, DOS format is only compatible on both systems (Atari ST and PC with DOS, Windows) - use it for file copy under DOS, Win.
Writng ST and MSA image files goes with specialized programs, mentioned above.
Note: this is intended to be sticky because Atari floppy writing on PC is often asked here.