In the course of an only seemingly unrelated test I made, I found a few "quirks" that need to be taken into account.
In the attachment there are 4 image files.
All of them are exactly 1,475,072 bytes in size, i.e. the "standard" 1.44 Mb floppy + 1 sector (for the MBR).
They represent (or should represent) a very small hard disk image.
They were created as follows:
fsz hdfloppy.img 1475072
(this created an empty files filled with 00's of the exact size).
After having filled partition table first entry manually and the "Magic bytes" (and adding a dummy disk signature of 12345678 - you never know) I saved the image as:
hdfloppyUF.img i.e. UnFormatted
I mounted a copy of hdfloppyUF.img in VSS services and formatted the volume with the Windows XP Format.
this is hdfloppyFVSS.img i.e. Formatted under VSS
I mounted a copy of hdfloppyUF.img IMDISK as "Auto" - it resulted as "Floppy" - formatted it with the IMDISK Format option (that however calls Windows Format)
this is hdfloppyFIMF.img i.e. Formatted under IMdisk as Floppy
I mounted a copy of hdfloppyUF.img IMDISK as "Hard Disk Volume", formatted it with the IMDISK Format option (that however calls Windows Format)
this is hdfloppyFIMHV.img i.e. Formatted under IMdisk as HardDisk Volume.
Under IMDISK (obviously since the MBR is "skipped alltogether") the MBR partition table is left "as it was" (partition type 01)
Under VSS the Windows Format does a strange thing, which I already noticed in other occasions with partition type 06, see here:http://reboot.pro/3191/page__st__26
the partition type is changed to 0E which confirms something between the lines of this:http://homepage.ntlw...ystem-type.html
it seems like WIndows XP attempts to "protect" the very common FAT12 01 type from being accessed by older filesystems, since it sets a 0E type, it "cuts off" MS-DOS <=6.22
I thought that this was only 06->0E but evidently the new paradigm is something like "anything FAT1x is 0E"
The number of "Reserved sectors" IN BOTH hdfloppyFVSS.img and hdfloppyFIMHV.img are 6 instead of the usual 1 (but it of course remains 1 in hdfloppyFIMF.img.
This can affect the spreadsheet/batch/Drugwash's app behaviour when selecting the F0 (240) or F8 (248) media.
The hdfloppyFIMHV.img sets correctly "Sectors Before" (1) and (maybe) "Sectors per track" (63) - this could be a "defaulT" needs to ask Olof - but gives a (wrong) Number of Heads (1).
The hdfloppyFVSS.img sets correctly "Sectors Before" (1) but NOT "Sectors per track" (1) and gives a (wrong) Number of Heads (1).
this is hdfloppyFIMF.img does not set (comprehensibly) "Sectors Before", that remain 0, and sets "Sectors per track" (18) and "Number of Heads" (2) correctly, but his probably is because of some hardcoded in FORMAT, this test must be repeated with a non-standard floppy size.
As always ideas, comments, suggestions, further tests and reports are welcome.