SvarDOS
Behaviour on uninitialized partitions differs to MS-DOS
The following are the DPBs of an uninitialized FAT-32 partition (boot sector filled with 0xF6). MS-DOS blocks access, ~~the EDR kernel not~~ the EDR kernel also blocks access since commit https://github.com/SvarDOS/edrdos/commit/4dbe13473d65b579e4c2cea4f5ca2016aed6567d:
MS-DOS DPB
Getting extended DPB for drive G: via INT 21h function 7302h.
device parameter block:
drive 6 6
unit 6 6
bytes per sector 200 512
cluster mask 7 7
cluster shift 3 3
reserved sectors 1 1
number of FATs 1 1
root directory entries 0 0
first data sector 1f5a 8026
highest cluster 3 3
sectors per fat 1 1
first root dir sector ffff 65535
device driver header 0070:005e
media id f8 248
dpb flags 0 0
next dpb ffff:ffff
next cluster 0 0
free clusters ffffffff 4294967295
active FAT / mirroring 0 0
fsinfo sector ffff 65535
backup boot sector ffff 65535
first data sector (big) 1f5a 8026
highest cluster (big) 3 3
sectors per fat (big) 1 1
root dir start cluster 0 0
next cluster (big) 0 0
EDR-DOS DPB
Getting extended DPB for drive G: via INT 21h function 7302h.
device parameter block:
drive 6 6
unit 6 6
bytes per sector 200 512
cluster mask 7 7
cluster shift 3 3
reserved sectors 3 3
number of FATs 2 2
root directory entries 0 0
first data sector 1f45 8005
highest cluster 0 0
sectors per fat 0 0
first root dir sector ffff 65535
device driver header 0070:016e
media id f8 248
dpb flags 0 0
next dpb ffff:ffff
next cluster 0 0
free clusters f6f6f6f6 4143380214
active FAT / mirroring 0 0
fsinfo sector 2 2
backup boot sector ffff 65535
first data sector (big) 1f45 8005
highest cluster (big) 7cc58 511064
sectors per fat (big) fa1 4001
root dir start cluster 2 2
next cluster (big) 0 0
What program did you use to generate this output? If you wrote it yourself, maybe you can upload it? I also created one, as an Extension for lDebug, though it only operates on the FAT12/FAT16 parts for now: https://hg.pushbx.org/ecm/ldebug/file/66e2ad622d18/source/eld/dpb.asm
Yes, I wrote this by myself. It is a C program, able to display BPB, default BPB and DPB, optionally in their extended forms. I did only invest 1-2 hours on this, so there are probably bugs. Previously had no intention to publish it, but you asked, so here it is: https://github.com/boeckmann/dpbinfo