Software Engineering Talk

Benjamin David Lunt · Guest

Hi guys,

I have updated my dump utility at
http://www.frontiernet.net/~fys/mtools.htm
for those who are interested.

It now will pick apart and display the FAT12/16/32 BPB,
Root Directory Entry, both Short and LFN types, as well
as the FAT32 Info block, among other items and File Systems.

For example, rather than dumping a file in the usual format
and having to parse the BPB yourself:

00007E00 EB 3C 90 46 59 53 4F 53-32 2E 30 00 02 04 01 00
..<.FYSOS2.0.....
00007E10 02 00 02 F8 7F F8 20 00-3F 00 10 00 3F 00 00 00
........?...?...
00007E20 00 00 00 00 00 00 29 F1-13 26 38 4E 4F 20 4C 41
.......)..&8NO.LA
00007E30 42 45 4C 00 00 00 46 41-54 31 36 20 20 20 FA B8
BEL...FAT16.....
00007E40 C0 07 8E D8 8E D0 BC 00-40 08 16 24 00 FB BE 90
.........@..$....

You can click on the FAT12/16 BPB radio button and see it like
this instead:

Fat12/16 BIOS Parameter Block (0x00007E00)
Jump: EB 3C 90
OEM Name: FYSOS2.0
Bytes per Sector: 512
Sectors per Cluster: 4
Sectors reserved: 1
Fats: 2
Root Entries: 512
Sectors: 32760
Descriptor: 0xF8
Sectors per FAT: 32
Sectors per Track: 63
Heads: 16
Hidden Sectors: 63
Sectors Extended: 0
Drive Num: 0
reserved: 00
Sig: 29
Serial: 382613F1
Label: NO LABEL··
sys type: FAT16

It will pick out and show errors in red, if it finds them:

Fat12/16 BIOS Parameter Block (0x00007E00)
Jump: EB 3C 90
OEM Name: FYSOS2.0
Bytes per Sector: 512
Sectors per Cluster: 4
Sectors reserved: 1
Fats: 3 <-- Should be 1 or 2.
Root Entries: 512
Sectors: 32760
Descriptor: 0xF8
Sectors per FAT: 32
Sectors per Track: 63
Heads: 16
Hidden Sectors: 63
Sectors Extended: 0
Drive Num: 0
reserved: 00
Sig: 29
Serial: 382613F1
Label: NO LABEL··
sys type: FAT16

Anyway, it sure has helped in my work and I thought it may help
others too. If you find that it doesn't work the way you think
it should, or you find errors it didn't catch, please let me
know.

Thanks,
Ben