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[Info-mtools] mtools version 4.0.16 minor errors for small sector size (


From: Jörg Jenderek
Subject: [Info-mtools] mtools version 4.0.16 minor errors for small sector size (32B)
Date: Sat, 7 May 2011 14:02:25 +0200
User-agent: KMail/1.9.6 (enterprise 20070904.708012)

There seems not to exist a mtools command equivalent for the DOS program
SYS.COM. 

I used the program TDSK ( see http://www.freedos.org/software/?prog=tdsk )
to create a small RAM disk driver by a command like:
        TDSK.EXE             160    32    8     1       /F:1  
 It produce an output like:
            .--------------------------+-------------------------¬
            | TURBODSK 2.3 - Drive G:  | Sector size:         32 |
            }--------------------------{ Root entries:         8 |
            | Size:       160 Kbytes   | Sectors/cluster:      1 |
            | Memory:   Extended (XMS) |  4810 clusters (FAT16)  |
            `--------------------------`-------------------------'
Then i copy 4 files to ramdisc and create an image (TDSK-5120x32b.img ) of 
this disc.

Then with mtools ( version 4.0.16) i got for mshowfat 'J:*'
refreshing directory
refreshing directory
refreshing directory
J:/readme.txt <2-186>
refreshing directory
refreshing directory
J:/descript.ion <187-199>
J:/save_x_.bin <200-219>
refreshing directory
refreshing directory
J:/save_x2.bin <220-235>

But the output of minfo contains some garbage

device information:
===================
filename="/tmp/wde_v30b.tmp/TDSK-5120x32b.img"
sectors per track: 1
heads: 1
cylinders: 5120

mformat command line: mformat -t 5120 -h 1 -s 1 -H -1437270016 j:

bootsector information
======================
banner:"TDSK 2.3 "
sector size: 32 bytes
cluster size: 1 sectors
reserved (boot) sectors: 1
fats: 1
max available root directory slots: 8
small size: 5120 sectors
media descriptor byte: 0xfa
sectors per fat: 301
sectors per track: 1
heads: 1
hidden sectors: -1437270016
big size: -6 sectors
physical drive id: 0x3
reserved=0x0
dos4=0x4
serial number: 06000500
disk label="           "
disk type="       "^  L"

Because the sector size is 32 only the information extracted from the
beginning of the image are correct. Hidden sectors= -1437270016 is wrong, 
because the hex value 0xAA550000 shows it is an misinterpreted
boot sector signature (0x55 0xAA ) from offset 30
Also big size: -6 sectors (=0xFFFFFFFA) is the misinterpreted beginning FAT
with the media descriptor 0xFA . The next 16 bit FAT entries are starting 
with number 3 til 186 for the first unfragmented file readme.txt 
So these ascending numbers are interpreted as physical drive id:0x3, 
dos4=0x4 and serial number: 06000500.

All sample image files for further examinations are stored under 
http://mitglied.multimania.de/jenderek/mtools/

regards
Jörg
-- 
Jörg Jenderek   email:  joerg.jen.der.ek (at) gmx.net
Germany         PGP:    B9FE A356 283E 0048 6389  18BF AFF2 B1C9 421A D4D6




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