NewDeal Technical Support Document 260
TESTDISK.BAT, CHECKING FLOPPY DISKS
If you have a floppy disk in your drive, but your NewDeal software keeps
reporting that it can't find a formatted disk, you can run TESTDISK.BAT to
take a look at the disk's boot sector data
How to use TESTDISK.BAT or DEBUG or SID to analyze
a disk and check for bad data or viruses
To run TESTDISK.BAT, make sure the questionable disk is in the drive,
change to the directory where you installed your NewDeal software, and
type TESTDISK A: (or B:, C:,
D:, or E:, depending on which disk you want to look at).
TESTDISK depends on DEBUG or SID (the DR-DOS equivalent of DEBUG) being
in your path, or otherwise available. If it is not, you will get a
"bad command or file name" error.
Using DEBUG or SID
If the you do not have TESTDISK.BAT, you can
do the same thing by hand with DEBUG or SID (SID is the DR-DOS equivalent
of DEBUG). At the command line, type DEBUG or SID, as appropriate. The
DEBUG command prompt is just a little dash, while SID's command prompt
is a pound sign. The commands to enter are shown below.
Where X appears, substitute 0 for drive
A:, 1 for B:, 2 for C:, 3 for
drive D:, or 4 for drive E:. Press <enter>
at the end of each line.
These are the commands to enter at the DEBUG prompt
L DS:0 X 0 1 [this loads boot sector data]
D DS:0 3E [this displays the loaded data]
Q [this quits DEBUG]
These are the commands to type at the SID Prompt
NOTE: Do not place any spaces between
the commands or SID will fail.
QRDS:0,X,0,1 [loads boot-sector data]
DDS:0,3E [displays boot-sector data]
Q [quits SID]
Analyzing the Results
The results will appear as a 3-line dump
of hexadecimal data. These are the first 30h bytes of the boot sector on
your disk. The first row of the data dump will look like
this, with numbers instead of x's:
xxxx:0000 EB 01 90 .... < these are the 3 bytes you want.
The first three bytes of the first row of the
data dump must be one of these combinations:
EB __ 90
(Where __ can be any value). Any other combination
will not be recognized by NewDeal as a properly formatted disk
and may indicate virus infection. Some known viruses:
E9 __ __
FA EB __
00 00 00
FA E9 CC was on a disk with the Music bug virus
Note: A proper disk sector does not necessarily
mean that a diskette is virusfree! Get a good virus testing program
such as McAfee's, Norton's, etc. to make this determination.
EA 05 00 the Stoned virus
The Media Descriptor Byte
In the second row, look for byte 15 (6th from the left).
xxxx:0010 __ __ __ __ __ F9 <this byte
It is the media descriptor:
The (invalid) media descriptor byte C0
may indicate the Michelangelo virus.
- F0 = 3.5" 1.44 Meg
- F8 = hard drive
- F9 = 5.25" 1.2Meg or 3.5" 720K FD=5.25" 360K
- FC = 5.25" 180K
- FE = 5.25" 160K
- FF = 5.25" 320K.
Last Modified 17 Feb 1999