home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Collection of Tools & Utilities
/
Collection of Tools and Utilities.iso
/
dskut
/
ess1.zip
/
FDW.DOC
< prev
next >
Wrap
Text File
|
1993-03-26
|
8KB
|
153 lines
╔════ ═╦══╗ ╦ ╦ ────────────────────────────┬ ┬┌─┬┬ ┌─┐┌──┌─┐ ┌─┐┌──┌┐┌──┐
╠═══ ║ ║ ║ ║ ║ floppy disk wipe utility ├─┤│ ││ │─┐├─ ├┬┘ │─┐├─ │││┌─┘
╨ ═╩══╝ ╚═╩═╝ v1.01 ┴ ┴┴─┘└──┴─┘└──┴└────┴─┘└──┘└┘└──
------ please read the warning note at the end of this file ------
Purpose: Fast erasing of floppy disks. The target disk will be erased by
overwriting the FAT and the root directory. Additionally, the boot
sector will be overwritten with the boot sector image stored in
the file FDW.DAT (or integrated into the program), if this is not
inhibited by the -P switch.
The stored boot sector image contains an extended BPB as
introduced by DOS 4.0, i.e. it contains a volume serial number and
a copy of the volume label. FDW will set these to VSN = <timestamp>
and LABEL = 'NO NAME '. The physical drive number will be set
to 0000h; this is the value I always find on removable media.
The FAT type signature will be set to 'FAT12 ' or 'FAT16 '
according to the information from the BPB.
Hard disks and exotic media with a sector size other than 512 byte
will not be erased; the former for safety reasons, the latter,
because I don't know any and because it would be too complicated.
Usage: FDW { -? | <d> [<nn>] [-V] [-C] [-P] [-I] [-Q] }
Options may occur anywhere on the command line; a '/' may be used
instead of '-'. Grouping options together as in -VC is NOT allowed,
you must specify -V-C.
Separating parameters by blanks and the colon after the drive letter
are optional, so that 'FDW A: 1 -V' and 'FDW A1-V' are considered
to be identical.
When specifying a parameter after an option, it must be separated
by blanks, i.e. 'FDW -VA' is not allowed, but 'FDW -V A' is.
Command line handling is not case sensitive.
Parameters: d = target drive
not allowed are:
- non removable media (for safety reasons),
- drives simulated by SUBST,
- network drives,
- drives not permitting direct I/O,
- media with a sector size <> 512 byte.
nn = number of floppies (optional, range 0 - 99, default 0)
The erasure will be repeated nn times; a value of 0 will
erase 1 disk, but suppress the prompt to insert a disk.
When -I is specified, any values greater than 1 are considered
to be 1.
Options: -? : show a help screen
-V : verify disk writes
If this option is specified, the DOS verify flag will be set
during operation of FDW. By default, it is cleared for better
performance. In any case, the original state of this flag
is restored at program termination.
-P : don''t overwrite boot sector, only FAT and root directory
Overwriting the boot sector is skipped. The file FDW.DAT
is not required.
Not recommended, since an existing volume label will be
deleted, but the duplicate volume label in the boot sector
will not be replaced by 'NO NAME ' (even though this
should do no harm).
When -I is specified, this option is ignored.
-C : clear data area
Fills the data area with a 00h byte. This method does NOT
comply to any data security regulations, but it should be
sufficient for the everyday user.
All sectors from the sector given as first data sector in
the disk parameter block up to the last disk sector are
regarded as data sectors. Normally, these are all sectors
on disk except boot-, FAT- and root directory sectors; this
is not checked, though.
When -I is specified, this option is ignored.
-I : initialize: Don''t wipe disk, but read its boot sector
for later use.
A boot sector with an extended BPB (DOS4+) is required.
This restriction is made for two reasons:
- they exist, so they should be used,
- I don't won't to distinguish between different formats
when overwriting the boot sector.
When this option is specified, -C, -P and <nn> used in
a special way, see there.
-Q : skip the greeting message.
This option is not documented in the help screen.
When -? is specified, this option is ignored.
FDW looks for its data file FDW.DAT first in the current directory.
When it doesn't find it there, it looks in the directory from which
FDW.EXE is run (as specified in the program environment).
If a boot-sector is incorporated, it will be used only if the file
FDW.DAT is not found.
When -I is specified, the file FDW.DAT will always be created in
the directory from which FDW.EXE is run.
The file is checked for the following properties:
- The signature (55AAh) at Offset 1FEh must be present.
- The file size must be 512 byte.
Speed:
The execution times shown below have been measured on a 10-MHz-AT
with a 5¼"-HD-drive. For comparison the execution time of FORMAT/U
with VERIFY ON is shown, too.
Obviously, using FDW with -C-V does not make much sense, and using
-C is not much faster than formatting in any case. Otherwise,
FDW accomplishes a very fast erasure of FAT and root directory.
call │ 360K │ 1.2M │
───────────────┼────────┼────────┤
FDW A -C-V │ 0:40 │ 1:32 │
FDW A -C │ 0:25 │ 1:00 │
FDW A │ 0:03 │ 0:03 │
FORMAT A:/U/V │ 0:45 │ 1:20 │
Warning: This program is 'dangerous', meaning:
═══════════════════════════════════════════════
1) Disks will be erased without a warning.
This erasure process can not be undone by common UNDEL utilities,
and, when -C was specified, not even with any UNFORMAT utility
(possibly it can be undone by specialiced technical equipment).
This is intended, since it is the purpose of this program.
The danger is limited by the fact, that FDW only erases removable,
non-network drives not created by SUBST.
I consider this restriction to be neccessary; if you don't think so,
you can skip the corresponding test in the source text and
re-assemble the program.
2) Defective disks will probably not be found, and sectors marked as
bad will be returned to active use without testing them. This may
lead to data losses. When -V-C is specified, defective sectors
probably are recognized, but the disk will not be processed further.
This, too, is intended. Handling of bad sectors would slow down
the program. Defective disks should be discarded anyway.
If you need to check for defective disks, use FORMAT d: /U.
3) The program uses direct disk I/O and depends on DOS-internal table
formats. Although these are (according to Ralf Brown's interrupt
list) documented in DOS 4.0 or later, there may occur errors under
some system configurations.
In particular, the program will probably fail when run from
multitasking or multi-user-systems (like Windows, OS/2 DOS
Compatibility BOX e.a.).
You should'nt circumvent the test for DOS Version 4.00 or later,