The Graham Utilities for OS/2 - Version 2

NullDisk - Wipe Disk data

Summary

NullDisk protects sensitive data by overwriting either the entire disk or the erased portion of it.

Icon

Command Line Format

Usage: NULLDISK {Switches} Drive Spec(s)

Switches

-a: All disks.
-e: Erase unused and deleted file areas only.
-g<n>: Government security rules for wiping.
-h: Hard disks only.
-n: No wipe, erase only.
-r<n>: Repeat wipe count; default of 1.
-v<n>: wipe Value; default of 0.

Description

NULLDISK protects sensitive data by either deleting all files currently on the disk and then overwriting the entire disk, or by overwriting the erased portion of it.

OS/2 when it deletes a file, does not actually remove the data. It only removes the directory entry. NULLDISK physically overwrites the data area of the disk. By default, it deletes all files and then overwrites the data area of the disk. An optional way of running NULLDISK is not to delete all of the files, but simply overwrite the unused portion of the disk. Use this method if you wish to wipe only a few files, or use NULLFILE.

NULLDISK erases the unused portion of the disk by filling it up with a temporary file. Be aware that if other processes are accessing the disk, there may be problems with them as the disk is filled. The temporary file is deleted when the program is finished.

To help protect you from accidental erasures you must enter a drive specification. NULLDISK will now inform you of the intended action and prompt you for confirmation before continuing.

-a All disks

NULLDISK will scan all logical disk drives defined by the system, starting at drive A:. The drives are scanned in order, starting at A:, then B: and so on.

-e Erase unused and deleted file areas only

By default, NULLDISK deletes all files and then overwrites all data areas of the disk. This switch forces NULLDISK to overwrite the unused data area portion of the disk.

-g Government security rules for wiping

This switch forces NULLDISK to erase the disk to the US Department of Defence security specification DoD 5220.22-M. It writes over all of the data area of the disk with 1's (FFh) then writes over it all again with 0's (00h). By default, it repeats this procedure 3 times. The optional n parameter for this test overrides the default repeat count of 3. Finally, the data area of the disk is overwritten with the value of F6h.

-h Hard disks only

NULLDISK will scan all logical disk drives defined by the system, starting at drive C:. The drives are scanned in order, starting at C:, then D: and so on.

-n No wipe, erase only

NULLDISK by default, wipes all files and then erases them. This switch will force NULLDISK to only erase (delete) all of the files. No wiping will occur.

-r Repeat wipe count

The default wipe count value is 1. This switch specifies a new repeat count. The repeat count is the number of times that the disk is overwritten.

-v Wipe Value

The default value of the data which is written to the disk is zero (0). Use this switch to specify another value.

Examples

NULLDISK

This will fail, as a drive specification was not entered.

NULLDISK C:

This will delete all files and wipe the contents of drive C:.

NULLDISK -he

NULLDISK will scan all available hard disk drives and wipe the erased file area of each disk.

NULLDISK -r4 D:

Wipe drive D: 4 times.

NULLDISK -v255 -r3 e:

Wipe drive E: 3 times, overwriting the disk with the value 255 (FFh) each time.

NULLDISK E: -e -g5

This will wipe drive G: 5 times using the government security rules - overriding the default of 3. Only the unused portion of the drive will be wiped.