wipe DOS 3.3 drive

[J***@nospam.invalid]

I have a very old PC I took out of storage. It has DOS 3.3 installed and
its only other drive is the old large floppy drive.

Is there something under old DOS that can "wipe" a drive?

This PC is from before the internet and therefore has no web connection
and no way to download anything to it. I do have modern PCs but they of
course do not have these old floppy drives.

Suggestions for how to wipe the drive before junking the PC?

Thanks.

[Herbert Kleebauer]

Post by J***@nospam.invalid
I have a very old PC I took out of storage. It has DOS 3.3 installed and
its only other drive is the old large floppy drive.
Is there something under old DOS that can "wipe" a drive?
This PC is from before the internet and therefore has no web connection
and no way to download anything to it. I do have modern PCs but they of
course do not have these old floppy drives.
Suggestions for how to wipe the drive before junking the PC?

Delete all files and directories (not the DOS directory) and then


echo 123456789012345678901234567890>a
copy a+a+a+a b
copy b+b+b+b a
copy a+a+a+a b
copy b+b+b+b a
:
:

until you get a disk full error

del a
del b

Then you have a clean hard disk with the operating system
still working.

[J***@nospam.invalid]

Post by Herbert Kleebauer

Post by J***@nospam.invalid
I have a very old PC I took out of storage. It has DOS 3.3 installed and
its only other drive is the old large floppy drive.
Is there something under old DOS that can "wipe" a drive?
This PC is from before the internet and therefore has no web connection
and no way to download anything to it. I do have modern PCs but they of
course do not have these old floppy drives.
Suggestions for how to wipe the drive before junking the PC?

Delete all files and directories (not the DOS directory) and then
echo 123456789012345678901234567890>a
copy a+a+a+a b
copy b+b+b+b a
copy a+a+a+a b
copy b+b+b+b a
until you get a disk full error
del a
del b
Then you have a clean hard disk with the operating system
still working.

Thank you so much!!!

[Jacob]

Post by Herbert Kleebauer

Post by J***@nospam.invalid
I have a very old PC I took out of storage. It has DOS 3.3 installed and
its only other drive is the old large floppy drive.
Is there something under old DOS that can "wipe" a drive?
This PC is from before the internet and therefore has no web connection
and no way to download anything to it. I do have modern PCs but they of
course do not have these old floppy drives.
Suggestions for how to wipe the drive before junking the PC?

Delete all files and directories (not the DOS directory) and then
echo 123456789012345678901234567890>a
copy a+a+a+a b
copy b+b+b+b a
copy a+a+a+a b
copy b+b+b+b a
until you get a disk full error
del a
del b
Then you have a clean hard disk with the operating system
still working.

Won't this miss previously-used parts of some sectors?

Probably adequate for the OP's purposes, but just sayin'.

[Herbert Kleebauer]

Post by Jacob

Post by Herbert Kleebauer
copy a+a+a+a b
copy b+b+b+b a
until you get a disk full error

Won't this miss previously-used parts of some sectors?

Only in the last sector of still existing files. And
I doubt that in the last sector of the operating
system files (all other files are deleted) are privat
data because this files are copied first to the disk.

[Todd Vargo]

Post by Herbert Kleebauer

Post by Jacob

Post by Herbert Kleebauer
copy a+a+a+a b
copy b+b+b+b a
until you get a disk full error

Won't this miss previously-used parts of some sectors?

Only in the last sector of still existing files. And
I doubt that in the last sector of the operating
system files (all other files are deleted) are privat
data because this files are copied first to the disk.

This copy method keeps growing the "wipe" files exponentially. However, once
the files reach above 50% of drive capacity the files can no longer be
copied, potentially leaving 49% of the drive unwiped. A disk full error in
this case really means there is not enough free space remaining to quadruple
again.

A sure fire solution to wipe to the end (on a DOS 3.3 system) would be to
keep appending to a file in cluster sized increments (or whatever size
desired) until you get a disk full error this way. The following batch
should work fine for filling available free space.

@echo off
echo 1234567890ABCDEF>a
:loop
type a >> a
goto loop

[billious]

Post by Todd Vargo

Post by Herbert Kleebauer

Post by Jacob

Post by Herbert Kleebauer
copy a+a+a+a b
copy b+b+b+b a
until you get a disk full error

Won't this miss previously-used parts of some sectors?

Only in the last sector of still existing files. And
I doubt that in the last sector of the operating
system files (all other files are deleted) are privat
data because this files are copied first to the disk.

This copy method keeps growing the "wipe" files exponentially. However,
once the files reach above 50% of drive capacity the files can no longer
be copied, potentially leaving 49% of the drive unwiped. A disk full error
in this case really means there is not enough free space remaining to
quadruple again.
A sure fire solution to wipe to the end (on a DOS 3.3 system) would be to
keep appending to a file in cluster sized increments (or whatever size
desired) until you get a disk full error this way. The following batch
should work fine for filling available free space.
@echo off
echo 1234567890ABCDEF>a
:loop
type a >> a
goto loop

You want to try that one again. Todd?

This batch would perform the file-doubling of which you complain

Now:

@echo off
echo 1234567890ABCDEF>B
:loop
type B >> a
goto loop

OR

@echo off
:loop
echo 1234567890ABCDEF>>a
goto loop

- different matter and would work according to your advert. It would also be
slow - but making the string ECHOed an appropriate size (like 128 bytes)
would tune it for maximum speed (I'm not sure, nor am I going to research,
the matter of whether a potential terminal control-Z is relevant to this
procedure.)

I also believe that you'd find that DOS will happily keep filling the drive,
even if it had reached 75% full and you asked it to "double" your fill-file.
IIRC, the "have I got enough room" facility was implemented on NT but not
DOS - at least as early as DOS3.3

[Todd Vargo]

Post by billious

Post by Todd Vargo

Post by Herbert Kleebauer

Post by Jacob

Post by Herbert Kleebauer
copy a+a+a+a b
copy b+b+b+b a
until you get a disk full error

Won't this miss previously-used parts of some sectors?

Only in the last sector of still existing files. And
I doubt that in the last sector of the operating
system files (all other files are deleted) are privat
data because this files are copied first to the disk.

This copy method keeps growing the "wipe" files exponentially. However,
once the files reach above 50% of drive capacity the files can no longer
be copied, potentially leaving 49% of the drive unwiped. A disk full
error in this case really means there is not enough free space remaining
to quadruple again.
A sure fire solution to wipe to the end (on a DOS 3.3 system) would be to
keep appending to a file in cluster sized increments (or whatever size
desired) until you get a disk full error this way. The following batch
should work fine for filling available free space.
@echo off
echo 1234567890ABCDEF>a
:loop
type a >> a
goto loop

You want to try that one again. Todd?
This batch would perform the file-doubling of which you complain

Doh! I changed the b to an a before posting. It was supposed to be similar
what you have below. Good job catching that.

Post by billious
@echo off
echo 1234567890ABCDEF>B
:loop
type B >> a
goto loop
OR
@echo off
:loop
echo 1234567890ABCDEF>>a
goto loop
- different matter and would work according to your advert. It would also
be slow - but making the string ECHOed an appropriate size (like 128
bytes) would tune it for maximum speed (I'm not sure, nor am I going to
research, the matter of whether a potential terminal control-Z is relevant
to this procedure.)
I also believe that you'd find that DOS will happily keep filling the
drive, even if it had reached 75% full and you asked it to "double" your
fill-file. IIRC, the "have I got enough room" facility was implemented on
NT but not DOS - at least as early as DOS3.3

If this is correct, then any of the multiplier methods will wipe the 3.3
drive.

[Herbert Kleebauer]

Post by Todd Vargo

Post by Herbert Kleebauer
copy a+a+a+a b
copy b+b+b+b a
until you get a disk full error

This copy method keeps growing the "wipe" files exponentially. However, once
the files reach above 50% of drive capacity the files can no longer be
copied, potentially leaving 49% of the drive unwiped. A disk full error in
this case really means there is not enough free space remaining to quadruple
again.

DOS doesn't check if there is enough space left. Try to copy
a 2 MByte file to a 1.44 MByte floppy. But I nevertheless prefer
to use a simple program to write to the disk until it is full.
Not because it is more save but because it is much faster
(doesn't have to read from disk) and you can wipe partitions
bigger than 2 GByte. You can speedup the copy method by not
overwriting already written files:

copy a+a+a+a b
copy b+b+b+b c
copy c+c+c+c d
:

But then it is much more work to type the commands.


I normally do it this way (as long as the system partition is FAT):

- (quick) format all non system partitions and wipe them using the below
program

- make a bootabel floppy "format /s a:"
copy format.com and the wipe program to the floppy

- boot from floppy and do a "format /s c:"
copy the wipe program to c:

- boot from hard disk and wipe c:

This way you get a bootable system full of data files containing
ASCII "0". This helps to save time if somebody tries to find
old data on the dumped PC.


; schreibe 0000.txt - 9999.txt auf aktuelle Platte bis
; diese voll ist

; size=$400 ; 32 Mbyte Dateien reicht fuer 32 GByte Partition
size=$8000 ; 1 Gbyte Dateien reicht fuer 10 TByte Partition


@=$100
move.w #'00',r0
move.w #buf,r6
move.w #$8000/2,r2
rep_r2 move.w r0,(r6.w)+-{s1}

_30: move.w #$3c00,r0
move.w #name,r1
eor.w r2,r2
trap #$21
bcs.b _100
move.w r0,r3

move.w #size,r4

_20: move.w #$4000,r0
move.w #buf,r1
move.w #$8000,r2
trap #$21
bcs.b _100
cmp.w r0,r2
bne.b _10
dec.w r4
bne.b _20

move.w #$3e00,r0
trap #$21
bcs.b _100

inc.b name+3
cmp.b #'9',name+3
bls.b _30

move.b #'0',name+3
inc.b name+2
cmp.b #'9',name+2
bls.b _30

move.b #'0',name+2
inc.b name+1
cmp.b #'9',name+1
bls.b _30

move.b #'0',name+1
inc.b name
cmp.b #'9',name
bls.b _30

_100: move.w #$4000,r0
move.w #text1,r1
move.w #text1_l,r2
move.w #1,r3
trap #$21
rts.w

_10: move.w #$4000,r0
move.w #text2,r1
move.w #text2_l,r2
move.w #1,r3
trap #$21
rts.w


text1: dc.b "fehler",13,10
text1_l=@-text1

text2: dc.b "disk voll",13,10
text2_l=@-text2

name: dc.b '0000.txt',0

even
buf: blk.b $8000

[Paul Bartlett]

Excerpted for brevity.

Post by Herbert Kleebauer
This way you get a bootable system full of data files containing
ASCII "0". This helps to save time if somebody tries to find
old data on the dumped PC.
; schreibe 0000.txt - 9999.txt auf aktuelle Platte bis
; diese voll ist
; size=$400 ; 32 Mbyte Dateien reicht fuer 32 GByte Partition
size=$8000 ; 1 Gbyte Dateien reicht fuer 10 TByte Partition
@=$100
move.w #'00',r0
move.w #buf,r6
move.w #$8000/2,r2
rep_r2 move.w r0,(r6.w)+-{s1}
_30: move.w #$3c00,r0
move.w #name,r1
eor.w r2,r2
trap #$21
bcs.b _100
move.w r0,r3
[trim]

Please understand that this code is for an idiosyncratic, non-standard
assembler (varying from usual x86 conventions) which is the personal
matter of the poster but not one which others may find readably
available. Try to find such a standard assembler (MASM, NASM,
whatever) which supports this syntax, and you may be disappointed.

[Herbert Kleebauer]

Post by Paul Bartlett
Please understand that this code is for an idiosyncratic, non-standard
assembler (varying from usual x86 conventions) which is the personal
matter of the poster but not one which others may find readably
available. Try to find such a standard assembler (MASM, NASM,
whatever) which supports this syntax, and you may be disappointed.

Really no big deal to convert it to NASM syntax:



; schreibe 0000.txt - 9999.txt auf aktuelle Platte bis
; diese voll ist

; nasm -O99 -o wipe.com wipe.asm
%include "mac.inc" ; from http://www.bitlib.de/assembler/xlinux.zip

; size equ $400 ; 32 Mbyte Dateien reicht fuer 32 GByte Partition
size equ $8000 ; 1 Gbyte Dateien reicht fuer 10 TByte Partition


org $100
move.w '00',r0
move.w buf,r6
move.w $8000/2,r2
rep_r2 move.w r0,[r6.w]+-{s1}

_30: move.w $3c00,r0
move.w name,r1
eor.w r2,r2
trap $21
bcs.b _100
move.w r0,r3

move.w size,r4

_20: move.w $4000,r0
move.w buf,r1
move.w $8000,r2
trap $21
bcs.b _100
cmp.w r0,r2
bne.b _10
dec.w r4
bne.b _20

move.w $3e00,r0
trap $21
bcs.b _100

inc.b byte [name+3]
cmp.b '9',[name+3]
bls.b _30

move.b '0',[name+3]
inc.b byte [name+2]
cmp.b '9',[name+2]
bls.b _30

move.b '0',[name+2]
inc.b byte [name+1]
cmp.b '9',[name+1]
bls.b _30

move.b '0',[name+1]
inc.b byte [name]
cmp.b '9',[name]
bls.b _30

_100: move.w $4000,r0
move.w text1,r1
move.w text1_l,r2
move.w 1,r3
trap $21
rts.w

_10: move.w $4000,r0
move.w text2,r1
move.w text2_l,r2
move.w 1,r3
trap $21
rts.w


text1: dc.b "fehler",13,10
text1_l equ $-text1

text2: dc.b "disk voll",13,10
text2_l equ $-text2

name: dc.b '0000.txt',0

align 2
buf:

[J***@nospam.invalid]

Post by Herbert Kleebauer

Post by J***@nospam.invalid
I have a very old PC I took out of storage. It has DOS 3.3 installed and
its only other drive is the old large floppy drive.
Is there something under old DOS that can "wipe" a drive?
This PC is from before the internet and therefore has no web connection
and no way to download anything to it. I do have modern PCs but they of
course do not have these old floppy drives.
Suggestions for how to wipe the drive before junking the PC?

Delete all files and directories (not the DOS directory) and then
echo 123456789012345678901234567890>a
copy a+a+a+a b
copy b+b+b+b a
copy a+a+a+a b
copy b+b+b+b a
until you get a disk full error
del a
del b
Then you have a clean hard disk with the operating system
still working.

Just wanted to thank Herbert one more time. I was in a bind because the
floppy drive was also n ot working consistently. Many suggestions were
given on other newsgroups including using debug, etc. but your solution
of copying a and b worked like a charm. It was simple and elegant.

Since this PC is to be trashed I followed your technique with
Format c: /u/s

Anyone who recovers anything from that disk is welcome to it.

Thank you again.

[Auric__]

Post by J***@nospam.invalid
Just wanted to thank Herbert one more time. I was in a bind because the
floppy drive was also n ot working consistently. Many suggestions were
given on other newsgroups including using debug, etc. but your solution
of copying a and b worked like a charm. It was simple and elegant.
Since this PC is to be trashed I followed your technique with
Format c: /u/s
Anyone who recovers anything from that disk is welcome to it.
Thank you again.

If you have to do this sort of thing again in the future (I had something
vaguely similar this morning, as it happens), *before* doing Mr. Kleebauer's
trick, run deltree against each directory in the root directory (except the
DOS directory). If deltree isn't there, do this:
C:
cd \
dir/a-d/b/s>kill.bat
edit kill.bat (well... maybe not "edit" but whatever text editor there is
that includes search and replace)
- remove any references to the DOS directory (most likely C:\DOS)
- replace all instances of "C:\" with "del C:\", save and exit
kill.bat (could take a while, if there are a lot of files -- maybe hours on
a slow drive)
Mr. Kleebauer's trick

This will make recovering sensitive data more difficult, since it's likely to
get overwritten by the new junk data.

[Todd Vargo]

Post by Auric__

Post by J***@nospam.invalid
Just wanted to thank Herbert one more time. I was in a bind because the
floppy drive was also n ot working consistently. Many suggestions were
given on other newsgroups including using debug, etc. but your solution
of copying a and b worked like a charm. It was simple and elegant.
Since this PC is to be trashed I followed your technique with
Format c: /u/s
Anyone who recovers anything from that disk is welcome to it.
Thank you again.

If you have to do this sort of thing again in the future (I had something
vaguely similar this morning, as it happens), *before* doing Mr. Kleebauer's
trick, run deltree against each directory in the root directory (except the
cd \
dir/a-d/b/s>kill.bat
edit kill.bat (well... maybe not "edit" but whatever text editor there is
that includes search and replace)
- remove any references to the DOS directory (most likely C:\DOS)
- replace all instances of "C:\" with "del C:\", save and exit
kill.bat (could take a while, if there are a lot of files -- maybe hours on
a slow drive)
Mr. Kleebauer's trick
This will make recovering sensitive data more difficult, since it's likely to
get overwritten by the new junk data.

I don't believe DOS 3.3 had DELTREE or EDIT.

[Auric__]

Post by Todd Vargo

Post by Auric__

Post by J***@nospam.invalid
Just wanted to thank Herbert one more time. I was in a bind because
the floppy drive was also n ot working consistently. Many suggestions
were given on other newsgroups including using debug, etc. but your
solution of copying a and b worked like a charm. It was simple and
elegant.
Since this PC is to be trashed I followed your technique with
Format c: /u/s
Anyone who recovers anything from that disk is welcome to it.
Thank you again.

If you have to do this sort of thing again in the future (I had
something vaguely similar this morning, as it happens), *before* doing
Mr. Kleebauer's trick, run deltree against each directory in the root
cd \
dir/a-d/b/s>kill.bat
edit kill.bat (well... maybe not "edit" but whatever text editor there
is that includes search and replace)
- remove any references to the DOS directory (most likely C:\DOS)
- replace all instances of "C:\" with "del C:\", save and exit
kill.bat (could take a while, if there are a lot of files -- maybe
hours on a slow drive)
Mr. Kleebauer's trick
This will make recovering sensitive data more difficult, since it's
likely to get overwritten by the new junk data.

I don't believe DOS 3.3 had DELTREE or EDIT.

That was what I assumed, which is why I posted my thing. (Deltree makes it
unnecessary.)

I know for a fact that 3.3 didn't have edit (thus "whatever text editor
there is that includes search and replace"). Instead it had EDLIN, so my
"thing" on the given computer would be:
C:
cd \
dir/a-d/b/s>kill.bat
edlin kill.bat
sC:\DOS (or whatever it was named)
[n,n]d (where "[n,n]" is the first and last lines containing the DOS dir)
rC:\^Zdel C:\ (where "^Z" is ctrl+z)
w
e
kill.bat
your trick

[Auric__]

Post by Herbert Kleebauer

Post by J***@nospam.invalid
I have a very old PC I took out of storage. It has DOS 3.3 installed and
its only other drive is the old large floppy drive.
Is there something under old DOS that can "wipe" a drive?
This PC is from before the internet and therefore has no web connection
and no way to download anything to it. I do have modern PCs but they of
course do not have these old floppy drives.
Suggestions for how to wipe the drive before junking the PC?

Delete all files and directories (not the DOS directory) and then
echo 123456789012345678901234567890>a
copy a+a+a+a b
copy b+b+b+b a
copy a+a+a+a b
copy b+b+b+b a
until you get a disk full error
del a
del b
Then you have a clean hard disk with the operating system
still working.

Genius! Never would've occurred to me; I would've done something else, like,
say, moving the hard drive to another computer and wiping it there.
(Actually, I'd just use the floppy drive, since I still have several dozen of
them...)

[Horst Franke]

Post by J***@nospam.invalid
I have a very old PC I took out of storage. It has DOS 3.3 installed
and its only other drive is the old large floppy drive.
Is there something under old DOS that can "wipe" a drive?

Sorry Jeff
There's no need to wipe the "drive" ? but only to wipe the floppy disk(s).
Best way to do this is to scrap them.
Horst

[Jack Russell]

Post by J***@nospam.invalid
I have a very old PC I took out of storage. It has DOS 3.3 installed and
its only other drive is the old large floppy drive.
Is there something under old DOS that can "wipe" a drive?
This PC is from before the internet and therefore has no web connection
and no way to download anything to it. I do have modern PCs but they of
course do not have these old floppy drives.
Suggestions for how to wipe the drive before junking the PC?
Thanks.

I just take the drive out, dismantle the drive and physically destroy
the platter

[Bill Baka]

Post by J***@nospam.invalid
I have a very old PC I took out of storage. It has DOS 3.3 installed and
its only other drive is the old large floppy drive.
Is there something under old DOS that can "wipe" a drive?
This PC is from before the internet and therefore has no web connection
and no way to download anything to it. I do have modern PCs but they of
course do not have these old floppy drives.
Suggestions for how to wipe the drive before junking the PC?
Thanks.

MAGNET, BIG.
Running a powerful enough magnet over the disk 3 and 1/4 "
floppy or and old huge 5 inch version
?

[H-Man]

Post by Bill Baka

Post by J***@nospam.invalid
I have a very old PC I took out of storage. It has DOS 3.3 installed and
its only other drive is the old large floppy drive.
Is there something under old DOS that can "wipe" a drive?
This PC is from before the internet and therefore has no web connection
and no way to download anything to it. I do have modern PCs but they of
course do not have these old floppy drives.
Suggestions for how to wipe the drive before junking the PC?
Thanks.

MAGNET, BIG.
Running a powerful enough magnet over the disk 3 and 1/4 "
floppy or and old huge 5 inch version
?

Find DBAN floppy image.