This article was posted to the Usenet group alt.hackers in
1995; any technical information is probably outdated.
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Re: Disk Serial Numbers.
Article: 7827 of alt.hackers From: jsl2228@acf4.nyu.edu (jsl2228) Newsgroups: alt.hackers Subject: Re: Disk Serial Numbers. Date: 17 May 1995 04:36:00 GMT Organization: New York University Lines: 32 Approved: Site administrator Message-ID: 3pbufg$la@cmcl2.NYU.EDU NNTP-Posting-Host: acf4.nyu.edu X-Newsreader: TIN [version 1.2 PL2] Status: RO
MICHAEL PAUL DANIEL (mdanie@wilbur.mbark.swin.oz.au) wrote:
: Just a quick question.. How does MS-DOS determine the serial number when
: you format a disk??
It's not a pesudo-randum number #, it actually has a formula. It's
based on the current date & time.
unsigned long int NS; (Serial numbers are 32 bits)
NS = ( ( ( ((seconds << 8) + hundreth) ) +
((day << 8) + month) ) << 16 ) +
( ((hour << 8) + minutes) + year);
Try this: get a disk that is already formatted (but whose data you
don't care about:)
>FORMAT A:/Q/U/V:""
Format the disk once, note the serial number, then immediately
format it again. Note that the second serial number only differs in
a few digits from the first.
ObHack:
A few years ago, to hack a Novell network, I wanted a copy of
the boot disk for diskless workstations. Getting the image file was
easy, but how to get it into a floppy? DiskEdit works, but is cumbersome
if you have to do it many times. So I wrote R-DOSGEN, to Reverse
the DOSGEN process (and also take out the changes made by RPLFIX)
Now Novell's DOSGEN can also reqrite a diskette based on the image...
but, I did add disk formatting to my pgm, and (you guessed it!)
adding new serial numbers to the disks, just like DISKCOPY does.
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