A Shareware Timelock

 BBS: Inland Empire Archive
Date: 04-08-92 (15:53)             Number: 190
From: RICHARD VANNOY               Refer#: 140
  To: SCOTT WUNSCH                  Recvd: NO  
Subj: A Shareware Timelock           Conf: (2) Quik_Bas

SW>  Hey!  Maybe I should've been paying more attention to this thread!
SW>What is the "blind spot" at the end of BIO.SYS.

For simplicity assume a sector is 1024 bytes, and BIO.SYS
is 1000 bytes long...

0                                       1000  1024
|-----------------------------------------|....|
 <-----BIO.SYS----------------------------^  ^ ^
                                             | |
"Blind spot" between EOF and end of sector---| |
                                               |
                             end of sector-----|
Bytes 1001 thru 1024 are "invisible" to DOS since DOS will
not write in the blind spot, but will start a new file or
write at the start of the NEXT sector.  So, if I were to
write a password, date or whatever, at byte 1002, the
theory is that it would be hidden and because it is on the
end of a system file, wouldn't even be disturbed by a
defragger.

> MegaMail 2.1b #0:Feathers are so expensive now that DOWN is UP!


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