From: GreggMan@aol.com
Date: Thu, 12 Oct 95 08:50:35 PDT
To: rah@shipwright.com
Subject: Re: PC disk wipe software
Message-ID: <951012115021_122212260@mail06.mail.aol.com>
MIME-Version: 1.0
Content-Type: text/plain


In a message dated 95-10-09 12:34:33 EDT, you write:

>>PC Tools has a wipe program that will either wipe individual files, or
>>wipe all unallocated diskspace. It also allows you to choose the level
>>of wipe (single overwrite, multiple, etc).
>
>There has been considerable discussion on the MCIP list about how most
>*Mac* programs that purport to do this, like Burn, for example, leave stuff
>over in disk blocks. My understanding is that this is not a trivial
>problem, and it occurs in MUSH-DOS as well....
>
>Cheers,
>Bob Hettinga
>
>

Actually not a problem for mess-DOS: just overwrite to the next multiple of
the allocation unit size. Trivial indeed.  What you must *not* do is just
write to the end of current file ... you have to extend.  Good idea too is to
flush file buffers/reset disk subsystem before the next file writes so that
buffer garbage doesn't get stuck in at end of last sector(s) of new files.