From: Brian Candler <b.candler@...>
Date: 2009-07-05T18:03:49+09:00
Subject: Re: file.seek and unused bytes

Eleanor McHugh wrote:
>> Can I count on those unused bytes always being zero?
> 
> Unfortunately you're getting lucky. A seek adjusts the file pointer
> but doesn't write anything to disk so whilst your 'unused' bytes won't
> be changing value as a result of writing data to the file unless you
> write the full record, you can't rely on them not having a value other
> than zero if you don't.

I don't believe that's the case today. If it were, then you would have a 
very easy way to examine the contents of unused sectors on the disk - 
which would allow you to see other people's deleted files, passwords 
etc.

It was possible on old mainframe systems in the 80's though :-)

But today, if you extend a file using seek, you should always read 
zeros.
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