From: Eleanor McHugh <eleanor@...>
Date: 2009-07-04T08:11:40+09:00
Subject: Re: file.seek and unused bytes

On 3 Jul 2009, at 23:06, Greg Willits wrote:
> So, my question is about those zeros. Does advancing the seek position
> (do we still call that the "cursor"?) intentionally and proactively  
> fill
> the unsed bytes with what apparently equates to zero? OR, am I just
> getting luck that my test files have used virgin disk space which  
> yields
> zeros, and the seek position just skips bytes which potentially would
> contain garbage from previously used disk sectors?
>
> 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.

Also you have to consider that zero may itself be a valid data value  
within a record :)


Ellie

Eleanor McHugh
Games With Brains
http://slides.games-with-brains.net
----
raise ArgumentError unless @reality.responds_to? :reason