nazgul@apollo.uucp (Kee Hinckley) (01/31/86)
...
Well the mail came back address unknown, so...
Date: Fri, 31 Jan 86 11:48:30 est
From: Kee Hinckley <nazgul>
To: medin@.UUCP
Subject: Re: Help DOS 3.3 end file
Newsgroups: net.micro.apple
In-Reply-To: <183@noscvax.UUCP>
Organization: Apollo Computer Inc., Chelmsford MA
Cc:
DOS only keeps very rough track of the length of it's files, but
counting the number of 256 character blocks. Thus it really
doesn't know how long your file is, but will assume that it runs
to nearest 256 byte boundry OR the next NULL byte. When you
first write a file each block is nulled, so you don't have to
worry about this. However, if you overwrite a file with a
shorter file there won't be a null byte at the end. So the
solution to all of this is to write a null byte as your last
character.
Note: There may be a bug in DOS that it won't free up extra
blocks if you overwrite with a smaller file. I seem to remember
reading this somewhere. This would mean that if you overwrote
a 4 block file with a 1 block file it would still think that the
other 3 blocks were allocated. This should be easy enough to
test.
-kee
...decvax!wanginst!apollo!nazgul
--
Little Bo-Peep
Has lost her sheep,
The radar has failed to find them.
They'll all, face to face,
Meet in parallel space,
Preceding their leaders behind them.
"A Space Child's Mother Goose"