Re: How to tell if a file is busy?
Re: How to tell if a file is busy?
- Subject: Re: How to tell if a file is busy?
- From: Chris Nebel <email@hidden>
- Date: Thu, 27 Sep 2001 10:10:34 -0700
- Organization: Apple Computer, Inc.
Michelle Steiner wrote:
>
On 9/26/01 11:49 PM, Chris Nebel <email@hidden> wrote:
>
>
>The difficulty, as Chris points out, is that some applications don't leave
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the
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>disk file open while the document is "open". The file system is telling the
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>truth -- the file itself is not busy, and anyone is free to read from or
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write
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>to it, but the application that opened the file earlier may stomp on your
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>changes later.
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>
Isn't this true of most memory-resident applications (the original
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MacWrite, for instance) that load the entire file into RAM, and write
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back to disk when saving the file?
Not necessarily. While most applications even today load the entire file into
RAM, many leave the disk file open to prevent anyone else from getting write
access to it -- that way, they don't have to worry about the kind of checks that
BBEdit does. (Project Builder has a similar feature.)
>
Of course with single-user, single-application OSs, like the original Mac
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OS, this isn't a problem.
Indeed. OSs and applications are much easier to write if you don't multi-task,
don't allow multiple users, and don't have a network. I remarked to someone
yesterday that computer security was a lot simpler when everyone on the net was
friendly...
--Chris Nebel
AppleScript Engineering