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Posted by Han on April 6, 2008, 5:00 pm
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> Newsgroups: alt.comp.software.financial.quicken
> Subject: Re: Quicken file on network
>
> Han wrote:
>> <script etc snipped>
>>
>> Thanks Andrew, I get it. My Reference Manager database system
>> probably does something like that, because if I have a DB open, I
>> can't even copy its files to another drive. The program also writes a
>> *.loc file to disk, and deletes it when the program or DB is closed.
>> Or is "locking" a file something different?
> The "inuse" file I used is what I called it - a sentenal (misspelled!
> Should have been sentinel - my bad). It stands guard.
>
> It depends. Locking a file is somewhat different IFF your OS supports
> file locks. Indeed, anything that prevents access can be thought of as
> a lock. A script such as the one I posted "locks" your Quicken
> database. About the only thing different is that this "lock" is
> applied by a user and has the semantic of meaning "Hey I'm working on
> this". Effectively it's saying "I want exclusive access to <resource>"
> where <resource> in this case is a Quicken database. So it's like a
> reservation or like checking a book out of a library.
>
> This is also what's called a cooperative lock in that all people
> passing through this script will be prevented from using <resource> if
> somebody else is using it. Anybody ignoring this script and simply
> opening the Quicken database obviously will not be impeded.
>
> If your OS supports locks - or more specifically if the file system
> supports locking - then the locking is enforced by the file system
> itself when you attempt to fopen or fwrite the file. Effectively this
> non-cooperative file locking is really no different except to say that
> there is really no other way to write the file thus your "cooperation"
> is not required! ;-)
>
> IOW You ain't getting to write this file bud because the file system
> is not gonna let you.
>
> Quicken doesn't have non-cooperative locking - this script is a hack
> to provide it via cooperative locking.
OK. Apparently, Reference Manager uses more sophisticated database
protection. It has some way to enforce 1 of 3 different sets of "access
rights": Read-Only Share, Read-Write Share, and Read-Write Exclusive.
Mine is a stand-alone version of software to manage a "library" of
scientific research articles, and ways to automatically output
bibliographies of quoted articles in a wordprocessor.
Everyone has for years been complaining that this version opens files by
default in Read-Write Share mode, which prevents you from editing some
useful stuff, such as journal titles (JBC is the same as J. Biol. Chem.
is the same as Journal of Biological Chemistry, and depending on
circumstances you might one or the other). At present you have to
expressly open the database in Read-Write Exclusive mode to do those
things. This is a pain in the 4$$. There is also a more expensive
network version, which would support simultaneous use of a database from
different computers. Made by Thomson ResearchSoft.
--
Best regards
Han
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