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Author Topic: library data disk i/o behavior  (Read 1241 times)

rjm

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library data disk i/o behavior
« on: November 16, 2009, 12:36:28 pm »

This has been an issue for a long time. Thought I would bring it to your attention.

MC does not behave very nicely when it has to compete for disk i/o to it's library files on startup.

To observe this, use Windows Explorer to copy a bunch of big files from the same drive that contains MC's library and thumbnails. Now start MC. I observe that rather than starting up with reduced performance (as you would expect), MC behaves as if it is locked up until the Windows copy operation completes.

For a long time I interpreted these lockups as crashes until I figured out what is going on.
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JimH

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Re: library data disk i/o behavior
« Reply #1 on: November 16, 2009, 12:48:14 pm »

I can't imagine that Microsoft would give itself priority.
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Daydream

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Re: library data disk i/o behavior
« Reply #2 on: November 16, 2009, 02:45:32 pm »

Well, I've just saw this happens over the weekend. Now, I wasn't using the Windows Copy routine but a different app - FastCopy - and the effect was just the same. Changing from Artists to Albums in Theater View took forever. So a couple of thoughts from the top of my head:
- is the database engine inside MC waiting for the HDD activity to reach a certain level?
- even if I use a third party copy app I believe this helps more with the way caching is managed, and at some point you have to use system calls to do what you want (in this case copy) 'cause otherwise you won't get access to resources. So unless MC will run on a different OS, this is something that we have to live with it and work around it.
- can MC be installed with all its stuff somewhere else and not be tied to the C drive? I believe last time I had some success with this idea I had to modify manually some 570 registry entries.
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Matt

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Re: library data disk i/o behavior
« Reply #3 on: November 16, 2009, 02:49:41 pm »

Library data is stored on disk.  On demand, information is placed in memory for fast access, and later unloaded to save resources.

So at a time when it needs to get data from disk to memory (like to make a new view that uses a field that isn't already available in memory, etc.), the program will have to wait for the system to fulfill a read request.

Placing your Media Center library on a fast drive is recommended.
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Matt Ashland, JRiver Media Center
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