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CallBackDisk Read & Write callbacks assumptions

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#13655
Posted: 06/14/2010 12:52:34
by Vladislav Rastrusny (Standard support level)
Joined: 06/14/2010
Posts: 5

Hello.

Can I make any assumtions about read and write callbacks of CallBackDisk? If so, what are they? For example, can I be sure, that reading and writting is done via blocks with sizes divisible by 512, block size can be no more than 1Mb and that starting address is also divisible by 512 (this is what I can see from log of working callbackdisk)?
#13656
Posted: 06/14/2010 14:04:55
by Volodymyr Zinin (EldoS Corp.)

Hello Vladislav,

Block size and its offset in the read and write callbacks are always multiple of the sector size (which by default is 512).
Address of the Buffer parameter in the read and write callbacks are always sector aligned.
#13657
Posted: 06/14/2010 15:25:36
by Vladislav Rastrusny (Standard support level)
Joined: 06/14/2010
Posts: 5

And what about block sizes?
#13658
Posted: 06/14/2010 16:11:29
by Volodymyr Zinin (EldoS Corp.)

Block sizes are always multiple of the sector size (which by default is 512).
#13659
Posted: 06/14/2010 16:23:45
by Vladislav Rastrusny (Standard support level)
Joined: 06/14/2010
Posts: 5

Is there maximum block size?
#13661
Posted: 06/15/2010 02:41:51
by Volodymyr Zinin (EldoS Corp.)

Now it's 128Kb. But this value can be changed in the future releases.
#13663
Posted: 06/15/2010 03:54:21
by Vladislav Rastrusny (Standard support level)
Joined: 06/14/2010
Posts: 5

Are you sure of that? I added some logging routines to your FileDisk Delphi example and I can see blocks of maximum 1Mb in size.
#13664
Posted: 06/15/2010 04:06:01
by Volodymyr Zinin (EldoS Corp.)

Sorry, you are right. The block size can be more then 128Kb. So there isn't maximum block size. The size is the same passed by the system to the CallbackDisk driver.
#13668
Posted: 06/15/2010 07:39:06
by Vladislav Rastrusny (Standard support level)
Joined: 06/14/2010
Posts: 5

Ok, thanks
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