Re: VM and Disk interfaces from a File System
Re: VM and Disk interfaces from a File System
- Subject: Re: VM and Disk interfaces from a File System
- From: Quinn <email@hidden>
- Date: Sat, 30 Nov 2002 11:00:44 +0000
At 21:51 +1100 28/11/02, Wally Crooze wrote:
Any help would be great. If there is a document that explains this
stuff and file systems on Mac OS X I would love to read it. I've
looked at Inside Mac OS X's System Overview, Kernel Programming and
User Porting Guide but are just confused which things are relevant
to KEXTs or just the kernel.
There is no documentation on this stuff, partly because there's no
guarantee that we (Apple) can support the current plug-in interface
in the long term.
I have noticed that part of the disk interface the functions
cluster_read and cluster_write, are there normal read and write
functions or is cluster the default?
What sort of file system are you porting? If it's a standard block
storage based system that supports caching, then cluster_read/write
is definitely the way to go. Also, you should call
cluster_pagein/pageout in your VOP_PAGEIN/OUT routines.
Note that the cluster routines actually do the I/O by calling your
VOP_CMAP routine to map the file block to a disk block and your
VOP_STRATEGY routine to do the actual I/O.
S+E
--
Quinn "The Eskimo!" <
http://www.apple.com/developer/>
Apple Developer Technical Support * Networking, Communications, Hardware
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