DiskIO Library - Revision history

Steven Solie at 17:18, 16 October 2015

2015-10-16T17:18:53Z

← Older revision		Revision as of 17:18, 16 October 2015
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	When all is done Cleanup() is called to get rid of the disk I/O handle (this also automatically flushes the write cache if any).		When all is done Cleanup() is called to get rid of the disk I/O handle (this also automatically flushes the write cache if any).

			AddDiskChangeHandler()/RemDiskChangeHandler() make it simple to add a disk change handler. As with Setup() all that is needed is a device/volume name and all the low level details are hidden.
	Some other functions I skipped are
	AddDiskChangeHandler()/RemDiskChangeHandler() which make it very simple
	to add a disk change handler. As with Setup() all that is needed is a
	device/volume name and all the messy low level details are hidden.

			Update() is used to make diskio.library start accessing a new storage medium. It's called implicitly the first time during Setup() and among other things takes care of things like getting rid of the old block cache if any and setting up a new one. The currently available file systems do not use this function because they create a new disk I/O handle every time a new disk/medium is inserted.
	The last noteworthy function is Update() which is used to make
	diskio.library start accessing a new storage medium. It's called
	implicitly the first time during Setup() and among other things takes
	care of things like getting rid of the old block cache if any and
	setting up a new one. None of the currently available filesystems use
	this function because they create a new disk i/o handle every time a new
	disk/medium is inserted.

		⚫	Example code is available in the NTFS-3G (libntfs-3g/amiga_io.c) and ExFAT (libexfat/amiga_io.c) ports.
	As far as examples go there is the code in ntfs-3g
⚫	(libntfs-3g/amiga_io.c) and ~~exfat~~ (libexfat/amiga_io.c) ports.

Steven Solie at 17:12, 16 October 2015

2015-10-16T17:12:03Z

@@ Line 1: / Line 1: @@
-Disk I/O Library is a higher level API for disk/partition I/I that automatically takes care of most technical details like getting the correct device name,
+Disk I/O Library is a higher level API for disk/partition I/O that automatically takes care of most technical details. Details like:
-unit and flags to call OpenDevice(), checking that it's of the correct
+* getting the correct device name, unit and flags to call OpenDevice()
-dimensions based on the //DosEnvec structure and TD_GETGEOMETRY (if
+* calculating the disk/partition dimensions based on the DosEnvec structure and TD_GETGEOMETRY (if de_LowCyl is zero).
 Some other functions I skipped are

Steven Solie: Created page with "Disk I/O Library is a higher level API for disk/partition I/I that automatically takes care of most technical details like getting the correct device name, unit and flags to..."

2015-10-16T04:39:24Z

Created page with "Disk I/O Library is a higher level API for disk/partition I/I that automatically takes care of most technical details like getting the correct device name, unit and flags to..."

New page

Disk I/O Library is a higher level API for disk/partition I/I that automatically takes care of most technical details like getting the correct device name,
unit and flags to call OpenDevice(), checking that it's of the correct
type and what commands to use and calculating the disk/partition
dimensions based on the //DosEnvec structure and TD_GETGEOMETRY (if
de_LowCyl is zero). As an additional safety measures it also checks that
all read and write accesses are within partition bounds and immediately
fails them if they are not.

Other than that it has functions that allow reading and writing data
that is not block aligned or a multiple of the block size and it has a
built-in block cache.

The functions themselves should be simple use and are described in the
autodoc.

The Setup() function is called to get the disk i/o handle. This just
takes a device/volume name, which is used to find the device node and
from there all the other necessary data, and an optional taglist
specifying additional parameters.

After Setup(), Query() should be used to get information on the
disk/partition and whether there is a storage medium available at all.

Reading and writing is done through ReadBytes/-Blocks()
WriteBytes/-Blocks() and the write cache is flushed to disk by using
FlushIOCache() (this also calls CMD_UPDATE to flush the device driver's
write cache if there is one).

And when all is done Cleanup() is called to get rid of the disk i/o
handle (this also automatically flushes the write cache if any).

Some other functions I skipped are
AddDiskChangeHandler()/RemDiskChangeHandler() which make it very simple
to add a disk change handler. As with Setup() all that is needed is a
device/volume name and all the messy low level details are hidden.

The last noteworthy function is Update() which is used to make
diskio.library start accessing a new storage medium. It's called
implicitly the first time during Setup() and among other things takes
care of things like getting rid of the old block cache if any and
setting up a new one. None of the currently available filesystems use
this function because they create a new disk i/o handle every time a new
disk/medium is inserted.

As far as examples go there is the code in ntfs-3g
(libntfs-3g/amiga_io.c) and exfat (libexfat/amiga_io.c) ports.