Re: [Stormdos-develop] NEW DRIVERS/DEVICES MODEL and test

[Stephane R. <sri...@to...>]

This is a test reply :-)....make sure all works good.

I like what I've read in there Juras, I like that device model...I think =
it
can make a good basis for everything else that might need a driver as wel=
l.

St=E9phane Richard
Software Developer

----- Original Message -----=20
From: "Juras" <yb...@tu...>
To: "stormdos-develop" <sto...@li...>
Sent: Wednesday, April 14, 2004 8:20 AM
Subject: [Stormdos-develop] NEW DRIVERS/DEVICES MODEL and test


> Hello stormdos-develop,
>
>   Post to this mail list for test purpose.
>
> New: DRIVERS/DEVICES model
>
> Drivers register virtual devices.
>
> a device may be of various types (and are handled as separate arrays to
maximize search speed):
>
>  - character and block
>  - volume (which can be mapped as disk c:, d: etc. i.e. it may be
referenced in the path, has FS)
>  - special (no file i/o, invisible to user FS functions)
>  - file system (invisible to user file functions)
>  * aliases and substitutes - respect to every category
>
> An alias is a device which really refers to the same functionality devi=
ce
> but with another name. e.g. C: is a real volume and c: refers to C: and=
 is
an alias.
>
> A substitute is a device which doesn't directly correspond to another o=
ne
but
> sends modified requests to a linked device. e.g. G: is a substituted
volume, it
> modifies requests' path name to be C:\myrefdir\sss\...
>
> A volume is a device which accepts file IO operations and serves as a
basis,
> e.g. C:\mypath\myfile.txt
> It has a block and file system devices attached.
>
> A file system device has nothing downward attached, it is used by volum=
es.
>
> A block device has nothing downward attached, it is used by volumes and
supports
> I/O operations.
>
> A character device is almost the same as a block device but can't conta=
in
a file system.
>
>
> A FS layer may operate on volumes and character/block devices only.
> If a path contains a colon or slahes then only volumes are operated.
>
>
> 1) initialize FS drivers (they simply register devices)
> 2) initialize block/char drivers
> 3) automount all block devices which can contain a FS
>
>
> ----------------------
>
> All devices could be sent a FLUSH request when closing the kernel etc.
>
>
> Character device requests:
>
> 1) handle=3Dopen()
> 2) close()
> 3) eof()
> 4) filelength
> 5) read
> 6) write
> 7) flush
> 8) seek
>
> Block device requests:
>
> 1) handle=3Dopen()
> 2) close()
> 3) eof
> 4) blocks_count
> 5) readblock
> 6) writeblock
> 7) readblocks
> 8) writeblocks
> 9) seek_block
> 10) eof
> 11) [format]
> 12) block_dev_info
>
> Volume device requests (mainly resends them to FS device, serves as a
named filter/router):
>
> 1) fhandle=3Dfile_open
> 2) file_close
> 3) file_seek
> 4) file_read
> 5) file_write
> 6) file_eof
> 7) file_findfirst
> 8) file_findnext
> 9) file_rename
> 10) file_move
> 11) file_delete
> 12) file_info
> 13) volume_info
> 14) volume_changed
> 15) volume_remount
>
> File system device requests:
>
> 0) handle=3Dmount(blockdev)
> 1) fhandle=3Dfile_open
> 2) file_close
> 3) file_seek
> 4) file_read
> 5) file_write
> 6) file_eof
> 7) file_findfirst
> 8) file_findnext
> 9) file_rename
> 10) file_move
> 11) file_delete
> 12) file_info
> 13) volume_info
> 14) unmount(handle)
>
> --=20
> Best regards,
>  Juras                          mailto:yb...@tu...
>
>
>
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