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

[Juras <yb...@tu...>]

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 device
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 one 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 volumes.

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 contain 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=open()
2) close()
3) eof()
4) filelength
5) read
6) write
7) flush
8) seek

Block device requests:

1) handle=open()
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=file_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=mount(blockdev)
1) fhandle=file_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)

-- 
Best regards,
 Juras                          mailto:yb...@tu...