ext2-os2 is a file system driver that allows OS/2 to seamlessly access Linux native partitions (ext2fs partitions) in both read and write modes. Once installed, Linux partitions appear as standard OS/2 drive letters.
My initial purpose was to get limited read only access to ext2fs partitions from my OS/2 system, so at the beginning (version 0.1 alpha back in June 1995), it was more a quick and dirty rewrite than a clean and full port of the Linux ext2fs file system kernel code.
Now I'm improving it to reuse as much original ext2fs code as possible in order to get a full featured ext2fs driver on OS/2. I wrote a kind of IFS to VFS translation layer, and ported some Linux kernel services in order to minimize the changes required into the ext2fs sources. At the moment most of the changes in ext2fs are actually due to the 32 to 16 bits port (the IFS interface is still 16 bits), and the IFS code is 50% OS/2 specific (IFS to VFS translation layer, Linux kernel services) and 50% ported from Linux (ext2fs sources).
This version is almost full featured for "client" use ; the main restrictions are that you cannot boot OS/2 from an ext2fs partition, and that you cannot put SWAPPER.DAT on an ext2fs partiton.
Before using ext2-os2, please read the following : "***** IMPORTANT WARNING - READ THIS FIRST *****"
Writing an IFS is not a simple thing, for several reasons : first there's only one IBM document on the IFS interface, and IBM provides it 'AS IS' ... it means lots of guess ! The second one is that the IFS interface is complex (lots of stuff to support, EAS ...) and still 16 bits. For instance making the Workplace Shell survive to my IFS was a headache... The third one is that the OS/2 IFS interface is quite different from the Linux VFS interface : I had to rewrite from scratch several Linux VFS or even kernel services. The fourth thing is the fact that OS/2 is a multithreaded OS : you can be reentered for the SAME open file instance in your IFS, so locking of resources must be more strict than under Linux, not even speaking of OS/2 SMP, which I really don't support ..... so don't blame me if it doesn't work as you hoped ... I'll try to do better the next time !
DISCLAIMER :
THE FACT THAT I WORK FOR IBM HAS NOTHING TO DO WITH THIS DRIVER. I'M WRITING IT AT HOME, DURING MY SPARE TIME, FOR MY OWN PURPOSES, ON MY OWN MACHINE, WITHOUT ANY IBM MEANS. I USED ONLY IBM PUBLISHED DOCUMENTS TO WRITE IT : I AM ABSOLUTELY NOT RELATED TO THE OS/2 DEVELOPMENT TEAM AND THUS I HAVE ABSOLUTELY NO ACCESS TO ANY CONFIDENTIAL OS/2 IFS RELATED INFORMATION.
Anyway I hope you'll enjoy trying this driver, and even if I don't have much time, I'll try to keep improving it. I wait for your feedback on this version : comments, ideas, bug reports and contributions are welcome.
Matthieu WILLM
Note : English is not my native language ... so this document isn't certainly perfect.
Copyright notice for the ext2fs IFS driver Copyright notice for the ext2fs partition filter
Linux ext2fs file system driver for OS/2 2.x and WARP - Allows OS/2 to
access your Linux ext2fs partitions as normal drive letters.
Copyright (C) 1995, 1996 Matthieu WILLM
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public
License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
This driver contains some copyrighted code whose owners are :
/************************************************************************/ /* Linux partition filter. */ /* (C) Copyright Deon van der Westhuysen, July 1995. */ /* */ /* Dedicated to Jesus Christ, my Lord and Saviour. */ /* */ /* This program is free software; you can redistribute it and/or modify */ /* it under the terms of the GNU General Public License as published by */ /* the Free Software Foundation; either version 2, or (at your option) */ /* any later version. */ /* */ /* This program is distributed in the hope that it will be useful, */ /* but WITHOUT ANY WARRANTY; without even the implied warranty of */ /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */ /* GNU General Public License for more details. */ /* */ /* You should have received a copy of the GNU General Public License */ /* along with this program; if not, write to the Free Software */ /* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* */ /* This code is still under development; expect some rough edges. */ /* */ /************************************************************************/
Ext2-os2 is a BETA FILE SYSTEM DRIVER. Being a driver it runs at the most privileged level of the OS/2 operating system, known as "kernel mode". IN KERNEL MODE THERE IS NO MORE CRASH PROTECTION. It means that if a bug occurs in the driver IT CAN CAUSE A HANG OR A SYSTEM HALT, AND THUS CAN CAUSE LOSS OF DATA.
I'm not a professionnal IFS writer, so don't expect this driver to meet the same high degree of stability and performance as the native OS/2 file systems (HPFS and FAT).
This chapter describes the installation and setup instructions
Step 1 - Things to do BEFORE installing ext2-os2 Step 2 - Make OS/2 see your Linux ext2fs partitions Step 3 - Copying the files to your hard drive Step 4 - Using the ext2-os2 monitoring tool Step 5 - Specifying command line parameters
Here are things you must do before installing this version of ext2-os2 :
This chapter describes how to make OS/2 see your Linux ext2fs partitions
OS2DASD.DMD is the block device managing fixed partitionnable disks and floppies. It is always (as far as I know) the first block device loaded by the system. It first scans every .add drivers for physical disks. Then it reads the partition table of each disk. It first looks for active primary OS/2 partitions (Types 01, 04, 06 and 07) and installs a block device for each of them It repeats this for each physical drive in the system. Then it looks for extended volumes on the first physical drive (type 05 partition), reads the extended boot record, looks for an OS/2 partition and assign it a drive letter, looks for another extended volume ... and so on until no more extended volume is found on the first disk. It them repeats this for each physical drive.
Example :
þ Scans all *.add driver for fixed disks - found 2
þ Reads the MBR of physical disk 1
þ Found an OS/2 type 7 partition (active primary OS/2 IFS) - Install a block device (C:)
þ Found an unknown type 0x83 partition - skip it
þ Found an OS/2 type 5 partition (extended volume) - skip it
þ No more primary partition
þ Reads the MBR of physical disk 2
þ Found an OS/2 type 7 partition - Install a block device (D:)
þ Found an unknown type 17 (inactive primary OS/2 IFS) - skip it
þ Found an OS/2 type 5 partition (extended vol) - skip it
þ No more primary partition
Now done for primary partitions - processing extended volumes
þ Reread the MBR of physical disk 1
þ Found an OS/2 type 5 partition (extended volume)
þ Reads the extended boot record of the extended volume
þ Found a OS/2 type 7 partition - Install a block device (E:)
þ Found an OS/2 type 5 partition
þ Reads the extended boot record
þ Found a OS/2 type 7 partition - Install a block device (F:)
þ No more partition
þ Reread the MBR of physical disk 2
þ Found an OS/2 type 5 partition (extended volume)
þ Reads the extended boot record of the extended volume
þ Found a OS/2 type 7 partition - Install a block device (G:)
þ No more partition
Make OS/2 see your Linux ext2fs partitions
During "normal" operations, OS/2 will not assign a drive letter to the Linux partitions, because their type (0x83) is not one of the types OS/2 normally recognize. An installable file system driver does not have any control on how block devices are assigned : this is a device driver issue. If we don't do anything, the ext2fs IFS won't be very useful, since OS/2 doesn't even call it (no block device allocated).
In order for OS/2 to see your ext2fs partition, you must either change your Linux ext2fs partition ID from 0x83 (Linux native) to 0x7 (OS/2 IFS - and not OS/2 HPFS as stated in the Linux fdisk documentation), or make OS/2 think type 0x83 partitions are type 0x7 partitions.
In the first case we must manually alter the partition table, and in the second case we must use a special filter device driver - ext2flt.flt - whose purpose is to show a "hacked" partition table to OS2DASD.DMD.
Here's how ext2flt.flt works : A virtual fixed disk is created for each partition under control of the driver. These virtual fixed disks each contain one extended partition with a logical drive in it. Since OS2DASD.DMD that controls fixed disks first assigns drive letters to primary partitions the virtual partitions are tacked on at the end of allocated drive letters. (To control the mounting order of all partitions OS2DASD is prevented from directly accessing the fixed disks and the filter presents it with an alternate list of partitions.)
BE CAREFUL : IF YOU DECIDE TO CHANGE PARTITION ID MANUALLY BE AWARE THAT IT CAN CHANGE YOUR DRIVE LETTERS AND MAKE OS/2 UNBOOTABLE !!
Examples being better than a long speach, let's look at some different situations :
Example 1 Example 2 Example 3
ext2flt installation
BASEDEV=EXT2FLT.FLT
ext2-os2 installation
IFS=path\ext2-os2.ifs -cache:256 -errors=panic RUN=path\ext2_lw.exe SET EXT2_TZ=your time zone in minutes from UTC
Note : In CONFIG.SYS, ext2-os2.ifs MUST be located AFTER the IFS managing the boot drive (HPFS.IFS usually)
ext2-os2.exe is a monitoring tool to retrieve data from ext2-os2.ifs. It is a PM notebook containing :
ext2-os2.ifs command line in CONFIG.SYS :
IFS = <drive>:path\ext2-os2.ifs [-q]
[-cache:max. disk cache size]
[-rw]
[-no_auto_fsck]
[-case_retensive]
[-IFS entry point to trace]
[-no_strat2]
[-errors=[panic|continue]]
NOTE : case is not significant (-q and -Q are equivalent), and '-' as well as '/' can be used as a command line switch on the ext2-os2.ifs command line.
ext2flt.flt command line in CONFIG.SYS :
BASEDEV = EXT2FLT.FLT [/Q]
[/V]
[/W]
[/A]
[/M mount list]
This chapter describes some imortant usage instructions.
This release uses only lazy writes : it means that data are not committed to the disk immediately. YOU *MUST ALWAYS* SHUTDOWN YOUR SYSTEM PROPERLY so that data can be written to disk. IF YOU DON'T FOLLOW THIS RULE, YOUR EXT2FS PARTITION WILL BE PROBABLY DAMAGED, AND YOUR DATA LOST.
I included a sync.exe utility that flushes the cache to disk if you need to be sure that data are committed without shutting down the system.
If you use ex2fs formatted removable media (floppy, ...) data should be commited to disk before the media is removed. You MUST run sync.exe BEFORE removing the media from its drive.
There is an automatic flush during system shutdown. At that time the removable media (if you used one) MUST be present in the drive.
Note : You'll notice that the shutdown process is slightly longer : this is absolutely normal.
When ext2-os2 mounts an ext2fs partition and when read writes are enabled, it will set the mount count in the superblock to its maximum value in order to force a disk check when Linux mounts the drive.
This is a safety precaution to ensure that ext2-os2.ifs didn't corrupt the file systems. I do NOT recommend to disable this automatic check ; I only included the -no_auto_fsck switch for those who have very large drives.
ext2-os2 fatal errors can appear in several forms :
In either case, your ext2fs partition is in great danger ; To minimize the risk of data loss, please do the following :
ext2fs is a case sensitive file system ; ext2-os2.ifs by default does case sensitive comparisions, but even if OS/2 supports case sensitive file systems, all the apps that uppercase or lowercase file names are broken. Some parts of OS/2 are also broken : for instance the OS/2 program loader itself will uppercase executable names, and so will fail loading programs or DLL if they reside in a path with low case components.
As a workaround, I introduced a command line switch (-case_retensive) to make ext2-os2.ifs behave like HPFS : once set, it will ignore case when comparing file names, but it will retain the case within the file system. It means that FILE, File, FiLe and file will be treated as the same file if they reside in the same directory ; but if you create FiLe, it will keep the case in the file system.
If you plan to run OS/2 programs from a Linux partition, this option is necessary because the OS/2 program loader uppercase executable names.
There's a dangerous drawback to this case retensive mode : if 2 files created from Linux in the same directory exist with the same name but different case (FILE and File for instance), and you run ext2-os2.ifs in case retensive mode, RESULTS WILL BE UNPREDICTABLE AND YOU CAN TRASH ONE OR EVEN BOTH FILES ! In fact only the first entry in the "." file of the parent directory will be used by ext2-os2.ifs ; This "first" entry is not necessarily the first entry displayed by the 'DIR' command, nor is it the first one created. EXT2-OS2.IFS DOES NOTHING TO SOLVE SUCH FILE NAME CONFLICT IN CASE RETENSIVE MODE.
If you want to use this case retensive mode, please make sure from Linux that there are never several files with the same name but different case in ANY directory on ANY ext2fs partitions on your system BEFORE trying case retensive mode. If there are some, then rename these files from Linux so that they have have different names.
Note that "System Commander" (from V-Communications) may make changes to the partition table at boot time. This may affect which partitions are visible, or what drive letters are assigned by OS/2 when booting from System Commander. In particular, by default System Commander will make primary partitions on the second hard drive invisible to OS/2. If one of these other primary paritions contains a Linux partition, it will not be visible to OS/2 or EXT2-FS, (even though you are using the /V /A /M options with EXT2FLT.FLT). To make a primary partition on a second hard drive visible when booting OS/2 from System Commander, do the following:
This has been reported by Steve Enns (ennss@eris.nhrc.sk.doe.ca)
ext2-os2.ifs now has a dynamic disk cache. The disk cache code is in fact a port of the Linux disk cache, but with a few important differences.
In Linux, the dynamic cache code is coupled to the virtual memory manager code, so that all free physical memory can be used as cache : when there's some free physical memory, the cache can grow, and when there's not enough free physical memory, the virtual memory manager asks the disk cache to free some pages (this can range from "Could you please give me some free pages" ... to "I URGENTLY need some memory so make whatever you can to free some pages"). On OS/2 I couldn't make things work that way, simply because I can't hack the OS/2 kernel code !! On OS/2, you MUST specify an upper limit for the amount of physical memory the disk cache can allocate. When needed, ext2-os2.ifs will allocate this memory as disk cache, but to simulate VMM calls to shrink the cache, a daemon (ext2_lw.exe) periodically tries to shrink the cache. While it is not a perfect solution, it seems to be a good compromise, at least if the max cache size is reasonable (small enough so that it doesn't cause physical memory starvation to the kernel).
Some important points :
ext2-os2 can now take your local time zone into account. File times should match Linux file times (local time) instead of being relative to UTC . The time zone can be set in CONFIG.SYS through the EXT2_TZ environment variable. It should be set to the minute shift from UTC (-1440 to +1440). 0 means GMT, 60 means GMT+1, 120 means GMT+2, -60 means GMT-1 and so on.
This option is rather experimental and can't be perfect because OS/2 does not natively support time zones. Please tell me if you find it useful and if it works correctly, otherwise simply remove the EXT2_TZ statement from CONFIG.SYS and tell me the problems you encountered.
Some remarks about EXT2_TZ :
There are still too many of them. This list is not complete but I'll try to keep it as much complete as possible and shrink it as fast as I can, if you give me your feedback...
This chapter describes the changes between each release of ext2-os2
This chapter describes how to build the IFS.
To build the IFS you will need these tools or their equivalent. As the IFS interface is still 16 bits, gcc can't be used for the IFS itself ; I'm using MS Visual C++ 1.51 in a DOS box. For the utilities a 32 bits compiler is required, I used IBM Visualage C++ but gcc should do the job.
First unzip the file src_07a.zip somewhere on your disk, for instance in the root directory, it will create a tree .\ext2-os2. Then modify the file makefile.inc according to your own configuration :
EXT2OS2_BASE The root path of ext2-os2 (usually \ext2-os2)
DDKPATH The path where is installed your DDK (usually
\DDKx86)
IFSTKTPATH The path where you put the "IFS toolkit" (fsd
.h, fsh.h and fshelper.lib)
The build tree looks like :
.\ files containing the main makefile and all
IFS FS_xxx entry points It contains also the
sources of the utilities (ext2_lw.exe and
sync.exe).
.\vfs Linux kernel services and VFS interfaces.
.\ext2 ext2fs routines (/usr/src/linux-1.2.1/fs/ext2
)
.\include\os2 OS/2 specific include files
.\include\linux Linux include files (/usr/src/linux-1.2.1/
include/linux)
.\include\asm Linux include files (/usr/src/linux-1.2.1/
include/asm)
.\console ext2-os2.exe monitoring tool sources
.\doc The ext2-os2 documentation
.\distrib The directory in which is built the ZIP file.
.\vfsapi The VFSAPI library sources.
.\ext2flt contains Deon van der Westhuysen's ext2flt.
flt sources, patched to compile with MS
Visual C++ as well as Borland C++.
First configure a DOS box session with DPMI_DOS_API enabled and have it open on your desktop. Then open also an OS/2 session, go to the base directory and type "nmake". It should build the IFS and the utilities. Normally you should be prompted to switch between the DOS box and the OS/2 box to complete the build...I know this is an awful hack, but it's the cheapest thing I could do to build the IFS with both DOS and OS/2 tools !
The purpose of the VFSAPI library is to provide an extension of the standard OS/2 standard file system oriented calls to access Linux VFS specific features like I-nodes, UNIX file modes, file ownership and so on. For the moment the library is quite limited, but with the time I'll include some more calls !
To be able to do what they are designed for, these routines talk directly to the ext2-os2.ifs file system driver, through the DosFsCtl call. DosFsCtl (almost) directly calls the IFS's FS_FSCTL entry point. Most of the work is done in kernel mode inside ext2-os2.ifs. DosFsCtl is the IFS equivalent of DosDevIOCtl : an extended interface to the IFS.
The library is compiled using IBM Visualage C++ 3.0, but it should also compile without problem with emx/gcc. The precompiled vfsapi.dll should work with emx/gcc (and other compilers) without recompilation.
The entry points follow the standard OS/2 32 bits API linkage convention (_System for IBM Visualage C++, _syscall for Borland C++).
Note : The funtion names, as well as data structure names, have been prefixed with "vfs_" in order to prevent name collisions with existing C/C++ runtime libraries.
int vfs_fstat(int fd, struct new_stat *s);
This is the ext2-os2 implementation of the Unix fstat() system call. It returns a "true" stat structure containing the "true" Unix file mode, the "true" file ownership... This stat structure is the same as the Linux stat structure defined in /usr/include/sys/stat.h. All the macros and definitions for file modes and file ownership are also the same as in Linux.
Parameter type Input Description
Output
int fd input must be a valid OS/2 file handle (for example
returned by DosOpen, or DosDupHandle).
struct vfs_stat *s in/out On input must point to a vfs_stat structure.
On output contains the I-node information.
int vfs_stat(const char *pathname, struct new_stat *s);
This is the ext2-os2 implementation of the Unix stat() system call. It returns a "true" stat structure containing the "true" Unix file mode, the "true" file ownership... This stat structure is the same as the Linux stat structure defined in /usr/include/sys/stat.h. All the macros and definitions for file modes and file ownership are also the same as in Linux.
Parameter type Input Description
Output
const char *pathname input Must be a valid OS/2 file name (a file name
acceptable by DosOpen).
struct vfs_stat *s in/out On input must point to a vfs_stat structure.
On output contains the I-node information.
int vfs_sync(void);
This is the ext2-os2 implementation of the Unix sync() system call. It commits all data to the disk.
Note : vfs_sync will ONLY work on ext2fs partitions, not on other partitions (FAT, HPFS).
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circumstances.
It is not the purpose of this section to induce you to infringe any
patents or other property right claims or to contest validity of any
such claims; this section has the sole purpose of protecting the
integrity of the free software distribution system, which is
implemented by public license practices. Many people have made
generous contributions to the wide range of software distributed
through that system in reliance on consistent application of that
system; it is up to the author/donor to decide if he or she is willing
to distribute software through any other system and a licensee cannot
impose that choice.
This section is intended to make thoroughly clear what is believed to
be a consequence of the rest of this License.
8. If the distribution and/or use of the Program is restricted in
certain countries either by patents or by copyrighted interfaces, the
original copyright holder who places the Program under this License
may add an explicit geographical distribution limitation excluding
those countries, so that distribution is permitted only in or among
countries not thus excluded. In such case, this License incorporates
the limitation as if written in the body of this License.
9. The Free Software Foundation may publish revised and/or new versions
of the General Public License from time to time. Such new versions will
be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.
Each version is given a distinguishing version number. If the Program
specifies a version number of this License which applies to it and "any
later version", you have the option of following the terms and conditions
either of that version or of any later version published by the Free
Software Foundation. If the Program does not specify a version number of
this License, you may choose any version ever published by the Free Software
Foundation.
10. If you wish to incorporate parts of the Program into other free
programs whose distribution conditions are different, write to the author
to ask for permission. For software which is copyrighted by the Free
Software Foundation, write to the Free Software Foundation; we sometimes
make exceptions for this. Our decision will be guided by the two goals
of preserving the free status of all derivatives of our free software and
of promoting the sharing and reuse of software generally.
NO WARRANTY
11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
REPAIR OR CORRECTION.
12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.
END OF TERMS AND CONDITIONS
Appendix: How to Apply These Terms to Your New Programs
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
convey the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.
<one line to give the program's name and a brief idea of what it does.>
Copyright (C) 19yy name of author
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
Also add information on how to contact you by electronic and paper mail.
If the program is interactive, make it output a short notice like this
when it starts in an interactive mode:
Gnomovision version 69, Copyright (C) 19yy name of author
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License. Of course, the commands you use may
be called something other than `show w' and `show c'; they could even be
mouse-clicks or menu items--whatever suits your program.
You should also get your employer (if you work as a programmer) or your
school, if any, to sign a "copyright disclaimer" for the program, if
necessary. Here is a sample; alter the names:
Yoyodyne, Inc., hereby disclaims all copyright interest in the program
`Gnomovision' (which makes passes at compilers) written by James Hacker.
signature of Ty Coon, 1 April 1989
Ty Coon, President of Vice
This General Public License does not permit incorporating your program into
proprietary programs. If your program is a subroutine library, you may
consider it more useful to permit linking proprietary applications with the
library. If this is what you want to do, use the GNU Library General
Public License instead of this License.
This is an example where drive letters won't be changed when you toggle the ext2fs partition ID from 0x83 to 0x7. ext2flt gives the same result without having to alter the partition table.
Before
Physical Description Partition Drive Type Status drive ID letter 1 Boot mgr 0a - - Startable 1 OS/2 07 C: Extended Bootable 1 Linux ext2fs 83 - Extended Bootable <=== We toggle it from 0x83 ...
If we toggle the ext2fs partition type
Physical Description Partition Drive Type Status drive ID letter 1 Boot mgr 0a - - Startable 1 OS/2 07 C: Extended Bootable 1 Linux ext2fs 07 D: Extended Bootable === ... to 0x07
If we use ext2flt.flt
Physical Description Partition Drive Type Status drive ID letter 1 Boot mgr 0a - - Startable 1 OS/2 07 C: Extended Bootable 1 Linux ext2fs 07 D: Extended
The pink partition is the one as shown by ext2flt.flt to OS/2.
In this case, the OS/2 drive letter is changed from C: to D: when you change the Linux partition ID. If you want to use the ext2 IFS driver you'll have to use ext2flt.flt so that the ext2fs partition appears after the OS/2 partition.
Before
Physical Description Partition Drive Type Status drive ID letter 1 Boot mgr 0a - - Startable 1 Linux ext2 83 - Primary Bootable <=== We toggle it from 0x83 ... 1 OS/2 System 07 C: Extended Bootable
If we toggle the partiton ID, the drive letters change :
Physical Description Partition Drive Type Status drive ID letter 1 Boot mgr 0a - - Startable 1 Linux ext2 07 C: Primary Bootable === ... to 0x07 1 OS/2 System 07 D: Extended Bootable
The solution is to use ext2flt.flt :
Physical Description Partition Drive Type Status drive ID letter 1 Boot mgr 0a - - Startable 1 OS/2 System 07 C: Extended Bootable 1 Linux ext2 07 D: Extended
The pink partition is the one as shown by ext2flt.flt to OS/2.
In this case, you cannot use the ext2 IFS driver alone and you are a good candidate for using ext2flt.flt. This is because only ONE primary partition can be active. ext2flt.flt will make your ext2fs partition appear as an extended volume located after your OS/2 partition.
Physical Description Partition Drive Type Status drive ID letter 1 Boot mgr 0a - - Startable 1 Linux ext2 83 - Primary Bootable 1 OS/2 System 07 C: Primary (active) Bootable
If we use ext2flt.flt :
Physical Description Partition Drive Type Status drive ID letter 1 Boot mgr 0a - - Startable 1 OS/2 System 07 C: Primary (active) Bootable 1 Linux ext2 07 D: extended
[-q] : quiet initialization of ext2-os2.ifs (no banner during boot). Default is verbose initialization.
[-cache:<max. disk cache size>] Specifies the MAXIMUM disk cache size. This value is the maximum amount of physical memory ext2-os2.ifs can dynamically allocate for disk cache buffers. The default value is 240 Kb. The minimum value is 240Kb. The maximum value depends on system resources (free physical memory).
Note : Please read the chapter "Dynamic disk cache considerations"
[rw] : enable write access. Default is write disabled.
Note : If you use ext2flt, don't forget to enable write access on the ext2flt.flt command line. (/W switch)
WARNING - DON'T FORGET TO BACKUP ALL YOUR DATA PRIOR TO ENABLE WRITE ACCESS !!!
[-no_auto_fsck] : prevents ext2-os2 from forcing Linux to run e2fsck on partitions "touched" by OS/2 Default is to force Linux to run e2fsck.
Note : Please read the chapter "Automatic check disk"
[-case_retensive] : makes ext2-os2.ifs behave like HPFS. If this option is set, case will not be significant but will be retained within the file system. For instance File and FILE are considered to be the same file. Default is case sensitive.
WARNING - PLEASE READ "Case sensitivity considerations" BEFORE USING THIS OPTION !!!
[-<IFS entry point to trace>] : traces a specific IFS entry point. Using this option makes ext2-os2.ifs produce an output in ext2-os2.exe whenever the specified IFS entry point is entered. You can specify several IFS entry points to trace for instance "IFS=ext2-os2.ifs -FS_MKDIR -FS_RMDIR".
Note : Please notice that tracing will have a performance hit (can be important).
Currently supported IFS entry points for tracing are :
[-no_strat2] : disable use of extended I/O operations (strategy 2 calls). Default is to use them when they are supported by the block device driver. Normally it works well with OS2DASD.DMD, but if you encounter problems with extended I/O with other drivers, you can disable them.
Note : Using extended I/O results in HUGE performance improvements ; disabling them with have a tremendous performance hit.
[-errors=[panic|continue]] : specifies the behaviour to adopt when the ext2fs file system code detects an error within the file system. "panic" halts the system, "continue" makes ext2-os2 only output a message in ext2-os2.exe and continue. Default is "panic" (unlike Linux, whose default is "continue").
Note : If a system halt occurs with a message beginning with "ext2-os2 detected a file system error on drive %c", it means that the ext2fs file system code found a file system corruption. You MUST run e2fsck from Linux to repair your file system. This type of error is generally not specific to ext2-os2, but the error would also have occured on Linux. "-errors=continue" will avoid a system halt and just mark the file system as bad (forcing e2fsck on next Linux boot) ; but if you continue to work intensively after a file system error, you are likely to spread the error and make things even worse.
/Q : Quiet install. Prevents the filter from displaying messages.
/V : Verbose install. Displays some diagnostic messages.
/W : Allows the virtual partitions to be written to.
/A : Virtualize all partitions found. The only good reason to use this is along with the /M option when you want to control the mounting order of all the partitions. You must use the /W option if you use the /A option; otherwise OS/2 may crash when it tries to write to the partition.
Note : Using the /A option may change your drive letters causing the your system to be unbootable. Use the /M option together with /A. (This may change in the future.
/M <mount list> : Mounts the partitions in the order specified in the mount list, which should be a list of numbers separated by commas. The partitions are numbered 0 on a first come basis. (Not the OS/2 uses.)
sync.exe does exactly what its Unix counterpart (sync) does : it commits all buffered data to disks.
Invocation :
sync
Note : Please ensure that all ext2fs formatted removable media are in their drives when you invoke sync.exe.