Initial import

7 files changed, 941 insertions, 0 deletions

diff --git a/Documentation/ide/00-INDEX b/Documentation/ide/00-INDEX
new file mode 100644
index 000000000..22f98ca79
--- /dev/null
+++ b/Documentation/ide/00-INDEX
@@ -0,0 +1,14 @@
+00-INDEX
+    	- this file
+ChangeLog.ide-cd.1994-2004
+	- ide-cd changelog
+ChangeLog.ide-floppy.1996-2002
+	- ide-floppy changelog
+ChangeLog.ide-tape.1995-2002
+	- ide-tape changelog
+ide-tape.txt
+	- info on the IDE ATAPI streaming tape driver
+ide.txt
+	- important info for users of ATA devices (IDE/EIDE disks and CD-ROMS).
+warm-plug-howto.txt
+	- using sysfs to remove and add IDE devices.
\ No newline at end of file
diff --git a/Documentation/ide/ChangeLog.ide-cd.1994-2004 b/Documentation/ide/ChangeLog.ide-cd.1994-2004
new file mode 100644
index 000000000..4cc3ad99f
--- /dev/null
+++ b/Documentation/ide/ChangeLog.ide-cd.1994-2004
@@ -0,0 +1,268 @@
+/*
+ * 1.00  Oct 31, 1994 -- Initial version.
+ * 1.01  Nov  2, 1994 -- Fixed problem with starting request in
+ *                       cdrom_check_status.
+ * 1.03  Nov 25, 1994 -- leaving unmask_intr[] as a user-setting (as for disks)
+ * (from mlord)       -- minor changes to cdrom_setup()
+ *                    -- renamed ide_dev_s to ide_drive_t, enable irq on command
+ * 2.00  Nov 27, 1994 -- Generalize packet command interface;
+ *                       add audio ioctls.
+ * 2.01  Dec  3, 1994 -- Rework packet command interface to handle devices
+ *                       which send an interrupt when ready for a command.
+ * 2.02  Dec 11, 1994 -- Cache the TOC in the driver.
+ *                       Don't use SCMD_PLAYAUDIO_TI; it's not included
+ *                       in the current version of ATAPI.
+ *                       Try to use LBA instead of track or MSF addressing
+ *                       when possible.
+ *                       Don't wait for READY_STAT.
+ * 2.03  Jan 10, 1995 -- Rewrite block read routines to handle block sizes
+ *                       other than 2k and to move multiple sectors in a
+ *                       single transaction.
+ * 2.04  Apr 21, 1995 -- Add work-around for Creative Labs CD220E drives.
+ *                       Thanks to Nick Saw <cwsaw@pts7.pts.mot.com> for
+ *                       help in figuring this out.  Ditto for Acer and
+ *                       Aztech drives, which seem to have the same problem.
+ * 2.04b May 30, 1995 -- Fix to match changes in ide.c version 3.16 -ml
+ * 2.05  Jun  8, 1995 -- Don't attempt to retry after an illegal request
+ *                        or data protect error.
+ *                       Use HWIF and DEV_HWIF macros as in ide.c.
+ *                       Always try to do a request_sense after
+ *                        a failed command.
+ *                       Include an option to give textual descriptions
+ *                        of ATAPI errors.
+ *                       Fix a bug in handling the sector cache which
+ *                        showed up if the drive returned data in 512 byte
+ *                        blocks (like Pioneer drives).  Thanks to
+ *                        Richard Hirst <srh@gpt.co.uk> for diagnosing this.
+ *                       Properly supply the page number field in the
+ *                        MODE_SELECT command.
+ *                       PLAYAUDIO12 is broken on the Aztech; work around it.
+ * 2.05x Aug 11, 1995 -- lots of data structure renaming/restructuring in ide.c
+ *                       (my apologies to Scott, but now ide-cd.c is independent)
+ * 3.00  Aug 22, 1995 -- Implement CDROMMULTISESSION ioctl.
+ *                       Implement CDROMREADAUDIO ioctl (UNTESTED).
+ *                       Use input_ide_data() and output_ide_data().
+ *                       Add door locking.
+ *                       Fix usage count leak in cdrom_open, which happened
+ *                        when a read-write mount was attempted.
+ *                       Try to load the disk on open.
+ *                       Implement CDROMEJECT_SW ioctl (off by default).
+ *                       Read total cdrom capacity during open.
+ *                       Rearrange logic in cdrom_decode_status.  Issue
+ *                        request sense commands for failed packet commands
+ *                        from here instead of from cdrom_queue_packet_command.
+ *                        Fix a race condition in retrieving error information.
+ *                       Suppress printing normal unit attention errors and
+ *                        some drive not ready errors.
+ *                       Implement CDROMVOLREAD ioctl.
+ *                       Implement CDROMREADMODE1/2 ioctls.
+ *                       Fix race condition in setting up interrupt handlers
+ *                        when the `serialize' option is used.
+ * 3.01  Sep  2, 1995 -- Fix ordering of reenabling interrupts in
+ *                        cdrom_queue_request.
+ *                       Another try at using ide_[input,output]_data.
+ * 3.02  Sep 16, 1995 -- Stick total disk capacity in partition table as well.
+ *                       Make VERBOSE_IDE_CD_ERRORS dump failed command again.
+ *                       Dump out more information for ILLEGAL REQUEST errs.
+ *                       Fix handling of errors occurring before the
+ *                        packet command is transferred.
+ *                       Fix transfers with odd bytelengths.
+ * 3.03  Oct 27, 1995 -- Some Creative drives have an id of just `CD'.
+ *                       `DCI-2S10' drives are broken too.
+ * 3.04  Nov 20, 1995 -- So are Vertos drives.
+ * 3.05  Dec  1, 1995 -- Changes to go with overhaul of ide.c and ide-tape.c
+ * 3.06  Dec 16, 1995 -- Add support needed for partitions.
+ *                       More workarounds for Vertos bugs (based on patches
+ *                        from Holger Dietze <dietze@aix520.informatik.uni-leipzig.de>).
+ *                       Try to eliminate byteorder assumptions.
+ *                       Use atapi_cdrom_subchnl struct definition.
+ *                       Add STANDARD_ATAPI compilation option.
+ * 3.07  Jan 29, 1996 -- More twiddling for broken drives: Sony 55D,
+ *                        Vertos 300.
+ *                       Add NO_DOOR_LOCKING configuration option.
+ *                       Handle drive_cmd requests w/NULL args (for hdparm -t).
+ *                       Work around sporadic Sony55e audio play problem.
+ * 3.07a Feb 11, 1996 -- check drive->id for NULL before dereferencing, to fix
+ *                        problem with "hde=cdrom" with no drive present.  -ml
+ * 3.08  Mar  6, 1996 -- More Vertos workarounds.
+ * 3.09  Apr  5, 1996 -- Add CDROMCLOSETRAY ioctl.
+ *                       Switch to using MSF addressing for audio commands.
+ *                       Reformat to match kernel tabbing style.
+ *                       Add CDROM_GET_UPC ioctl.
+ * 3.10  Apr 10, 1996 -- Fix compilation error with STANDARD_ATAPI.
+ * 3.11  Apr 29, 1996 -- Patch from Heiko Eißfeldt <heiko@colossus.escape.de>
+ *                       to remove redundant verify_area calls.
+ * 3.12  May  7, 1996 -- Rudimentary changer support.  Based on patches
+ *                        from Gerhard Zuber <zuber@berlin.snafu.de>.
+ *                       Let open succeed even if there's no loaded disc.
+ * 3.13  May 19, 1996 -- Fixes for changer code.
+ * 3.14  May 29, 1996 -- Add work-around for Vertos 600.
+ *                        (From Hennus Bergman <hennus@sky.ow.nl>.)
+ * 3.15  July 2, 1996 -- Added support for Sanyo 3 CD changers
+ *                        from Ben Galliart <bgallia@luc.edu> with
+ *                        special help from Jeff Lightfoot
+ *                        <jeffml@pobox.com>
+ * 3.15a July 9, 1996 -- Improved Sanyo 3 CD changer identification
+ * 3.16  Jul 28, 1996 -- Fix from Gadi to reduce kernel stack usage for ioctl.
+ * 3.17  Sep 17, 1996 -- Tweak audio reads for some drives.
+ *                       Start changing CDROMLOADFROMSLOT to CDROM_SELECT_DISC.
+ * 3.18  Oct 31, 1996 -- Added module and DMA support.
+ *
+ * 4.00  Nov 5, 1996   -- New ide-cd maintainer,
+ *                                 Erik B. Andersen <andersee@debian.org>
+ *                     -- Newer Creative drives don't always set the error
+ *                          register correctly.  Make sure we see media changes
+ *                          regardless.
+ *                     -- Integrate with generic cdrom driver.
+ *                     -- CDROMGETSPINDOWN and CDROMSETSPINDOWN ioctls, based on
+ *                          a patch from Ciro Cattuto <>.
+ *                     -- Call set_device_ro.
+ *                     -- Implement CDROMMECHANISMSTATUS and CDROMSLOTTABLE
+ *                          ioctls, based on patch by Erik Andersen
+ *                     -- Add some probes of drive capability during setup.
+ *
+ * 4.01  Nov 11, 1996  -- Split into ide-cd.c and ide-cd.h
+ *                     -- Removed CDROMMECHANISMSTATUS and CDROMSLOTTABLE
+ *                          ioctls in favor of a generalized approach
+ *                          using the generic cdrom driver.
+ *                     -- Fully integrated with the 2.1.X kernel.
+ *                     -- Other stuff that I forgot (lots of changes)
+ *
+ * 4.02  Dec 01, 1996  -- Applied patch from Gadi Oxman <gadio@netvision.net.il>
+ *                          to fix the drive door locking problems.
+ *
+ * 4.03  Dec 04, 1996  -- Added DSC overlap support.
+ * 4.04  Dec 29, 1996  -- Added CDROMREADRAW ioclt based on patch
+ *                          by Ales Makarov (xmakarov@sun.felk.cvut.cz)
+ *
+ * 4.05  Nov 20, 1997  -- Modified to print more drive info on init
+ *                        Minor other changes
+ *                        Fix errors on CDROMSTOP (If you have a "Dolphin",
+ *                          you must define IHAVEADOLPHIN)
+ *                        Added identifier so new Sanyo CD-changer works
+ *                        Better detection if door locking isn't supported
+ *
+ * 4.06  Dec 17, 1997  -- fixed endless "tray open" messages  -ml
+ * 4.07  Dec 17, 1997  -- fallback to set pc->stat on "tray open"
+ * 4.08  Dec 18, 1997  -- spew less noise when tray is empty
+ *                     -- fix speed display for ACER 24X, 18X
+ * 4.09  Jan 04, 1998  -- fix handling of the last block so we return
+ *                         an end of file instead of an I/O error (Gadi)
+ * 4.10  Jan 24, 1998  -- fixed a bug so now changers can change to a new
+ *                         slot when there is no disc in the current slot.
+ *                     -- Fixed a memory leak where info->changer_info was
+ *                         malloc'ed but never free'd when closing the device.
+ *                     -- Cleaned up the global namespace a bit by making more
+ *                         functions static that should already have been.
+ * 4.11  Mar 12, 1998  -- Added support for the CDROM_SELECT_SPEED ioctl
+ *                         based on a patch for 2.0.33 by Jelle Foks
+ *                         <jelle@scintilla.utwente.nl>, a patch for 2.0.33
+ *                         by Toni Giorgino <toni@pcape2.pi.infn.it>, the SCSI
+ *                         version, and my own efforts.  -erik
+ *                     -- Fixed a stupid bug which egcs was kind enough to
+ *                         inform me of where "Illegal mode for this track"
+ *                         was never returned due to a comparison on data
+ *                         types of limited range.
+ * 4.12  Mar 29, 1998  -- Fixed bug in CDROM_SELECT_SPEED so write speed is
+ *                         now set ionly for CD-R and CD-RW drives.  I had
+ *                         removed this support because it produced errors.
+ *                         It produced errors _only_ for non-writers. duh.
+ * 4.13  May 05, 1998  -- Suppress useless "in progress of becoming ready"
+ *                         messages, since this is not an error.
+ *                     -- Change error messages to be const
+ *                     -- Remove a "\t" which looks ugly in the syslogs
+ * 4.14  July 17, 1998 -- Change to pointing to .ps version of ATAPI spec
+ *                         since the .pdf version doesn't seem to work...
+ *                     -- Updated the TODO list to something more current.
+ *
+ * 4.15  Aug 25, 1998  -- Updated ide-cd.h to respect machine endianness,
+ *                         patch thanks to "Eddie C. Dost" <ecd@skynet.be>
+ *
+ * 4.50  Oct 19, 1998  -- New maintainers!
+ *                         Jens Axboe <axboe@image.dk>
+ *                         Chris Zwilling <chris@cloudnet.com>
+ *
+ * 4.51  Dec 23, 1998  -- Jens Axboe <axboe@image.dk>
+ *                      - ide_cdrom_reset enabled since the ide subsystem
+ *                         handles resets fine now. <axboe@image.dk>
+ *                      - Transfer size fix for Samsung CD-ROMs, thanks to
+ *                        "Ville Hallik" <ville.hallik@mail.ee>.
+ *                      - other minor stuff.
+ *
+ * 4.52  Jan 19, 1999  -- Jens Axboe <axboe@image.dk>
+ *                      - Detect DVD-ROM/RAM drives
+ *
+ * 4.53  Feb 22, 1999   - Include other model Samsung and one Goldstar
+ *                         drive in transfer size limit.
+ *                      - Fix the I/O error when doing eject without a medium
+ *                         loaded on some drives.
+ *                      - CDROMREADMODE2 is now implemented through
+ *                         CDROMREADRAW, since many drives don't support
+ *                         MODE2 (even though ATAPI 2.6 says they must).
+ *                      - Added ignore parameter to ide-cd (as a module), eg
+ *                         	insmod ide-cd ignore='hda hdb'
+ *                         Useful when using ide-cd in conjunction with
+ *                         ide-scsi. TODO: non-modular way of doing the
+ *                         same.
+ *
+ * 4.54  Aug 5, 1999	- Support for MMC2 class commands through the generic
+ *			  packet interface to cdrom.c.
+ *			- Unified audio ioctl support, most of it.
+ *			- cleaned up various deprecated verify_area().
+ *			- Added ide_cdrom_packet() as the interface for
+ *			  the Uniform generic_packet().
+ *			- bunch of other stuff, will fill in logs later.
+ *			- report 1 slot for non-changers, like the other
+ *			  cd-rom drivers. don't report select disc for
+ *			  non-changers as well.
+ *			- mask out audio playing, if the device can't do it.
+ *
+ * 4.55  Sep 1, 1999	- Eliminated the rest of the audio ioctls, except
+ *			  for CDROMREADTOC[ENTRY|HEADER]. Some of the drivers
+ *			  use this independently of the actual audio handling.
+ *			  They will disappear later when I get the time to
+ *			  do it cleanly.
+ *			- Minimize the TOC reading - only do it when we
+ *			  know a media change has occurred.
+ *			- Moved all the CDROMREADx ioctls to the Uniform layer.
+ *			- Heiko Eißfeldt <heiko@colossus.escape.de> supplied
+ *			  some fixes for CDI.
+ *			- CD-ROM leaving door locked fix from Andries
+ *			  Brouwer <Andries.Brouwer@cwi.nl>
+ *			- Erik Andersen <andersen@xmission.com> unified
+ *			  commands across the various drivers and how
+ *			  sense errors are handled.
+ *
+ * 4.56  Sep 12, 1999	- Removed changer support - it is now in the
+ *			  Uniform layer.
+ *			- Added partition based multisession handling.
+ *			- Mode sense and mode select moved to the
+ *			  Uniform layer.
+ *			- Fixed a problem with WPI CDS-32X drive - it
+ *			  failed the capabilities
+ *
+ * 4.57  Apr 7, 2000	- Fixed sense reporting.
+ *			- Fixed possible oops in ide_cdrom_get_last_session()
+ *			- Fix locking mania and make ide_cdrom_reset relock
+ *			- Stop spewing errors to log when magicdev polls with
+ *			  TEST_UNIT_READY on some drives.
+ *			- Various fixes from Tobias Ringstrom:
+ *			  tray if it was locked prior to the reset.
+ *			  - cdrom_read_capacity returns one frame too little.
+ *			  - Fix real capacity reporting.
+ *
+ * 4.58  May 1, 2000	- Clean up ACER50 stuff.
+ *			- Fix small problem with ide_cdrom_capacity
+ *
+ * 4.59  Aug 11, 2000	- Fix changer problem in cdrom_read_toc, we weren't
+ *			  correctly sensing a disc change.
+ *			- Rearranged some code
+ *			- Use extended sense on drives that support it for
+ *			  correctly reporting tray status -- from
+ *			  Michael D Johnson <johnsom@orst.edu>
+ * 4.60  Dec 17, 2003	- Add mt rainier support
+ *			- Bump timeout for packet commands, matches sr
+ *			- Odd stuff
+ * 4.61  Jan 22, 2004	- support hardware sector sizes other than 2kB,
+ *			  Pascal Schmidt <der.eremit@email.de>
+ */
diff --git a/Documentation/ide/ChangeLog.ide-floppy.1996-2002 b/Documentation/ide/ChangeLog.ide-floppy.1996-2002
new file mode 100644
index 000000000..46c19ef32
--- /dev/null
+++ b/Documentation/ide/ChangeLog.ide-floppy.1996-2002
@@ -0,0 +1,63 @@
+/*
+ * Many thanks to Lode Leroy <Lode.Leroy@www.ibase.be>, who tested so many
+ * ALPHA patches to this driver on an EASYSTOR LS-120 ATAPI floppy drive.
+ *
+ * Ver 0.1   Oct 17 96   Initial test version, mostly based on ide-tape.c.
+ * Ver 0.2   Oct 31 96   Minor changes.
+ * Ver 0.3   Dec  2 96   Fixed error recovery bug.
+ * Ver 0.4   Jan 26 97   Add support for the HDIO_GETGEO ioctl.
+ * Ver 0.5   Feb 21 97   Add partitions support.
+ *                       Use the minimum of the LBA and CHS capacities.
+ *                       Avoid hwgroup->rq == NULL on the last irq.
+ *                       Fix potential null dereferencing with DEBUG_LOG.
+ * Ver 0.8   Dec  7 97   Increase irq timeout from 10 to 50 seconds.
+ *                       Add media write-protect detection.
+ *                       Issue START command only if TEST UNIT READY fails.
+ *                       Add work-around for IOMEGA ZIP revision 21.D.
+ *                       Remove idefloppy_get_capabilities().
+ * Ver 0.9   Jul  4 99   Fix a bug which might have caused the number of
+ *                        bytes requested on each interrupt to be zero.
+ *                        Thanks to <shanos@es.co.nz> for pointing this out.
+ * Ver 0.9.sv Jan 6 01   Sam Varshavchik <mrsam@courier-mta.com>
+ *                       Implement low level formatting.  Reimplemented
+ *                       IDEFLOPPY_CAPABILITIES_PAGE, since we need the srfp
+ *                       bit.  My LS-120 drive barfs on
+ *                       IDEFLOPPY_CAPABILITIES_PAGE, but maybe it's just me.
+ *                       Compromise by not reporting a failure to get this
+ *                       mode page.  Implemented four IOCTLs in order to
+ *                       implement formatting.  IOCTls begin with 0x4600,
+ *                       0x46 is 'F' as in Format.
+ *            Jan 9 01   Userland option to select format verify.
+ *                       Added PC_SUPPRESS_ERROR flag - some idefloppy drives
+ *                       do not implement IDEFLOPPY_CAPABILITIES_PAGE, and
+ *                       return a sense error.  Suppress error reporting in
+ *                       this particular case in order to avoid spurious
+ *                       errors in syslog.  The culprit is
+ *                       idefloppy_get_capability_page(), so move it to
+ *                       idefloppy_begin_format() so that it's not used
+ *                       unless absolutely necessary.
+ *                       If drive does not support format progress indication
+ *                       monitor the dsc bit in the status register.
+ *                       Also, O_NDELAY on open will allow the device to be
+ *                       opened without a disk available.  This can be used to
+ *                       open an unformatted disk, or get the device capacity.
+ * Ver 0.91  Dec 11 99   Added IOMEGA Clik! drive support by
+ *     		   <paul@paulbristow.net>
+ * Ver 0.92  Oct 22 00   Paul Bristow became official maintainer for this
+ *           		   driver.  Included Powerbook internal zip kludge.
+ * Ver 0.93  Oct 24 00   Fixed bugs for Clik! drive
+ *                        no disk on insert and disk change now works
+ * Ver 0.94  Oct 27 00   Tidied up to remove strstr(Clik) everywhere
+ * Ver 0.95  Nov  7 00   Brought across to kernel 2.4
+ * Ver 0.96  Jan  7 01   Actually in line with release version of 2.4.0
+ *                       including set_bit patch from Rusty Russell
+ * Ver 0.97  Jul 22 01   Merge 0.91-0.96 onto 0.9.sv for ac series
+ * Ver 0.97.sv Aug 3 01  Backported from 2.4.7-ac3
+ * Ver 0.98  Oct 26 01   Split idefloppy_transfer_pc into two pieces to
+ *                        fix a lost interrupt problem. It appears the busy
+ *                        bit was being deasserted by my IOMEGA ATAPI ZIP 100
+ *                        drive before the drive was actually ready.
+ * Ver 0.98a Oct 29 01   Expose delay value so we can play.
+ * Ver 0.99  Feb 24 02   Remove duplicate code, modify clik! detection code
+ *                        to support new PocketZip drives
+ */
diff --git a/Documentation/ide/ChangeLog.ide-tape.1995-2002 b/Documentation/ide/ChangeLog.ide-tape.1995-2002
new file mode 100644
index 000000000..877fac877
--- /dev/null
+++ b/Documentation/ide/ChangeLog.ide-tape.1995-2002
@@ -0,0 +1,257 @@
+/*
+ * Ver 0.1   Nov  1 95   Pre-working code :-)
+ * Ver 0.2   Nov 23 95   A short backup (few megabytes) and restore procedure
+ *                        was successful ! (Using tar cvf ... on the block
+ *                        device interface).
+ *                       A longer backup resulted in major swapping, bad
+ *                        overall Linux performance and eventually failed as
+ *                        we received non serial read-ahead requests from the
+ *                        buffer cache.
+ * Ver 0.3   Nov 28 95   Long backups are now possible, thanks to the
+ *                        character device interface. Linux's responsiveness
+ *                        and performance doesn't seem to be much affected
+ *                        from the background backup procedure.
+ *                       Some general mtio.h magnetic tape operations are
+ *                        now supported by our character device. As a result,
+ *                        popular tape utilities are starting to work with
+ *                        ide tapes :-)
+ *                       The following configurations were tested:
+ *                       1. An IDE ATAPI TAPE shares the same interface
+ *                        and irq with an IDE ATAPI CDROM.
+ *                       2. An IDE ATAPI TAPE shares the same interface
+ *                        and irq with a normal IDE disk.
+ *                        Both configurations seemed to work just fine !
+ *                        However, to be on the safe side, it is meanwhile
+ *                        recommended to give the IDE TAPE its own interface
+ *                        and irq.
+ *                       The one thing which needs to be done here is to
+ *                        add a "request postpone" feature to ide.c,
+ *                        so that we won't have to wait for the tape to finish
+ *                        performing a long media access (DSC) request (such
+ *                        as a rewind) before we can access the other device
+ *                        on the same interface. This effect doesn't disturb
+ *                        normal operation most of the time because read/write
+ *                        requests are relatively fast, and once we are
+ *                        performing one tape r/w request, a lot of requests
+ *                        from the other device can be queued and ide.c will
+ *			  service all of them after this single tape request.
+ * Ver 1.0   Dec 11 95   Integrated into Linux 1.3.46 development tree.
+ *                       On each read / write request, we now ask the drive
+ *                        if we can transfer a constant number of bytes
+ *                        (a parameter of the drive) only to its buffers,
+ *                        without causing actual media access. If we can't,
+ *                        we just wait until we can by polling the DSC bit.
+ *                        This ensures that while we are not transferring
+ *                        more bytes than the constant referred to above, the
+ *                        interrupt latency will not become too high and
+ *                        we won't cause an interrupt timeout, as happened
+ *                        occasionally in the previous version.
+ *                       While polling for DSC, the current request is
+ *                        postponed and ide.c is free to handle requests from
+ *                        the other device. This is handled transparently to
+ *                        ide.c. The hwgroup locking method which was used
+ *                        in the previous version was removed.
+ *                       Use of new general features which are provided by
+ *                        ide.c for use with atapi devices.
+ *                        (Programming done by Mark Lord)
+ *                       Few potential bug fixes (Again, suggested by Mark)
+ *                       Single character device data transfers are now
+ *                        not limited in size, as they were before.
+ *                       We are asking the tape about its recommended
+ *                        transfer unit and send a larger data transfer
+ *                        as several transfers of the above size.
+ *                        For best results, use an integral number of this
+ *                        basic unit (which is shown during driver
+ *                        initialization). I will soon add an ioctl to get
+ *                        this important parameter.
+ *                       Our data transfer buffer is allocated on startup,
+ *                        rather than before each data transfer. This should
+ *                        ensure that we will indeed have a data buffer.
+ * Ver 1.1   Dec 14 95   Fixed random problems which occurred when the tape
+ *                        shared an interface with another device.
+ *                        (poll_for_dsc was a complete mess).
+ *                       Removed some old (non-active) code which had
+ *                        to do with supporting buffer cache originated
+ *                        requests.
+ *                       The block device interface can now be opened, so
+ *                        that general ide driver features like the unmask
+ *                        interrupts flag can be selected with an ioctl.
+ *                        This is the only use of the block device interface.
+ *                       New fast pipelined operation mode (currently only on
+ *                        writes). When using the pipelined mode, the
+ *                        throughput can potentially reach the maximum
+ *                        tape supported throughput, regardless of the
+ *                        user backup program. On my tape drive, it sometimes
+ *                        boosted performance by a factor of 2. Pipelined
+ *                        mode is enabled by default, but since it has a few
+ *                        downfalls as well, you may want to disable it.
+ *                        A short explanation of the pipelined operation mode
+ *                        is available below.
+ * Ver 1.2   Jan  1 96   Eliminated pipelined mode race condition.
+ *                       Added pipeline read mode. As a result, restores
+ *                        are now as fast as backups.
+ *                       Optimized shared interface behavior. The new behavior
+ *                        typically results in better IDE bus efficiency and
+ *                        higher tape throughput.
+ *                       Pre-calculation of the expected read/write request
+ *                        service time, based on the tape's parameters. In
+ *                        the pipelined operation mode, this allows us to
+ *                        adjust our polling frequency to a much lower value,
+ *                        and thus to dramatically reduce our load on Linux,
+ *                        without any decrease in performance.
+ *                       Implemented additional mtio.h operations.
+ *                       The recommended user block size is returned by
+ *                        the MTIOCGET ioctl.
+ *                       Additional minor changes.
+ * Ver 1.3   Feb  9 96   Fixed pipelined read mode bug which prevented the
+ *                        use of some block sizes during a restore procedure.
+ *                       The character device interface will now present a
+ *                        continuous view of the media - any mix of block sizes
+ *                        during a backup/restore procedure is supported. The
+ *                        driver will buffer the requests internally and
+ *                        convert them to the tape's recommended transfer
+ *                        unit, making performance almost independent of the
+ *                        chosen user block size.
+ *                       Some improvements in error recovery.
+ *                       By cooperating with ide-dma.c, bus mastering DMA can
+ *                        now sometimes be used with IDE tape drives as well.
+ *                        Bus mastering DMA has the potential to dramatically
+ *                        reduce the CPU's overhead when accessing the device,
+ *                        and can be enabled by using hdparm -d1 on the tape's
+ *                        block device interface. For more info, read the
+ *                        comments in ide-dma.c.
+ * Ver 1.4   Mar 13 96   Fixed serialize support.
+ * Ver 1.5   Apr 12 96   Fixed shared interface operation, broken in 1.3.85.
+ *                       Fixed pipelined read mode inefficiency.
+ *                       Fixed nasty null dereferencing bug.
+ * Ver 1.6   Aug 16 96   Fixed FPU usage in the driver.
+ *                       Fixed end of media bug.
+ * Ver 1.7   Sep 10 96   Minor changes for the CONNER CTT8000-A model.
+ * Ver 1.8   Sep 26 96   Attempt to find a better balance between good
+ *                        interactive response and high system throughput.
+ * Ver 1.9   Nov  5 96   Automatically cross encountered filemarks rather
+ *                        than requiring an explicit FSF command.
+ *                       Abort pending requests at end of media.
+ *                       MTTELL was sometimes returning incorrect results.
+ *                       Return the real block size in the MTIOCGET ioctl.
+ *                       Some error recovery bug fixes.
+ * Ver 1.10  Nov  5 96   Major reorganization.
+ *                       Reduced CPU overhead a bit by eliminating internal
+ *                        bounce buffers.
+ *                       Added module support.
+ *                       Added multiple tape drives support.
+ *                       Added partition support.
+ *                       Rewrote DSC handling.
+ *                       Some portability fixes.
+ *                       Removed ide-tape.h.
+ *                       Additional minor changes.
+ * Ver 1.11  Dec  2 96   Bug fix in previous DSC timeout handling.
+ *                       Use ide_stall_queue() for DSC overlap.
+ *                       Use the maximum speed rather than the current speed
+ *                        to compute the request service time.
+ * Ver 1.12  Dec  7 97   Fix random memory overwriting and/or last block data
+ *                        corruption, which could occur if the total number
+ *                        of bytes written to the tape was not an integral
+ *                        number of tape blocks.
+ *                       Add support for INTERRUPT DRQ devices.
+ * Ver 1.13  Jan  2 98   Add "speed == 0" work-around for HP COLORADO 5GB
+ * Ver 1.14  Dec 30 98   Partial fixes for the Sony/AIWA tape drives.
+ *                       Replace cli()/sti() with hwgroup spinlocks.
+ * Ver 1.15  Mar 25 99   Fix SMP race condition by replacing hwgroup
+ *                        spinlock with private per-tape spinlock.
+ * Ver 1.16  Sep  1 99   Add OnStream tape support.
+ *                       Abort read pipeline on EOD.
+ *                       Wait for the tape to become ready in case it returns
+ *                        "in the process of becoming ready" on open().
+ *                       Fix zero padding of the last written block in
+ *                        case the tape block size is larger than PAGE_SIZE.
+ *                       Decrease the default disconnection time to tn.
+ * Ver 1.16e Oct  3 99   Minor fixes.
+ * Ver 1.16e1 Oct 13 99  Patches by Arnold Niessen,
+ *                          niessen@iae.nl / arnold.niessen@philips.com
+ *                   GO-1)  Undefined code in idetape_read_position
+ *				according to Gadi's email
+ *                   AJN-1) Minor fix asc == 11 should be asc == 0x11
+ *                               in idetape_issue_packet_command (did effect
+ *                               debugging output only)
+ *                   AJN-2) Added more debugging output, and
+ *                              added ide-tape: where missing. I would also
+ *				like to add tape->name where possible
+ *                   AJN-3) Added different debug_level's
+ *                              via /proc/ide/hdc/settings
+ *				"debug_level" determines amount of debugging output;
+ *				can be changed using /proc/ide/hdx/settings
+ *				0 : almost no debugging output
+ *				1 : 0+output errors only
+ *				2 : 1+output all sensekey/asc
+ *				3 : 2+follow all chrdev related procedures
+ *				4 : 3+follow all procedures
+ *				5 : 4+include pc_stack rq_stack info
+ *				6 : 5+USE_COUNT updates
+ *                   AJN-4) Fixed timeout for retension in idetape_queue_pc_tail
+ *				from 5 to 10 minutes
+ *                   AJN-5) Changed maximum number of blocks to skip when
+ *                              reading tapes with multiple consecutive write
+ *                              errors from 100 to 1000 in idetape_get_logical_blk
+ *                   Proposed changes to code:
+ *                   1) output "logical_blk_num" via /proc
+ *                   2) output "current_operation" via /proc
+ *                   3) Either solve or document the fact that `mt rewind' is
+ *                      required after reading from /dev/nhtx to be
+ *			able to rmmod the idetape module;
+ *			Also, sometimes an application finishes but the
+ *			device remains `busy' for some time. Same cause ?
+ *                   Proposed changes to release-notes:
+ *		     4) write a simple `quickstart' section in the
+ *                      release notes; I volunteer if you don't want to
+ *		     5) include a pointer to video4linux in the doc
+ *                      to stimulate video applications
+ *                   6) release notes lines 331 and 362: explain what happens
+ *			if the application data rate is higher than 1100 KB/s;
+ *			similar approach to lower-than-500 kB/s ?
+ *		     7) 6.6 Comparison; wouldn't it be better to allow different
+ *			strategies for read and write ?
+ *			Wouldn't it be better to control the tape buffer
+ *			contents instead of the bandwidth ?
+ *		     8) line 536: replace will by would (if I understand
+ *			this section correctly, a hypothetical and unwanted situation
+ *			 is being described)
+ * Ver 1.16f Dec 15 99   Change place of the secondary OnStream header frames.
+ * Ver 1.17  Nov 2000 / Jan 2001  Marcel Mol, marcel@mesa.nl
+ *			- Add idetape_onstream_mode_sense_tape_parameter_page
+ *			  function to get tape capacity in frames: tape->capacity.
+ *			- Add support for DI-50 drives( or any DI- drive).
+ *			- 'workaround' for read error/blank block around block 3000.
+ *			- Implement Early warning for end of media for Onstream.
+ *			- Cosmetic code changes for readability.
+ *			- Idetape_position_tape should not use SKIP bit during
+ *			  Onstream read recovery.
+ *			- Add capacity, logical_blk_num and first/last_frame_position
+ *			  to /proc/ide/hd?/settings.
+ *			- Module use count was gone in the Linux 2.4 driver.
+ * Ver 1.17a Apr 2001 Willem Riede osst@riede.org
+ *			- Get drive's actual block size from mode sense block descriptor
+ *			- Limit size of pipeline
+ * Ver 1.17b Oct 2002   Alan Stern <stern@rowland.harvard.edu>
+ *			Changed IDETAPE_MIN_PIPELINE_STAGES to 1 and actually used
+ *			 it in the code!
+ *			Actually removed aborted stages in idetape_abort_pipeline
+ *			 instead of just changing the command code.
+ *			Made the transfer byte count for Request Sense equal to the
+ *			 actual length of the data transfer.
+ *			Changed handling of partial data transfers: they do not
+ *			 cause DMA errors.
+ *			Moved initiation of DMA transfers to the correct place.
+ *			Removed reference to unallocated memory.
+ *			Made __idetape_discard_read_pipeline return the number of
+ *			 sectors skipped, not the number of stages.
+ *			Replaced errant kfree() calls with __idetape_kfree_stage().
+ *			Fixed off-by-one error in testing the pipeline length.
+ *			Fixed handling of filemarks in the read pipeline.
+ *			Small code optimization for MTBSF and MTBSFM ioctls.
+ *			Don't try to unlock the door during device close if is
+ *			 already unlocked!
+ *			Cosmetic fixes to miscellaneous debugging output messages.
+ *			Set the minimum /proc/ide/hd?/settings values for "pipeline",
+ *			 "pipeline_min", and "pipeline_max" to 1.
+ */
diff --git a/Documentation/ide/ide-tape.txt b/Documentation/ide/ide-tape.txt
new file mode 100644
index 000000000..3f348a0b2
--- /dev/null
+++ b/Documentation/ide/ide-tape.txt
@@ -0,0 +1,65 @@
+IDE ATAPI streaming tape driver.
+
+This driver is a part of the Linux ide driver.
+
+The driver, in co-operation with ide.c, basically traverses the
+request-list for the block device interface. The character device
+interface, on the other hand, creates new requests, adds them
+to the request-list of the block device, and waits for their completion.
+
+The block device major and minor numbers are determined from the
+tape's relative position in the ide interfaces, as explained in ide.c.
+
+The character device interface consists of the following devices:
+
+ht0		major 37, minor 0	first  IDE tape, rewind on close.
+ht1		major 37, minor 1	second IDE tape, rewind on close.
+...
+nht0		major 37, minor 128	first  IDE tape, no rewind on close.
+nht1		major 37, minor 129	second IDE tape, no rewind on close.
+...
+
+The general magnetic tape commands compatible interface, as defined by
+include/linux/mtio.h, is accessible through the character device.
+
+General ide driver configuration options, such as the interrupt-unmask
+flag, can be configured by issuing an ioctl to the block device interface,
+as any other ide device.
+
+Our own ide-tape ioctl's can be issued to either the block device or
+the character device interface.
+
+Maximal throughput with minimal bus load will usually be achieved in the
+following scenario:
+
+     1.	ide-tape is operating in the pipelined operation mode.
+     2.	No buffering is performed by the user backup program.
+
+Testing was done with a 2 GB CONNER CTMA 4000 IDE ATAPI Streaming Tape Drive.
+
+Here are some words from the first releases of hd.c, which are quoted
+in ide.c and apply here as well:
+
+| Special care is recommended.  Have Fun!
+
+Possible improvements:
+
+1. Support for the ATAPI overlap protocol.
+
+In order to maximize bus throughput, we currently use the DSC
+overlap method which enables ide.c to service requests from the
+other device while the tape is busy executing a command. The
+DSC overlap method involves polling the tape's status register
+for the DSC bit, and servicing the other device while the tape
+isn't ready.
+
+In the current QIC development standard (December 1995),
+it is recommended that new tape drives will *in addition*
+implement the ATAPI overlap protocol, which is used for the
+same purpose - efficient use of the IDE bus, but is interrupt
+driven and thus has much less CPU overhead.
+
+ATAPI overlap is likely to be supported in most new ATAPI
+devices, including new ATAPI cdroms, and thus provides us
+a method by which we can achieve higher throughput when
+sharing a (fast) ATA-2 disk with any (slow) new ATAPI device.
diff --git a/Documentation/ide/ide.txt b/Documentation/ide/ide.txt
new file mode 100644
index 000000000..7aca987c2
--- /dev/null
+++ b/Documentation/ide/ide.txt
@@ -0,0 +1,256 @@
+
+	Information regarding the Enhanced IDE drive in Linux 2.6
+
+==============================================================================
+
+
+   The hdparm utility can be used to control various IDE features on a
+   running system. It is packaged separately.  Please Look for it on popular
+   linux FTP sites.
+
+
+
+***  IMPORTANT NOTICES:  BUGGY IDE CHIPSETS CAN CORRUPT DATA!!
+***  =================
+***  PCI versions of the CMD640 and RZ1000 interfaces are now detected
+***  automatically at startup when PCI BIOS support is configured.
+***
+***  Linux disables the "prefetch" ("readahead") mode of the RZ1000
+***  to prevent data corruption possible due to hardware design flaws.
+***
+***  For the CMD640, linux disables "IRQ unmasking" (hdparm -u1) on any
+***  drive for which the "prefetch" mode of the CMD640 is turned on.
+***  If "prefetch" is disabled (hdparm -p8), then "IRQ unmasking" can be
+***  used again.
+***
+***  For the CMD640, linux disables "32bit I/O" (hdparm -c1) on any drive
+***  for which the "prefetch" mode of the CMD640 is turned off.
+***  If "prefetch" is enabled (hdparm -p9), then "32bit I/O" can be
+***  used again.
+***
+***  The CMD640 is also used on some Vesa Local Bus (VLB) cards, and is *NOT*
+***  automatically detected by Linux.  For safe, reliable operation with such
+***  interfaces, one *MUST* use the "cmd640.probe_vlb" kernel option.
+***
+***  Use of the "serialize" option is no longer necessary.
+
+================================================================================
+Common pitfalls:
+
+- 40-conductor IDE cables are capable of transferring data in DMA modes up to
+  udma2, but no faster.
+
+- If possible devices should be attached to separate channels if they are
+  available. Typically the disk on the first and CD-ROM on the second.
+
+- If you mix devices on the same cable, please consider using similar devices
+  in respect of the data transfer mode they support.
+
+- Even better try to stick to the same vendor and device type on the same
+  cable.
+
+================================================================================
+
+This is the multiple IDE interface driver, as evolved from hd.c.
+
+It supports up to 9 IDE interfaces per default, on one or more IRQs (usually
+14 & 15).  There can be up to two drives per interface, as per the ATA-6 spec.
+
+Primary:    ide0, port 0x1f0; major=3;  hda is minor=0; hdb is minor=64
+Secondary:  ide1, port 0x170; major=22; hdc is minor=0; hdd is minor=64
+Tertiary:   ide2, port 0x1e8; major=33; hde is minor=0; hdf is minor=64
+Quaternary: ide3, port 0x168; major=34; hdg is minor=0; hdh is minor=64
+fifth..     ide4, usually PCI, probed
+sixth..     ide5, usually PCI, probed
+
+To access devices on interfaces > ide0, device entries please make sure that
+device files for them are present in /dev.  If not, please create such
+entries, by using /dev/MAKEDEV.
+
+This driver automatically probes for most IDE interfaces (including all PCI
+ones), for the drives/geometries attached to those interfaces, and for the IRQ
+lines being used by the interfaces (normally 14, 15 for ide0/ide1).
+
+Any number of interfaces may share a single IRQ if necessary, at a slight
+performance penalty, whether on separate cards or a single VLB card.
+The IDE driver automatically detects and handles this.  However, this may
+or may not be harmful to your hardware.. two or more cards driving the same IRQ
+can potentially burn each other's bus driver, though in practice this
+seldom occurs.  Be careful, and if in doubt, don't do it!
+
+Drives are normally found by auto-probing and/or examining the CMOS/BIOS data.
+For really weird situations, the apparent (fdisk) geometry can also be specified
+on the kernel "command line" using LILO.  The format of such lines is:
+
+	ide_core.chs=[interface_number.device_number]:cyls,heads,sects
+or	ide_core.cdrom=[interface_number.device_number]
+
+For example:
+
+	ide_core.chs=1.0:1050,32,64  ide_core.cdrom=1.1
+
+The results of successful auto-probing may override the physical geometry/irq
+specified, though the "original" geometry may be retained as the "logical"
+geometry for partitioning purposes (fdisk).
+
+If the auto-probing during boot time confuses a drive (ie. the drive works
+with hd.c but not with ide.c), then an command line option may be specified
+for each drive for which you'd like the drive to skip the hardware
+probe/identification sequence.  For example:
+
+	ide_core.noprobe=0.1
+or
+	ide_core.chs=1.0:768,16,32
+	ide_core.noprobe=1.0
+
+Note that when only one IDE device is attached to an interface, it should be
+jumpered as "single" or "master", *not* "slave".  Many folks have had
+"trouble" with cdroms because of this requirement, so the driver now probes
+for both units, though success is more likely when the drive is jumpered
+correctly.
+
+Courtesy of Scott Snyder and others, the driver supports ATAPI cdrom drives
+such as the NEC-260 and the new MITSUMI triple/quad speed drives.
+Such drives will be identified at boot time, just like a hard disk.
+
+If for some reason your cdrom drive is *not* found at boot time, you can force
+the probe to look harder by supplying a kernel command line parameter
+via LILO, such as:
+
+	ide_core.cdrom=1.0	/* "master" on second interface (hdc) */
+or
+	ide_core.cdrom=1.1	/* "slave" on second interface (hdd) */
+
+For example, a GW2000 system might have a hard drive on the primary
+interface (/dev/hda) and an IDE cdrom drive on the secondary interface
+(/dev/hdc).  To mount a CD in the cdrom drive, one would use something like:
+
+	ln -sf /dev/hdc /dev/cdrom
+	mkdir /mnt/cdrom
+	mount /dev/cdrom /mnt/cdrom -t iso9660 -o ro
+
+If, after doing all of the above, mount doesn't work and you see
+errors from the driver (with dmesg) complaining about `status=0xff',
+this means that the hardware is not responding to the driver's attempts
+to read it.  One of the following is probably the problem:
+
+  - Your hardware is broken.
+
+  - You are using the wrong address for the device, or you have the
+    drive jumpered wrong.  Review the configuration instructions above.
+
+  - Your IDE controller requires some nonstandard initialization sequence
+    before it will work properly.  If this is the case, there will often
+    be a separate MS-DOS driver just for the controller.  IDE interfaces
+    on sound cards usually fall into this category.  Such configurations
+    can often be made to work by first booting MS-DOS, loading the
+    appropriate drivers, and then warm-booting linux (without powering
+    off).  This can be automated using loadlin in the MS-DOS autoexec.
+
+If you always get timeout errors, interrupts from the drive are probably
+not making it to the host.  Check how you have the hardware jumpered
+and make sure it matches what the driver expects (see the configuration
+instructions above).  If you have a PCI system, also check the BIOS
+setup; I've had one report of a system which was shipped with IRQ 15
+disabled by the BIOS.
+
+The kernel is able to execute binaries directly off of the cdrom,
+provided it is mounted with the default block size of 1024 (as above).
+
+Please pass on any feedback on any of this stuff to the maintainer,
+whose address can be found in linux/MAINTAINERS.
+
+The IDE driver is modularized.  The high level disk/CD-ROM/tape/floppy
+drivers can always be compiled as loadable modules, the chipset drivers
+can only be compiled into the kernel, and the core code (ide.c) can be
+compiled as a loadable module provided no chipset support is needed.
+
+When using ide.c as a module in combination with kmod, add:
+
+	alias block-major-3 ide-probe
+
+to a configuration file in /etc/modprobe.d/.
+
+When ide.c is used as a module, you can pass command line parameters to the
+driver using the "options=" keyword to insmod, while replacing any ',' with
+';'.
+
+
+================================================================================
+
+Summary of ide driver parameters for kernel command line
+--------------------------------------------------------
+
+For legacy IDE VLB host drivers (ali14xx/dtc2278/ht6560b/qd65xx/umc8672)
+you need to explicitly enable probing by using "probe" kernel parameter,
+i.e. to enable probing for ALI M14xx chipsets (ali14xx host driver) use:
+
+* "ali14xx.probe" boot option when ali14xx driver is built-in the kernel
+
+* "probe" module parameter when ali14xx driver is compiled as module
+  ("modprobe ali14xx probe")
+
+Also for legacy CMD640 host driver (cmd640) you need to use "probe_vlb"
+kernel paremeter to enable probing for VLB version of the chipset (PCI ones
+are detected automatically).
+
+You also need to use "probe" kernel parameter for ide-4drives driver
+(support for IDE generic chipset with four drives on one port).
+
+To enable support for IDE doublers on Amiga use "doubler" kernel parameter
+for gayle host driver (i.e. "gayle.doubler" if the driver is built-in).
+
+To force ignoring cable detection (this should be needed only if you're using
+short 40-wires cable which cannot be automatically detected - if this is not
+a case please report it as a bug instead) use "ignore_cable" kernel parameter:
+
+* "ide_core.ignore_cable=[interface_number]" boot option if IDE is built-in
+  (i.e. "ide_core.ignore_cable=1" to force ignoring cable for "ide1")
+
+* "ignore_cable=[interface_number]" module parameter (for ide_core module)
+  if IDE is compiled as module
+
+Other kernel parameters for ide_core are:
+
+* "nodma=[interface_number.device_number]" to disallow DMA for a device
+
+* "noflush=[interface_number.device_number]" to disable flush requests
+
+* "nohpa=[interface_number.device_number]" to disable Host Protected Area
+
+* "noprobe=[interface_number.device_number]" to skip probing
+
+* "nowerr=[interface_number.device_number]" to ignore the WRERR_STAT bit
+
+* "cdrom=[interface_number.device_number]" to force device as a CD-ROM
+
+* "chs=[interface_number.device_number]" to force device as a disk (using CHS)
+
+================================================================================
+
+Some Terminology
+----------------
+IDE = Integrated Drive Electronics, meaning that each drive has a built-in
+controller, which is why an "IDE interface card" is not a "controller card".
+
+ATA = AT (the old IBM 286 computer) Attachment Interface, a draft American
+National Standard for connecting hard drives to PCs.  This is the official
+name for "IDE".
+
+The latest standards define some enhancements, known as the ATA-6 spec,
+which grew out of vendor-specific "Enhanced IDE" (EIDE) implementations.
+
+ATAPI = ATA Packet Interface, a new protocol for controlling the drives,
+similar to SCSI protocols, created at the same time as the ATA2 standard.
+ATAPI is currently used for controlling CDROM, TAPE and FLOPPY (ZIP or
+LS120/240) devices, removable R/W cartridges, and for high capacity hard disk
+drives.
+
+mlord@pobox.com
+--
+
+Wed Apr 17 22:52:44 CEST 2002 edited by Marcin Dalecki, the current
+maintainer.
+
+Wed Aug 20 22:31:29 CEST 2003 updated ide boot options to current ide.c
+comments at 2.6.0-test4 time. Maciej Soltysiak <solt@dns.toxicfilms.tv>
diff --git a/Documentation/ide/warm-plug-howto.txt b/Documentation/ide/warm-plug-howto.txt
new file mode 100644
index 000000000..98152bcd5
--- /dev/null
+++ b/Documentation/ide/warm-plug-howto.txt
@@ -0,0 +1,18 @@
+
+IDE warm-plug HOWTO
+===================
+
+To warm-plug devices on a port 'idex':
+
+# echo -n "1" > /sys/class/ide_port/idex/delete_devices
+
+unplug old device(s) and plug new device(s)
+
+# echo -n "1" > /sys/class/ide_port/idex/scan
+
+done
+
+NOTE: please make sure that partitions are unmounted and that there are
+no other active references to devices before doing "delete_devices" step,
+also do not attempt "scan" step on devices currently in use -- otherwise
+results may be unpredictable and lead to data loss if you're unlucky