sa(4) driver changes available for test
Dan Langille
dan at langille.org
Mon Mar 2 00:28:40 UTC 2015
> On Mar 1, 2015, at 7:18 PM, Kenneth D. Merry <ken at FreeBSD.ORG> wrote:
>
> On Sun, Mar 01, 2015 at 17:06:24 -0500, Dan Langille wrote:
>>
>>> On Feb 13, 2015, at 7:32 PM, Kenneth D. Merry <ken at freebsd.org> wrote:
>>>
>>>
>>> I have a fairly large set of changes to the sa(4) driver and mt(1) driver
>>> that I'm planning to commit in the near future.
>>>
>>> A description of the changes is here and below in this message.
>>>
>>> If you have tape hardware and the inclination, I'd appreciate testing and
>>> feedback.
>>>
>>> ============
>>> Rough draft commit message:
>>>
>>> http://people.freebsd.org/~ken/sa_changes_commitmsg.20150213.3.txt
>>>
>>> The patches against FreeBSD/head as of SVN revision 278706:
>>>
>>> http://people.freebsd.org/~ken/sa_changes.20150213.3.txt
>>>
>>> And (untested) patches against FreeBSD stable/10 as of SVN revision 278721.
>>>
>>> http://people.freebsd.org/~ken/sa_changes.stable_10.20150213.3.txt
>>> ============
>>>
>>> The intent is to get the tape infrastructure more up to date, so we can
>>> support LTFS and more modern tape drives:
>>>
>>> http://www.ibm.com/systems/storage/tape/ltfs/
>>>
>>> I have ported IBM's LTFS Single Drive Edition to FreeBSD. The port depends
>>> on the patches linked above. It isn't fully cleaned up and ready for
>>> redistribution. If you're interested, though, let me know and I'll tell
>>> you when it is ready to go out. You need an IBM LTO-5, LTO-6, TS1140 or
>>> TS1150 tape drive. HP drives aren't supported by IBM's LTFS, and older
>>> drives don't have the necessary features to support LTFS.
>>>
>>> The commit message below outlines most of the changes.
>>>
>>> A few comments:
>>>
>>> 1. I'm planning to commit the XPT_DEV_ADVINFO changes separately.
>>>
>>> 2. The XML output is similar to what GEOM and CTL do. It would be nice to
>>> figure out how to put a standard schema on it so that standard tools
>>> could read it. I don't know how feasible that is, since I haven't
>>> time to dig into it. If anyone has suggestions on whether that is
>>> feasible or advisable, I'd appreciate feedback.
>>>
>>> 3. I have tested with a reasonable amount of tape hardware (see below for a
>>> list), but more testing and feedback would be good.
>>>
>>> 4. Standard 'mt status' output looks like this:
>>>
>>> # mt -f /dev/nsa3 status -v
>>> Drive: sa3: <IBM ULTRIUM-HH6 E4J1> Serial Number: 101500520A
>>> ---------------------------------
>>> Mode Density Blocksize bpi Compression
>>> Current: 0x5a:LTO-6 variable 384607 enabled (0xff)
>>> ---------------------------------
>>> Current Driver State: at rest.
>>> ---------------------------------
>>> Partition: 0 Calc File Number: 0 Calc Record Number: 0
>>> Residual: 0 Reported File Number: 0 Reported Record Number: 0
>>> Flags: BOP
>>>
>>> 5. 'mt status -v' looks like this:
>>>
>>> # mt -f /dev/nsa3 status -v
>>> Drive: sa3: <IBM ULTRIUM-HH6 E4J1> Serial Number: 101500520A
>>> ---------------------------------
>>> Mode Density Blocksize bpi Compression
>>> Current: 0x5a:LTO-6 variable 384607 enabled (0xff)
>>> ---------------------------------
>>> Current Driver State: at rest.
>>> ---------------------------------
>>> Partition: 0 Calc File Number: 0 Calc Record Number: 0
>>> Residual: 0 Reported File Number: 0 Reported Record Number: 0
>>> Flags: BOP
>>> ---------------------------------
>>> Tape I/O parameters:
>>> Maximum I/O size allowed by driver and controller (maxio): 1081344 bytes
>>> Maximum I/O size reported by controller (cpi_maxio): 5197824 bytes
>>> Maximum block size supported by tape drive and media (max_blk): 8388608 bytes
>>> Minimum block size supported by tape drive and media (min_blk): 1 bytes
>>> Block granularity supported by tape drive and media (blk_gran): 0 bytes
>>> Maximum possible I/O size (max_effective_iosize): 1081344 bytes
>>
>>
>> # mtx -f /dev/pass0 status
>> Storage Changer /dev/pass0:2 Drives, 10 Slots ( 0 Import/Export )
>> Data Transfer Element 0:Empty
>> Data Transfer Element 1:Empty
>> Storage Element 1:Empty
>> Storage Element 2:Empty
>> Storage Element 3:Empty
>> Storage Element 4:Full :VolumeTag=FAI260
>> Storage Element 5:Full :VolumeTag=FAI261
>> Storage Element 6:Full :VolumeTag=FAI262
>> Storage Element 7:Full :VolumeTag=FAI263
>> Storage Element 8:Empty
>> Storage Element 9:Empty
>> Storage Element 10:Empty
>>
>>
>> It was at this point I spent the next 90 minute trying to get the tape
>> drive out of the tape library to free a stuck tape. Some of this was spent
>> attempting, and failing, to undo a stripped screw. I stopped the attempt when
>> I noticed the screw did need to be removed. :/
>
> Thanks for all of the effort! Looks like it is paying off! :)
>
>> When I do this command, I hear the drive move a bit, to read the tape:
>>
>> # mt -f /dev/nsa1 status
>> Drive: sa1: <DEC TZ89 (C) DEC 2561> Serial Number: CXA09S1340
>> ---------------------------------
>> Mode Density Blocksize bpi Compression
>> Current: 0x1b:DLTapeIV(35GB) variable 85937 enabled (IDRC)
>> ---------------------------------
>> Current Driver State: at rest.
>> ---------------------------------
>> Partition: 0 Calc File Number: 0 Calc Record Number: 0
>> Residual: 0 Reported File Number: -1 Reported Record Number: -1
>> Flags: None
>
> Looks like the drive isn't reporting position information. It will still
> be useful to try it with Bacula, though.
>
>> # mt -f /dev/nsa1 ostatus
>> Mode Density Blocksize bpi Compression
>> Current: 0x1b:DLTapeIV(35GB) variable 85937 IDRC
>> ---------available modes---------
>> 0: 0x1b:DLTapeIV(35GB) variable 85937 IDRC
>> 1: 0x1b:DLTapeIV(35GB) variable 85937 IDRC
>> 2: 0x1b:DLTapeIV(35GB) variable 85937 IDRC
>> 3: 0x1b:DLTapeIV(35GB) variable 85937 IDRC
>> ---------------------------------
>> Current Driver State: at rest.
>> ---------------------------------
>> File Number: 0 Record Number: 0 Residual Count 0
>>
>>
>> After doing a very small tar -c and tar -x, I have:
>>
>> # mt -f /dev/nsa1 /dev/nsa1 ostatus
>> Mode Density Blocksize bpi Compression
>> Current: 0x1b:DLTapeIV(35GB) variable 85937 IDRC
>> ---------available modes---------
>> 0: 0x1b:DLTapeIV(35GB) variable 85937 IDRC
>> 1: 0x1b:DLTapeIV(35GB) variable 85937 IDRC
>> 2: 0x1b:DLTapeIV(35GB) variable 85937 IDRC
>> 3: 0x1b:DLTapeIV(35GB) variable 85937 IDRC
>> ---------------------------------
>> Current Driver State: at rest.
>> ---------------------------------
>> File Number: 0 Record Number: 7 Residual Count 0
>
> Woohoo! It works.
>
>> # mt -f /dev/nsa1 status -v
>> Drive: sa1: <DEC TZ89 (C) DEC 2561> Serial Number: CXA09S1340
>> ---------------------------------
>> Mode Density Blocksize bpi Compression
>> Current: 0x1b:DLTapeIV(35GB) variable 85937 enabled (IDRC)
>> ---------------------------------
>> Current Driver State: at rest.
>> ---------------------------------
>> Partition: 0 Calc File Number: 0 Calc Record Number: 7
>> Residual: 0 Reported File Number: -1 Reported Record Number: -1
>> Flags: None
>> ---------------------------------
>> Tape I/O parameters:
>> Maximum I/O size allowed by driver and controller (maxio): 65536 bytes
>> Maximum I/O size reported by controller (cpi_maxio): 0 bytes
>> Maximum block size supported by tape drive and media (max_blk): 16777214 bytes
>> Minimum block size supported by tape drive and media (min_blk): 2 bytes
>> Block granularity supported by tape drive and media (blk_gran): 0 bytes
>> Maximum possible I/O size (max_effective_iosize): 65536 bytes
>>
>> I may not get to testing Bacula today.
>>
>> Based on the above, is there any commands you'd like me to try?
>
> Aside from making sure things work okay with Bacula, that is probably
> sufficient. These drives won't support density reports or position
> information.
>
>> Read below regarding two tape drives
>>
>>>
>>> 6. Existing applications should work without changes. If not, please let
>>> me know. Hopefully they will move over time to the new interfaces.
>>>
>>> 7. There are lots of additional features that could be added later.
>>> Append-only support, encryption, more log pages, etc.
>>>
>>> 8. I have SCSI READ ATTRIBUTE changes for camcontrol(8) that will go in
>>> separately. These changes allow displaying the contents of the MAM
>>> (Medium Auxiliary Memory) chips on LTO, TS and other modern tape drives.
>>> These are good, and a future possible direction is adding attributes
>>> to the status XML from the sa(4) driver.
>>>
>>> ============
>>> Significant upgrades to sa(4) and mt(1).
>>>
>>> The primary focus of these changes is to modernize FreeBSD's
>>> tape infrastructure so that we can take advantage of some of the
>>> features of modern tape drives and allow support for LTFS.
>>>
>>> Significant changes and new features include:
>>>
>>> o sa(4) driver status and parameter information is now exported via an
>>> XML structure. This will allow for changes and improvements later
>>> on that will not break userland applications. The old MTIOCGET
>>> status ioctl remains, so applications using the existing interface
>>> will not break.
>>>
>>> o 'mt status' now reports drive-reported tape position information
>>> as well as the previously available calculated tape position
>>> information. These numbers will be different at times, because
>>> the drive-reported block numbers are relative to BOP (Beginning
>>> of Partition), but the block numbers calculated previously via
>>> sa(4) (and still provided) are relative to the last filemark.
>>> Both numbers are now provided. 'mt status' now also shows the
>>> drive INQUIRY information, serial number and any position flags
>>> (BOP, EOT, etc.) provided with the tape position information.
>>> 'mt status -v' adds information on the maximum possible I/O size,
>>> and the underlying values used to calculate it.
>>>
>>> o The extra sa(4) /dev entries (/dev/saN.[0-3]) have been removed.
>>
>> How does this affect a tape library with more than one tape drive?
>>
>> [root at cuppy:~] # camcontrol amcontrol devlist
>> <DEC TL800 (C) DEC 0525> at scbus0 target 0 lun 0 (pass0,ch0)
>> <DEC TZ89 (C) DEC 2561> at scbus0 target 2 lun 0 (sa1,pass2)
>> <WDC WD5000AAKS-00YGA0 12.01C02> at scbus1 target 0 lun 0 (pass3,ada0)
>> <WDC WD5000AAKS-00YGA0 12.01C02> at scbus2 target 0 lun 0 (pass4,ada1)
>> <AHCI SGPIO Enclosure 1.00 0001> at scbus3 target 0 lun 0 (pass5,ses0)
>>
>> This system has two tapes drives and I can access them through the front panel but:
>>
>> # ls -l /dev/*sa*
>> crw-rw---- 1 root operator 0x65 Feb 28 22:04 /dev/esa1
>> crw-rw---- 1 root operator 0x64 Mar 1 22:43 /dev/nsa1
>> crw-rw---- 1 root operator 0x63 Feb 28 22:04 /dev/sa1
>> crw-rw---- 1 root operator 0x62 Feb 28 22:04 /dev/sa1.ctl
>>
>> ... only one tape drives shows up.
>
>
> Hmm. The tape drive is listed as sa1, which implies that there may be an
> sa0 that was there previously or is in the process of probing. What does
> dmesg show? How about 'camcontrol devlist -v'?
# camcontrol devlist -v
scbus0 on ahc0 bus 0:
<DEC TL800 (C) DEC 0525> at scbus0 target 0 lun 0 (pass0,ch0)
<DEC TZ89 (C) DEC 2561> at scbus0 target 2 lun 0 (sa1,pass2)
<> at scbus0 target -1 lun ffffffff ()
scbus1 on ahcich2 bus 0:
<WDC WD5000AAKS-00YGA0 12.01C02> at scbus1 target 0 lun 0 (pass3,ada0)
<> at scbus1 target -1 lun ffffffff ()
scbus2 on ahcich4 bus 0:
<WDC WD5000AAKS-00YGA0 12.01C02> at scbus2 target 0 lun 0 (pass4,ada1)
<> at scbus2 target -1 lun ffffffff ()
scbus3 on ahciem0 bus 0:
<AHCI SGPIO Enclosure 1.00 0001> at scbus3 target 0 lun 0 (pass5,ses0)
<> at scbus3 target -1 lun ffffffff ()
scbus-1 on xpt0 bus 0:
<> at scbus-1 target -1 lun ffffffff (xpt0)
BUT!
# grep sa /var/run/dmesg.boot
VT-x: (disabled in BIOS) PAT,HLT,MTF,PAUSE,EPT,UG,VPID
module_register_init: MOD_LOAD (vesa, 0xffffffff80de3720, 0) error 19
alc0: Using 1 MSIX message(s).
isab0: <PCI-ISA bridge> at device 31.0 on pci0
isa0: <ISA bus> on isab0
orm0: <ISA Option ROM> at iomem 0xce800-0xcefff on isa0
atkbdc0: <Keyboard controller (i8042)> at port 0x60,0x64 on isa0
sa0 at ahc0 bus 0 scbus0 target 1 lun 0
sa0: <DEC TZ89 (C) DEC 2561> Removable Sequential Access SCSI-2 device
sa0: Serial Number CXA22S2338
sa0: 10.000MB/s transfers (10.000MHz, offset 15)
sa0: quirks=0x100<NO_LONG_POS>
sa1 at ahc0 bus 0 scbus0 target 2 lun 0
sa1: <DEC TZ89 (C) DEC 2561> Removable Sequential Access SCSI-2 device
sa1: Serial Number CXA09S1340
sa1: 10.000MB/s transfers (10.000MHz, offset 15)
sa1: quirks=0x100<NO_LONG_POS>
>
> I would look at cabling and termination. Is this your library?
Yes, it is.
>
> http://manx.classiccmp.org/collections/mds-199909/cd3/tape/tl891uga.pdf
>
> If it is close enough, there are 6 connectors on the back. You would want
> to have something plugged into all 6, either a cable or a terminator.
Yes, that's mine, and yes, there's two short cables, a terminator, and the cable to the SCSI card in my computer.
>
> In the manual above, the SCSI IDs are set via the front panel. If the
> other drive is on the same bus as the drive above and the library device,
> it should be at a separate SCSI ID.
I did have the entire thing torn apart today, to extract a tape which would not budge.
>
>>> The extra devices were originally added as place holders for
>>> density-specific device nodes. Some OSes (NetBSD, NetApp's OnTap
>>> and Solaris) have had device nodes that, when you write to them,
>>> will automatically select a given density for particular tape drives.
>>>
>>> This is a convenient way of switching densities, but it was never
>>> implemented in FreeBSD. Only the device nodes were there, and that
>>> sometimes confused users.
>>>
>>> For modern tape devices, the density is generally not selectable
>>> (e.g. with LTO) or defaults to the highest availble density when
>>> the tape is rewritten from BOT (e.g. TS11X0). So, for most users,
>>> density selection won't be necessary. If they do need to select
>>> the density, it is easy enough to use 'mt density' to change it.
>>>
>>> o Protection information is now supported. This is either a
>>> Reed-Solomon CRC or CRC32 that is included at the end of each block
>>> read and written. On write, the tape drive verifies the CRC, and
>>> on read, the tape drive provides a CRC for the userland application
>>> to verify.
>>>
>>> o New, extensible tape driver parameter get/set interface.
>>>
>>> o Density reporting information. For drives that support it,
>>> 'mt getdensity' will show detailed information on what formats the
>>> tape drive supports, and what formats the tape drive supports.
>>>
>>> o Some mt(1) functionality moved into a new mt(3) library so that
>>> external applications can reuse the code.
>>>
>>> o The new mt(3) library includes helper routines to aid in parsing
>>> the XML output of the sa(4) driver, and build a tree of driver
>>> metadata.
>>>
>>> o Support for the MTLOAD (load a tape in the drive) and MTWEOFI
>>> (write filemark immediate) ioctls needed by IBM's LTFS
>>> implementation.
>>>
>>> o Improve device departure behavior for the sa(4) driver. The previous
>>> implementation led to hangs when the device was open.
>>>
>>> o This has been tested on the following types of drives:
>>> IBM TS1150
>>> IBM TS1140
>>> IBM LTO-6
>>> IBM LTO-5
>>> HP LTO-2
>>> Seagate DDS-4
>>> Quantum DLT-4000
>>> Exabyte 8505
>>> Sony DDS-2
>>>
>>> contrib/groff/tmac/doc-syms,
>>> share/mk/bsd.libnames.mk,
>>> lib/Makefile,
>>> Add libmt.
>>>
>>> lib/libmt/Makefile,
>>> lib/libmt/mt.3,
>>> lib/libmt/mtlib.c,
>>> lib/libmt/mtlib.h,
>>> New mt(3) library that contains functions moved from mt(1) and
>>> new functions needed to interact with the updated sa(4) driver.
>>>
>>> This includes XML parser helper functions that application writers
>>> can use when writing code to query tape parameters.
>>>
>>> rescue/rescue/Makefile:
>>> Add -lmt to CRUNCH_LIBS.
>>>
>>> sys/cam/cam_ccb.h
>>> Add a new flag value for the XPT_DEV_ADVINFO CCB, CDAI_FLAG_NONE.
>>>
>>> sbin/camcontrol/camcontrol.c,
>>> sys/cam/scsi/scsi_da.c,
>>> sys/cam/scsi/scsi_enc_ses.c,
>>> sys/dev/mps/mps_sas.c:
>>> Make sure the flags for the XPT_DEV_ADVINFO CCB are set correctly.
>>> This prevents unintended attempts to set advanced information
>>> values when XPT_DEV_ADVINFO CCBs are not pre-zeroed.
>>>
>>> src/share/man/man4/mtio.4
>>> Clarify this man page a bit, and since it contains what is
>>> essentially the mtio.h header file, add new ioctls and structure
>>> definitions from mtio.h.
>>>
>>> src/share/man/man4/sa.4
>>> Update BUGS and maintainer section.
>>>
>>> sys/cam/scsi/scsi_all.c,
>>> sys/cam/scsi/scsi_all.h:
>>> Add SCSI SECURITY PROTOCOL IN/OUT CDB definitions and CDB building
>>> functions.
>>>
>>> sys/cam/scsi/scsi_sa.c
>>> sys/cam/scsi/scsi_sa.h
>>> Many tape driver changes, largely outlined above.
>>>
>>> Increase the sa(4) driver read/write timeout from 4 to 32
>>> minutes. This is based on the recommended values for IBM LTO
>>> 5/6 drives. This may also avoid timeouts for other tape
>>> hardware that can take a long time to do retries and error
>>> recovery. Longer term, a better way to handle this is to ask
>>> the drive for recommended timeout values using the REPORT
>>> SUPPORTED OPCODES command. Modern IBM and Oracle tape drives
>>> at least support that command, and it would allow for more
>>> accurate timeout values.
>>>
>>> Add XML status generation. This is done with a series of
>>> macros to eliminate as much duplicate code as possible. The
>>> new XML-based status values are reported through the new
>>> MTIOCEXTGET ioctl.
>>>
>>> Add XML driver parameter reporting, using the new MTIOCPARAMGET
>>> ioctl.
>>>
>>> Add a new driver parameter setting interface, using the new
>>> MTIOCPARAMSET and MTIOCSETLIST ioctls.
>>>
>>> Add a new MTIOCRBLIM ioctl to get block limits information.
>>>
>>> Add CCB/CDB building routines scsi_locate_16, scsi_locate_10,
>>> and scsi_read_position_10().
>>>
>>> scsi_locate_10 implements the LOCATE command, as does the
>>> existing scsi_set_position() command. It just supports
>>> additional arguments and features. If/when we figure out a
>>> good way to provide backward compatibility for older
>>> applications using the old function API, we can just revamp
>>> scsi_set_position(). The same goes for
>>> scsi_read_position_10() and the existing scsi_read_position()
>>> function.
>>>
>>> Revamp sasetpos() to take the new mtlocate structure as an
>>> argument. It now will use either scsi_locate_10() or
>>> scsi_locate_16(), depending upon the arguments the user
>>> supplies. As before, once we change position we don't have a
>>> clear idea of what the current logical position of the tape
>>> drive is.
>>>
>>> For tape drives that support long form position data, we
>>> read the current position and store that for later reporting
>>> after changing the position. This should help applications
>>> like Bacula speed tape access under FreeBSD once they are
>>> modified to support the new ioctls.
>>>
>>> Add a new quirk, SA_QUIRK_NO_LONG_POS, that is set for all
>>> drives that report SCSI-2 or older, as well as drives that
>>> report an Illegal Request type error for READ POSITION with
>>> the long format. So we should automatically detect drives
>>> that don't support the long form and stop asking for it after
>>> an initial try.
>>>
>>> Add a partition number to the sa(4) softc.
>>>
>>> Improve device departure handling. The previous implementation
>>> led to hangs when the device was open.
>>>
>>> If an application had the sa(4) driver open, and attempted to
>>> close it after it went away, the cam_periph_release() call in
>>> saclose() would cause the periph to get destroyed because that
>>> was the last reference to it. Because destroy_dev() was
>>> called from the sa(4) driver's cleanup routine (sacleanup()),
>>> and would block waiting for the close to happen, a deadlock
>>> would result.
>>>
>>> So instead of calling destroy_dev() from the cleanup routine,
>>> call destroy_dev_sched_cb() from saoninvalidate() and wait for
>>> the callback.
>>>
>>> Acquire a reference for devfs in saregister(), and release it
>>> in the new sadevgonecb() routine when all devfs devices for
>>> the particular sa(4) driver instance are gone.
>>>
>>> Add a new function, sasetupdev(), to centralize setting
>>> per-instance devfs device parameters instead of repeating the
>>> code in saregister().
>>>
>>> Add an open count to the softc, so we know how many
>>> peripheral driver references are a result of open
>>> sessions.
>>>
>>> Add the D_TRACKCLOSE flag to the cdevsw flags so
>>> that we get a 1:1 mapping of open to close calls
>>> instead of a N:1 mapping.
>>>
>>> This should be a no-op for everything except the
>>> control device, since we don't allow more than one
>>> open on non-control devices.
>>>
>>> However, since we do allow multiple opens on the
>>> control device, the combination of the open count
>>> and the D_TRACKCLOSE flag should result in an
>>> accurate peripheral driver reference count, and an
>>> accurate open count.
>>>
>>> The accurate open count allows us to release all
>>> peripheral driver references that are the result
>>> of open contexts once we get the callback from devfs.
>>>
>>> sys/sys/mtio.h:
>>> Add a number of new mt(4) ioctls and the requisite data
>>> structures. None of the existing interfaces been removed
>>> or changed.
>>>
>>> This includes definitions for the following new ioctls:
>>>
>>> MTIOCRBLIM /* get block limits */
>>> MTIOCEXTLOCATE /* seek to position */
>>> MTIOCEXTGET /* get tape status */
>>> MTIOCPARAMGET /* get tape params */
>>> MTIOCPARAMSET /* set tape params */
>>> MTIOCSETLIST /* set N params */
>>>
>>> usr.bin/mt/Makefile:
>>> mt(1) now depends on libmt, libsbuf and libbsdxml.
>>>
>>> usr.bin/mt/mt.1:
>>> Document new mt(1) features and subcommands.
>>>
>>> usr.bin/mt/mt.c:
>>> Implement support for mt(1) subcommands that need to
>>> use getopt(3) for their arguments.
>>>
>>> Implement a new 'mt status' command to replace the old
>>> 'mt status' command. The old status command has been
>>> renamed 'ostatus'.
>>>
>>> The new status function uses the MTIOCEXTGET ioctl, and
>>> therefore parses the XML data to determine drive status.
>>> The -x argument to 'mt status' allows the user to dump out
>>> the raw XML reported by the kernel.
>>>
>>> The new status display is mostly the same as the old status
>>> display, except that it doesn't print the redundant density
>>> mode information, and it does print the current partition
>>> number and position flags.
>>>
>>> Add a new command, 'mt locate', that will supersede the
>>> old 'mt setspos' and 'mt sethpos' commands. 'mt locate'
>>> implements all of the functionality of the MTIOCEXTLOCATE
>>> ioctl, and allows the user to change the logical position
>>> of the tape drive in a number of ways. (Partition,
>>> block number, file number, set mark number, end of data.)
>>> The immediate bit and the explicit address bits are
>>> implemented, but not documented in the man page.
>>>
>>> Add a new 'mt weofi' command to use the new MTWEOFI ioctl.
>>> This allows the user to ask the drive to write a filemark
>>> without waiting around for the operation to complete.
>>>
>>> Add a new 'mt getdensity' command that gets the XML-based
>>> tape drive density report from the sa(4) driver and displays
>>> it. This uses the SCSI REPORT DENSITY SUPPORT command
>>> to get comprehensive information from the tape drive about
>>> what formats it is able to read and write.
>>>
>>> Add a new 'mt protect' command that allows getting and setting
>>> tape drive protection information. The protection information
>>> is a CRC tacked on to the end of every read/write from and to
>>> the tape drive.
>>>
>>> Sponsored by: Spectra Logic
>>> MFC after: 1 month
>>>
>>> Thanks,
>>>
>>> Ken
>>> --
>>> Kenneth Merry
>>> ken at FreeBSD.ORG
>>> _______________________________________________
>>> freebsd-scsi at freebsd.org mailing list
>>> http://lists.freebsd.org/mailman/listinfo/freebsd-scsi
>>> To unsubscribe, send any mail to "freebsd-scsi-unsubscribe at freebsd.org"
>>
>> ?
>> Dan Langille
>> http://langille.org/
>>
>>
>>
>>
>>
>
> --
> Kenneth Merry
> ken at FreeBSD.ORG
—
Dan Langille
http://langille.org/
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