Tribblix: manual page: st.4d

ST(4D) Devices ST(4D)

NAME

st - driver for SCSI tape devices

SYNOPSIS

st@target,lun:l,m,h,c,ubn

DESCRIPTION

The st device driver provides a standard interface to various SCSI
tape devices. See mtio(4I) for details.

To determine if the st device driver supports your tape device, SPARC
users should enter the following on a command line:

% strings /kernel/drv/sparcv9/st | grep -i <tape device name>

x86 users can do the following to determine if the st device driver
supports a particular tape device:

% strings /kernel/drv/st | grep -i <tape device name>

The driver can be opened with either rewind on close or no rewind on
close options. It can also be opened with the O_NDELAY (see open(2))
option when there is no tape inserted in the drive. A maximum of four
tape formats per device are supported (see FILES below). The tape
format is specified using the device name. (Tape format is also
referred to as tape density).

Following are a list of SCSI commands that can be executed while
another host reserves the tape drive. The commands are:

SCMD_TEST_UNIT_READY
SCMD_REQUEST_SENSE
SCMD_READ_BLKLIM
SCMD_INQUIRY
SCMD_RESERVE
SCMD_RELEASE
SCMD_DOORLOCK
SCMD_REPORT_DENSITIES
SCMD_LOG_SENSE_G1
SCMD_PERSISTENT_RESERVE_IN
SCMD_PERSISTENT_RESERVE_OUT
SCMD_REPORT_LUNS

In multi-initiator environments, the driver will not reserve the
tape drive if above commands are issued. For other SCSI commands, the
driver reserves the tape drive and releases the drive at close if it
has been reserved. Refer to the MTIOCRESERVE and MTIOCRELEASE ioctls
in mtio(4I) for information about how to allow a tape drive to remain
reserved upon close. See the flag options below for information about
disabling this feature.

If a SCSI-3 persistent reservation is done through the driver, the
driver disables all existing SCSI-2 reservations.

If the tape drive is opened in O_NDELAY mode, no reservation occurs
during the open, as per the POSIX standard (see standards(7)).
However, if a command not found in the above list is used, a
reservation will occur to provide reserve/release functionality
before the command is issued.

Persistent Errors and Asynchronous Tape Operation

The st driver now supports persistent errors (see mtio(4I) and
asynchronous tape operations (see mtio(4I), aioread(3C), and
aiowrite(3C)).

Read Operation

If the driver is opened for reading in a different format than the
tape is written in, the driver overrides the user-selected format.
For example, if a 1/4" cartridge tape is written in QIC-24 format and
opened for reading in QIC-150, the driver detects a read failure on
the first read and automatically switches to QIC-24 to read the data.

Note that if the low density format is used, no indication is given
that the driver has overridden the format you selected. Other formats
issue a warning message to inform you of an overridden format
selection. Some devices automatically perform this function and do
not require driver support (1/2" reel tape drive, for example).

Write Operation

Writing from the beginning of tape is performed in the user-specified
format. The original tape format is used for appending onto
previously written tapes.

Tape Configuration

The st driver has a built-in configuration table for most Sun-
supported tape drives. For those tape drives that are not in the
table, the st driver tries to read the configuration from the tape
drive through optional SCSI-3 commands. To support the addition of
third party tape devices which are not in the built-in configuration
table or not able to report their configuration, device information
can be supplied in st.conf as global properties that apply to each
node, or as properties that are applicable to one node only. By
supplying the information in st.conf, the built-in configuration is
overridden and the st driver will not query the configuration from
tape drives. The st driver looks for the property called tape-config-
list. The value of this property is a list of triplets, where each
triplet consists of three strings.

The formal syntax is:

tape-config-list = <triplet> [, <triplet> *];

where

<triplet> := <vid+pid>, <pretty print>, <data-property-name>

and

<data-property-name> = <version>, <type>, <bsize>,
<options>, <number of densities>,
<density> [, <density>*], <default-density>;

or

<data-property-name> = <version 2>, <type>, <bsize>,
<options>, <number of densities>,
<density> [, <density>*], <default-density>,
<non-motion time-out>, <I/O time-out>,
<rewind time-out>, <space time-out>,
<load time-out>, <unload time-out>,
<erase time-out>;

A semicolon (;) is used to terminate a prototype devinfo node
specification. Individual elements listed within the specification
should not be separated by a semicolon. (Refer to driver.conf(5) for
more information.)

<vid+pid> is the string that is returned by the tape device on a SCSI
inquiry command. This string may contain any character in the range
0x20-0x7e. Characters such as " " " (double quote) or " ' " (single
quote), which are not permitted in property value strings, are
represented by their octal equivalent (for example, \042 and \047).
Trailing spaces may be truncated.

<pretty print> is used to report the device on the console. This
string may have zero length, in which case the <vid+pid> will be used
to report the device.

<data-property-name> is the name of the property which contains all
the tape configuration values (such as <type>, <bsize>, etc.)
corresponding for the tape drive for the specified <vid+pid>.

<version> is a version number and should be 1 or 2. In the future,
higher version numbers may be used to allow for changes in the syntax
of the <data-property-name> value list.

<type> is a type field. Valid types are defined in
/usr/include/sys/mtio.h. For third party tape configuration, the
following generic types are recommended:

MT_ISQIC 0x32
MT_ISREEL 0x33
MT_ISDAT 0x34
MT_IS8MM 0x35
MT_ISOTHER 0x36
MT_ISTAND25G 0x37
MT_ISDLT 0x38
MT_ISSTK9840 0x39
MT_ISBMDLT1 0x3A
MT_LTO 0x3B

<bsize> is the preferred block size of the tape device. The value
should be 0 for variable block size devices.

<options> is a bit pattern representing the devices, as defined in
/usr/include/sys/scsi/targets/stdef.h. Valid flags for tape
configuration are shown in the following table. Note that this table
does not list flags that are non-configurable in st.conf (including
ST_KNOWS_MEDIA which uses the media type reported from the mode
select data to select the correct density code).

ST_VARIABLE 0x0001
ST_QIC 0x0002
ST_REEL 0x0004
ST_BSF 0x0008
ST_BSR 0x0010
ST_LONG_ERASE 0x0020
ST_AUTODEN_OVERRIDE 0x0040
ST_NOBUF 0x0080
ST_KNOWS_EOD 0x0200
ST_UNLOADABLE 0x0400
ST_SOFT_ERROR_REPORTING 0x0800
ST_LONG_TIMEOUTS 0x1000
ST_NO_RECSIZE_LIMIT 0x8000
ST_MODE_SEL_COMP 0x10000
ST_NO_RESERVE_RELEASE 0x20000
ST_READ_IGNORE_ILI 0x40000
ST_READ_IGNORE_EOFS 0x80000
ST_SHORT_FILEMARKS 0x100000
ST_EJECT_TAPE_ON_CHANGER_FAILURE 0x200000
ST_RETRY_ON_RECOVERED_DEFERRED_ERROR 0x400000
ST_WORMABLE 0x1000000

ST_VARIABLE

The flag indicates the tape device supports variable length
record sizes.

ST_QIC

The flag indicates a Quarter Inch Cartridge (QIC) tape device.

ST_REEL

The flag indicates a 1/2-inch reel tape device.

ST_BSF

If flag is set, the device supports backspace over EOF marks (bsf
- see mt(1)).

ST_BSR

If flag is set, the tape device supports the backspace record
operation (bsr - see mt(1)). If the device does not support bsr,
the st driver emulates the action by rewinding the tape and using
the forward space record (fsf) operation to forward the tape to
the correct file. The driver then uses forward space record (fsr
- see mt(1)) to forward the tape to the correct record.

ST_LONG_ERASE

The flag indicates the tape device needs a longer time than
normal to erase.

ST_AUTODEN_OVERRIDE

The auto-density override flag. The device is capable of
determining the tape density automatically without issuing a
"mode-select"/"mode-sense command."

ST_NOBUF

The flag disables the device's ability to perform buffered
writes. A buffered write occurs when the device acknowledges the
completion of a write request after the data has been written to
the device's buffer, but before all of the data has been written
to the tape.

ST_KNOWS_EOD

If flag is set, the device can determine when EOD (End of Data)
has been reached. When this flag is set, the st driver uses fast
file skipping. Otherwise, file skipping happens one file at a
time.

ST_UNLOADABLE

The flag indicates the device will not complain if the st driver
is unloaded and loaded again (see modload(8) and modunload(8)).
That is, the driver will return the correct inquiry string.

ST_SOFT_ERROR_REPORTING

The flag indicates the tape device will perform a "request sense"
or "log sense" command when the device is closed. Currently, only
Exabyte and DAT drives support this feature.

ST_LONG_TIMEOUTS

The flag indicates the tape device requires timeouts that are
five times longer than usual for normal operation.

ST_NO_RECSIZE_LIMIT

The flag applies to variable-length tape devices. If this flag is
set, the record size is not limited to a 64 Kbyte record size.
The record size is only limited by the smaller of either the
record size supported by the device or the maximum DMA transfer
size of the system. (Refer to Large Record Sizes and WARNINGS.)
The maximum block size that will not be broken into smaller
blocks can be determined from the mt_bf returned from the
MTIOCGET ioctl(). This number is the lesser of the upper block
limit returned by the drive from READ BLOCK LIMITS command and
the dma-max property set by the Host Bus Adapter (HBA) to which
the drive is attached.

ST_MODE_SEL_COMP

If the ST_MODE_SEL_COMP flag is set, the driver determines which
of the two mode pages the device supports for selecting or
deselecting compression. It first tries the Data Compression mode
page (0x0F); if this fails, it tries the Device Configuration
mode page (0x10). Some devices, however, may need a specific
density code for selecting or deselecting compression. Please
refer to the device specific SCSI manual. When the flag is set,
compression is enabled only if the "c" or "u" device is used.
Note that when the lower 2 densities of a drive are identically
configured and the upper 2 densities are identically configured,
but the lower and upper differ from each other and
ST_MODE_SEL_COMP is set, the "m" node sets compression on for the
lower density code (for example, 0x42) and the "c" and "u" nodes
set compression on for the higher density (for example, 0x43).
For any other device densities, compression is disabled.

ST_NO_RESERVE_RELEASE

The ST_NO_RESERVE_RELEASE flag disables the use of reserve on
open and release on close. If an attempt to use a ioctl of
MTRESERVE or MTRELEASE on a drive with this flag set, it will
return an error of ENOTTY (inappropriate ioctl for device).

ST_READ_IGNORE_ILI

The ST_READ_IGNORE_ILI flag is applicable only to variable block
devices which support the SILI bit option. The ST_READ_IGNORE_ILI
flag indicates that SILI (suppress incorrect length indicator)
bit will be set during reads. When this flag is set, short reads
(requested read size is less than the record size on the tape)
will be successful and the number of bytes transferred will be
equal to the record size on the tape. The tape will be positioned
at the start of the next record skipping over the extra data (the
remaining data has been has been lost). Long reads (requested
read size is more than the record size on the tape) will see a
large performance gain when this flag is set, due to overhead
reduction. When this flag is not set, short reads will return an
error of ENOMEM.

ST_READ_IGNORE_EOFS

The ST_READ_IGNORE_EOFS flag is applicable only to 1/2" Reel Tape
drives and when performing consecutive reads only. It should not
be used for any other tape command. Usually End-of-recorded-media
(EOM) is indicated by two EOF marks on 1/2" tape and application
cannot read past EOM. When this flag is set, two EOF marks no
longer indicate EOM allowing applications to read past two EOF
marks. In this case it is the responsibility of the application
to detect end-of-recorded-media (EOM). When this flag is set,
tape operations (like MTEOM) which positions the tape at end-of-
recorded-media will fail since detection of end-of-recorded-media
(EOM) is to be handled by the application. This flag should be
used when backup applications have embedded double filemarks
between files.

ST_SHORT_FILEMARKS

The ST_SHORT_FILEMARKS flag is applicable only to EXABYTE 8mm
tape drives which supports short filemarks. When this flag is
set, short filemarks is used for writing filemarks. Short
filemarks could lead to tape incompatible with some otherwise
compatible device. By default long filemarks will be used for
writing filemarks.

ST_EJECT_TAPE_ON_CHANGER_FAILURE

If ST_EJECT_TAPE_ON_CHANGER_FAILURE flag is set, the tape is
ejected automatically if the tape cartridge is trapped in the
medium due to positioning problems of the medium changer.

The following ASC/ASCQ keys are defined to the reasons for
causing tape ejection if ST_EJECT_TAPE_ON_CHANGER_FAILURE option
is set to 0x200000:

Sense ASC/ASCQ Description

Key

4 15/01 Mechanical Failure

4 44/00 Internal Target Failure

2 53/00 Media Load or Eject Failed

4 53/00 Media Load or Eject Failed

4 53/01 Unload Tape Failure

ST_RETRY_ON_RECOVERED_DEFERRED_ERROR

If ST_RETRY_ON_RECOVERED_DEFERRED_ERROR flag is set, the st
driver will retry the last write if this cmd caused a check
condition with error code 0x71 and sense code 0x01. Some tape
drives, notably the IBM 3090, require this option.

ST_WORMABLE

When ST_WORMABLE is set, st attempts to detect the presence of
WORM media in the device.

<number of densities> is the number of densities specified. Each tape
drive can support up to four densities. The value entered should
therefore be between 1 and 4; if less than 4, the remaining densities
will be assigned a value of 0x0.

<density> is a single-byte hexadecimal number. It can either be found
in the device specification manual or be obtained from the device
vendor.

<default-density> has a value between 0 and (<number of densities> -
1).

<non-motion time-out> Time in seconds that the drive should be able
to perform any SCSI command that doesn't require tape to be moved.
This includes mode sense, mode select, reserve, release, read block
limits, and test unit ready.

<I/O time-out> Time in seconds to perform data transfer I/O to or
from tape including worst case error recovery.

<rewind time-out> Time in seconds to rewind from anywhere on tape to
BOT including worst case recovery forcing buffered write data to
tape.

<space time-out> Time in seconds to space to any file, block or end
of data on tape. Including worst case when any form of cataloging is
invalid.

<load time-out> Time in seconds to load tape and be ready to transfer
first block. This should include worst case recovery reading tape
catalog or drive specific operations done at load.

<unload time-out> Time in seconds to unload tape. Should include
worst case time to write to catalog, unthread, and tape cartridge
unloading. Also should include worst case time for any drive specific
operations that are preformed at unload. Should not include rewind
time as the driver rewinds tape before issuing the unload.

<erase time-out> Time in seconds to preform a full (BOT to EOT) erase
of longest medium with worst case error recovery.

Device Statistics Support

Each device maintains I/O statistics both for the device and for each
partition allocated on that device. For each device/partition, the
driver accumulates reads, writes, bytes read, and bytes written. The
driver also takes hi-resolution time stamps at queue entry and exit
points, which facilitates monitoring the residence time and
cumulative residence-length product for each queue.

Each device also has error statistics associated with it. These must
include counters for hard errors, soft errors and transport errors.
Other data may be implemented as required.

IOCTLS

The behavior of SCSI tape positioning ioctls is the same across all
devices which support them. (Refer to mtio(4I).) However, not all
devices support all ioctls. The driver returns an ENOTTY error on
unsupported ioctls.

The retension ioctl only applies to 1/4" cartridge tape devices. It
is used to restore tape tension, thus improving the tape's soft error
rate after extensive start-stop operations or long-term storage.

In order to increase performance of variable-length tape devices
(particularly when they are used to read/write small record sizes),
two operations in the MTIOCTOP ioctl, MTSRSZ and MTGRSZ, can be used
to set and get fixed record lengths. The ioctl also works with fixed-
length tape drives which allow multiple record sizes. The min/max
limits of record size allowed on a driver are found by using a SCSI-2
READ BLOCK LIMITS command to the device. If this command fails, the
default min/max record sizes allowed are 1 byte and 63k bytes. An
application that needs to use a different record size opens the
device, sets the size with the MTSRSZ ioctl, and then continues with
I/O. The scope of the change in record size remains until the device
is closed. The next open to the device resets the record size to the
default record size (retrieved from st.conf).

Note that the error status is reset by the MTIOCGET get status ioctl
call or by the next read, write, or other ioctl operation. If no
error has occurred (sense key is 0), the current file and record
position is returned.

ERRORS

EACCES
The driver is opened for write access and the tape is
write-protected or the tape unit is reserved by another
host.

EBUSY
The tape drive is in use by another process. Only one
process can use the tape drive at a time. The driver will
allow a grace period for the other process to finish before
reporting this error.

EINVAL
The number of bytes read or written is not a multiple of
the physical record size (fixed-length tape devices only).

EIO
During opening, the tape device is not ready because either
no tape is in the drive, or the drive is not on-line. Once
open, this error is returned if the requested I/O transfer
could not be completed.

ENOTTY
This indicates that the tape device does not support the
requested ioctl function.

ENXIO
During opening, the tape device does not exist.

ENOMEM
This indicates that the record size on the tape drive is
more than the requested size during read operation.

EXAMPLES

Example 1: Global tape-config list property

The following is an example of a global tape-config-list property:

tape-config-list =
"Magic DAT", "Magic 4mm Helical Scan", "magic-data",
"Major Appliance", "Major Appliance Tape", "major-tape";

magic-data = 1,0x34,1024,0x1639,4,0,0x8c,0x8c,0x8c,3;
major-tape = 2,0x3c,0,0x18619,4,0x0,0x0,0x0,0x0,
3,0,0,30,120,0,0,36000;

name="st" class="scsi"
target=0 lun=0;
name="st" class="scsi"
target=1 lun=0;
name="st" class="scsi"
target=2 lun=0;
.
.
.
name="st" class="scsi"
target=6 lun=0;

Example 2: Tape-config-list property applicable to target 2 only

The following is an example of a tape-config-list property applicable
to target 2 only:

name="st" class="scsi"
target=0 lun=0;
name="st" class="scsi"
target=1 lun=0;
name="st" class="scsi"
target=2 lun=0
tape-config-list =
"Magic DAT", "Magic 4mm Helical Scan", "magic-data"
magic-data = 1,0x34,1024,0x1639,4,0,0x8c,0x8c,0x8c,3;
name="st" class="scsi"
target=3 lun=0;
.
.
.
name="st" class="scsi"
target=6 lun=0;

Large Record Sizes

To support applications such as seismic programs that require large
record sizes, the flag ST_NO_RECSIZE_LIMIT must be set in drive
option in the configuration entry. A SCSI tape drive that needs to
transfer large records should OR this flag with other flags in the
'options' field in st.conf. (Refer to Tape Configuration.) By
default, this flag is set for the built-in config entries of Archive
DAT and Exabyte drives.

If this flag is set, the st driver issues a SCSI-2 READ BLOCK LIMITS
command to the device to determine the maximum record size allowed by
it. If the command fails, st continues to use the maximum record
sizes mentioned in the mtio(4I) man page.

If the command succeeds, st restricts the maximum transfer size of a
variable-length device to the minimum of that record size and the
maximum DMA size that the host adapter can handle. Fixed-length
devices are bound by the maximum DMA size allocated by the machine.
Note that tapes created with a large record size may not be readable
by earlier releases or on other platforms.

(Refer to the WARNINGS section for more information.)

EOT Handling

The Emulex drives have only a physical end of tape (PEOT); thus it is
not possible to write past EOT. All other drives have a logical end
of tape (LEOT) before PEOT to guarantee flushing the data onto the
tape. The amount of storage between LEOT and PEOT varies from less
than 1 Mbyte to about 20 Mbyte, depending on the tape drive.

If EOT is encountered while writing an Emulex, no error is reported
but the number of bytes transferred is 0 and no further writing is
allowed. On all other drives, the first write that encounters EOT
will return a short count or 0. If a short count is returned, then
the next write will return 0. After a zero count is returned, the
next write returns a full count or short count. A following write
returns 0 again. It is important that the number and size of trailer
records be kept as small as possible to prevent data loss. Therefore,
writing after EOT is not recommended.

Reading past EOT is transparent to the user. Reading is stopped only
by reading EOF's. For 1/2" reel devices, it is possible to read off
the end of the reel if one reads past the two file marks which mark
the end of recorded media.

FILES

/kernel/drv/st.conf

driver configuration file

/usr/include/sys/mtio.h

structures and definitions for mag tape io control commands

/usr/include/sys/scsi/targets/stdef.h

definitions for SCSI tape drives

/dev/rmt/[0- 127][l,m,h,u,c][b][n]

where l,m,h,u,c specifies the density (low, medium, high,
ultra/compressed), b the optional BSD behavior (see mtio(4I)),
and n the optional no rewind behavior. For example, /dev/rmt/0lbn
specifies unit 0, low density, BSD behavior, and no rewind.

For 1/2" reel tape devices (HP-88780), the densities are:

l 800 BPI density
m 1600 BPI density
h 6250 BPI density
c data compression
(not supported on all modules)

For 8mm tape devices (Exabyte 8200/8500/8505):

l Standard 2 Gbyte format
m 5 Gbyte format (8500, 8505 only)
h,c 5 Gbyte compressed format (8505 only)

For 4mm DAT tape devices (Archive Python):

l Standard format
m,h,c data compression

For all QIC (other than QIC-24) tape devices:

l,m,h,c density of the tape cartridge type
(not all devices can read and
write all formats)

For QIC-24 tape devices (Emulex MT-02):

l QIC-11 Format
m,h,c QIC-24 Format

DIAGNOSTICS

The st driver diagnostics may be printed to the console or messages
file.

Each diagnostic is dependent on the value of the system variable
st_error_level. st_error_level may be set in the /etc/system file.
The default setting for st_error_level is 4 (SCSI_ERR_RETRYABLE)
which is suitable for most configurations since only actual fault
diagnostics are printed. Settings range from values 0 (SCSI_ERR_ALL)
which is most verbose, to 6 (SCSI_ERR_NONE) which is least verbose.
See stdef.h for the full list of error-levels. SCSI_ERR_ALL level the
amount of diagnostic information is likely to be excessive and
unnecessary.

The st driver diagnostics are described below:

Error for Command: <scsi_cmd_name()> Error Level:<error_class>
Requested Block: <blkno> Error Block: <err_blkno>
Vendor: <name>: Serial Number: <inq_serial>
Sense Key: <es_key> ASC: 0x<es_add_code> (scsi_asc_ascq_name()>), ASCQ:
0x<es_qual_code>, FRU: 0x<ex_fru_code>

where <error_class> may be any one of the following: "All,"
"Unknown," "Informational," "Recovered," "Retryable," "Fatal"

The command indicated by <scsi_cmd_name> failed. Requested Block
represents the block where the transfer started. Error Block
represents the block that caused the error. Sense Key, ASC, ASCQ and
FRU information is returned by the target in response to a request
sense command. See SCSI protocol documentation for description of
Sense Key, ASC, ASCQ, FRU.

The st driver attempts to validate entries in the st.conf file. Each
field in the entry is checked for upper and lower limits and invalid
bits set. The fields are named as follows in config string order:

conf version
drive type
block size
options
number of densities
density code
default density
non motion timeout
I/O timeout
space timeout
load timeout
unload timeout
erase timeout

The st.conf diagnostics are described below:

<con-name> <field-in-err> <problem-with-field>

where <con-name> is the name of the config string. Where <field-in-
err> is the field containing invalid entries and where <problem-with-
field> describes the nature of the invalid entry.

Write/read: not modulo <n> block size

The request size for fixed record size devices must be a multiple of
the specified block size.

Recovery by resets failed

After a transport error, the driver attempted to recover by issuing a
device reset and then a bus reset if device reset failed. These
recoveries failed.

Periodic head cleaning required

The driver reported that periodic head cleaning is now required. This
diagnostic is generated either due to a threshold number of retries,
or due to the device communicating to the driver that head cleaning
is required.

Soft error rate (<n>%) during writing/reading was too high

The soft error rate has exceeded the threshold specified by the
vendor.

SCSI transport failed: reason 'xxxx': {retrying|giving up}

The Host Bus Adapter (HBA) has failed to transport a command to the
target for the reason stated. The driver will either retry the
command or, ultimately, give up.

Tape not inserted in drive

A media access command was attempted while there was no tape inserted
into the specified drive. In this case, the drive returns sense key
of DRIVE NOT READY.

Transport rejected

The Host Bus Adapter (HBA) driver is not accepting commands after
failing to successfully transport a scsi packet to the target. The
actual status received by the st driver from the underlying HBA
driver was either TRAN_FATAL_ERROR or TRAN_BADPKT.

Retrying command

The st driver failed to complete a command. However the command is
retryable and will be retried.

Giving up

The st driver has exhausted retries or otherwise is unable to retry
the command and so is giving up.

No target struct for st%d

The st driver failed to obtain state information because the
requested state structure was not allocated. The specified device was
probably not attached.

File mark detected

The operation detected an end of file mark. (File marks signify the
end of a file on the tape media).

End-of-media detected

The operation reached the end of the tape media.

Exabyte soft error reporting failed. DAT soft error reporting failed

The st driver was unable to determine if the soft error threshold had
been exceeded because it did not successfully read the data it
requires or did not obtain enough data. This data is retrieved using
the log sense command.

Log sense parameter code does not make sense

The log sense command retrieves hardware statistics that are stored
on the drive (for example, soft error counts and retries.) If the
data retrieved from the drive is invalid, this message is printed and
the data is not used.

Restoring tape position at fileno=%x, blkno=%lx....

The st driver is positioning to the specified file and block. This
occurs on an open.

Failed to restore the last <file/block> position:
In this state, tape will be loaded at BOT during next open

The st driver could not position to the specified location and will
revert to the beginning of the tape when the next open is attempted.

Device does not support compression

The compression facility of the device was requested. However the
device does not have a hardware compression capability.

DAT soft error reset failed

After DAT soft error reporting, the counters within the device that
accumulate this sense data need to be re-set. This operation failed.

Errors after pkt alloc (b_flags=0x%x, b_error=0x%x)

Memory allocation for a scsi packet failed.

Incorrect length indicator set

The drive reported the length of data requested in a READ operation,
was incorrect. Incorrect Length Indicator (ILI) is a very commonly
used facility in SCSI tape protocol and should not be seen as an
error per-se. Applications typically probe a new tape with a read of
any length, using the returned length to the read system call for
future reads. Along with this operation, an underlying ILI error is
received. ILI errors are therefore informational only and are masked
at the default st_error_level.

Data property (%s) has no value
Data property (%s) incomplete
Version # for data property (%s) greater than 1

These diagnostics indicate problems in retrieving the values of the
various property settings. The st driver is in the process of setting
the property/parameter values for the tape drive using information
from either the built-in table within the driver or from uncommented
entries in the st.conf file. The effect on the system may be that the
tape drive may be set with default or generic driver settings which
may not be appropriate for the actual type of tape drive being used.

st_attach-RESUME: tape failure tape position will be lost

On a resume after a power management suspend, the previously known
tape position is no longer valid. This can occur if the tape was
changed while the system was in power management suspend. The
operation will not be retried.

Write Data Buffering has been deprecated. Your applications should
continue to work normally. However, they should be ported to use
Asynchronous I/O.

Indicates that buffering has been removed from Solaris.

Cannot detach: fileno=%x, blkno=%lx

The st driver cannot unload because the tape is not positioned at BOT
(beginning of tape). May indicate hardware problems with the tape
drive.

Variable record length I/O
Fixed record length (%d byte blocks) I/O

Tape-drives can use either Fixed or Variable record length. If the
drive uses Fixed length records, then the built in property table or
the st.conf file will contain a non-zero record-length property. Most
DAT, Exabyte and DLT drives support Variable record lengths. Many QIC
format tape drives have historically been of Fixed record length.

Command will be retried
un_ncmds: %d can't retry cmd

These diagnostics are only seen with tape drives with the
ST_RETRY_ON_RECOVERED_DEFERRED_ERROR bit set. See stdef.h for
explanation of the specific usage of this setting.

WARNINGS

Effective with Solaris 2.4, the ST_NO_RECSIZE_LIMIT flag is set for
the built-in config entries of the Archive DAT and Exabyte drivers by
default. (Refer to Large Record Sizes.) Tapes written with large
block sizes prior to Solaris 2.4 may cause some applications to fail
if the number of bytes returned by a read request is less than the
requested block size (for example, asking for 128 Kbytes and
receiving less than 64 Kbytes).

The ST_NO_RECSIZE_LIMIT flag can be disabled in the config entry for
the device as a work-around. (Refer to Tape Configuration.) This
action disables the ability to read and write with large block sizes
and allows the reading of tapes written prior to Solaris 2.4 with
large block sizes.

(Refer to mtio(4I) for a description of maximum record sizes.)

BUGS

Tape devices that do not return a BUSY status during tape loading
prevent user commands from being held until the device is ready. The
user must delay issuing any tape operations until the tape device is
ready. This is not a problem for tape devices supplied by Sun
Microsystems.

Tape devices that do not report a blank check error at the end of
recorded media may cause file positioning operations to fail. Some
tape drives, for example, mistakenly report media error instead of
blank check error.

April 9, 2016 ST(4D)