IBM TS2340 User Guide - Page 50

New Logical Name, Read Error Recovery Time, Record Space Mode, Rewind Immediate, Trailer Labels

Page 50 highlights

AIX Device Driver (Atape) New Logical Name Setting this parameter changes the logical name of the device to a new name as specified. After the logical name is changed, the new logical name parameter is cleared. There is no installation default value for this parameter. Read Error Recovery Time This parameter controls the read error recovery time for the IBM TotalStorage Enterprise Tape System 3590. If this parameter is set to On, the recovery time for read errors is limited to a maximum of 5 seconds. If this parameter is set to Off, full recovery is used by the device and can take up to 10 minutes. This parameter is intended for use by real-time applications that cannot tolerate long delays when reading data from the tape. The installation default is Off (do not limit the read error recovery time). Record Space Mode This parameter specifies how the device driver operates when a forward or backward space record operation encounters a filemark. The two modes of operation are SCSI and AIX. The SCSI mode is the default mode of operation. When a forward or backward space record operation is issued to the driver and a filemark is encountered, the device driver returns -1 and the errno variable is set to input/output error (EIO). The tape is left positioned after the filemark (the end-of-tape side of the filemark on the forward space and the beginning-of-tape side of the filemark on the backward space). The AIX mode returns the same EIO errno value as the SCSI mode when a filemark is encountered except that the tape is left positioned before the filemark (the beginning-of-tape side of the filemark on the forward space and the end-of-tape side of the filemark on the backward space). The installation default is SCSI mode. Rewind Immediate This parameter turns the immediate bit On and Off in rewind commands. If it is set to On, then the rewind tape operation executes faster, but the next command takes a long time to finish unless the rewind operation is physically complete. Setting this parameter reduces the amount of time that it takes to close a device for a Rewind on Close special file. The installation default is Off (no rewind immediate) except for the IBM 7332 4mm Tape Cartridge Autoloader, for which the default is On (rewind immediate). Trailer Labels If this parameter is set to On, then writing a record past the early warning mark on the tape is allowed. The first write operation to detect EOM fails, and the errno variable is set to ENOSPC. No data is written during the operation. All subsequent write operations are allowed to continue until the physical end of the volume is reached and EIO is returned. This parameter can also be selected using one of three device special files that allow trailer-label processing. The special files are rmtx.40, rmtx.41, and rmtx.60, where x is the name of the device (for example, rmt0.40). 32 IBM Tape Device Drivers Installation and User's Guide

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New Logical Name
Setting this parameter changes the logical name of the device to a new name as
specified. After the logical name is changed, the new logical name parameter is
cleared.
There is no installation default value for this parameter.
Read Error Recovery Time
This parameter controls the read error recovery time for the IBM TotalStorage
Enterprise Tape System 3590. If this parameter is set to On, the recovery time for
read errors is limited to a maximum of 5 seconds. If this parameter is set to Off,
full recovery is used by the device and can take up to 10 minutes. This parameter
is intended for use by real-time applications that cannot tolerate long delays when
reading data from the tape.
The installation default is Off (do not limit the read error recovery time).
Record Space Mode
This parameter specifies how the device driver operates when a forward or
backward space record operation encounters a filemark. The two modes of
operation are SCSI and AIX.
The SCSI mode is the default mode of operation. When a forward or backward
space record operation is issued to the driver and a filemark is encountered, the
device driver returns -1 and the
errno
variable is set to input/output error (EIO).
The tape is left positioned after the filemark (the end-of-tape side of the filemark
on the forward space and the beginning-of-tape side of the filemark on the
backward space).
The AIX mode returns the same EIO
errno
value as the SCSI mode when a filemark
is encountered except that the tape is left positioned before the filemark (the
beginning-of-tape side of the filemark on the forward space and the end-of-tape
side of the filemark on the backward space).
The installation default is SCSI mode.
Rewind Immediate
This parameter turns the immediate bit On and Off in rewind commands. If it is
set to On, then the rewind tape operation executes faster, but the next command
takes a long time to finish unless the rewind operation is physically complete.
Setting this parameter reduces the amount of time that it takes to close a device for
a Rewind on Close special file.
The installation default is Off (no rewind immediate)
except
for the IBM 7332 4mm
Tape Cartridge Autoloader, for which the default is On (rewind immediate).
Trailer Labels
If this parameter is set to On, then writing a record past the early warning mark
on the tape is allowed. The first write operation to detect EOM fails, and the
errno
variable is set to ENOSPC. No data is written during the operation. All subsequent
write operations are allowed to continue until the physical end of the volume is
reached and EIO is returned.
This parameter can also be selected using one of three device special files that
allow trailer-label processing. The special files are
rmtx.40
,
rmtx.41
, and
rmtx.60
,
where
x
is the name of the device (for example,
rmt0.40
).
AIX Device Driver (Atape)
32
IBM Tape Device Drivers Installation and User’s Guide