IBM TS2340 User Guide - Page 160

Solaris Device Driver (IBMtape) Table 27. Configuration Parameters Recognized by IBMtape (continued) Parameter Values Description buffering (0=Off, 1=On) When a write command is processed, the data is either directly stored on the physical tape or buffered in device hardware. Buffering can be turned On and Off with this option. If buffering is disabled, the effective performance of the device may be degraded seriously, because the tape devices cannot take advantage of their buffering optimization. Buffer flushing (or committing data to the tape) can be controlled by the application through the STIOC_SYNC_BUFFER ioctl function immediate (0=Off, 1=On) If immediate is set to 0, the SCSI commands Write FM, Locate, Load-Unload, Erase, and Rewind return with status when the command actually completes on the tape drive. If immediate is set to 1, these commands return with status before the command actually completes. rew_immediate (0=Off, 1=On) If rew_immediate is set to 0, the SCSI Rewind command returns with status when the command actually completes on the tape drive. If it is set to set to 1, the Rewind command returns with status before the command actually completes. If immediate is set to 1, the setting of rew_immediate is ignored. trailer (0=Off, 1=On) If a tape drive encounters logical end-of-tape (EOT) during a write operation, it returns a check condition status. The driver returns 0 bytes written to notify the application of this EOT situation. A check condition is also returned by the tape drive for every subsequent write operation when past EOT. If trailer is enabled, writing records past EOT is allowed by the device driver. Following the first time the write operation notifies the application of EOT, all subsequent EOT notifications are suppressed by the driver, and the actual number of bytes written is returned. When physical end of media is reached, all write operations fail with a return code of -1, regardless of the trailer setting. When trailer is enabled, managing the media past EOT is the application's responsibility. sili (0=Off, 1=On) Normally, during a read operation, if a larger block of data is requested than is actually read from the tape, the tape device raises a check condition. The IBMtape device driver must perform error handling procedures, which add overhead to the read operation. The IBMtape driver does not surface this as an error condition to the application and ultimately returns the actual number of bytes read. However, this driver error processing results in less than optimum read performance in some scenarios. When SILI mode is enabled, the tape device is forced to Suppress Illegal Length Indication during read operations. This eliminates the error processing performed by the driver and results in improved read performance for some scenarios. The actual number of bytes read is still returned to the application in SILI mode. Removing IBMtape All active processes using IBM devices supported by the IBM SCSI Tape and Medium Changer Device Driver for Solaris must be stopped in order for the removal procedure to complete successfully. Use the pkgrm command to remove the IBMtape package from the system. % /usr/sbin/pkgrm IBMtape Adding or Removing Devices To add support for a new IBM tape system or to remove support for a previously attached IBM tape system, perform the following steps: 1. Edit the IBMtape.conf file in the /usr/kernel/drv directory to reflect the change in IBM device support. Either add a new stanza to provide support for a device that is to be added, or remove (comment out) a stanza for a device that is no longer supported. 142 IBM Tape Device Drivers Installation and User's Guide