ptx/SPDRIVERS V2.x.x contains the tc device driver that is for use with Magstar tape drives internal to IBM 3590 High Performance Tape Subsystems that are using a 10-cartridge ACF. The tc tape driver is not supported for use with Magstar tape drives in IBM 3494 Tape Libraries.
This appendix provides information specific to connecting the IBM 3590 Tape Subsystem to a DYNIX/ptx host, cabling considerations, and important operational considerations when using this device with a DYNIX/ptx host. For information about the IBM 3590 Tape Subsystem, the Magstar tape drive, general hardware installation or configuration, or media handling and maintenance, refer to the vendor's documentation that is supplied with the IBM 3590 Tape Subsystem.
The following caveats apply to the connection of the IBM 3590 Tape Subsystem to a DYNIX/ptx host:
The IBM 3590 Tape Subsystem must be running internal firmware revision 9_4AF when used with a NUMA system.
Only one IBM 3590 Tape Subsystem should be connected per SCSI channel. On NUMA systems, only one IBM 3590 Tape Subsystem should be connected per Fibre Channel Bridge.
NUMA systems do not support connection of these devices in dual-initiator configurations. In other words, do not connect the IBM 3590 Tape Subsystem to more than one DYNIX/ptx host at a time.
Connect the IBM 3590 Tape Subsystem as follows:
Cable connections for the IBM 3590 Tape Subsystem are different from other tape devices used with DYNIX/ptx systems. Use the following guidelines:
Do not connect a cable or a terminator to SCSI port 1. Whereas most tape devices with DYNIX/ptx systems have a single SCSI bus with SCSI-in and SCSI-out connectors, with the IBM 3590 Tape Subsystem the two connectors are separate SCSI buses. They have no electrical or logical connection.
ATTENTION Using the IBM 3590 Tape Subsystem's dual-port connection with DYNIX/ptx systems could result in data loss or corruption.
Each SCSI bus on the IBM 3590 Tape Subsystem has only one SCSI port, and this port is not internally terminated. You therefore must attach a terminator to the port.
The IBM SCSI cable uses a "hammerhead" connector to connect to the IBM 3590 Tape Subsystem. With this connector, you can piggyback another cable or a terminator onto the back of the connector, as shown in Figure A-1.
Do not use the IBM SCSI terminator. The IBM terminator disables certain signals that are needed with DYNIX/ptx systems. Use the DYNIX/ptx SCSI terminator.
Do not attach the IBM SCSI cable directly to a DYNIX/ptx host. The IBM cable uses mounting screws that are incompatible with the DYNIX/ptx system. Use the adapter cables to connect the IBM cables to a DYNIX/ptx system, as shown in Figure A-1.
Do not use an IBM SCSI cable longer than 20 meters. The maximum length for any SCSI bus is 25 meters. Since a DYNIX/ptx system requires an adapter cable, using an IBM cable longer than 20 meters can extend the total length beyond the 25-meter limit. For best performance, always use the shortest cables possible. For example, IBM provides a 4.5-meter, 12-meter, and 18-meter cable for host to device connection that you can use.
Figure A-1 illustrates the cable connections between DYNIX/ptx hosts and IBM 3590 Tape Subsystems.
Figure A-1. Cable Connections between DYNIX/ptx Hosts and IBM 3590 Tape Subsystems
The required DYNIX/ptx cables and terminator are as follows:
FC Adapter Cable for connecting IBM 3590 SCSI Cable to Fibre Channel Bridge.
QCIC Adapter Cable for connecting IBM 3590 SCSI Cable to QCIC.
Terminator (2-56 thread) for wide-SCSI IBM 3590 connector.
This section describes the following operational considerations:
Operational caveats you should be familiar with before using the IBM 3590 Tape Subsystem with a DYNIX/ptx host are as follows:
The tc device driver does not support IBM tape labels. On a labeled tape, the first file is the tape label. Before writing to a labeled tape, you must issue an mt command to skip the first file, then perform the write. If you do not issue the mt command to skip the first file, the tape label will be overwritten.
Currently, DYNIX/ptx supports a maximum transfer block size of 128K bytes.
The tc driver supports the following IBM 3590 Tape Subsystem operating modes:
Manual
Accumulate
Automatic
Random
These modes are described in the user's guide for the IBM 3590 Tape Subsystem. This IBM document includes detailed instructions for selecting and initiating each of these modes. However, the following paragraphs cover several points of emphasis for operation with a DYNIX/ptx system. Be sure you review this information before using the IBM 3590 Tape Subsystem on a DYNIX/ptx system.
In Random mode, the Automated Cartridge Facility (ACF) stacker is intended to be operated as a closed subsystem. That is, it is not expected that tapes will be added to or removed from the subsystem. The following paragraphs detail important considerations for Random mode operation.
Complete the following steps to begin Random mode operation:
Load all but one of the desired tape cartridges into the ACF. The front of each cartridge must be flush with the front of the ACF. This is referred to as the Import position. (When the front of the cartridge extends beyond the front of the ACF, allowing the operator to grasp it, the cartridge is in the Export position.)
ATTENTION At least one of the ACF cells must be left empty before Random mode startup. Otherwise, the cartridge in the tape drive will have no place to be stored when it is removed from the drive.
The cartridge present in the drive during Random mode initiation will be assigned to the first empty slot found during startup, and will be placed in that slot upon subsequent removal from the drive during normal mt ranload operations.
Load the final tape cartridge into the tape drive.
Engage the ACF mechanical lock.
Select Random mode operation via the Set ACF Mode front panel option.
Reboot the host to begin DYNIX/ptx control of the IBM 3590 Tape Subsystem and to initialize Random mode for the ACF stacker.
You may occasionally need to add, remove, or change a tape in the IBM 3590 Tape Subsystem, for example, to replace a defective tape or to use the cleaning cartridge. However, changing the ACF contents can cause the tc driver to become confused about the contents of the ACF, leading to possible data loss or the inability to recover system configuration information without rebooting the DYNIX/ptx system.
To avoid these problems, follow these steps to add or remove a tape when operating the IBM 3590 Tape Subsystem in Random mode:
Stop all ACF activity.
Set the ACF mode to Manual. Note that an ACF error will be reported on the 3590's display whenever the mode changes from Random to Manual. This is because the ACF lock, which is only valid in Random mode, will be on in Manual mode. This error message will be removed when Random mode is reselected.
Insert or remove the desired cartridges.
ATTENTION Be sure to insert or remove any required cartridges using the Priority slot. When a cartridge is reinserted into the drive, it must be reinserted from the Priority slot, not from the ACF. Disturbing any cartridges in the ACF while the system is not in Random mode can cause the tc driver to become confused and possibly unable to recover without rebooting the DYNIX/ptx system. That is, the number of cartridges and the slots that contain them must be exactly the same before and after you insert or remove any cartridges.
Reset the ACF mode to Random.
Do not use the mt command with the ejectmag, offline, or rewoffl commands in Random mode. If you use any of these commands, the IBM 3590 Tape Subsystem will mark the cartridge that was in the drive as unloaded, but will not physically remove the cartridge from the drive. This action prevents mt ranload from inserting a new cartridge.
If this situation accidentally occurs, do the following:
Select Manual mode via the IBM 3590 Tape Subsystem front panel. This will cause the "unloaded " cartridge to be physically unloaded into the Priority slot. As noted earlier, this will also generate an ACF error message on the IBM 3590 Tape Subsystem's display; this error message will be removed when the mode is reset to Random.
Push the cartridge back into the Import position.
Select Start via the front panel to reload the cartridge.
Use the Set ACF Mode on the front panel to reselect Random mode.
Select Start on the front panel to initiate Random mode.
To end Random mode operation:
Release the ACF mechanical lock.
Select the new mode using the Set ACF Mode option on the front panel.
Reboot the DYNIX/ptx system.
ATTENTION System reboot is not required for temporary mode changes (for example, from Random to Manual to Random) made for normal maintenance operations or operator interventions .
The IBM 3590 Tape Subsystem can notify software when the device needs cleaning. However, the tc driver does not support this functionality. Instead, site personnel must manually schedule tape cleaning. In general, the cleaning cartridge should be used as follows:
After every 150 GB of data transfer (more often in dusty environments).
Whenever the *CLEAN message appears on the front panel of the IBM 3590 Tape Subsystem.
Failure to clean the IBM 3590 Tape Subsystem often enough can lead to interrupted tape movements when using Random mode. If the *CLEAN message appears, subsequent attempts to replace the current tape cartridge using the mt command will be aborted after the current tape has been logically, but not physically, removed from the drive. Manual intervention will be required to recover from this condition.
For example, suppose that the drive is allowed to become dirty and the *CLEAN message is displayed. You then attempt to use mt to move the tape in the drive back to its home slot, slot 4, and load a new tape from slot 6 into the drive. This operation will be aborted, leaving the tape from slot 4 logically ejected but physically still in the drive.
To recover from this condition, you must manually complete the aborted mt command by doing the following:
Select Manual mode from the front panel of the IBM 3590 Tape Subsystem to physically remove the tape from the drive.
Unlock the ACF.
Place the removed tape into its home slot, in this example, slot 4.
Load the cleaning tape, clean the drive, and remove the cleaning tape.
Manually remove the tape that you wanted in the tape drive from its slot, in this example, slot 6, and load it into the tape drive.
Lock the ACF.
Use the front panel to reselect Random mode.
Failure to follow this recovery procedure may lead to loss of device configuration data and possible user data corruption or loss, and may require a reboot of the DYNIX/ptx system to reestablish proper system configuration data.