Displaying tape information

6.10 LPAR mode z/VM guest

Use the lstape command to display summary information about your tape devices, or read tape information from sysfs.

Each physical tape device is represented in a sysfs directory of the form

/sys/bus/ccw/devices/<device_bus_id>

where <device_bus_id> is the device bus-ID that corresponds to the physical tape device. This directory contains a number of attributes with information about the physical device. The attributes: blocksize, state, operation, and medium_state, might not show the current values if the device is offline.

Table 1. Tape device attributes
Attribute	Explanation
online	`1` if the device is online or `0` if it is offline (see Setting a tape device online or offline)
cmb_enable	`1` if channel measurement block is enabled for the physical device or `0` if it is not enabled (see Channel measurement facility)
cutype	Type and model of the control unit
devtype	Type and model of the physical tape device
blocksize	Currently used record size in bytes or `0` for auto
state	State of the physical tape device, either of: UNUSED The device is not in use and is available to any operating system image in a shared environment. IN_USE The device is being used by a process on this Linux® instance. OFFLINE The device is offline. NOT_OP Device is not operational.
operation	The current tape operation, for example: --- No operation WRI Write operation RFO Read operation MSN Medium sense Several other operation codes exist, for example, for rewind and seek.
medium_state	The current state of the tape cartridge: 1 Cartridge is loaded into the tape device 2 No cartridge is loaded 0 The tape device driver does not have information about the current cartridge state

Procedure

Issue a command of this form to read an attribute:

# cat /sys/bus/ccw/devices/<device_bus_id>/<attribute>

where <attribute> is one of the attributes of Table 1.

Example

The following lstape command displays information about a tape device with bus ID 0.0.015f:

# lstape 0.0.015f --ccw-only
TapeNo  BusID      CuType/Model DevType/Model   BlkSize State   Op      MedState
2       0.0.015f   3480/01      3480/04         auto    UNUSED  ---     LOADED

This sequence of commands reads the same information from sysfs:

# cat /sys/bus/ccw/devices/0.0.015f/online
1
# cat /sys/bus/ccw/devices/0.0.015f/cmb_enable
0
# cat /sys/bus/ccw/devices/0.0.015f/cutype
3480/01
# cat /sys/bus/ccw/devices/0.0.015f/devtype
3480/04
# cat /sys/bus/ccw/devices/0.0.015f/blocksize
0
# cat /sys/bus/ccw/devices/0.0.015f/state
UNUSED
# cat /sys/bus/ccw/devices/0.0.015f/operation
---
# cat /sys/bus/ccw/devices/0.0.015f/medium_state
1