Displaying tape information

7.1 LPAR mode z/VM guest

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

Each 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 tape device. This directory contains a number of attributes with information about the 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 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 tape device
blocksize	Currently used record size in bytes or `0` for auto
state	State of the 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   3490/54      3490/54         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
3490/54
# cat /sys/bus/ccw/devices/0.0.015f/devtype
3490/54
# 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