The device_allocate File

You can modify the device_allocate file to change devices from allocatable to nonallocatable, or to add new devices. A sample device_allocate file follows.

st0;st;;;;/etc/security/lib/st_clean
fd0;fd;;;;/etc/security/lib/fd_clean
sr0;sr;;;;/etc/security/lib/sr_clean
audio;audio;;;*;/etc/security/lib/audio_clean

You define which devices should be allocatable during initial BSM configuration. You can decide to accept the default devices and their defined characteristics, as shown in the preceding sample device_allocate file. Whenever you add a device to any machine after the system is up and running, you must decide whether to make the new device allocatable.

After installation, you can modify the entries for devices in the device_allocate file. Any device that needs to be allocated before use must be defined in the device_allocate file on each machine. Currently, cartridge tape drives, diskette drives, CD-ROM devices, and audio chips are considered allocatable and have device-clean scripts.

Xylogics^TM tape drives or Archive tape drives also use the st_clean script that is supplied for SCSI devices. Other devices that you can make allocatable are modems, terminals, graphics tablets, and similar devices. However, you need to create your own device-clean scripts for such devices, and the script must fulfill object-reuse requirements for that type of device.

An entry in the device_allocate file does not mean that the device is allocatable, unless the entry specifically states that the device is allocatable. In the sample device_allocate file, note the asterisk (*) in the fifth field of the audio device entry. An asterisk in the fifth field indicates to the system that the device is not allocatable. That is, the system administrator does not require a user to allocate the device before it is used nor to deallocate it afterward. Any other string placed in this field indicates that the device is allocatable.

In the device_allocate file, you represent each device by a one-line entry of the form:

device-name;device-type;reserved;reserved;alloc;device-clean

For example, the following line shows the entry for device name st0:

st0;st;;;;;/etc/security/lib/st_clean

Lines in the device_allocate file can end with a “\” to continue an entry on the next line. Comments can also be included. A “#” makes a comment out of all subsequent text until the next newline not immediately preceded by a “\”. Leading and trailing blanks are allowed in any field.

The following paragraphs describe each field in the device_allocate file.

device-name

Specifies the name of the device; for example, st0, fd0, or sr0. When you make a device allocatable, retrieve the device-name from the device-name field in the device_maps file, or use the dminfo command. (The name is also the DAC file name for the device.)

device-type

Specifies the generic device type (which is the name for the class of devices, such as st, fd, and sr). This field groups related devices. When you make an allocatable device, retrieve the device-type from the device-type field in the device_maps file, or use the dminfo command.

reserved

These two fields are reserved for future use.

alloc

Specifies whether the device is allocatable. An asterisk (*) in this field indicates that the device is not allocatable. Any other string, or an empty field, indicates that the device is allocatable.

device-clean

Supplies the path name of a script to be invoked for special handling, such as cleanup and object-reuse protection during the allocation process. The device-clean script is run any time that the device is acted on by the deallocate command, such as when a device is forcibly deallocated with deallocate -F.