DEVRESERV(1M) Maintenance Commands DEVRESERV(1M)
devreserv - reserve devices for exclusive use
reserves devices for exclusive use. When the device is no
longer required, use devfree
to release it. devreserv
reserves at most one device per device-list
. Each list is
searched in linear order until the first available device is found. If a
device cannot be reserved from each list, the entire reservation fails.
is invoked without arguments, it lists the devices that
are currently reserved and shows to which key it was reserved. When devreserv
is invoked with only the key
argument, it lists the devices
that are currently reserved to that key.
The following operands are supported: device-list
Defines a list of devices that devreserv
will search to
find an available device. The list must be formatted as a
single argument to the shell. key
Designates a unique key on which the device will be
reserved. The key must be a positive integer.
Example 1: Reserving a Floppy Disk and a Cartridge Tape
The following example reserves a floppy disk and a cartridge tape:
$ echo "The current Process ID is equal to: $key"
The Current Process ID is equal to: 10658
$ devreserv $key diskette1 ctape1
Example 2: Listing All Devices Currently Reserved
The following example lists all devices currently reserved:
Example 3: Listing All Devices Currently Reserved to a Particular Key
The following example lists all devices currently reserved to a
$ devreserv $key
The following exit values are returned: 0
Successful completion. 1
Command syntax was incorrect, an invalid was option used, or an
internal error occurred. 2
Device table or device reservation table could not be opened for
Device reservation request could not be fulfilled.
FILES /etc/device.tab /etc/devlkfile
SEE ALSO devfree(1M)
The commands devreserv
are used to manage the availability of
devices on a system. Their use is on a participatory basis and they do
not place any constraints on the actual access to the device. They serve
as a centralized bookkeeping point for those who wish to use them.
Devices which have been reserved cannot be used by processes which
utilize the device reservation functions until the reservation has been
canceled. However, processes that do not use device reservation may use a
device that has been reserved since such a process would not have checked
for its reservation status.
July 5, 1990 DEVRESERV(1M)