devreserv(1M)                                          devreserv(1M)


       NAME
             devreserv - reserve devices for exclusive use

       SYNOPSIS
             devreserv [key [devicelist . . .]]

          Arguments
             key           Designates a unique key on which the device will
                           be reserved.  The key must be a positive
                           integer.

             devicelist    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.)

       DESCRIPTION
             devreserv reserves devices for exclusive use.  When the device
             is no longer required, use devfree to release it.

          Files
             /etc/device.tab
             /etc/devlkfile

          Return Values
             devreserv exits with one of the following values:

             0     The task completed successfully.

             1     Command syntax incorrect, invalid option used, or
                   internal error occurred.

             2     Device table or device reservation table could not be
                   opened for reading.

             3     Device reservation request could not be fulfilled.

       USAGE
             devreserv reserves at most one device per devicelist.  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.

             If you execute devreserv without arguments, devices that are
             currently reserved are listed, and the keys to which they are
             reserved.  When devreserv is executed with only the key


                           Copyright 1994 Novell, Inc.               Page 1

      devreserv(1M)                                          devreserv(1M)


            argument, it lists the devices currently reserved to that key.

            The commands devreserv and devfree 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
            actual access to the device.  They provide a centralized
            bookkeeping point for those who want to use them.  To
            summarize, devices that have been reserved cannot be used by
            processes that 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.

         Examples
            To reserve a floppy disk and a cartridge tape:
                  $ key=$$
                  $ echo "The current Process ID is equal to: $key"
                  The Current Process ID is equal to: 10658
                  $ devreserv $key diskette1,ctape1

            To list all devices currently reserved:
                  $ devreserv
                  disk1         2423
                  diskette1     10658
                  ctape1        10658

            To list all devices currently reserved to a particular key:
                  $ devreserv $key
                  diskette1
                  ctape1

      REFERENCES
            devfree(1M)














                          Copyright 1994 Novell, Inc.               Page 2