Manual Pages for UNIX Operating System command usage for man devreserv

System Administration Commands                      devreserv(1M)



NAME
     devreserv - reserve devices for exclusive use

SYNOPSIS
     devreserv [key [device-list]...]


DESCRIPTION
     devreserv reserves devices for exclusive use. When the  dev-
     ice 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.


     When  devreserv 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.

OPERANDS
     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.


EXAMPLES
     Example 1 Reserving a Floppy Disk and a Cartridge Tape


     The following example reserves 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





SunOS 5.11           Last change: 5 Jul 1990                    1






System Administration Commands                      devreserv(1M)



     Example 2 Listing All Devices Currently Reserved


     The following example lists all devices currently reserved:


       $ devreserv
         disk1         2423
         diskette1     10658
         ctape1        10658



     Example 3 Listing All Devices Currently Reserved to  a  Par-
     ticular Key


     The following example lists all devices  currently  reserved
     to a particular key:


       $ devreserv $key
         diskette1
         ctape1



EXIT STATUS
     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 reading.


     3    Device reservation request could not be fulfilled.


FILES
     /etc/device.tab


     /etc/devlkfile






SunOS 5.11           Last change: 5 Jul 1990                    2






System Administration Commands                      devreserv(1M)



ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWcs                      |
    |_____________________________|_____________________________|


SEE ALSO
     devfree(1M), attributes(5)

NOTES
     The commands devreserv and devfree are used  to  manage  the
     availability of devices on a system. Their use is  on a par-
     ticipatory 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  reserva-
     tion  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 reserva-
     tion status.



























SunOS 5.11           Last change: 5 Jul 1990                    3