Maintenance 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:

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

     device-list
           Defines a list of devices that devreserv  will  search
           to  find an available device. The list must be format-
           ted as a single argument to the shell.

EXAMPLES
     Example 1: Reserving a floppy disk and a cartridge tape.

     This 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

     Example 2: Listing all devices currently reserved.

     This example lists all devices currently reserved:

          $ devreserv
          disk1         2423
          diskette1     10658
          ctape1        10658

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Maintenance Commands                                devreserv(1M)

     Example 3: Listing all devices currently reserved to a  par-
     ticular key.

     This example lists all devices currently reserved to a  par-
     ticular 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

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

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWcsu                     |
    |_____________________________|_____________________________|

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 reservation has been canceled. However,  processes
     that do not use device reservation may use a device that has

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Maintenance Commands                                devreserv(1M)

     been reserved since such a process would  not  have  checked
     for its reservation status.

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