devreserv

 

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 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
 
 
 
 
 
 SunOS 5.8            Last change: 5 Jul 1990                    1
 
 
 
 
 
 
 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
 
 
 
 SunOS 5.8            Last change: 5 Jul 1990                    2
 
 
 
 
 
 
 Maintenance Commands                                devreserv(1M)
 
 
 
      been reserved since such a process would  not  have  checked
      for its reservation status.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 SunOS 5.8            Last change: 5 Jul 1990                    3
 
 
 

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