The Tape Dispatcher API is a set of perl functions that are used to interact with the main server process. At the end of this section we also provide a pair of small practical use cases. And here is a a complete list of API functions:

• $session = TDisp->connect(tdhost,port,service,devtype,device,tape);
  This function is used to connect to the server process and reserve one device.
  Arguments:
  • tdhost - obligatory, specifies the host name (or IP address) of machine that runs the tape dispatcher process
  • port - obligatory, specifies the port used by the tape dispatcher process
  • service - obligatory, denotes an existing or a new service nickname
  • devtype - optional, possible values are "DLT7000","LTO" etc. or "*"
  • device - optional, local device address, e.g. "/dev/rmt/1" or "*"
  • tape - optional, tape VID
  
  
• $ok = $session->connected(); - connection state
• $ok = $session->errmes(); - error message from last request
• ($device,@drivetypes) = $session->device(); - assigned local device, tape types supported
  (e.g. "/dev/rmt/1" and an array containing a list of tape types supported by this device)
• ($tapeVID,$tapetype) = $session->tape(); - last tape mounted and its type;
• $session->disconnect(); - drop connection and free the device
• $ok = $session->mount(tapeVID); - request to mount a tape with a certain tapeVID
• $ok = $session->mountscratch(); - request to mount a scratch tape
• $ok = $session->unmount(); - unmount tape but keep the device

#!/usr/bin/perl -w

require "TDisp.pm";

$tdhost="server.name";
$port=7800;

$session = TDisp->connect($tdhost,$port,'testnickname','LTO');
die $session->errmes() unless $session->connected();

($dev,@drivetytes) = $session->device();
print "Device $dev will be used\n";

die $session->errmes() unless $session->mountscratch();
$tapeVID = $session->tape();
print "Tape $tapeVID is mounted and will be used\n";

system("tar cvf $dev /home/pincopallino");

# Please note that this example does not end with disconnect() operation.
# In fact, disconnection will occur automatically and the tape resource
# will be freed upon the end of "system" call.

#!/usr/bin/perl -w

require "TDisp.pm";

$tdhost="server.name";
$port=7800;

$session = TDisp->connect($tdhost,$port,'testnickname','LTO');
die $session->errmes() unless $session->connected();

($dev,@drivetytes) = $session->device();
print "Device $dev will be used\n";

die $session->errmes() unless $session->mount("VID001");
system("tar xf $dev /home/buratino/file1");

die $session->errmes() unless $session->mount("VID002");
system("tar xf $dev /home/pinocchio/file2");

die $session->errmes() unless $session->mount("VID025");
system("tar xf $dev /home/gatto/file3");

$session->disconnect();


$session = TDisp->connect($tdhost,$port,'testnickname','STK9840');
die $session->errmes() unless $session->connected();

($dev,@drivetytes) = $session->device();
print "Device $dev will be used\n";

die $session->errmes() unless $session->mount("VID599");
system("tar xf $dev /home/volpe/file4");