NAME

tape − allocate magnetic tape drives

SYNOPSIS

tape [-ebs] [-c shell-command] tapename=parameters ... 
tape -r [-ebs] [-c shell-command] tapename=parameters ... 
tape -f
tape -q

CX/SX ONLY (B1 SECURITY OPTIONS)

tape [-mx] tapename
tape -t
 

DESCRIPTION

Tape arbitrates requests for tape drives among several competing users.  For a request to complete, the tape drive must be put online with the proper write-ring status.  When a request is satisfied, all special device files for the allocated device will be owned by the requesting user to prevent use by others.  The name of the appropriate device (based on the parameters supplied to the request) will be printed for the user, and may be put into environment variables easily. 

For interactive use, periodic messages with the status of a pending tape request will be output.  These messages may be suppressed with the -s option. 

REQUESTING RESOURCES

The tape command is assumed to be requesting resources, unless either the -f or -q options are used.  Requests consist of a tapename=parameters pair, where tapename is any character string, and is the “reel name” that will be included on all communication to the system operator.  For each tapename, several comma-delimited parameters may be specified.  The parameters recognized include:

nnnnbpi Density of the tape -- nnnn must be one of 800, 1600, 3200, or 6250.  Currently, this parameter is required. 

wring A write ring is required for this request. 

nowring A write ring must not be installed for this request. 

rewind The rewind device is selected. 

norewind The norewind device is selected. 

raw The raw device (/dev/rmt/xxx) is selected. 

blocked The blocked device (/dev/mt/xxx) is selected. 

fast The fast device (if available) is selected. 

slow The slow device (if available) is selected. 

:nn Only the specific tape drive with the specified unit number is selected. 

message=text An arbitrary message displayed to the operator with the tape mount request.  The text must be enclosed in quotes if spaces or commas are to be embedded. 

location=text The location of the tape, which will be displayed to the operator.  The text must be enclosed in quotes if spaces or commas are to be embedded. 

Other attributes may be added by the system administrator.  The actual text used to specify the parameters may be abbreviated to the shortest unique value -- for example, “wring” may be represented by “wr”.  The default values for unspecified device attributes are nowring,rewind,raw,fast. 

When a request is satisfied, tape will print the names of the allocated tape drives, in the order of the requests.  If the -e option is specified, tape will output a command string to set environment variables to the specified values.  A string suitable for use with csh may be requested by using the -b option together with the -e option. 

If a (Bourne shell) command is specified with the -c option, tape will resource the tape drive, fork a shell to execute the command, free the drive upon completion of the command, and exit.  tape will produce no output in this case. 

FREEING RESOURCES

The tape daemon (taped) will monitor the process requesting tape drives.  If that process should exit for any reason, all allocated resources and any pending requests will be released.  If the allocated resources should be released before the process exits, the tape -f command may be used.  All resources for the process will be released, online tape drives will be rewound and taken offline if possible, and the system operator will be notified to remove the tapes. 

REPLACING ALLOCATED TAPE REEL

A previously allocated tape may be replaced (swapped) with the use of the -r option.  The tapename specified must match a name previously allocated by the requesting process. 

RESOURCE QUERIES

The tape -q command may be used to print a list of all allocated, pending, and queued requests. 

EXAMPLES:

tape mytape=1600bpi,wring

will request a 1600bpi tape named ’mytape’, and wait until the allocated tape drive is online with a write ring enabled. 

tape   -e   REEL1=6250bpi,norew   REEL2=1600bpi,wr

will request two tapes to be mounted (REEL1 and REEL2), and ensure that a write ring is present for only REEL2.  A command string similar to:

TAPE=/dev/rmt/0hfn; TAPEDEV=0; TAPE2=/dev/rmt/1mf; TAPEDEV2=1;
export TAPE TAPEDEV TAPE2 TAPEDEV2;

will be output to stdout. 
 

SECURITY FEATURES

The following security features are in effect on systems running CX/SX configured to B1 security. 

All user accessible (mountable) tapes are listed in the system tape library (/mls/tapelib).  An exception is provided for secadm (security administrator) group members at system high, so that they may handle foreign tapes.  Every tapename and operating label combination is unique in the tape library. 

A user can request an operator to create a tape entry for a new (clean) tape at the label of his subject process with the -m option. The -t option may be used to list the tape library entries that are readable (dominated by) the user’s process label.  The user can delete a tape entry by mounting the tape with the write ring set, executing the -x command option (which will erase the tape), and then freeing the tape with the -f option. 
 

BUGS

Tapename must not contain embedded blanks nor an ’=’ character. 

The -f option frees all requests for a given process -- it may not be used to free selected resources. 

SEE ALSO

taped(1M), tapeop(1M)

CX/UX User’s Reference Manual