tcl.t-att Verb: Access/Tape Commands

tcl.t-att

Command tcl.t-att Verb: Access/Tape Commands
Applicable release versions: AP, R83
Category Tape Commands (36)
Description attaches the tape unit or floppy disk drive to the current process unit and optionally assigns the blocksize to the tape i/o buffer.

On Advanced Pick releases prior to 6.1.0, only one device at a time can be attached to the system. It is advised to use the "set-" commands, since they establish which type of device is being used, as well as the default blocksize.

"blocksize" is an integer number indicating the number of bytes in each block.

Floppy disks may be set at any number between 20 and 512, but are usually set to 500 or 512. The default is 500.

Half-inch tapes may be set to anything between 512 and 16384, inclusive. The default is 8192.

Streaming cartridge tapes (SCT) may be set to anything between 2048 and 16384 and must be a multiple of 512. The default is 16384.

8-millimeter tapes may be set to anything between 512 and 16384 and must be a multiple of 512.

After attaching the device to the current process, all of the regular "tape" handling verbs, like "t-rew" and "t-fwd", are available, even when using floppy diskettes. Diskettes must be "rewound" before writing to them or reading from them. Usually, this doesn't take long.

If the tape unit is attached to another line, the process displays the port that has it attached. The "u" option in the "t-det" command attaches the tape "unconditionally", regardless of what it may be doing. This may be necessary if the transaction logger is enabled. (see "t-det").

The "t-att" verb should be used before any tape manipulation process, such as executing tape control verbs, generating print file output to the tape using the "t" option in "sp-assign" or "sp-edit", executing tape reads and writes in Pick/BASIC, or generating tape output using the "reformat" and "sreformat" verb.

All tape manipulation processes on the system check for attachment, attach the tape if possible, generate the required message, and terminate if the tape is not available.

The implied "t-att" uses the current tape block size specification and remains "set" until one of the following events occur:

1) using "t-att" with a numeric argument.

2) using "t-att" without a numeric argument.

3) using any tape verb which checks for tape attachment.

4) executing the "t-rdlbl" verb when a labeled tape is mounted. The tape block size is stored in labels written to tape. By reading a tape label through "t-rdlbl" or "t-read", the current blocksize is changed to the size stored in the label read.
Syntax t-att {blocksize} {(options}
Options u Unconditionally attaches the tape. It is strongly advised to verify that the tape is not actually being used before stealing it from another process.

z Unconditionally attaches the tape, except if the tape is attached to the transaction logger.
Example
Purpose
Related basic.weof
basic.writet
tcl.t-rdlbl
tcl.sel-restore
tcl.set-floppy
tcl.set-device
proc.it
basic.readt
tcl.set-sct
access.t-dump
tcl.set-half
access.reformat
access.sreformat
tcl.set-floppy
tcl.t-status
basic.rewind
tcl.admin.tape
tcl.startlog
tcl.t-erase
tcl.t-status
tcl.sp-assign
tcl.fuser
tape.handling.verbs
tcl.set-8mm
basic.readtx
basic.readtl
basic.onerr
tcl.format
access.t-load
access.tape
start.buffer.mark
tcl.config.tape
tcl.t-select
dummy.restore
tcl.t-att.link
tcl.abs-dump