T-FORMAT Command

The T-FORMAT command rewinds the attached tape and sets the tape format.

Format

T-FORMAT [?] | [[QICn | RAW-ON | RAW-OFF] [(options)]

Parameter(s)

?

Displays the format of the attached tape drive.

QICn

Selects the specified QIC format, e.g. T-FORMAT QIC1000.

RAW-ON

Reads the non-mvBase format from sectors of a diskette. Valid for use with floppy drives only.

RAW-OFF

Default format and reads mvBase-formatted diskettes. Valid for use with floppy drives only.

options

Can be one or more of the following:

S

Can be one or more of the following:

A

Enables/re-enables automatic density selection. Not available for all tape drives. For additional information regarding this option, see the A Option below.

N

Re-tension of 1/4-inch tapes will not occur at BOT, before writing begins. For additional information regarding this option, see the N Option below.

Qn

Selects the specified QIC format, e.g. T-FORMAT (Q1000. Rather than using the QICn format discussed above, this option may be used as an alternate syntax.

Description

If you enter T-FORMAT and do not specify a format in the command line, the system prompts you to enter one.

  1. If the attached tape drive is a 1/4-inch 60MB tape drive, the following menu displays:

    2. QUARTER-INCH FORMAT SELECTION MENU

    FORMAT SELECTION

    QIC24   = SELECT QIC 24 FORMAT

    QIC11   = SELECT QIC 11 FORMAT

    SELECTION:

    Type QIC24 or QIC11 at the prompt.

  2. If the attached tape drive is a 1/4-inch 150MB tape drive, the following menu displays:

    3. QUARTER-INCH FORMAT SELECTION MENU

    FORMAT SELECTION

    QIC150   = SELECT QIC 150 FORMAT

    QIC120   = SELECT QIC 120 FORMAT

    QIC24   = SELECT QIC 24 FORMAT (READ ONLY)

    QIC11   = SELECT QIC 11 FORMAT (READ ONLY)

    SELECTION:

    Type QIC150, QIC120, QIC24, or QIC11 at the prompt.

  3. If the attached drive is a floppy disk drive, the following menu displays:

    4. FLOPPY FORMAT SELECTION MENU

    FORMAT SELECTION

    RAW-ON   = SELECTS RAW DATA READ/WRITE

    RAW-OFF   = SELECTS FORMATTED DATA

    READ/WRITE

    SELECTION:

    Type RAW-ON or RAW-OFF at the prompt.

  4. If an invalid selection is entered at either prompt, the following message displays:

    5. [6013] INVALID TAPE FORMAT SPECIFIED

     

    NOTE

    Various T-FORMAT menus are displayed depending on the capabilities of the tape drive.

Label Sizes

Tape labels can be either long (512 bytes) or short (80 bytes). The default label length is long. Short labels are used for backward compatibility with previous Mentor releases. Currently, the 60MB 1/4-inch QIC tape drive supports the S option for reading and writing short labels in QIC11 and QIC24 formats. QIC tape drives of 150MB or greater also support the S option; however, the option’s use is limited to reading short-label QIC11 and QIC24 tapes.

NOTE

1/4-inch SCSI tape drives do not support short labels.

Long labels may be set by typing T-FORMAT and the desired format. For example:

>T-FORMAT (Q24

[6015] TAPE FORMAT SET TO QIC 24

[6035] TAPE FORMAT SET TO LONG LABEL

Short labels may be set by entering T-FORMAT and the desired format with the S option. For example:

>T-FORMAT (Q24 S)

[6015] TAPE FORMAT SET TO QIC 24

[6010] TAPE FORMAT SET TO SHORT LABEL

After using T-SELECT to select and attach a tape drive, type T-FORMAT with the ? option to see the tape format currently set. For the 1/4-inch 60MB tape drive, messages similar to the following display:

[6019] QUARTER INCH TAPE, QIC 11 FORMAT

[6010] TAPE FORMAT SET TO SHORT LABEL

If the tape unit has not been selected and attached when you type T-FORMAT, the following message displays:

[93] ATTACH THE TAPE UNIT.

Use T-SELECT to select and attach the unit to your process, then reissue the T-FORMAT command.

When you set the tape format, or if the tape unit is already set to the format you’ve specified, a message similar to the following displays:

TAPE FORMAT SET TO QIC 120

The A Option (Automatic Density Selection)

SCSI 1/4-inch tape drives with auto-sensing capabilities are set for Automatic Density Selection upon installation. This feature enables the tape drive to identify the tape in the drive and automatically write to the tape using the highest allowable format for that tape. Tape drives supporting automatic density selection will always read the tape using the format in which the tape was written.

If T-STATUS is entered immediately after the installation of an auto-sensing SCSI 1/4-inch tape drive, the following displays:

UNDEFINED, AUTOSENSE

The format is undefined since the tape drive cannot identify the tape’s format until a READ or WRITE is executed.

The tape drive remains in auto-sensing mode until a T-FORMAT command, specifying a QIC format, is issued. The tape is written in the specified format from the time the T-FORMAT command is issued until automatic density selection is re-enabled. To re-enable automatic density selection, issue the T-FORMAT command with the A option.

NOTE

T-FORMAT QICn (A is invalid and will produce an error message.

Data Compression

1/4-inch tape drives supporting data compression are enabled for data compression upon installation. Tapes default to the highest capacity. Reading and writing compressed data is supported by the QIC2000 format. Other tapes drives and formats do not support data compression.

The tape drive will remain enabled for data compression until a T-FORMAT command, specifying a QIC format (and therefore disabling automatic density selection) is issued. For example, execution of the following:

T-FORMAT QIC2000

disables data compression on a tape drive supporting the feature. This allows a user to create a QIC2000 tape that is readable on a tape drive that does not support data compression.

Data compression is re-enabled (on tape drives supporting the feature), when automatic density selection is re-enabled.

The N Option (No Retension)

By default, 1/4-inch tapes at Beginning-Of-Tape (BOT) are retensioned before data is written to them. Users may find this feature inconvenient when writing to high capacity tapes, since the retension pass takes a significant amount of time. Retension may be disabled by issuing the T-FORMAT command with the N option specified. The retension feature is re-enabled upon issuing the T-FORMAT command without the N option specified.