Exabyte EXB-8205 Instrucciones de operaciones descargar pdf (Pagina 32)

Physical Beginning of Tape (PBOT)

PBOT is located at the point on the tape where the translucent leader

material is attached to the media. This position is detected by an

optical sensor in the tape transport mechanism.

Note: The leader material of the EXATAPE 160m XL data cartridge

contains a Recognition System stripe that identifies it as

data-grade media. All 160m tapes used in the EXB-8505XL or

EXB-8205XL are required to have this stripe to ensure the

proper characteristics for data storage.

Logical Beginning of Tape (LBOT)

When you issue a write operation at the beginning of tape, the CTS

automatically records LBOT approximately 29 inches (74 cm) from

PBOT.

LBOT consists of a series of tracks that are used to indicate LBOT’s

location and to calibrate the servo system. The first track containing

data blocks is recorded directly after the last track containing the

LBOT information. You cannot alter or access the data contained in

the LBOT blocks.

The tape can be repositioned and a write operation can be performed

to erase the LBOT and record a new LBOT in the same space. This

process occurs, for example, when a write operation is performed at

LBOT on a previously written tape.

If a read-after-write check indicates an error while the CTS is writing

LBOT, the blocks are not rewritten. Errors in writing the LBOT blocks

are not reported to the initiator. If excessive read-after-write checks

occur, the tape is rewound and the entire process is repeated. If the

retry fails, a Medium Error is reported.

During read operations, LBOT blocks are not transferred to the

initiator.

End of Data (EOD)

After writing data, the CTS writes an end-of-data (EOD) mark to

indicate the location of the last data on tape. In 8500c and 8500

format, the EOD mark includes two or more tracks of erase gap and

600 tracks of EOD physical blocks. In 8200c format, the EOD mark

includes 249 tracks of erase gap and 600 tracks of EOD physical

blocks.

1-10

EXB-8205 and EXB-8505

(Standard and XL)

510503

1 CTS Features

1 2 ... 27 28 29 30 31 32 33 34 35 36 37 ... 445 446

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Exabyte EXB-8205 Instrucciones de operaciones Pagina 32