Exabyte EXB-8205 Instruções de Operação descarregar pdf (Página 371)

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101

Overview of Directory Support

The sample application in this appendix shows one method for

creating a tape that uses the directory support feature. This sample

uses the READ POSITION (34h) and LOCATE (2Bh) commands to

implement directory support, but you can use the SPACE (11h)

command as well. Figure B-1 shows how the information will be

arranged on a tape that was created using this method.

The components in Figure B-1 are as follows:

LBOT is the logical beginning of tape.

MASTER DIR isthemasterdirectoryforthetape.Themaster

directory contains data from READ POSITION commands that

points to the locations of other directories on the tape.

EOD 1 is the first end-of-data mark on the tape. EOD 1 is

automatically written at the end of the master directory when you

rewind the tape to LBOT.

PAD is an area on tape that accounts for the space required to

create and update the master directory.

LFM is a long filemark separating the master directory and pad

space from the data sets written to the tape.

DS 1 through DS n are data sets containing groups of data files.

DIR 1 through DIR n are directories for data sets DS 1 through

DS n. These directories contain data from READ POSITION

commands that points to the locations of the individual files

within each data set.

EOD 2 is the second end-of-data mark on the tape. EOD 2 is

automatically written after the last data set directory when you

rewind the tape.

LBOT

MASTER DIR EOD1 DS 1 DIR1 DIR

...

PAD

LFM

EOD2

Figure B-1 Typical arrangement of information on a directory support tape

B-2

EXB-8205 and EXB-8505

(Standard and XL)

510503

Appendix B Directory Support

1 2 ... 366 367 368 369 370 371 372 373 374 375 376 ... 445 446

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