Oce DJDE, Справочное руководство

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Input Processing Summary of BLOCK Command Parameters
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Points to note:
• The LENGTH parameter may be overridden by ANSI, IBM OS or Standard labels that
specify block length.
• The values for LTHFLD, OFFSET, FORMAT, and PREAMBLE may be overridden if
RECORD STRUCTURE is changed as the result of ANSI, IBM OS or Standard label
processing.
• The search for the block delimiter constant starts after the block preamble and proceeds
forward to the first appearance of the constant.
• The maximum block size that may be processed by the input task is 24,576 bytes. The
input task is able to allocate at least one input buffer for offline tape jobs when the tapes
are written in maximum size blocks.
• If a block length is specified which is less than this minimum block length found on the
tape, input processing allocates input buffers, which are sized to the minimum tape
block length. It is wise to specify the maximum block length in the JSL, so that input buff-
ers are large enough to handle the largest block. If the actual tape block length is small-
er than the JSL block length, then no error message is reported; otherwise, an error is
displayed.
• If a block delimiter constant is positioned and is part of a record or block, the user should
use caution, since the record or block will be truncated. As a result, the data will not be
formatted as specified.
Online versus offline JDLs
An offline JDL statement set that modifies the system default values, specifically in the
BLOCK or RECORD commands, may experience incorrect results if running an online job
(JDE). In other words, if an online job (JDE) is called out in an offline JDL that has changed
the system default values (of the BLOCK and RECORD command parameters), the job
may not print correctly. It is best then to separate and run online and offline jobs (JDEs) in-
dependently from each other.