Specifying input parameters

If a block length is specified that is less than the minimum block length that is found on the tape, the system 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 buffers are large enough to handle the largest block. However, specifying the maximum block length in the JSL may slow performance. If the actual tape block length is smaller than the JSL block length, no error message is reported; otherwise, an error is displayed.

The length on a 4 by 3 packed format tape is the number of 6- bit bytes or characters in the tape block.

BLOCK LMULT

Specifies a multiplication factor that is applied to the contents of the block length field to determine the true block length.

Syntax BLOCK LMULT = value

Options

Table 2-9. BLOCK LMULT parameter options and definitions

Option

Definition

 

 

 

 

value

An integer in the range of 1 to 15 that is multiplied by the value in the length

 

field (refer to LENGTH parameter) to compute the number of bytes in the block.

 

 

Default 1

BLOCK LTHFLD

Specifies the length of the field that contains the block length.

Syntax BLOCK LTHFLD = size

Options

Table 2-10. BLOCK LTHFLD parameter options and definitions

Option

Definition

 

 

 

 

size

An integer from 0 to 5 that specifies in bytes the length of the field that contains

 

the block length.

 

 

Using LCDS Print Description Language

2-15

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Xerox 701P21091 manual Options Block Lmult parameter options and definitions, Block Lthfld