HP 3000 Manuals HP 3000 Manuals
CHANGE BLOCKMAX
Changes the maximum block length of one or more data sets.
Syntax
{DataSetName }
CHA[NGE] BLOCKM[AX] {FirstDataSetName/LastDataSetName} BlockMaxNumber
{@ }
Parameters
DataSetName is the name of the data set to be assigned the
new maximum block length.
FirstDataSetName/ are names that define a range of data sets to
LastDataSetName be assigned the new maximum block length.
@ is used to change the maximum block length for
all the data sets in the database.
BlockMaxNumber is the new maximum physical block length in
words. It must be a number from 128 to 2048 or
0. If 0 is specified, it takes the value
calculated by DBSCHEMA.
Description
Use this command to change the maximum block length of one or more data
sets. Multiple CHANGE BLOCKMAX commands may be issued. If multiple
commands include overlapping ranges of data sets, the MaxBlockNumber in
the last CHANGE BLOCKMAX command is in effect for the data set range
indicated. For example, if one CHANGE BLOCKMAX command is issued for
data sets 1 through 4 and the next CHANGE BLOCKMAX command is issued for
data sets 3 through 5, the first BlockMaxNumber is in effect for data
sets 1 and 2 and the second BlockMaxNumber is in effect for data sets 3
through 5. To verify the order of the data sets before using the CHANGE
BLOCKMAX command, use the REVIEW BLOCKS or REVIEW SETS command.
The BLOCKMAX must be large enough to accommodate the blocking factor.
That is, if the media record is 6 words, and the blocking factor is 14,
the BLOCKMAX must be at least 85 words.
To change the blocking factor of the data set, use CHANGE BLOCKFACTOR.
Example
>change blockmax sales 1024
In this example, the maximum block length of the SALES data set is
changed to 1024.
Before the change, the SALES data set entry in the schema looks like
this:
$CONTROL BLOCKMAX = 640 <---- block length to be changed
NAME: SALES ,D(11/14,18);
ENTRY: ACCOUNT ( CUSTOMER (PURCH-DATE )),
STOCK# (!PRODUCT ),
QUANTITY ,
PRICE ,
TAX ,
TOTAL ,
PURCH-DATE ( DATE-MASTER ),
DELIV-DATE ( DATE-MASTER );
CAPACITY: 504(14);
After the change, the SALES data set entry in the schema looks like this:
$CONTROL BLOCKMAX = 1024 <---- block length changed
NAME: SALES ,D(11/14,18);
ENTRY: ACCOUNT ( CUSTOMER (PURCH-DATE )),
STOCK# (!PRODUCT ),
QUANTITY ,
PRICE ,
TAX ,
TOTAL ,
PURCH-DATE ( DATE-MASTER ),
DELIV-DATE ( DATE-MASTER );
CAPACITY: 504(14);