HP 3000 Manuals HP 3000 Manuals
RELOADING A KSAM FILE
You use FCOPY to reload a KSAM file when KEYINFO cannot recover the file.
You must first use the KSAMUTIL BUILD command to build the new file, and
then use FCOPY to copy the file. In general, you should use the KEY=0
option of FCOPY (see section II for a complete description of the FCOPY
options for KSAM files). KEY=0 copies the file in chronological sequence
so that the new file will be an exact copy of the original file, except
that records marked for deletion are physically deleted from the file.
For example, to reload the file TEST to a new KSAM file, NEWTEST:
:RUN FCOPY.PUB.SYS
>FROM=TEST;TO=(NEWTEST,NEWKEY) ;KEY=0;NEW
After the file is successfully reloaded, you should purge the old file
TEST and rename the file NEWTEST. To do this, run KSAMUTIL and use the
PURGE and RENAME commands as follows;
RUN KSAMUTIL.PUB.SYS
HP32208V2.4 THU, MAR 8,1979,1:05 PM KSAMUTIL VERSION:A.3.0
>PURGE TEST
TEST,TESTKEY PURGED
>RENAME NEWTEST,TEST
>RENAME NEWKEY,TESTKEY
Now you can run any existing programs that referenced the old file TEST.
The only time you might not want to use the KEY= option to reload a
damaged file is if the key file has been accidentally purged. In this
case, and if the file has fixed-lengt,h records, you can use the NOKSAM
option. This option needs only the original data file. As it copies the
data file in chronological order to a new KSAM file, it creates a key
file with key entries for the data records. The NOKSAM option does not,
however, allow you to copy a data file with variable-length records.
Refer to the instructions for copying variable-length KSAM files in
Section II.
For example, to reload a KSAM data file for which you have only a data
file with fixed-length records, first build the new data file, NEWFIL,
then use the following FCOPY command:
>FROM=DATAFIL;TO=NEWFIL;NOKSAM;NOUSERLABELS;
SUBSET=#%377,%377,,EXCLUDE |
\__________________________/ |
| |
| |
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to exclude records marked you must not copy
for deletion by -1 in user labels to a
first two characters KSAM file
This command copies only the non-deleted records; it creates a new KSAM
file with only valid records and a key file that has key entries for each
data record.
After a system crash in which the key file is lost, it is possible that
the MPE end-of-file follows the KSAM end-of-file because it was written
to disc just before the crash. If this is the case and you use the
NOKSAM option you should also use a SUBSET option to copy only the
records up to the KSAM end-of-file, not the undefined area between the
KSAM and MPE end-of-files.
EXPAND KEY BLOCK BUFFER AREA
Depending on the length of the existing file, the reloading procedure can
take a long time. One way to shorten this time is to increase the number
of key block buffers in the extra data segment for the file. Since
reloading is a write-only operation, the more buffers that can be
allocated to key blocks, the less swapping is needed between the extra
data segment and disc as new key entries are added.
In order to increase the number of key block buffers, enter the following
commands:
:RUN FCOPY.PUB.SYS
>FROM=TEST;TO=(NEW,NEWK);SUBSET=1,0 <------------ create new file with 0 records
>:FILE F=NEW;DEV=,,20 <------------ increase number of key block buffers
>FROM=TEST;TO=*F;KEY=0 <------------ copy data in chronological order
|
|------ remember to back reference file