HP 3000 Manuals HP 3000 Manuals
NM File Close Log Record Enhancements
by Donna Gracyk/Alwin Okuna--Commercial Systems Division
Two new fields have been added to the end of the NM file close log record
(type 105) to report the number of file system records processed. The
fields contain the number of records read and the number of records
written. These fields have been added to accommodate those customers who
use similar data on their MPE V/E systems for billing and want the
equivalent information on MPE XL. The "number of records processed" is
already recorded in the MPE XL CM file close record (type 160).
The following tables illustrate the new fields added and the comparison
between the CM and NM file close log record.
word CM FILE CLOSE RECORD word NM FILE CLOSE RECORD
% (TYPE 160) % (TYPE 105)
---------------------- -------------------- |
0 | Record type | 0 | Record type = #105 |
|----------------------| |-------------------- |
1 | Record length | The value --> 1 | Record length =%156 |
|----------------------| in this field |---------------------|
2 | Pin | will change. 2 | Pin |
|----------------------| Old length |---------------------|
3 | Time stamp | was = %146. 3 | Time stamp |
|----------------------| |---------------------|
6 | Job Type | Job | 6 | Job Type | Job |
|----------- Number | | Number |
|----------------------| |---------------------|
10 | Fname.group.account | 10 | # of logical reads |
|----------------------| |---------------------|
25 | Reserved | 14 | # of bytes read |
|----------------------| |---------------------|
26 | disposition | domain | 20 | # of logical writes |
|----------------------| |---------------------|
27 | # sectors allocated | 24 | # of bytes written |
|--------------------- | |---------------------|
31 | device type | unused | 30 | Fname.group.account |
|----------------------| |---------------------|
32 | # records processed | 60 | Creator |
|----------------------| |-------------------- |
34 | # blocks processed | 70 | User.group.account |
|----------------------| |-------------------- |
36 | Ldev | 120 | UFID |
----------------------- |---------------------|
132 | reserved |
|---------------------|
134 | Close Disposition |
|---------------------|
136 | Open Domain |
|---------------------|
140 | File size in bytes |
|---------------------|
142 | File open count |
|-------------------- |
NEW FIELDS ---> 146 | # records read |
(each field |---------------------|
is 4 16 bit words) ---> 152 | # records written |
----------------------
Note that the "# of logical reads" and "# of logical writes" fields in
the NM file close records (type 105) do NOT mean the same thing as the "#
of records read/written". The "# of logical reads/writes" fields refer
to the actual number of calls to FREAD, FWRITE, FREADDIR, and FWRITEDIR.
The "# of records read/written" on the other hand refers to the number of
file system records processed.
There are cases where a single logical read or write will transfer
multiple records. For a file opened with the MR (multi-record) and NOBUF
(physical block transfer rather than logical record transfer) file system
options, the "# of records read/written" will most likely not match the
"# of logical reads/writes".
For example, KSAM opens the KSAM key file MR/NOBUF so that it can read in
an entire key block with one FREADDIR. For a ksam key file built with a
key block size of 8 (eight records in one key block), a single call to
FREADDIR to read in the key block would increment the "# of logical
reads" by one and it would increment the "# of records read" by eight.
ENHANCEMENT LIMITATION WITH MAPPED FILES
Be aware that when using mapped files, the new fields will contain 0 in
the file close records. This is because when an application program uses
mapped files and accesses data in the file using a pointer, it bypasses
many of the file system services that normally keep track of file system
data such as logical record pointers and EOF.
This limitation also applies to Image data base files since Image files
are now opened as mapped files. See "Accessing a File Using Mapped
Access" in the Accessing Files Programmer's Guide (P/N 32650-90017) for
more information on mapped files.