Guardian Procedure Calls Reference Manual

If item 65 is set to 1 and item 42 is set to 0 in item-list, an odd unstructured file is created.
In that case, the values of record-specifier, read-count, and write-count are all
interpreted exactly; for example, a write-count or read-count of 7 transfers exactly 7
bytes.
• Even unstructured files
If items 65 and 42 are both set to 0 in item-list, an even unstructured file is created. In
that case, the values of read-count and write-count are each rounded up to an even
number; for example, a write-count or read-count of 7 is rounded up to 8, and 8 bytes
are transferred.
An even unstructured file must be positioned to an even byte address; otherwise, the
FILE_GETINFO_ procedure returns error 23 (bad address).
If you use the File Utlity Program (FUP) CREATE or HP Tandem Advanced Command Language
(TACL) CREATE command to create a file, it creates an even unstructured file by default.
• Upper limit for maximum-extents
If you specify a value greater than 500 for maximum-extents (item 52 in item-list),
there is no guarantee that a file will be created successfully. In addition, FILE_CREATELIST_
returns error 21 if the values for primary and secondary extent sizes (items 50, 51, and 91
in item-list) and maximum-extents (item 52) yield a file size greater than (2**32) -
4096 bytes (approximately four gigabytes) or a partition size greater than 2**31 bytes (two
gigabytes).
• For unstructured files on a disk device other than a legacy device with 514-byte sectors
5
, both
primary-extent-size and secondary-extent-size must be divisible by 14.
When you create an unstructured disk file that has no secondary partitions, if you specify file
extents that are not divisible by 14 in the FILE_CREATELIST_ call, the extents are automatically
rounded up to the next multiple of 14, and the specified MAXEXTENTS is lowered to
compensate. FILE_CREATELIST_ does not return an error code to indicate this change. This
change is visible only if you call FILE_GETINFOLIST_ to verify the extent size and the
MAXEXTENTS attributes.
However, when you create an unstructured disk file that has one or more secondary partitions,
extent sizes that are multiples of 14 pages must be explicitly specified in the FILE_CREATELIST_
call. Otherwise, FILE_CREATELIST_ returns error code 1099 to the caller.
• Insertion ordered alternate keys
All the nonunique alternate keys of a file must have the same duplicate-key-ordering attribute.
That is, a file cannot have both insertion ordered alternate keys and standard (duplicate
ordering by primary key) nonunique alternate keys. An insertion -ordered alternate key cannot
share an alternate-key file with other keys of different lengths or with other keys that are not
insertion-ordered.
The FILE_CREATELIST_ procedure returns error 46 if the rules of usage for insertion ordered
alternate keys are violated.
When an alternate-key record is updated, the timestamp portion of the key is also updated.
Alternate-key records are updated only when the corresponding alternate-key field of the
primary record is changed.
The relative position of an alternate-key record within a set of duplicates might change if an
unrecoverable error occurs during a writeupdate of the primary record.
There is a performance penalty for using insertion ordered duplicate alternate keys. Updates
and deletes of alternate-key fields force the disk process to sequentially search the set of
alternate-key records having the same alternate key value until a match is found on the
primary-key-value portion of the key. (The value of the timestamp field in an alternate key
5. Devices with 514-byte sectors are not used on TNS/E systems.
FILE_CREATELIST_ Procedure 401