Guardian Procedure Calls Reference Manual

• Disk accesses and the refresh EOF option
If a disk file has the refresh EOF option set (options.<10> = 1), the file label is immediately
written to disk each time the end-of-file (EOF) pointer is changed. (For a description of the
refresh EOF option, see the information on unstructured disk files in the Enscribe Programmer's
Guide.) Depending on the particular application, there can be a significant decrease in
processing throughput due to the increased number of disk writes when the refresh EOF option
is set.
• Creating an HP NonStop Storage Management Foundation (SMF) file
When creating a file on a SMF virtual volume, the system chooses the physical volume on
which the file will reside. If you want to specify the physical volume, you must create the file
using the FILE_CREATELIST_ procedure.
• Creating format 2 key-sequenced files with increased limits
In H06.28/J06.17 RVUs with specific SPRs and later RVUs, format 2 legacy key-sequenced
files can be created with increased file limits. (For a list of the required H06.28/J06.17 SPRs,
see SPR Requirements for Increased Enscribe Limits for the H06.28/J06.17 Release (page 31)
.) The creation of a file with increased limits occurs if the file-type parameter has a value
of 3 (key-sequenced) and at least one of the following is specified:
◦ A blocklen value of 32,768 bytes (or a value greater than 4096 bytes, which is
rounded up to 32,768 bytes)
◦ A keylen value of 256 to 2048 bytes
Note the following considerations when using these increased limits with the FILE_CREATE_
procedure:
◦ recordlen may have a value up to 27,648 bytes (depending on the value of blocklen.
◦ The key-length of a key-sequenced file is limited to 255 bytes when either the index or
data compression option is specified. If an attempt is made to create a key-sequenced
file with a key longer than 255 bytes with either index or data compression, an error 46
is returned.
◦ The CEXTDECS file uses the unsigned short data type (instead of short) for the
blocklen parameter.
◦ The creation of files with these increased limits is not supported on legacy 514-byte sector
disks; the creation attempt will fail with an FEINVALOP (2) error.
◦ When using the C API to create a file with the 32,768 byte block length, you can avoid
various C integer conversion warnings by using 0x8000 (32768 in hex).
• Exceeding the file system file label space
An attempt to create a file receives an error 1027 if the file system file label space for the
primary partition would be exceeded.
If the file specification has up to 16 partitions, reduce the number of alternate-key files, alternate
keys, extents, secondary partitions and/or the size of the partition keys.
If the file specification has more than 16 partitions, reduce the number of alternate-key files,
alternate keys, and/or extents.
Safeguard Considerations
For information on files protected by Safeguard, see the Safeguard Reference Manual.
390 Guardian Procedure Calls (F)