Guardian Procedure Calls Reference Manual

• Named processes
If you supply a process file name for a named process, it can represent any process with the
same name. System messages are normally sent to the current primary process. The exception
is when a named process supplies its own name to FILE_OPEN_. In that case the name refers
to the backup process and system messages are sent there.
A named process can be represented with or without a sequence number. FILE_OPEN_ treats
the two name forms differently.
◦ If you supply a process file name that includes a sequence number, the process must have
a matching sequence number or the open fails with error 14. When retrying I/O on a
process opened under such a name, the file system does not attempt to send messages
to a possible backup process of the same name unless it has a matching sequence number.
This is to assure that it is a true backup.
◦ If you supply a process file name that does not include a sequence number, any process
with a matching name can be opened and can be sent I/O retries. A newly created
process that receives an I/O retry intended for another process of the same name will
usually reject it with an error 60, but this is under the control of the application.
• Partitioned files
A separate FCB exists for each partition of a partitioned file. There is one ACB per accessor
(as for single-volume files), but this ACB requires more main memory since it contains the
information necessary to access all of the partitions, including the location and partial-key
value for each partition.
• Disk file open—security check
When a disk file open is attempted, the system performs a security check. The accessor's (that
is, the caller's) security level is checked against the file security level for the requested access
mode, as follows:
read security level is checked.for read access:
write security level is checked.for write access:
read and write security levels are checked.for read-write access:
A file has one of seven levels of security for each access mode. (The owner of the file can set
the security level for each access mode by using SETMODE function 1 or by using the File
Utility Program SECURE command.)
Table 19 shows the seven levels of security.
Table 19 Levels of Security
AccessProgram ValuesFUP Code
Local super ID only7–
Owner (local or remote), that is, any user with owner's ID6U
Member of owner's group (local or remote), that is, any member of owner's
community
5C
Any user (local or remote)4N
Owner only (local)2O
Member of owner's group (local)1G
Any user (local)0A
464 Guardian Procedure Calls (F)