Safeguard User's Guide (G06.24+, H06.03+)

Securing Disk Files
Safeguard User’s Guide—422089-009
3-17
The TRUST Attribute
To verify the setting:
=INFO DISK progfile, DET
You can use the special WHERE PROGID option with most disk file commands to
select only PROGID files. For example, the following command lists PROGID files on
$DATA:
=INFO DISKFILE $data.*.*, WHERE PROGID
You can also use the WHERE PROGID option with the ALTER, DELETE, FREEZE,
and THAW commands.
The TRUST Attribute
The TRUST attribute enables the operating system to optimize I/O performance and
applies only to object files. It is available only in H-series RVUs and can be set only by
the super ID.
On systems running H-series RVUs, these two types of user I/O buffer access should
not be performed:
•
Reading from a nowaited I/O buffer that has an ongoing read operation
•
Writing to an I/O buffer that has any type of ongoing operation
These actions are detected and prevented by the operating system. The prevention
mechanism detects the access, suspends the process until the I/O operation has
completed, and then resumes the process. This suspend/resume behavior can
significantly affect process performance.
The TRUST attribute informs the operating system that the process can be “trusted”
not to access I/O buffers in the preceding manner. The system will bypass the
checking behavior, thus improving performance.
The TRUST attribute has three settings:
•
TRUST OFF specifies that the program is not to be trusted. The initial value of the
TRUST attribute is OFF.
•
TRUST ME specifies that the program can be trusted not to access I/O buffers
private to the process before I/O completion.
LAST-MODIFIED OWNER STATUS WARNING-MODE
$DATA.SALES
PROGFILE 24JUL05, 11:38 5,5 THAWED OFF
005,005 R,W,E,P
004,* R,E
005,* R,W
AUDIT-ACCESS-PASS = NONE AUDIT-MANAGE-PASS = NONE
AUDIT-ACCESS-FAIL = NONE AUDIT-MANAGE-FAIL = NONE
LICENSE = OFF PROGID = ON CLEARONPURGE = OFF PERSISTENT = OFF
TRUST = OFF