Write access may be subject to a different type of control. By specifying a value for MINIMUM-PAGES (WRITE-CONTROL operand), the start of a tape session may be made contingent on the quantity of data to be written: tape access is delayed until the total volume of all write requests has reached the specified number of 2-Kbyte blocks (PAM pages). If the minimum number of pages is not reached until the end of the HSMS session, the requests are retained for the next HSMS session.
Only the following are counted for MINIMUM-PAGES:
write requests from S0 to S2
write requests from nonprivileged users.
This means that the following are not counted:
write requests from the HSMS administrator
requests to copy save files
requests for migration from S1 to S2.
By specifying START-TIME=*IMMEDIATELY, PERIOD=0 and MINIMUM-PAGES >= 0 it is possible to determine that write access is not time-controlled at all but always delayed until a minimum number of PAM pages can be written.
By specifying MINIMUM-PAGES in conjunction with NEW-STD-SAVE-FILE=*EACH-TAPE-SESSION, the latter defining for the archive concerned that a new standard save file is to be started for each tape session, the approximate degree of utilization of the tape save file created by the write request can be controlled; this is applicable to migration and long-term archives provided they have been defined accordingly.
Since write requests from the HSMS administrator are not counted in the number of pages to be written, i.e. would require additional space on the volume, it is advisable in this case always to start write requests from the HSMS administrator as express requests.