On Wed, 27 Mar 2013 10:03:03 -0500, John Gilmore wrote: > >Consider now what happens if storage is allocated on a doubleword >boundary D. The next doubleword boundary is at D + 8. Placing the >halfword current-length prefix at D + 6 ensures that any doubleword >alignment for what begins at D + 8 is satisfied. > Does the OS guarantee that when a program is invoked from JCL the PARM is so aligned? If so, good reason; if not, poor reason.
>Be grateful that quadword alignment is still only a very specialized >requirement. If it were enforced the maximal length of a >current-length prefixed PARM string would be 32752. > Perhaps, in anticipation, the limit should immediately be reduced (with little pain) to 32752 to protect against the need for incompatible futur changes. But I'd still envision that could be satisfied by doing a STORAGE OBTAIN for 32784 bytes and placing the halfword current-length prefix at Q+14. Does STORAGE OBTAIN still, in the 21st Century, limit the size of the obtained block to 32768? What about page alignment? (But what page size?) Survey question: Has any reader here ever coded in JCL a PARM for which the called program required alignment? (I heard long ago of an F+2 alignment to satisfy S/360 specifications.) -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
