September 20, 2005

FDRPAS ANNOUNCEMENTS

Dear FDRPAS Customer,

This letter is to notify you of a fix to FDRPAS that is mandatory if you are running on a system that supports MIDAWs.

The Modified Indirect Data Address Word (MIDAW) Facility is a new channel I/O construct supported only on the new IBM System z9-109 processor. MIDAWs are a more efficient way of addressing large blocks of data than IDAWs, the construct used for large blocks prior to the z9. MIDAW use is optional, depending on the access method.

MIDAWs are used only on z9-109 systems and only if you have installed z/OS 1.7 or applied enabling PTFs to z/OS 1.6 (see below). Earlier releases of z/OS will not use MIDAWs on z9 systems.

IBM recently discovered an issue with MIDAWs on non-IBM disk equipment, and the IBM fix requires a corresponding fix in FDRPAS.

In the IBM fix, z/OS now detects non-IBM disk equipment and determines if it supports MIDAWs. A new flag in the UCB indicates if the disk supports MIDAWs; it will be on for all IBM disk equipment but it will be on for non-IBM disks only if they indicate that they support MIDAWs.

The IBM swap service that FDRPAS calls will no longer allow a swap between a MIDAW-enabled disk and a non-MIDAW disk or vice versa. So, to prevent problems in FDRPAS, we have added tests to detect a mismatch in MIDAW support between the source and target disks of each swap; if they do not match, the swap will be rejected. This test is made at the beginning of the swap, at several places during the swap and just before the IBM swap service is called.

SETIOS MIDAW=NO (or YES to re-enable)

You must use this command at a time when no FDRPAS swaps are active, and allow a few minutes for all MIDAW use to quiesce before starting any swaps.

The MIDAW fix is incorporated into FDRPAS V5.4 level 50 which will be GA on or about September 30, 2005. FDRPAS V5.4/50 is required if you install z/OS 1.7.

If you are running z/OS 1.6 with the MIDAW-enabling PTFs installed, a zap P-54.4386 is also available for FDRPAS V5.4 levels 42 and 43. This zap is mandatory at those levels; failure to apply the zap may result in a disk being swapped on some systems but not all, leading to data corruption and other failures.

If you meet the criteria above and are exposed to the problem, you must apply the zap or install level 50. If you are using FDRPAS V5.4 level 41 or below, you must upgrade.

The zap can be downloaded from the Innovation FTP site for FDRPAS at http://www.innovationdp.fdr.com/ftp/ftp_fdrpas.cfm

Enter your access code and click LOGIN.
Click on the Maintenance directory.

If you do not remember your access code, please send an e-mail to ftpid@fdrinnovation.com to request it.

You can also contact Innovation to get the zap e-mailed.

The IBM APARs that enable MIDAWs are OA10984, OA13324 and OA13384. On z/OS 1.6 you must install the PTFs for all of these APARs to enable MIDAW usage. On z/OS 1.7, the GA release may contain some but not all of the PTFs; IBM will advise you if any of them must be manually applied.

If you have questions on this issue, please contact Innovation.