IBM Mainframe Discussion List <[email protected]> wrote on 02/01/2008 09:16:32 AM:
> 2. z9, z/OS 1.7 (with service), Shark ESS 800 with Microcode 2.4.4.112. > > D IOS,MIDAW > IOS097I 10.41.07 MIDAW FACILITY 542 > MIDAW FACILITY IS ENABLED > > MVS command: > D M=DEV(8D10) > ?? > SCP TOKEN NED = 002105.000.IBM.75.0000000xxxxx.0D00 > SCP DEVICE NED = 002105.000.IBM.75.0000000xxxxx.0D10 > PAV BASE AND ALIASES 4 > FUNCTIONS ENABLED = MIDAW > > shows that MIDAV is enabled > > But another Command show that is still *unavailable*: > > DS,QD,8D10,RDC > UNIT VOLSER SCUTYPE DEVTYPE CYL SSID SCU-SERIAL DEV-SERIAL EF-CHK > 8D10 ZXXXXX 2105800 2105000 3339 8D00 0175-XXXXX 0175-XXXXX **OK** > READ DEVICE CHARACTERISTIC > 2105E833900A5E80 BFF720240D0B000F E000E5A205940222 1309067400000000 > 0000000000000000 24241B02DFEE0001 0677080F007F4800 0035000000000000 > > X'80' means (in ...A5E80) means that MIDAW is disabled. > Q2: Is the microcode level correct for MIDAW? > Q3: If yes, what should be done to enable this function? When MIDAW was being designed, it was thought that it would work with all DASD controllers with no changes required to the DASD. When it was subsequently discovered that MIDAW did not work correctly with some non-IBM DASD, the solution was to define the bit in Read Device Characteristics so that the DASD controller could indicate if it supported MIDAW. But since all IBM DASD already did work with MIDAW, the MVS code first checks to see if the manufacturer field in the NED is 'IBM', and if so, MVS assumes that the device supports MIDAW. This avoided the need to update IBM DASD simply to turn on the Read Device Characteristics bit. If the manufacturer is not 'IBM', then the Read Device Characteristics bit is used to determine if the device supports MIDAW. Jim Mulder z/OS System Test IBM Corp. Poughkeepsie, NY ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
