Device support modifications

z/OS DFSMS device support provides hardware device-specific code, which allows tape drives, tape volumes, and DASD to interface with z/OS DFSMS. Specifically, it provides:

The interfacing exits to the input/output supervisor (IOS) and EXCP device support code
Error recovery procedure routines
Services to acquire and log statistical and error data
Services to acquire and display device states
Utilities for functions like initializing tapes

You can use the MVS DEVSERV command to request basic status information on a device, a group of devices, or storage control units. You can use the QTAPE parameter of the DEVSERV command to display tape device information. Use DEVSERV QTAPE to display the real device type and the emulated device type.

With the DEVSERV QTAPE MED (medium) option, you can display information for the device type, media type, and cartridge volume serial number.

The syntax of the DEVSERV QTAPE command with the MED option is as follows:

DS QT,xxxx,MED,nnn

xxxx: Represents a three-digit or a four-digit device number in hexadecimal format.
nnn: Stands for the number of devices, starting at the address xxxx, for which the DEVSERV command displays the MED information. The value nnn is optional and can be any decimal number from 1 to 256, with 1 as the default value.

Figure 1 shows the display content when you issue the DEVSERV QTAPE MED command.

Figure 1. DEVSERV QTAPE MED display content

 
    ----------------------------------------------  
    ----      DS QT MED Display Content      -----  
    ----------------------------------------------  
 
    IEE459I          DEVSERV QTAPE                   
    UNIT RDTYPE EDTYPE EXVLSR INVLSR RMEDIA EMEDIA WWID  X

 X  UNIT   - tape device address
    RDTYPE - real device type
    EDTYPE - emulated device type
    EXVLSR - external volume serial of cartridge
    INVLSR - internal volume serial of cartridge
    RMEDIA - real media type of the volume mounted on the drive
    EMEDIA - emulated media type of the volume mounted on the drive
    WWID   - world-wide identifier or world-wide unique cartridge identifier

Note:

EDTYPE, EXVLSR, INVLSR, RMEDIA, EMEDIA, and WWID are blank if information is not available.
Valid values for RMEDIA and EMEDIA are:
- 1=CST
- 2=EC-CST
- 3=3590 STD length tape
- 4=3590 EXT length tape
- 5=3592 Enterprise Tape Cartridge
- 6-W=3592 Enterprise WORM Tape Cartridge
- 7=3592 Enterprise Economy Tape Cartridge
- 8-W=3592 Enterprise Economy WORM Tape Cartridge
RMEDIA and EMEDIA are blank when the media type is not defined or cannot be determined.

These examples show sample output and messages of the DEVSERV QTAPE command with the MED option.

Figure 2 shows the output of DS QT,962,MED when a 3592 Model J tape drive emulates a 3590 Model B1x tape drive.

Figure 2. DS QT,962,MED output

 
     IEE459I 11.32.31 DEVSERV QTAPE 608
     UNIT RDTYPE EDTYPE EXVLSR INVLSR RMEDIA EMEDIA  WWID
     0962 3592-J 3590-1                 6-W    3     85804D003C00000BC211CA0C

Figure 3 shows the output of DS QT,940,MED when a 3592 Model J tape drive emulates a 3590 Model B1x tape drive.

Figure 3. DS QT,940,MED output

 
     IEE459I 11.32.31 DEVSERV QTAPE 608
     UNIT RDTYPE EDTYPE EXVLSR INVLSR RMEDIA EMEDIA WWID
     0940 3592-J 3590-1 003700          5      3

Figure 4 shows the output of DS QT,DA0,MED when a 3592 Model J tape drive emulates a 3490 tape drive.

Figure 4. DS QT,DA0,MED output

 
     IEE459I 11.32.31 DEVSERV QTAPE 608
     UNIT RDTYPE EDTYPE EXVLSR INVLSR RMEDIA EMEDIA WWID
     0DA0 3592-J 3490   AN4000          5      1

Figure 5 displays the message that is issued when the input device address is valid, but the device is not a Model B1x, Model E1x, Model H1x, 3592 Model J, or 3490E drive.

Figure 5. DS QT,B60,MED message

 
     IEE459I 11.32.31 DEVSERV QTAPE 608
     UNIT RDTYPE EDTYPE EXVLSR INVLSR RMEDIA EMEDIA WWID
     **** UNLISTED DEVICE(S) AND REASON CODES :
       0B60(10)  Y 
     **** (10) - UNSUPPORTED DEVICE TYPE

Y Reason Code 10, UNSUPPORTED DEVICE TYPE, is shown when the device type given is not a Model B1x, Model E1x, Model H1x, 3592 Model J, or 3490E drive.

Figure 6 shows the message and reason code 11 that you receive if the input device address and device type are valid, but the device is not ready.

Figure 6. DS QT,DA0,MED message

 
     IEE459I 11.32.31 DEVSERV QTAPE 608
     UNIT RDTYPE EDTYPE EXVLSR INVLSR RMEDIA EMEDIA WWID
     **** UNLISTED DEVICE(S) AND REASON CODES :
       0DA0(11)  Z  
     **** (11) - DEVICE NOT READY

A bit, DFVT3592, is added to the IHADFVT mapping macro that maps the data facilities vector table. If the enabling PTF for base 3592 and MEDIA5 is installed, DFVT3592 is set to indicate that all of the base software support for the 3592 Model J tape drive is on the system and supports the 3592 drive and MEDIA5.

A bit, DFVTWORM, is added to the IHADFVT mapping macro that maps the data facilities vector table. If the enabling PTF for the media types, MEDIA6, MEDIA7, and MEDIA8, is installed, DFVTWORM is set to indicate that all of the software support for 3592 WORM media types (MEDIA6 and MEDIA8) and economy R/W media type (MEDIA7) is on the system.

System-wide DEVSUPxx parmlib member options control and manage media type selection for Automatic Tape Library (ATL) partitioning: MEDIA5=xxxx, MEDIA6=xxxx, MEDIA7=xxxx, and MEDIA8=xxxx, where xxxx is a 4-digit hexadecimal category code.

The IECUCBCX mapping macro is changed to support the 3592 Model J tape drive. The EPI values are:

X'10' --REAL3592_EMUL3590
X'11'--REAL3592_EMUL3490

There are also these bits:

UCBCX_MAXBUFBLK is set if the device can report the maximum block size since the last synchronizing event.
UCBCX_FASTACC is set if the medium supports a fast access segment.
UCBCX_WORM is set if the device has WORM capability.

Additionally, the order of these two fields is reversed so that UCBCX_VOLSEQ is now a two-byte field and UCBCXRS6 is now a four-byte fields.

The IECLOGT mapping macro is changed to support the WORM media on the system. A bit, VLOG_WORM, is set for WORM media. There are also these fields:

VLOG_WWID, a 12-byte hexadecimal medium world-wide identifier for WORM media that is unique for each tape cartridge and cannot be changed by a user command.
VLOG_WMCNT, a two-byte Volume Write Mount Count indicator of the number of mounts that have occurred for the WORM volume when logical blocks were written to the medium. This field can be updated during an OPEN/CLOSE sequence when no user data is written to the tape because tape labels can be rewritten.