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.

DEVSERV QTAPE will display '3592E07' for the real device type, where E07 is the drive model, if the underlying physical device is a 3592 Model E07 (TS1140). If the MEDIUM option is specified for DEVSERV QTAPE command, the real device type will be displayed as '3592-4E'.

Figure 1 shows the output of DS QT,960 when a TS1140 (3592 Model E07) tape drive emulates a 3590 Model B1x tape drive.

Figure 1. DS QT,960 output

11.20.46 SYSTEM1           DS QT,960                                 
11.20.46 SYSTEM1           IEE459I 11.20.46 DEVSERV QTAPE 760        
UNIT DTYPE  DSTATUS CUTYPE  DEVTYPE  CU-SERIAL  DEV-SERIAL ACL LIBID 
0960 3590   ON-RDY  3592C06 3592E07* 0178-00030 0178-00030

Figure 2 shows the output of DS QT,960,MED when a TS1140 (3592 Model E07) tape drive emulates a 3590 Model B1x tape drive.

Figure 2. DS QT,960,MED output

11.21.21 SYSTEM1           ds qt,960,MED                             
11.21.21 SYSTEM1           IEE459I 11.21.21 DEVSERV QTAPE 763        
UNIT RDTYPE  EDTYPE EXVLSR INVLSR RMEDIA EMEDIA         WWID         
0960 3592-4E 3590-1        1P0694   9      3

A bit DFVTJAG4 is added to the IHADFVT mapping macro that maps the data facilities vector table. When this bit is set, it indicates that all of the software support for the 3592 Model E07 (TS1140) drive is on the system. This bit is set by the enabling module IECTEPTF, if it is installed.

The IECUCBCX mapping macro is changed to support the TS1140:

The new EPI value is X'15' - REALJAG4_EMUL3590

The DDR Swap Exit handles swaps involving the 3592 Model E07 drive and the new recording formats EFMT4 and EEFMT4. Appropriate rules are also put in place for handling a lower technology EFMT2, EFMT3, EEFMT2, or EEFMT3 (MEDIA9 and MEDIA10) request on a 3592 Model E07 to a 3592 Model J, E05, or E06 (as appropriate and as consistent with past 3592 support). Table 1 shows a summary of what swaps are allowed.

Table 1. Format swaps allowed for TS1140
Format	From device	Allowed to device	Message
EFMT1	3592-J	3592-J 3592-2 3592-2E	'MUST SWAP TO A 3592-J OR 3592-2'
EFMT1	3592-2 3592-2E	3592-2 3592-2E	'MUST SWAP TO A 3592-2'
EFMT2	3592-2 3592-2E	3592-2 3592-2E 3592-3E	'MUST SWAP TO A 3592-2 OR 3592-3E'
EEFMT2	3592-2E	3592-2E 3592-3E	'MUST SWAP TO A 3592-2E OR 3592-3E'
EFMT2/EEFMT2 or EFMT3/EEFMT3 (MEDIA5 - MEDIA8)	3592-3E	3592-3E	'MUST SWAP TO A 3592-3E'
EFMT3/EEFMT3 (MEDIA9 - MEDIA10)	3592-3E	3592-3E 3592-4E	'MUST SWAP TO A 3592-3E OR 3592-4E'
EFMT3/EEFMT3 (MEDIA9 - MEDIA10) or EFMT4/EEFMT4	3592-4E	3592-4E	'MUST SWAP TO A 3592-4E'
EFMT1 EFMT2/EEFMT2 (MEDIA5 - MEDIA10)	3592-3E	3592-3E 3592-4E	'MUST SWAP TO A 3592-3E OR 3592-4E' (Read attempt only - write attempts suppressed in ERP)
EFMT1 EFMT2/EEFMT2 (MEDIA5 - MEDIA8) EFMT3/EEFMT3 (MEDIA5 - MEDIA8)	3592-4E	3592-4E	'MUST SWAP TO A 3592-4E' (Read attempt only - write attempt's suppressed in ERP)