An installation writes a Tape Device Selection function routine
to ensure that tape devices 270 and 271 are available only for HSM
tape requests. (This example is included in SYS1.SAMPLIB as member
IEFTASSI.)
TAPESSI CSECT
TAPESSI AMODE 31
TAPESSI RMODE ANY
******************* START OF SPECIFICATIONS ***************************
* *
*01* NAME= *
* *
*01* TYPE= Sample Subsystem *
* *
*01* FIRST ELIGIBLE PRODUCT= HBB5520 *
* *
*01* FIRST INELIGIBLE PRODUCT= HBB5510 *
* *
*01* OPERATION= *
* This is a sample taple allocation subsystem. It will *
* reserve devices 270 and 271 for only HSM jobs. *
* *
* 1. Chain save areas *
* 2. See if the JOBNAME is HSM* *
* 3. If it is not then will ensure that *
* devices 270 and 271 are not eligible *
* 4. Return to SSI *
* *
*03* SOFTWARE DEPENDENCIES: *
* *
*04* REQUIRED PRODUCTS= HBB5520 *
* *
*02* OUTPUT: *
* *
*03* MSGIDS= NONE *
* *
*03* ABENDCODES= NONE *
* *
******************** END OF SPECIFICATIONS ****************************
***********************************************************************
* *
* Base register: 12 *
* *
* Other register use: *
* 10 SSCVT *
* 2 SSOB *
* 9 SSIB *
* 8 SSTA *
* *
* Attributes: *
* This routine must be reentrant and reside in a library *
* accessible at the time subsystem initialization occurs. *
* Supervisor state, AMODE(31), RMODE(ANY) *
* *
***********************************************************************
***********************************************************************
* Chain saveareas *
***********************************************************************
USING TAPESSI,12
SAVE (14,12) Save caller registers
LR 12,15 Establish module base register
*
LR 10,0 Establish addressability
USING SSCT,10 to the SSCVT
LR 2,1 Establish addressability
USING SSOB,2 to the SSOB
*
GETMAIN R,LV=84,SP=230 Get working storage
ST 13,4(1) Chain saveareas forward
ST 1,8(13) Chain saveareas backward
LR 13,1 Point to this module's savearea
LR 11,1 Point to dynamic storage
USING DYNAM,11 Base dynamic storage
*
***********************************************************************
* Validate the request *
***********************************************************************
L 9,SSOBSSIB Establish addressability
USING SSIB,9 to the SSIB
CLC SSIBSSNM,SSCTSNAM Verify the subsystem name
BNE ERROR This should never happen
L 8,SSOBINDV Pointer to function dependent
* area
***********************************************************************
* Check for job name beginning with HSM *
***********************************************************************
USING SSTA,8 Set basing
CLC HSMNAME,SSTAJNAM Check job name
BE NOCHECK Skip checks if not HSM*
***********************************************************************
* Job name does not begin with HSM so must not allow devices *
* 0270 and 0271 to be eligible to satisfy request. *
***********************************************************************
L 7,SSTADDAP Get address of DD entries
USING SSTADDA,7 Base DD entries
L 4,SSTANDDS Get number of DDs
LTR 4,4 Check for zero
BZ NOCHECK If zero then no DDs to check
ST 4,NUMDDS Else save in local storage
DDLOOPS EQU * Start looping through DDs
L 6,SSTADRAP Get address of first request
USING SSTADRA,6 Base request entries
L 4,SSTANDRA Get number of requests
LTR 4,4 Check for zero
BZ DDLOOPE If zero then no requests
ST 4,NUMREQS Else save in local storage
REQLOOPS EQU * Start looping through requests
L 5,SSTADEVP Get address of first device
USING SSTAEDA,5 Base device entries
L 4,SSTANDVS Get number of devices eligible
LTR 4,4 Check for zero
BZ REQLOOPE If zero then no devices
ST 4,NUMDEVS Else save in local storage
***********************************************************************
* Check each eligible device entry to make sure that devices *
* 0270 and 0271 are not eligible to this request. *
***********************************************************************
DEVLOOPS EQU * Start looping through devices
CLC SSTADNUM,HSMDEV1 Is device reserved for HSM?
BE MAKEINEL Yes, go make ineligible
CLC SSTADNUM,HSMDEV2 Is device reserved for HSM?
BNE DEVLOOPE No, bypass making ineligible
MAKEINEL EQU *
OI SSTAUSE1,B'10000000' Mark device ineligible
DEVLOOPE EQU * End of eligible device loop
LA 3,12 Get size of SSTAEDA entry
ALR 5,3 Add to pointer to get next
L 4,NUMDEVS Get local counter
LA 3,1 Get amount to decrement count
SLR 4,3 Decrement count
ST 4,NUMDEVS Save device count
LTR 4,4 Check device count
BNZ DEVLOOPS Loop back if more to process
REQLOOPE EQU * End of request loop
L 6,SSTADRAN Get address of next request
L 4,NUMREQS Get local counter
LA 3,1 Get amount to decrement count
SLR 4,3 Decrement count
ST 4,NUMREQS Save request count
LTR 4,4 Check request count
BNZ REQLOOPS Loop back if more to process
DDLOOPE EQU * End of DD loop
L 7,SSTADDAN Get address of next DD entry
L 4,NUMDDS Get local counter
LA 3,1 Get amount to decrement count
SLR 4,3 Decrement count
ST 4,NUMDD Save DD count
LTR 4,4 Check DD count
BNZ DDLOOPS Loop back if more to process
NOCHECK EQU *
MVC SSOBRETN,=F'0' Indicate function success
B RETURN
ERROR EQU *
MVC SSOBRETN,=F'20' Indicate function failure
***********************************************************************
***********************************************************************
* Return to the SSI *
***********************************************************************
RETURN EQU *
L 8,4(13) Pointer to caller's savearea
FREEMAIN R,LV=84,A=(13),SP=230
LR 13,8
LM 14,12,12(13) Restore caller' registers
LA 15,0 RC=0
BSM 0,14 Return to the SSI
*
HSMNAME DC CL3'HSM' HSM Jobname
HSMDEV1 DC CL4H'270' Device reserved for HSM
HSMDEV2 DC CL4H'271' Device reserved for HSM
*
DYNAM DSECT Dynamic storage
SAVEAREA DS 18F Module save area
NUMDDS DS F Number of DDs
NUMREQS DS F Number of requests
NUMDEVS DS F Number of eligible devices
*
IEFJSCVT
IEFSSOBH
IEFJSSIB
IEFSSTA
END
z/OS MVS Using the Subsystem Interface
Copyright IBM Corporation 1990, 2014