600 608 610 618 620 628 630 638 640 648 650 658 660 668 670 678 680 688 690 698 6AO 6A8 6BO 6B8 6CO 6C8 6DO 6D8 6EO 6E8 6FO 6F8 SYSREF V(FVS) V(OPSECT) V(DEVTAB) V(FSTLKP) V(DMSINM) V(FSTLKW) V(PIE) V(lADT) V(USERSECT) V(DMSDIOR) V(DMSSCNN) A(O)
V(TABEND) V(SUBSECT) A(O) V(DMSDIOW) V(DMSSTGST) V(ADTSECT) V(FREE) V(FRET) V(DMSPIOCC) V(PGMSECT) V(lOSECT) V(DMSDBD) V(DIOSECT) V(DMSABNUA) V(DMSERL) V(DMSCRD) V(DMSFREB) V(SVCSECT) V(ADTLKP) V(DMSAUDUP) A(O) V(OSRET) V(CMSRET) V(DMSSCNO) V(DMSEXC) V(DMSLDRA)
V(ADTLKW) V(USABRV) V(EXTSECT) V(SCBPTR) A(O) H'O' I H'O' V(DMSLAF) V(DMSLAFNX)
V(DMSLAFFE) V(DMSLAFFT) V(ADTNXT) V(DMSTRK)
V(DMSTRKX) V(DMSTOO) V(DMSTOOX) V(DMSERS) V(TYPSRCH) V(DMSUAD) V(KILLEX) V(DMSFNST) V(DMSBRD) V(DMSBWR) V(DMSFNS) V(DMSSTTE) V(DMSSTTW) V(POINT) Figure 71. CMS Control B1ocl{S :: .•. : : \ :::: ) ( > ) / ) >: :< < ;:... :::.::: ) I I DMSNUC F S :-- ree torage USERSECT SUBSECT CMSCB TSOBLKS DMSERL I/O I FCBIO 'OBDCBPTlIOBECBPT DBGSECT 10SECT CMSCVT DCB I DECB PGMSECT DMSABW EXTSECT DMSERT r\\ DIOSECT AFT I USABRV I continued SYSNAMES DMSFRT FVS SVCSECT AFTSECT - -'" ADTSECT ,,- .......... I'.. DEVTAB ICMSAVEI B DOSCON ...... AVSAMSYS Terminal Buffer and Saveareas SYSREF /> FREELIST MAINLIST NUCON TXTDIRC (See Legend) MACDIR PRECMND SYSNAME Legend: INSTALID The projection of SYSREF is a SYSEMID sampling of areas within NUCON. Debugging With eMS 531

Reason for the Abelld Collect Illformation
Determine the immediate reason for the abend and identify the failing module.
The abend message DMSABN148T contains an abend code and failing address.
The VM /SP System Messages and Codes manual lists all the CMS abend codes,
identifies the module that caused the abend, and describes the action that should be
taken whenever CMS abnormally terminates.
You may have to examine several fields in the nucleus constant area (NUCON) of
low storage.
1. Examine the program old PS\Y (PGMOPS\Y) at location X'28'. Using the PSW and current CMS load map, determine the failing address.
2. Examine the SVC old PSW (SVCOPSW) at location X'20'.
3. Examine the external old PSW (EXTOPSW) at location X'18'. If the virtual
machine operator terminated CMS, this PSW points to the instruction execut­
ing when the termination request was recognized.
4. For a machine check, examine the machine check old PSW (MCKOPSW) at
location X'30'. Refer to Figure 74 on page 541 in "Appendix A: System/370 Information" for a description of the PSW. Examine several other fields in NUCON to analyze the status of the CMS system.
As you proceed with the dump, you may return to NUCON to pick up pointers to
specific areas (such as pointers to file tables) or to examine other status fields. The
complete contents of NUCON and the other CMS control blocks are described in
the VM/SP Data Areas and Control Block Logic, Volume 2. The following areas of NUCON may contain useful debugging information.
Save Area for Low Storage
Before executing, DEBUG saves the first 160 bytes of low storage in a NUCON field called LOWSA VE. LOWSA VE begins at X'CO'.
Register Save Area
DMSABN, the abend routine, saves the user's floating-point and general regis­
ters.
Field FPRLOG GPRLOG ECRLOG Device
Location
X'160'
X'180'
X'lCO'
Contents
User floating-point registers
User general registers
User extended control registers
The name of the device causing the last I/O interrupt is in the DEVICE field
atX'26C'. • Last Two Commands or Procedures Executed
532 VIyI/SP System Programmer's Guide