OF • ix CONVERSATIONAL MONITOR (CMS) ••• 2-1 INTRODUCTION TO CMS •• The CMS Command Language
The File System. • • • • Program Development ••• INTERRUPT HANDLING IN CMS. • SVC Interruptions. • • . • Internal Linkage SVCs •••• Other SVCs. • • • • •• Input/Output Interruptions • Termina: Interruptions • • Reader/Punch/Printer Interruptions User-Controlled Device Interruptions • .2- 3
.2- 3
.2-4
.2- 5
.2-7
.2-7
.2-7
.2-7
.2- 8
.2- 9
.2- 9 • 2-9
.2-9 Program Interruptions •••• External Interruptions • • • • Machine Check Interruptions. • • • • 2- 10 . 2-10 FUNCTION AL INFORMAr ION • • 2- 11 Usage .. • • • 2-11 Structure of DMSNUC. • • 2-11 U:JERSSCT (User Area) •••••• 2-12 DEVT AB (Device rable) • • • 2-12
Structure of CMS Storage •• 2-12 Free Storage Management. • • • • 2- 14
GETMAIN Free Storage Management .•• 2-14 DMSFREE Free Storage Management. 2-17
Releasing Allocated Storage ••••• 2-21
DMSFREE Service Routines •••••• 2-22
Error Codes from DMSFRES, DMSFREE, and DMSFRET • • • • • • • • •• 2-24 CMS Handling of P SW Keys • • • . • • 2- 25 CMS SVC Handling •••••••••• 2-26 SiC Types and Linkage Conventions •• 2-26 Search Hierarchy for SVC 202 •••• 2-28 User and Transient Program Areas •• 2-29
Called Routine Start-Up Table •••• 2-31
Returning to the Calling Routine. 2-31 CMS Interface for Display Terminals •• 2-34 Os MACRO SIMULATION UNDER CMS ••••• 2-35 OS Data Management Simulation ••••• 2-35
Handling Files that Reside on CMS Disks • • • • • • • • • • 2-35
Handling Files that Reside on OS or DOS Disks • • • • • • • . 2-36
Simulation Notes • • • • • • • 2-38
Access Method Support. • • 2-42
Reading OS Data Sets and DOS Files Using Os Macros • • 2-45 DOS/VS SUPPORT ONDER CMS ••••••• 2-48 CMS Support for OS and DOS VSAM Functions • • • • • • • • • 2-48 CMS METHOD OF OPERATION AND PROGRAM ORGANIZATION. • ••••••••••• 2-51 Contents INITIALIZATION OF THE VIRTUAL MACHINE ENVIRONMENT . • • • • •• 2-57
Initialization: Loading a CMS Virtual Machine from Ca ra. Reader. • • • 2- 57
Initializes Storage Contents and System Tables • • • • • • • • 2-58
Processes IPL Command Line
Parameters. • • • • • • • • • 2-58
Initialize OS SVC-Handling without
the Use of the CMSSEG Segment ••• 2-59
Initializing a Named or Saved System • 2-bO Handling the First Commanj Line Passed to :MS. • • • • • • • • • • • • • • • 2-60 Setting and QueryinJ Virtual Machine Environment Options ••••••••• 2-60 DMSSET: SET DOS ON (VSAM) Processing 2-60 DMSSET: SET SYSNAME Processing ••• 2-61 PRCCSSSING AND EXECUTING CMS PILES •• 2-62 an Interactive Console
Environment e • • • • • • • • 2-62 Console Management and Command
Handling in CMS • • • • • 2-62
Maintaining an Interactive
Command/Response Session ••••••• 2-62
Execute Commands Passed via DMSINS • 2-63
Handle Commands Entered During a CMS Terminal Session •••••••••• 2-63 Method of Operation for DMSINT • • • • 2-64
Method of Operation for DMSITS •••• 2-65
Types of SVCs and Conventions • • • • • • • • • • • • 2-66
Search Hierarchy for SVC 202 • • • • 2-68 User ana Transient Areas • • 2-68
Called ROlltine Start-Up Tabl e.. 2-69 Returning to the Caller ••.•••• 2-69 System ana User Save Area 2-70 Load and :sxecute Text Files. • • • • • 2-71 SL: :ard Routine • • • • • . • • • • 2-72
rcs Card Routine -C2AE1 .. •••• 2-73 ESD Type a Card Routine -C3AA3. 2-74 ESD Type 1 Card Routine - ENTESD • • 2-74 ESC Type 2 Card Routine - C3AH1. 2-75 ESD Type 4 Routine -pc. . . .• 2-76 ESD TYFes 5 and 6 Card Routine - PRVESD ana. COMESD ••••••••• 2-76 ESD Type 10 Routine - WEAK EXTRN • • 2-77 TXT :ard Routine -C4AA1 • • •• 2-77 REP C3.rd RO;Jt.ine - C4AA3 •••••• 2-78
END Card Routine -C6AA1 • • • 2-80 Control Card Routine -CTLCRD1 . 2-81 REFAD R Routine (DMSLDRB) • • • • 2- 82 PRSERCH Routine (DMSLDRD). • • • 2- 82
Loader Data Ba ses. • • • • • • 2- 83 ESIDTB Entry • • • • • •• • •• 2-83 Pa tch Control Block (PCB). • • • 2- 85
Loader Input Restrictions. • • 2-85 Processing Commands That Manipulate the File System. • • • • • • • 2-85 Managing the CMS File System ••••• 2-86
Contents v

How CMS Files Are in
File Status rabIes • Chain Links. . • • • . • • • 2- 86 • • • • 2- 86 • 2- 87 CMS Record Formats • . • • • • • 2- 88 Disk ••.•• Physical Organization of Virtual • 2-88
Disks • • • • • • • • • • • •• 2-88
The Master File Directory ••••.. 2-89 Keeping rrack of Read/Write Disk
Storage: QMSK and QQMSK •••••• 2-90 Dynamic Storage Management: Active
Disks and Files •••••••.•• 2-93 CMS Routines Used To Access the File System. • • • ••••••••••• 2-93
Access a Virtual Disk: DMSACC •••• 2-93
Handling IIO Operations. • • • • 2-94 Unit Record I/O Processing • • 2-94 Han.dlin;, Interruptions •••••••• 2- 98
Disk 1/0 in CMS. • • • • 2- 98 Read or Write Disk I/O •• 2-98 Managin] eMS _ .•.•• 2-99 Types of Allocated Free Storage ••• 2-99 Free Storage Management Pointers. • • ••••••••••• 2-100 DMSFREE Free Storage Pointers •••• 2-101 DMSFRS Method of Operation.. .2-104 Relative Efficiency of DMSFREE Requests. • • • • • • • • • • .2-105 Releasing Allocated Storage ••••• 2-105 DMSFRE Service Routines. • .2-105 Stora;,e Protection Keys. • • • • • .2-107 CMS System Handling of PSW Keys ••• 2-107 CP Handling for Saved Syste.s •••• 2-108 Error Codes from DMSFRRF., DMSFRES, and DMSFRET • • • • • .2-110 The DMSFRES Macro. • • .2-111
The DMSKEY Macro.. • ••••• 2-111
The DMSEXS Macro. • • •• 2-112 SIMULATE NON-CMS OPERATING ENVIRONMENTS ••••••••••••• 2-113
Access Method Support for Non-CMS Operating Environments •••••••• 2-113 OS Access Method Support •••••• 2-113 CMS Support for the Virtual Storage Access Method •••••••••••• 2-114
Creating the DOSCB Chain •••••• 2-114
Executing an AMSERV Function ••••• 2-114
Executing a VSAM Function for a DOS User. • • • • • • • • .2-116 CMS/DOS SVC Handling •••••••• 2-116
Executing VSAM Function for an as User. • . • • • • • . . • . . . .2-118 Completion processing for OS and DOS VSAr. Programs •..•••••. 2-121 OS Simulation by CMS ••.•.•.•. 2-122 Simulating a DOS Environment under eMS ••••••••••••••••• 2-137
Initializing DOS and Processing DOS System Control Commands •••••• 2-137 Setting or System Environment Options •••••••• 2-139 Process CMS/DOS OPEN CLOSE Functions ••••••••••••• 2-140 Process CMS/DOS Exe=ution-Related Control Commands •••••••••• 2-142 Simulate DOS SVC Functions ••••• 2-144 SV:s Tredted as No-Op by CMS/DOS •• Process CMS/DOS sarvice .Commands •• 2-148
Terminate processing the CMS/DOS Environment • • • • • • .2-148 PERFORMING MISCELLANEOUS CMS FUN:TIONS • . • • • • eMS 3atch Facility •• Error Printouts. • • • • • .2-149 • • .2-149 • •••••• 2-153
C MS DI RECl'ORI ES. • • .2-155 MODULE ENTRY POINT DIRECTORY. • .2-157 CROSS REFERENCE •••• 2-169 LABEL-TO-MODULE CROSS REFERENCE •••• 2-189 CMS DIAGNOSTIC AIDS. • .2-237 SUPPORTED DEVICES. • • • .2-239 DMSFREX CODES. • • • • .2-240 Error :odes from DMSFREE, DMSFRES, and DMSFRET • • • • .2-240 ABEND CODES. • ••••••••• 2-241
Abend Recovery ••••••• 2-241
Unrecoverable Termination --The
HALT Option of DMSERR • • • • .2-242 APPENDIX A: CMS MACRO LIBRARY • .2-241 APPENDIX E: CMS/DOS Macro Library ••• 2-251 INDEX. • .2-253
vi IBM VM/370 System Logic and Program Determination--Volume 2