File No. 7090-36 Form C28-6383-2 Systems Reference Library IBM 7090-7040 Direct Couple Operating System Systems Programmer's Guide This publication contains information useful to programmers who require a thorough understanding of the IBM 7090-7040 Direct Couple Operating System (DCOS), #7090-PR-161. This system consists of the following parts: 7090/7094 Operating System (IBSYS) 7040/7044 Control Program (DCMUP) The publication provides descriptions of general DCOS program logic, the format of the DCOS System Library, the Operating System Monitor (DC-IBSYS), and the lnput/Output Executor (DC-IOEX). It also includes instructions for system library preparation and maintenance. Separate publications contain descriptions of the compo­ nents of the 7090/7094 Operating System (IBSYS). Other related publications contain information needed by applica­ tions programmers and instructions for machine operators. Form C28-6383-2 Page Revised 6/11/65 By TNL N28-0158-0 PREFACE This publication is primarily intended IBM 7040/7044 Principles of Operation, for systems programmers who are responsible Form A22-6649 for the maintenance of the 7090-7040 Direct Couple Operating System (DCOS} and any modifications to it at the installation. IBM 7090 Principles of Operation, Form It may also be of interest to individuals A22-6528 who desire a more thorough understanding of the system. IBM 7094 principles of Operation, Form A22-6703 The reader of this publication is Directly Coupled Processing Units--7040 assumed to be familiar with the contents of to 7090/7094; 7040 to 7094/7094 II, Form the publication IBM 7090-7040 Direct Couple A22-6803 Operating System: Programmer's Guide, Form C28-6382. The Direct Couple Operating System is designed for five machine configurations: Information required by machine opera­ tors is contained in the publication IBM 1. 7090-DC-7040 7090-7040 Direct Couple Operatinq Syst~ 2. 7094-DC-7040 Operator's Guide, Form C28-6384. 3. 7094-DC-7044 4. 7094 II-DC-7044 For information on the IBJOB processor, 5. 7094 II-DC-7040 the major subsystem of DCOS, the reader is referred to the following IBM publications: Throughout this publication, the terms 7090 and 7040 are used to refer to the IBM 7090/7094 IBSYS Operating System: 7090, 7094, or 7094 II and to the 7040 or IBJOB Processor, Form C28-6389 7044, respectively, as permitted in the IBM 7090/7094 Proqramming Systems: FOR­ configurations above. TRAN IV Language, Form C28-6390 IBM 7090/7094 Programminq Systems: Macro This publication is divided into ten Assembly Program (MAP) Language, Form sections. The first section is devoted to C28-6392 the logic flow of the 7040 side of the IBM 7090/7094 Programming Systems: COBOL system. The next three sections are devot­ Language, Form C28-6391 ed to the 7090 side of the system. The IBM 7090/7094 IBSYS Operating System: fifth section explains the logic used by IBJOB Processor Debugging Package, the 7040 when servicing 7090 input/output Form C28-6393 requirements. The sixth section describes the DCOS Distribution Tape. The seventh Information about the IBM 7040/7044 Data section describes system editing proce­ Processing Systems, the IBM 7090/7094/7094 dures. The eighth and ninth sections deal II Data Processing Systems, and for the with system library preparation and main­ Direct Couple feature are given in the tenance. The last section discusses DCOS following publications: unit assignment philosophies. Major Revision (March 196~ This edition, Form C28-6383-2, is a major revision of Form C28-6383-1. This publication amplifies material pre­ viously presented, and, in some cases, provides additional material. Major changes and additions are concerned with: examples of system modification, unit control blocks (7040 tape units), the DCOS distribution tape, the system editor (IBEDT), job setup, the $JOB card, and the *REMARK card. Additions or changes are indicated by a vertical line to the left of the text; new or revised illustrations are denoted by the symbol • to the left of the caption. The following publications are made obsolete by this revision: C28-6383-1, C28-6383-0,and the Technical Newslet­ ters N28-0146-0 and N28-0144-0. Copies of this and other IBM publications can be obtained through IBM Branch Offices. A form for readers' comments appears'at the back of this publication. It may be mailed directly to IBM. Address any additional comments concerning this publication to the IBM Corporation, Programming Systems Publications, Department D39, 1271 Avenue of the Americas, New York, NY., 10020. C 1964 by International Business Machines Corporation Form C2B-6383-2 Page Revised 6/11/65 By TNL N2B-015B-O CONTENTS INTRODUCTION TO DCOS 7 $UNITS Card • • • • • • • • • • • • • 26 DCOS Use of Disk/Drum Storage Units 7 DC-IBSYS NUCLEUS 27 Modes of Operation • • • • 8 Communication Region 27 The Direct Mode •• • • 8 The Compatibility Mode • 8 System Unit Function Table 28 General Logic Flow 8 Unit Availability Table •• 29 The DCOS Commutator 10 The Job Queue Table 10 Job Control Communication With The Job Description Block 10 Subsystems • • • • • • • • • • 29 Unit Control Blocks (7040 Tape Communication Region Locations Uni tS) •••••••••••••• 10 SYSRET, SYSGET, and SYSJOB •••• 29 File Control Blocks •••••• 10 Channel Information Blocks • • • •• 10 Recognition of DC-IBSYS Supervisor Input/Output File Control Block Base Control Cards by SUbsystems 30 (IOBASE) ••••••• 12 $IBSYS Card 30 Data Buffer Format • • • 13 $EXECUTE Card 30 Input Service Routine 14 $STOP Card • 30 Job Setup 14 $ID Card • • • • • 30 Initialization for 7090 Execution 17 Job Breakdown 17 DIRECT COUPLE INPUT/OUTPUT EXECUTOR • • 31 Punch Stage • • • • • 17 Print Stage • • • • • 18 Unit Control Blocks • 31 Background Utility Routines 19 Word 1 • • • • 31 7040/7044 Utility Routines • 19 Word 2 • • • • • 33 Word 3 • • • • • 33 DC-IBSYS MONITOR 21 Word 4 33 DC-IBSYS SUPERVISOR • • 22 Unit Priority on a Channel 33 Channel-Priority Location • • • • • 33 Initialization Procedures • 22 Use of Channel-Priority Location 34 Activating a Channel and/or Assigning Basic Supervisor Control Cards 22 Priority • • ~ • • • • • • • • • • 34 $Job Card 22 $EXECUTE Card 22 Non-Data Selects ••••• 35 $ID Card • • 23 Structuring of Input/Output Requests in Direct Mode • • • • 35 Unit Assignment Control Cards • 23 $ASSIGN Card • 23 INPUT/OUTPUT IN THE TWO DCOS MODES 37 $RELEASE Card 24 $RESET Card 24 Processing Input/Output Requests $SWITCH Card 24 (Direct Mode) •••••••••• 37 $CARDS Calrd 24 Processing Input/Output Requests $TAPE Card •• 24 (Compatibili ty Mode) 40 Tape-Manipulation Control Cards 24 DISTRIBUTION OF DCOS 41 $ENDFILE Card 24 $REWIND Card 25 Listings 41 $REMOVE Card • • 25 $UNLOAD Card • • • • • • 25 DCOS Distribution Tape 41 File 1 • • • • • 41 Miscellaneous Control Cards 25 File 2 41 $STOP Card • • • • • • • 25 File 3 41 $IBSYS Card • • • • 25 File 4 42 Files 5-15 42 DC-IBSYS Supervisor Control Cards • 25 $RESTORE Card 25 SYSTEM EDITOR (IBEDT) 43 $IBEDT Card 26 *EDIT Card • • • • • 48 Form C28-6383-2 Page Revised 6/11/65 By TNL N28-0158-0 Arrangement of DCMUP, DC-IBSYS, IBSYS Respecification of 7040 Disk (Drum) Subsystems and the System Editor •••• 48 Environment • • •• • • • 67 *PLACE Card • • • • • • • • • • • • • 48 Maintenance of the System Name and Preparation of a New DCSYS from a DCOS Loader Tables. • 48 PRESYS Library. • 68 Alteration Cards • • • • • • • • • • 49 Posteditor Output. • 69 Absolute Column-Binary Cards. • 50 7040 System Name Table. • 69 Octal Cards • • • • • • • • • • 50 Track Allocation and Module Definition Table ••••• • 70 Standard PRESYS Library Record Formats • 50 Utility Name Table ••••• • 70 Posteditor Output Tape (DCSYS) Maintenance Control Cards ••• • 51 Format • • • • • • • • • • • • • 71 *MODIFY Card. • • 51 *REPLACE Card • • 51 Posteditor Restrictions and Error *INSERT Card. • 52 Messages. • 71 *REMOVE Card. • • .53 *AFTER Card • • • 53 DCOS UNIT ASSIGNMENT PROCEDURES •• • 73 *DUP Card ••• • 53 7040 File Control Blocks •••• • 73 *REWIND Card. • • 54 Assignment of 7040 Tape Units to *CHECK Card • • • 54 7040 File Control Blocks • • • • 74 *REMARK Card. • • 54 Communication Of 7040 File Control Termination of Editing • • 54 Block--7090 Unit Control Block Relationship. • • • • • • • • • • • 74 Editing Relocatable Records. • • • 54 IBLDR Unit Assignment Process ••• 75 Editing Examples • • 55 Assignment of Secondary Units • 76 Example 1 • 55 Example 2 • • • • 55 Unit Assignment In Other IBSYS Subsystems. • • • • • • • • • • • • 76 DCOS PRESYS LIBRARY MAINTENANCE. • 57 Unit Assignment Procedures for Preparing a Backup DCOS Distribution Non-IBSYS Systems/Programs •• 78 Tape or PRESYS Library Tape •• •• 57 Unit Assignment Considerations 78 Changing The System Input/Output Configurations ••••••••• • 57 APPENDIXES • 80 7040 Input/Output Configuration • 58 Appendix A: DCMUP Tables and Control Incorporating a User-Designed Blocks. • • • • • • • • • 80 Installation Accounting Routine Under The Job Queue Table • • 80 DC-IBSYS. • • • • • • • • • • • • • • • 61 Job Description Block • • 80 Designing An Installation DCMUP Track Allocation Maps 83 Accounting Routine • • • • • • 61 File Control Block. • • • • • 83 Incorporating an Accounting Routine Unit Control Blocks (7040 Tape into a Subsystem. • • • • 61 Uni tS) • • • • • • • • • • • 84 Channel Information Block • 85 Incorporating IBSYS Subsystems Under DC-IBSYS. • • • • • • • • 62 Appendix B: Procedure for Defining Compatibility Mode. • • • • • • 62 an IOBASE Table • • • • • • 86 Direct Mode • • • • • • • • • • 62 Zero