These PDF documents, starting from 1964, are those parts of the OS/360 "System Reference Library" (SRL) with enduring relevance and are also the earliest System/360 publications available on the web. Given IBM's stubborn insistance on full upward compatibility, all facilities described here (most of which are still supported) continue to function as described, even on the most recent z/Architecture systems. Where applicable, these publications often present the essence of the topic while being much shorter and easier to digest.
A22-6821 Principles of Operation Details of System/360 and the Instruction Set
A22-6822 System/360 Bibliography Guide to System/360 Publications
C28-6535 Concepts and Facilities
C28-6644 Master Index Alphabetized list of keywords with manual references
C20-1620 System/360 Pointers: Programming Techniques - Many examples in Assembler
C20-1646 Introduction to Architecture, Instructions and Assembler Language
C20-1649 Introduction to Direct Access Storage
R23-2933 Introductory Programming, Book 1 - Introduction
R23-2950 Introductory Programming, Book 2 - Program Control and Execution
R23-2957 Introductory Programming, Book 3 - Fixed Point Binary Operations
R23-2958 Introductory Programming, Book 4 - Branching, Logical and Decimal Operations
R23-2959 Introductory Programming, Book 5 - Input/Output Operations
Introductory Programming: Student Workbook
System Facilities: Student Guide
C24-3337 Report Program Generator Specifications
C28-6514 Assembler Language Reference
C28-6515 FORTRAN IV Language Reference
C28-6516 COBOL Language Reference
C28-6571 PL/I Language Specifications
C28-6594 PL/I Programmer's Guide
C20-1651 A Guide to PL/I for Commercial Programmers
C28-6808 Student Text - A PL/I Primer
C28-8201 PL/I Reference Manual
C28-6537 Data Management Data Formats and I/O Macros
C28-6538 Linkage Editor and Loader
C28-6539 Job Control Language Essential for "batch" program exection
C28-6541 Control Program Services
C28-6550 System Programmer's Guide
C28-6628 System Control Blocks