DEC-10-OMCMA-A D Monitor Calls Ver 6.01 May74

This document, the "DECsystem-10 Monitor Calls Manual" (DEC-10-OMCMA-A-D), serves as a comprehensive reference for experienced assembly language programmers using the DECsystem-10. It details the monitor's programmed operators (UUOs) and reflects software releases 5.07 and 6.01.

The manual covers:

1. Memory Format: Describes how user programs are loaded and organized in memory, including segmentation, protection, and relocation mechanisms for KA10 and KI10 processors (including virtual memory). It also details the Job Data Area.
2. User Programming Introduction: Explains the different processor operating modes (User, User I/O, Executive) and introduces Programmed Operators (UUOs) as the primary interface for user programs to request monitor services, categorizing them and outlining their naming conventions.
3. Non-I/O UUOs: Presents UUOs for execution control (starting, stopping, program trapping, and software interrupts), core memory management (allocation, locking, page fault handling), segment control, program identification, inter-program communication, and retrieval of environmental information (timing, job status, monitor examination).
4. I/O Programming (General): Provides a general overview of I/O operations, covering device selection and initialization, the use of ring buffers for data transfer, file selection (LOOKUP, ENTER, RENAME), data transmission modes (buffered/unbuffered), status checking, and file/device termination and reassignment. It also introduces the multiplexed channel feature.
5. I/O Programming (Specific Devices): Offers detailed guidance on I/O programming for various non-directory devices (e.g., card punch/reader, line printer, magnetic tape, paper-tape, plotter, pseudo-TTY, and terminals) and directory devices (DECtape and Disk), including their data modes, file structures, access protection, disk quotas, and spooling mechanisms.
6. Inter-Process Communication Facility (IPCF): Explains how jobs communicate using packets, Process IDs (PIDs), and queues, along with the UUOs (IPCFS, IPCFR, IPCFQ) that manage these interactions.
7. Monitor Algorithms: Delves into the underlying algorithms of the DECsystem-10 monitor, such as job scheduling, program swapping, device optimization, monitor error handling (hardware and software), directory management, and priority interrupt routines.

Appendices offer supplementary technical information, including DECtape compatibility, reentrant program guidelines, card codes, device status bits, error codes, a comparison of disk-like devices, and magnetic tape codes.