Supplement to the LAP6-DIAL Programmer's Reference Manual

This document serves as a supplement and update to the LAP6-DIAL Programmer's Reference Manual, DEC-12-SE2D-D, published in December 1970. It details several new features, system improvements, and corrections for the DIAL-MS operating system.

Key enhancements and updates include:

• Expanded Hardware Support: DIAL-MS now supports up to four RK8 disks and the LPØ8 line printer, alongside existing RSØ8 disks and other peripherals. It provides specific unit number mappings for accessing these new devices.
• User Interaction and System Efficiency: Modifications to DIAL-MS and related utilities like PIP (Peripheral Interchange Program) enhance usability. PIP now allows multiple card deck input and offers faster rebootstrapping for PDP-12 systems with sufficient memory and disk.
• Assembler Functionality: A new CHAIN pseudo-op has been introduced in the assembler to facilitate the assembly of large programs by allowing multiple source files to be linked and assembled sequentially. This feature obsoletes the SAVSYM and LODSYM pseudo-ops.
• Editor Improvements: The DIAL Editor's automatic formatting feature has been expanded, with Sense Switch Ø controlling options for tag field repression. The cursor now flickers to make it easier to locate in lengthy displays.
• Simplified Procedures: System initialization and build procedures no longer require an EXIT command, allowing direct acceptance of DIAL-MS commands.
• Corrections: A list of specific corrections and clarifications for the main LAP6-DIAL Programmer's Reference Manual is provided, addressing issues such as input commands, forbidden user-defined symbols, disk unit handling, buffer modes, and correct Right Switch settings for system startup.