File name Mesa_4.0_Change_Summary_May78.pdfInter-Office Memorandum
To Mesa Users Date May 31, 1978
From Dave Redell. John Wick Location Palo Alto
Subject Mesa 4.0 Change Summary Organization SOD/SO
XEROX
Filed on: [IRIS] OOC>SUMMARY40.BRAVO
This memo outlines changes made in Mesa since the last release (October 17, 1977).
References
The following documents can be found on [IRIS]; all files are in Bravo format.
Hardcopy is available through your support group; in addition. the PRESS files MESA40A,
MESA40B, and MESA40C are a compilation of this material (about 75 pages).
Mesa 4,0 Change Summary. SUMMARY40.BRAVO
Mesa 4.0 Compiler Update. COMPILER40.BRAVO, ARITHMETIC40.BRAVO
Mesa 4.0 Process Update. PROCESS40.BRAVO
Mesa 4.0 Binder Update. BINOER40.BRAVO
Mesa 4.0 System Update. SYSTEM40.BRAVO
Mesa 4.0 Microcode Update. MICROCODE40.BRAVO
Mesa 4.0 Debugger Update. DEBUGGER40.BRAVO
The section on processes is a preliminary draft of a new chapter of the Mesa Language
Manual (which will be sent to the printer shortly); thanks are due to Dave Redell and the
Pilot Functional Specification for contributing much of this material.
The MESA)DOC directory also includes new versions of the Mesa System Documentation and
the Mesa Debugger Documentation (the relevant PRESS files are SYSTEM 1, SYSTEM2, and
DEBUGGER).
Highlights
The primary emphasis in this release has been on three areas: implementation of features
required by Pilot and Dstar applications for effective use of the new machine architecture
(processes. monitors, long pointers, etc.), reduction of overhead in the basic system structures
and improved performance of the Mesa runtime environment (faster microcode, smaller
global frames, more efficient memory management). and extension of the debugger's
capabilities (primarily an interpreter for a subset of the Mesa language).
Mesa 4.0 Change Summary 2
The primary impact of Mesa 4.0 on existing systems is in the area of concurrent
programming. A brief intoduction to the new process mechanism appears below. It is
intended to present enough information to enable programmers to experiment with the new
features of the language and the runtime system. However, before attempting to revise or
redesign existing systems to use these facilities, programmers are urged to carefully examine
the material in the Mesa 4.0 Process Update and the Mesa System Documentation.
Warning: Because Pilot will be available soon, the Alto/Mesa operating system software
has not been revised and redesigned to fully exploit the capabilities of the new process
mechanism. In particular, arbitrary preemptive processes are | 