VAX-11 PASCAL Installation Guide/Release Notes (Ver 1.0-1)

This document, the VAX-11 PASCAL Installation Guide/Release Notes (November 1979, Order No. AA-J181A-TE), provides instructions for installing the VAX-11 PASCAL V1.0-1 compiler on the VAX/VMS V1.6 operating system. It also contains critical information not found elsewhere in the main documentation set, including details on software errors and changes made late in the development cycle.

Intended for VAX/VMS system managers and PASCAL programmers, the guide is organized into three main sections:

1. Installation Procedure:

   • Describes an automated installation process using three floppy diskettes.
   • Requires system manager privileges to perform steps like setting the User Identification Code (UIC), default directory, and running @VMSUPDATE.
   • Emphasizes the importance of correctly mounting diskettes in sequence.
   • A crucial post-installation step is to establish the logical names SYS$OUTPUT PAS$OUTPUT and SYS$INPUT PAS$INPUT in SYSTARTUP.COM for proper I/O handling.
   • Once installed, the compiler can be invoked with the $PASCAL command.

2. Interface to the VAX-11 Symbolic Debugger:

   • States that the debugger currently lacks specific features to support PASCAL directly.
   • PASCAL programs can be debugged similarly to MACRO assembly language programs, requiring familiarity with VAX instruction architecture.
   • Recommends using MACRO mode over FORTRAN mode for debugging PASCAL programs due to limitations in examining structured variables and setting breakpoints in FORTRAN mode.
   • Notes that line number tables produced by PASCAL are not fully compatible with the debugger for traceback.
   • Only INTEGER, REAL, SINGLE, and DOUBLE types have complete symbol table entries; other variable types require knowledge of PASCAL's internal data formats.

3. Release Notes:

   • Summarizes known restrictions and problems in this release of the VAX-11 PASCAL compiler. Key issues include:
     • The (*$L+*) source qualifier for generating listings does not work; /LIST must be specified explicitly on the command line.
     • Restrictions on rewriting non-empty files on remote DECnet nodes.
     • Requirement to reinstall VAX-11 PASCAL after a new VAX/VMS system generation to update system libraries.
     • When reading REAL or DOUBLE precision numbers, the exponent designator must be a capital 'E' or 'D'.
     • Single-precision real numbers are printed with 9 digits, but only about 7 are significant due to hardware limitations.
     • No run-time checking is performed for dereferencing NIL pointers (leading to access violations).
     • Overflow conditions for REAL and INTEGER numbers are not diagnosed.
     • Boolean comparisons in VAX-11 PASCAL may be incompatible with those from FORTRAN IV-PLUS and other VAX/VMS languages that use 0 for FALSE and 1 for TRUE.
     • Run-time error termination messages are noted to change in future releases.