PDP-1 Expensive Desk Calculator Jan63

This document is a collection of correspondence and a program review concerning the "Expensive Desk Calculator" (EDC) program, designated DECUS #31, developed by Robert A. Wagner of MIT in January 1963.

The primary purpose of the document is to highlight and address significant issues found within the EDC program and its accompanying original write-up. A program review by M. Hill details several problems:

1. Program Defects and Write-up Errors: Bugs were found in the automatic multiply/divide function, with difficulties arising from both program defects and errors in the original documentation.
2. Arithmetic Inaccuracies: The program exhibits inconsistencies in decimal arithmetic, rounding, and significant figure handling, often requiring specific decimal notation for accurate results. Typing NS (N significant digits) sometimes produces an unexpected number of zeroes.
3. Unclear Documentation: Instructions for procedures like iteration and macro definition (particularly the "middle dot" usage for the POLY macro) are ambiguous, leading to difficulties for users.
4. Unspecified Features: Certain program behaviors, such as an error type-out "sce" and the function of sense switch 6 for punching, are mentioned but not clearly explained in the write-up.
5. Output Formatting Challenges: Achieving desired tabular output for function values is problematic, with values often intermixed with user input.

DECUS, through its Secretary Elsa Newman, acknowledges these issues, referring to "faulty tapes" and expressing concern about program certification. They are actively working with MIT (Ralph Butler) to obtain corrected program tapes and are in the process of providing a revision of the write-up. The document concludes with the original, detailed write-up for DECUS #31, which is the subject of the review.