[Editor's note:
The document that follows was written around 50 years ago. I have transcribed into HTML to the best of my ability. I have attempted to recapture the original style of the document. In order to do this I have used the only technique then available for highlighting and emphasis: underlining and quoting. This may cause some confusion with hypertext links, but I felt that from the point of view of historical authenticity it was worth it. I have made use of hypertext links to make the document easy to navigate.

There are a few minor blemishes - I have been unable to reproduce some of the special symbols that were available on the typewriters of the day, but hope that with improvements to HTML, I’ll be able to sort these out eventually.

I have been unable to reproduce aome of the underlining across tabular matter. It seems that HTML does not allow such quirky constructs!

There are a couple of "typos" in the original document which I have preserved - they are fairly obvious. I cannot, however, guarantee that I have not introduced a few typos of my own in the transcription process. I take full responsibility for any such errors, and will be happy to correct them if you let me know.

I have added a few "editors notes" in the form [ed: note note note] in places where the text caused me grief when I first was trying to learn this. I hope that these are not too intrusive and do not offend purists.

Bill Purvis, February, 2010]

A Guide to Programming
the 803
Electronic Digital Computer

4th Edition
May 1961

Copyright Reserved
Elliott Brothers (London) Ltd., Computing Division,
Elstree Way, Borehamwood, Hertfordshire, England

NCR Electronics, National Cash Register Co. Ltd.,
206-216 Marylebone Road, London, N.W.1.

The information contianed in this guide is issued for instructional purposes only, and does not constitute a specification of the equipment described. The main part of the text is written with reference to the basic 803 computer, while an appendix describes the Automatic Floating-point Unit.

Contents List

1. Introduction
   1. General
   2. The Component Parts of the Computer
   3. Form of Instructions
   4. Transfer Instructions
2. Representation of Data and Instructions
   1. General
   2. Representation of Numbers within the Computer
   3. Scaling
   4. The Overflow Indicator
   5. The Telecode
   6. Representation of Instructions
   7. Store Parity Checking
3. The Instruction Code
   1. Group 0
   2. Groups 1 to 3
   3. Group 4
   4. Group 5
   5. Group 6
   6. Group 7
4. B-Line Modification and Subroutines
   1. B-Line Modification
   2. Subroutines
5. Input Routines
   1. The Initial Instructions
   2. The Translation Input Routine, DI 2
   3. Example 20: A Complete Programme
6. The Keyboard
   1. Description of the Keyboard
   2. Manual Control of the Computer
   3. Recent Additions to the Keyboard

1. Appendix 1: The Elliott Telecode
2. Appendix 2: Powers of 2 in Decimal
3. Appendix 3: The 803 Instruction Code
4. Appendix 4:
   1. Functions which can cause Overflow
   2. The Accuracy of the Division Process
5. Appendix 5: The Automatic Floating-point Unit