# Documentation Contents

The documentation for the Elliott 803 simulator consists of the following pages:

- Contents and Introduction. Project introduction - this page.
- History and Further Details. A brief introduction and history of the Elliott 803 computer and links to further information.
- Quick Start. Using the simulator to run a simple program.
- Operation Guide. More detailed operating instructions.
- Sample Assembler Programs. Some details about the sample assembler programs supplied with the simulator.
- ALGOL Programming. Details about running the ALGOL compiler, including some sample ALGOL programs.
- Elliott Telecode A summary of the 5-hole paper tape character encoding.
- Utility Applications. Details of the utility applications supplied with the simulator.
- Additional Functions. Details for extra function unique to the simulator.

For programmers interested in understanding or changing the Java source code for the simulator, some extra documentation is available:

- Source code details. Some comments and notes about the source code for the simulator.

## Project Home Page

The project itself is available from SourceForge:

>     http://elliott803.sourceforge.net

## Introduction

### Project Aims

The aim of this project is to produce a simulation of the Elliott 803 computer that is capable of running original 803 programs (provided they can be made available as system files rather than real paper tapes). In particular it is an aim to run ALGOL 60 programs using the original Elliott ALGOL compiler and achieve correct results.

The project has been written in Java to enable it to run easily on most systems and the user interface elements have been written as simple Java Swing interfaces. Some elements of the interface such as the operator console have been made to look and work in a manner very similar to the real 803 version (as far as the Swing interface allows); other elements such as the paper tape readers and punches are just simple implementations to allow easy operation and don't look anything like the real thing.

The simulation can be set to run at a very close approximation to the speed of a real 803B complete with authentic console speaker sounds, or can be set to run as fast as the implementation allows - which can be useful for speeding up tedious operations such as loading the large compiler tapes.

### Notable Omissions

The following elements of the Elliott 803 are currently not implemented in this project.

- Full Floating Point
  The simulation does fully implement all the group 6 floating point instructions but it currently does this using a little cheating. The Elliott 39-bit floating point values are converted to Java doubles and the operation is performed in Java, the resulting Java double is then converted back to an Elliott 39-bit float format.
  This is a simple and reasonably successful approach (ALGOL programs, for example, run correctly), but the resulting numbers are not always absolutely identical to those that would be produced by the real 803 hardware - sometimes there are minor differences in the least significant decimal places.
- Missing Hardware
  Some bits of the original hardware are currently missing from the simulation. It is hoped to add these in the future:
  - Film Handlers (although most of the enjoyment of these was in seeing the real huge handlers working!).

## Additional Documentation

- 803 Facts - a scan of the Elliott 803 Facts booklet. No 803 programmer should be without this!

Tim Baldwin December 2013 tjb803@tinymail.co.uk | © Tim Baldwin 2009,2013