Compilers
The Initial Instructions described as the Example Program above is effectively a primary bootloader which is normally used to read a secondary bootloader known as T23, prepended to all program tapes. T23 allows more flexible program loading facilities including sumchecking of the loaded code.
Machine code programs are written in an octal/decimal representation exemplified in the Example Program above, and loaded by a rudimentary assembler known as the Translation Input Routine. It has no symbolic addressing facilities, but instead allows the source to be broken into blocks which can be manually relocated to allow for the expansion or contraction of a previous block in development. There is also an Autocode for simple programming tasks, allowing faster program development without the need for a knowledge of machine code. This has no formula translation facilities and requires all calculations to be reduced to a series of assignments with no more than a single operator on the right hand side.
The 803B with 8192 words of memory is capable of running the Elliott ALGOL compiler, a major subset of the Algol60 language, capable of loading and running several ALGOL programs in succession. This was largely written by Tony Hoare, employed by Elliotts as a programmer in August 1960. Hoare recounts some of his experiences at Elliotts in his 1980 ACM Turing Award lecture.
The 803B at The National Museum of Computing is now working well enough to run this compiler again. There is a short video on YouTube of it compiling and running a simple program.
Read more about this topic: Elliott 803