Updating 1900 Pascal

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 A rather ambitious attempt to make the 1900 Pascal compiler emit semi-compiled. This should allow a number of benefits: -

• A reduction in program size as the current RTL of around 3.3KW is only ever rarely used in its entirety. Only the required RTL code would be consolidated into the final program.
• The ability to perform separate compilation, allowing libraries to be created and reference.
• The restoration of some facilities lost from the copy we have - source file inclusion etc.
• The reconstructed RTL would not require to be able to switch modes as currently implemented. A program compilation would state the required operating modes much as ICL Algol or FORTRAN would have and the consolidation phase would adjust the resulting binary accordingly.

Still very much a work-in-progress as there is significant research required to understand the ICL 1900 semi-compiled data structures. Only one small fragment of ICL documentation regarding semi-compiled file structure is currently known to exist (SCM - See download links). - It does provide a lot of useful information, regarding the layout of each record type in the file, but does not describe the order that they are required to appear in within the file or how they relate to each other.

During the time when we were working on the 1905 emulator, we were in contact with some of the people involved with the design and building of the Canadian FP6000, designed by Ferranti Packard in Canada, and which was to become the ICT 1904 success story. One contact, Roger D Moore provided a collection of material regarding the FP6000, its development and software. (That could be a whole new area for this website). Among that was information of their #CNSL program, the consolidator. That provided some extra invaluable insights as the FPC's semi-compiled was adopted directly as the 1900 semi-compiled format, then later enhanced to allow the addition of the extra modes etc for later 1900s with the introduction of the 1906 and 1907 machines.