#3 Simple upgrade or near-complete rewrite? #1

What do you really want to do with the program? There are at least 2 alternatives: 1. Adjust the program so that it runs properly on modern hardware but leave the basic functionality as-is. 2. Make better use of the multi-tasking facilities and other enhanced features of modern hardware. Perhaps add import/export of other file formats. In case (1) you would be making minor - and perhaps minimal - changes. You might call this version "CAC Classic" and the aim would be to have it running on as much RISC OS hardware as possible (Acorn A5000, Acorn RiscPC, Iyonix, Raspberry Pi, Titanium etc.) - to this end you would need to restrict yourself to the feature set present in RISC OS 3. Case (2) would require a substantial rewrite. The mere act of getting the program to multitask would involve pulling it apart and reconstructing it in a form suited to cooperative multitasking. You could style this version "CAC - The Next Generation". The emphasis would be firmly on modern hardware (Raspberry Pi, Titanium etc.) and RISC OS 5 features would be to the fore. -- zedtoo-de Stuart Painting