Why do calculator manufactures like to reinvent the wheel?

[Paul Dale]

Something not mentioned yet is memory fragmentation. Most scripting languages allocate and deallocate memory fairly naïvely even though they garbage collect. Lua is definitely in this camp, I think Python is too but don't remember for certain. Not compacting memory will result in fragmentation long term. A permanently on device simply cannot fragment memory -- you'll run out eventually. A calculator is permanently on -- you can't wait for it to boot every time you press the ON button, it has to come up instantly. This is the reason for the 41's PACKING and the RPL devices garbage collection pauses.

The 34S avoids this by copying large chunks of memory around all too often and keeping memory compacted all the time. This costs but the CPU in the device is fast and memory is small.


Out of interest, we squeezed Python into a 1Mb flash/4Mb RAM device a decade or so back and this included a full Linux kernel and command line support. This is nothing for modern memory sizes.


- Pauli