What the MAIN difference between systems prototyping and throwaway prototyping?

Systems prototyping is a rapid application development methodology; while throwaway prototyping is not

Systems prototyping involves users while throwaway prototyping does not

Throwaway prototyping develops systems that will be use as $$stop$-$gap$$ systems $$ and generally for less than six months; while systems prototyping results in systems that will be used extensively for several years.

Systems prototyping works with users to quickly develop a simplified working version of the proposed system; while throwaway prototyping focuses more on exploring design alternatives

Throwaway prototyping involves users while systems prototyping does not