Brings tears to my eyes... my ZX81, the BBC micros at school.... The games were better. The colours were brighter, sound effects were actually synthesised inside the little computers. Those were the days of my life.
it was the RAM size: Commodore 64 had 64K of RAM installed. Commodore 128 had 128K of RAM installed. Commodore 16 had 16K od RAM installed. But mind you, VIC20 didn't have 20K and Commodore 116 didn't have 116K! Also Commodore Plus4 didn't have 4K or 68K - it had 64K, just like C64. Those Commodore people were defitely non-consistent in naming their products!