The PEEK function would not work on memory locations above 49152 so as to prevent the user from viewing the copyrighted code in the system ROMs.

Aside from the 8K BASIC ROM, the PET also included a 4K character ROM and an 8K kernal ROM. The first half of the kernal contained screen editor functions (the screen editor on 80 column PETs differed from 40-column models) with the second half containing a number of function calls