These days there's so much technology and ways you can learn. There are videos and CD roms. Mick Taylor
$1 contains a register with control bits for enabling/disabling the system ROMS as well as the I/O area at $D000. Source: Internet
American machines, or those with a second processor, may have US BASIC or HIBASIC: the ROM routines will not be in the same place for these ROMS." Source: Internet
Android ROMs also use this type of checksum. Source: Internet
As the processor could only address 64 kB at a time, the ROM was mapped into memory and only 38,911 bytes of RAM (plus 4 kb between ROMs) were available at startup. Source: Internet
External ROMs were developed with Ace Forth to be used as control applications. citation citation System Architecture The ACE had an 8 kB ROM containing the Forth kernel and operating system, and the predefined dictionary of Forth words in about 5 kB. Source: Internet