jhamby on Nostr: IIRC, the preceding VIC-20 was also intended to have much faster disk I/O routines ...

IIRC, the preceding VIC-20 was also intended to have much faster disk I/O routines than it shipped with, but in that case the VIA I/O chip had some internal defect that made the serial feature unusable. I do know the later versions of the 6522 VIA, including WDC's CMOS W65C22, work fine and were used for I/O in early Macintoshes and later Apple II's.