13.11) What is the difference between NTSC and PAL machines?

Software written for NTSC (North America) will always work on PAL machines,
but software designed on PAL machines (Europe) won't necessarily work on
NTSC machines.

Wayne Booth, mailto:trek@ihgp15.ih.att.com writes:

The differences with PAL and NTSC have to do with the number of lines
displayed on the screen and whether they are using 50 or 60 Hertz.

If I remember correctly, I believe PAL has 625 lines/screen and they
refresh the screen 50 times a second doing 1/2 the lines each refresh
so they effectively repaint the screen 25 times a second.  NTSC is
525 lines/screen with a 60 times a second refresh - again only half
the lines each refresh so a 30 times a second frame rate.  This
would change the amount of time available during vertical sync pulse,
and the number of lines that need to be redrawn each time.