cyclebabble

cyclebabble

   <jargon> Advertising raw {clock speed}, instead of {bus
   speed}.

   {IBM} uses raw clock speed as the speed of the computer.  In
   the {IBM PC} and {IBM PC XT}, the clock is divided by 4 to
   produce the 4-phase bus clocks.  Thus a 4 MHz IBM XT really
   runs at 0.895 MHz, because that 4 MHz was really 3.58 MHz
   which gets divided by four.

   A {Tandy} {Color Computer} ran at exactly the same speed, but
   clock speed was specified as bus speed, 0.895 MHz, leaving the
   impression that it was 4 times slower.  Actually it ran a
   little faster with a more efficient {instruction set}.  If the
   actual {clock rate} had been specified on a {CoCo 3}, it would
   have been 14.32 MHz, although the bus speed was still 0.895
   MHz.  That high speed also generated video, color, and {hidden
   refresh} timing.

   100 MHz computers are running at bus speeds of around 25 MHz.

   (1997-02-13)