On Wed, 3 Feb 2021 at 09:59, Clem Cole wrote: > > > On Wed, Feb 3, 2021 at 5:14 AM Ed Bradford wrote: > >> Hay, Arnold, >> >> MC 68K was created in 1980 or thereabouts. We talked about 10's of >> Megahertz, I think, in those times. >> > The original X series part was originally unnumbered but a sticker was > later set for the lids that said X68000 (I had one on my desk - which was > used for the Tektronix Magnolia prototype).[1] The X series ran at 8 Mhz, > but the original released (distributed - MC68000) part was binned at 8 and > 10 as were the later versions with the updated paging microcode called > the MC68010 a year later. When the 68020 was released Moto got the speeds > up to 16Mhz and later 20. By the '040 I think they were running at 50MHz > > Was the "X" prefix always used for prototypes? I remember having an XC68020 in something - might have been an Sun 3/60, or an early Mac IIcx? -Henry