XPost: comp.os.ms-windows.misc, alt.windows7.general, microsoft.   
   ublic.windowsxp.general   
   From: G6JPG@255soft.uk   
      
   In message  at Sun, 31 Dec 2023 23:17:19,   
   Daniel65  writes   
   >J. P. Gilliver wrote on 31/12/23 7:27 am:   
   >> In message <3fj0pi1he28cfgbul4lbmu4jua526btugq@4ax.com> at Sat, 30   
   >> Dec 2023 12:10:57, Tim Slattery  writes   
   >>> "J. P. Gilliver"  wrote:   
   >>>   
   >>>> For 386 and 486, the confusingly changed what "SX" and "DX"   
   >>>> meant; on one (I forget which), SX meant it _didn't_ have a   
   >>>> floating-point maths co-processor on board, DX meant it did. On   
   >>>> the other, SX meant it had a half-width (so 16?) bus outside the   
   >>>> chip (so requiring two fetches to   
   >>>  The 486 was the first Intel chip to have the numeric coprocessor   
   >>>onboard. Intel wanted to prese4ve the "SX" price point, so they   
   >>>produced a 486SX chip which was identical to the DX except that   
   >>> the numeric coprocessor was disabled! Machines sold with this chip   
   >>> had an empty socket where you could plug in a 486DX chip to get a   
   >>> coproc. So once you did that, you could unplug the SX chip and use   
   >>> it elsewhere, right? WRONG!!! It was set up so that the DX in those   
   >>> machines wouldn't work unless the SX was plugged in, doing   
   >>> nothing.   
   >>>   
   >> Did anyone ever manage to "crack" the 486SX or the 487 to enable the   
   >>  disabled part, or make it work without the other?   
   >   
   >"487"?? All DuckDuckGo shows seems to concern a Californian Penal Code   
   >clause 487!! ;-P   
      
   Maybe it was 486DX as Tim says. I had _thought_ the '387 was the   
   co-processor for that series.   
      
   I'm not sure when they started to drop the "80" from (e. g.) 80386. I   
   know they started using names around the time of the '586, alias   
   Pentium, because someone in charge of the administration of trademarks   
   said, basically, no more trademarking just numbers. (It wasn't just   
   Intel - other manufacturers had to invent names too; I remember one chip   
   called "roboclock"; I think it was Maxim or IDT.) Presumably that's why   
   things moved to Pentium II, etc., rather than 686.   
   --   
   J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf   
      
   ... the pleasure of the mind is an amazing thing. My life has been driven by   
   the satisfaction of curiosity. - Jeremy Paxman (being interviewed by Anne   
   Widdecombe), Radio Times, 2-8 July 2011.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)