http://blogs.msdn.com/oldnewthing/archive/2003/09/04/54794.aspxSet the wayback machine to 1983.en-USCommunityServer 2.1 SP1 (Build: 61025.2)http://blogs.msdn.com/oldnewthing/archive/2003/09/04/54794.aspx#54795Thu, 04 Sep 2003 18:25:00 GMT91d46819-8472-40ad-a661-2c78acb4018c:54795Joe BedaHey Raymond, 256MB? Do you mean KB?http://blogs.msdn.com/oldnewthing/archive/2003/09/04/54794.aspx#54796Thu, 04 Sep 2003 19:31:00 GMT91d46819-8472-40ad-a661-2c78acb4018c:54796DamitEven 256KB would be quite a lot... how much memory could the 8086 support anyway? (I recall it was somewhere near 1MB, but you couldn't use that much)http://blogs.msdn.com/oldnewthing/archive/2003/09/04/54794.aspx#54797Thu, 04 Sep 2003 19:38:00 GMT91d46819-8472-40ad-a661-2c78acb4018c:54797MartinJAn 80x86 can handle 640KB in real mode (that's 16 bit). Even though addresses were handled in 32 bits, the system addressing was overlapped (multiply the upper 16 bits by 16 and add the lower 16 bits).http://blogs.msdn.com/oldnewthing/archive/2003/09/04/54794.aspx#54798Thu, 04 Sep 2003 21:44:00 GMT91d46819-8472-40ad-a661-2c78acb4018c:54798BlakeMartin: It's more complicated than that. The 8086 which is what's Damit was asking about had 20 address pins. 2^20 results in 1MB of address space. The IBM PC developers decided that of that 1MB, 384K should be reserved for mapping in devices and 640K should be available to address main memory. The 640K limitation is a PC thing, not a x86 thing. And of course then it gets even more complicated, if you look at the 286 and 386 (and perhaps 186 but I can't remember) where there were more than 20 address pins you could actually address that extra 64K beyond 1MB that became known as the High Memory Area and was used by DOS 5 and QEMM and such.http://blogs.msdn.com/oldnewthing/archive/2003/09/04/54794.aspx#54799Fri, 05 Sep 2003 18:07:00 GMT91d46819-8472-40ad-a661-2c78acb4018c:54799w.h.I always loved how the 65816 (the 16 bit version of the 6502) went from 16 bit addresses to 24-bit addresses without really obnoxious segment registers. The segment register was 8 bits slapped on the side without any of the usual funkieness. Although, the segment registers like that did prevent a few tricks that were useful when you were doing graphics, i.e. setting the segment register to the beginning of a bitmap and using the 16 bit addresses. I love the history of computing. ;)http://blogs.msdn.com/oldnewthing/archive/2003/09/04/54794.aspx#54800Sat, 06 Sep 2003 20:01:00 GMT91d46819-8472-40ad-a661-2c78acb4018c:54800dz&quot;co&#246;peratively.&quot; &quot;pre&#235;mptive.&quot; I thought only The New Yorker rose to that level of pr&#235;t&#235;ns&#239;&#246;n.http://blogs.msdn.com/oldnewthing/archive/2003/09/04/54794.aspx#54801Thu, 25 Sep 2003 02:51:00 GMT91d46819-8472-40ad-a661-2c78acb4018c:54801Peter LundThat would be 8088 and 4.77 MHz, wouldn't it?http://blogs.msdn.com/oldnewthing/archive/2003/09/04/54794.aspx#4866695Tue, 11 Sep 2007 18:07:53 GMT91d46819-8472-40ad-a661-2c78acb4018c:4866695The Old New Thing : What's the difference between EM_UNDO and WM_UNDO?<p>PingBack from <a rel="nofollow" target="_new" href="http://blogs.msdn.com/oldnewthing/archive/2007/09/11/4857870.aspx">http://blogs.msdn.com/oldnewthing/archive/2007/09/11/4857870.aspx</a></p>