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<DIV><FONT face=Arial><FONT color=#0000ff><FONT size=2><SPAN
class=417501111-23112001>></SPAN>I want to know the exact definition
of the 32 bit computer (PC ) vs 64 bit computer.</FONT></FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT color=#0000ff><FONT size=2><SPAN
class=417501111-23112001>></SPAN>I don't know how much(the maximum number)
the 32 bit computer vs 64 bit makes exact calculation without
error.</FONT></FONT></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=417501111-23112001>It is
a common misunderstanding to equate a 32 bit compiter with 32-bit numbers in
calculations. </SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=417501111-23112001>For
example my old ZX-Spectrum was an 8-bit computer (and so could only address 64kB
of memory) but stored floating point numbers in 40 bits. </SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=417501111-23112001></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=417501111-23112001>What
also can add to the confusion is that Intel Pentiums (which are 32-bit
machines) have always had 64-bit floating point numbers, but internal to the CPU
floating point units they are stored as 80-bits. </SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2></FONT> </DIV>
<DIV><FONT face=Arial><FONT color=#0000ff><FONT size=2><SPAN
class=417501111-23112001>></SPAN>and With different architecture PCs - for
example AMD, Intel, MAC cpu , Is it possible to communicate the calculation
results each other ?</FONT></FONT></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=417501111-23112001>></SPAN></FONT><FONT face=Arial color=#0000ff
size=2>and With same os - for example LINUX, Is it possible to make one
beowulf Using Alpha(64 bit) & Intel(32 bit) Computers ?</FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=417501111-23112001>Your
other question was about communication between heterogeneous architectures. This
again has always been possible. Before MPI (unfortunately) came to dominate
message-passing, PVM was the standard library used. PVM is designed for
heterogeneous systems. For example I have a code that uses MPI internally on
both a Cray T3E and also a Fujitsu Vector Processor but which uses PVM to
communicate between the two big machines.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2></FONT> </DIV>
<DIV><FONT
size=2>Yours,<BR>Daniel.<BR><BR>--------------------------------------------------------------<BR>Dr.
Dan Kidger, Quadrics Ltd.
daniel.kidger@quadrics.com<BR>One Bridewell St., Bristol, BS1 2AA,
UK 0117 915
5505<BR>----------------------- www.quadrics.com
--------------------<BR></DIV></FONT>
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