[Gllug] IA32? IA64? x86...

[Dylan]

Spot on! Thankyou vvvm

Dylan


On Thursday 03 October 2002 12:51, Jonathan Harker wrote:
> At 22:09 03/10/2002, you wrote:
> >Hi guys
> >
> >I'm getting a bit fuddled here...
> >
> >Can one of the hardware gurus explain what's what? Which processors are
> > IA32 (i{3|4|5}86?), which IA64? Where does i686 fit in the scheme? How is
> > the Itanium related (if at all?)
>
> Okay here goes...
>
> Intel have 2 main "machine code" (?) languages - IA32, which was introduced
> with the 386 processor waaay back, and IA64, which it introduced with the
> Itanium.
>
> IA32: Introduced with the 386, Intel's first 32 bit PC chip. They then
> renamed it the 386-DX and brought out a crippled 386-SX which had a 16 bit
> bus so you could stick it in older motherboards (32 bit motherboards were
> expensive and fighting between IBM's MCA bus, as used on the PS/2, and the
> EISA bus; PCI hadn't arrived yet). The 486 came out with a faster core,
> redesigned memory management, and a floating point unit on the 486-DX
> (formerly an additional 387 chip was required alongside the 386 for
> efficient FP) The Pentium (they couldn't trademark 586, even with an 'i' in
> front of it, so they started naming them) added a better bus and some extra
> instructions (eg. the infamous FDIV bug). Then Pentium Pro was the 686
> evolution, mainly a die shrink, newer pipeline, faster floating point, but
> they priced it well out of reach for most people. With another die shrink
> (to 0.35 micron IIRC?) Intel added MMX instructions to its Pentium and
> Pentium Pro chips, which then became the Pentium MMX, and Pentium II,
> respectively. The Pentium III was a slight tweak adding SIMD (single
> instruction multiple data), and a die shrink. Pentium 4 is a complete
> redesign, but still fundamentally a 686 IA32 chip.
>
> Confusion of nomenclature is rife since Cyrix and AMD were doing clones of
> Intel chips. AMD K5 was a Pentium clone, K6 (to which they added their own
> version of MMX and SIMD, called 3D Now, and marketed it as a 686 chip) and
> Cyrix 6x86 were competitors to the Pentium II, but fit into the old Socket
> 7 (for Pentium chips) rather than the more expensive and proprietary Slot 1
> (Pentium II, III). In late 1999 AMD released the Athlon (K7), and marketed
> it as a 786 generation chip. It has remained superior to or on par with the
> Pentium III and Pentium 4 in performance ever since.
>
> IA64: Used on Itanium, which uses Intel's new EPIC marketecture, which is
> some evolution of RISC (or is it semi-parallel? Someone feel free to
> clarify?). Software requires recompilation to gain any performance benefit
> from Itanium, as IA32 is sort-of emulated on the chip, and runs slower than
> a Pentium III at the same MHz as a result. Which is why it has generally
> bombed.
>
> x86-64 is AMD's take on 64 bit processor architecture, which seems to me
> much more sensible; essentially it is IA32 with additional 64 bit versions
> of the important instructions (much as Intel's 386 was a 32 bit extension
> of the 286). This means IA32 stuff will work fine, with no emulation layer.
> We'll see very soon when they release the Hammer at the end of the year!
>
> CISC - Complex Instruction Set Chip - means that the chip instructions can
> have varying lengths and take varying arguments. All Intel IA32  chips and
> various clones, AMD Athlon.
> RISC - Reduced Instruction Set Chip - instructions and data are all the
> same lengths, which makes pipelining and chip design (theoretically)
> faster, simpler, more efficient, etc. PowerPC, Alpha, IBM Power4, MIPS,
> etc. EPIC - As far as I can tell, mostly marketing bollocks to hide the
> fact that it's really CISC. Itanium.
>
> (phew)
> night night,
>
> Luv Jon.


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