ISA or Micro-Architecture?

[jongyoo]

I'm taking this class on computer architecture. And this is what my professor, Dr. Yale Patt brought up. He wanted to know what the difference between ISA and Micro-Architecture were. I could have googled it but it's more interactive here...haha

-jong

 

[ScottMac]

I believe you (or he) meant "Microchannel."

Microchannel was an architechture brought to market by IBM. It was the "big thing" when they brought out their PS/2 line of computers. The computers ranged from the "Model 30" (which still had ISA) up to the "Model 80" (the top -of-the-line: lots o' slots and the current hot processor).

The licensing fees for Microchannel were "a little high" so Compaq and other PC manufacturers (The "Gang of Seven," I think) developed EISA to address many of the same concerns that Microchannel was supposed to clear up.

Both systems required driver disks that would register the new expansion card (NIC, Video, Serial, Irma, etc) with the system for proper resource allocation (IRQ, DMA, Memory Map, etc).

There were another couple attempts to overhaul the PC bus after that (like VLBus) until PCI came along.

Those were interesting times....

FWIW

Scott

 

[AndyHui]

Conversely, micro-architecture vs instruction set architecture...

As in the 386, 486, Pentium, P6 family, P4 family, are all micro-architectures that share the same x86 instruction set architecture.

 

[CTho9305]

ScottMac, in this context ISA means "Instruction Set Architecture".

 

[ScottMac]

Well, nuts. I wish they'd find new acronyms....

"It sucks to be old" 😱

Scott

 

[CTho9305]

"Instruction Set Architecture" goes back to at least 1975 😉. It's just not used much outside of computer architecture.

 

[imgod2u]

Instruction Set Architecture is the front end. It dictates the instruction format and instruction type that an MPU can process. Micro-architecture is the implementation. It's pretty much how the processor takes those instructions and processes them.

 

[Sahakiel]

Originally posted by: CTho9305
"Instruction Set Architecture" goes back to at least 1975 😉. It's just not used much outside of computer architecture.

As far as I know, the only guys who use the phrase "instruction set architecture" design logic. Everyone else looks at them like they're nuts.

 

[CTho9305]

I figure microarchitecture is much more interesting, because you have two choices when it comes to ISA: 1) implement a really cool new ISA that's great in every way, or 2) build an x86 part and actually sell more than 2 chips 😉.