speedups and parallelism in programs

there are many approaches to increasing the number of instructions microprocessors can do per clock tick:
  1. pipelining (described already)
  2. multiple pipelines = superscalar = multiple issue = multiple execution units
  3. multiple microprocessors

problem: instruction fetching is always trying to fetch instructions, so there is bus contention.

solution: introduce a prefetch queue

64bit x86
it's somewhere between CISC and VLIW
127 64bit registers

instructions are 256 bits
HP+intel joint venture
gnux (gnu linux) is currently the only operating system that will run on it native
nobody could get win64 to run on it.