Computer Architecture & Organization Architecture  attributes visible to the programmer Instruction set, number of bits used for data representation, I/O mechanisms, addressing techniques, etc. e.g. Is there a multiply instruction? Control signals, interfaces, memory technology, etc. e.g. Is there a hardware multiply unit or is it done by repeated addition? hmmm … chicken/egg problem ? Organization  how features are implemented

What Should I already know re Computer Arch & Org ? “Black Box” ! connected devices Peripherals communication links keyboard computer mouse network . . display telephone cable disk / optical wireless speakers printer other ? other ?

Function & Structure ITBB SYSC 2001 will look inside the black box (ITBB)! peripherals and commn links are outside black box Will construct various models of ITBB components: Function  the operation of individual components as parts of the structure Structure  how components relate to each other

Coordinates How Information is Used IMPORTANT SLIDE ! Function ALL computer functions are: Data PROCESSING Data STORAGE Data MOVEMENT CONTROL NOTHING ELSE! Data = Information Coordinates How Information is Used

Functional view of Black Box Operating Environment source/sink for information connections to peripherals and commn links MOVEMENT ITBB CONTROL PROCESSING STORAGE

Operations (1) Data movement e.g. copy a file between disks

e.g. load a text file for editing Operations (2) Storage e.g. load a text file for editing

Operation (3) Processing from/to storage e.g. compute an intermediate result from some operands & save for later use

Operation (4) Processing from storage to I/O e.g. compute and display a result from some operands

Structure - Top Level ITBB More Black Boxes ITBB! Peripherals Computer Input Output Computer Central Processing Unit Systems Interconnection Communication lines Main Memory What about Function?

Structure - The CPU Drilling Down I(ITBB)! What about Function? CPU Computer Arithmetic and Logic Unit Registers I/O System Bus CPU Internal CPU Interconnection Memory Drilling Down I(ITBB)! Control Unit What about Function?

Structure - The Control Unit Too deep for SYSC 2001 Control Unit CPU Sequencing Logic ALU Control Unit Internal Bus Control Unit Registers and Decoders Registers Control Memory What about Function?

Brief History of Computer Evolution Two phases: before VLSI 1945 – 1978 ENIAC IAS IBM PDP-8 VLSI 1978  present day microprocessors ! VLSI = Very Large Scale Integration see text discussion

Growth in CPU Transistor Count Cell 234 M Growth in CPU Transistor Count Pentium Evolution PowerPC Evolution Moore’s Law

Speeding Up the Processor Pipelining On board cache On board L1 & L2 cache Branch prediction Data flow analysis Speculative execution chicken / egg again ! we’ll see some of these as the course progresses

But Performance Mismatch! Processor speed increased Memory capacity increased Memory speed lags behind (and increasing slower than) processor speed

DRAM and Processor Characteristics

Some Solutions Increase number of bits retrieved at one time Make DRAM “wider” rather than “deeper” Change DRAM interface Cache Reduce frequency of memory access More complex cache, and cache on chip Increase interconnection bandwidth High speed buses Hierarchy of buses