1 CSE SUNY New Paltz Chapter 1 Introduction CSE-45432Introduction to Computer Architecture Dr. Izadi

2 CSE SUNY New Paltz Introduction Rapidly changing field: –vacuum tube -> transistor -> IC -> VLSI –doubling every 1.5 years: memory capacity processor speed (Due to advances in technology and organization) Things you’ll be learning: –how computers work, a basic foundation –how to analyze their performance (or how not to!) –issues affecting modern processors (caches, pipelines)

3 CSE SUNY New Paltz What is a computer? 5 Classic Components: 1.input (mouse, keyboard) 2.output (display, printer) 3.memory (disk drives, DRAM, SRAM, CD) 4. datapath (processor) 5. control (processor) ProcessorI/O Control Datapath Memory Input Output

4 CSE SUNY New Paltz Computer System Components Proc Caches Busses Memory I/O Devices: Controllers adapters Disks Displays Keyboards Networks

5 CSE SUNY New Paltz What is “Computer Architecture” Computer Architecture = Instruction Set Architecture + Machine Organization... the attributes of a [computing] system as seen by the programmer, i.e. the conceptual structure and functional behavior, as distinct from the organization of the data flows and controls the logic design, and the physical implementation. – Amdahl, Blaaw, and Brooks, 1964

6 CSE SUNY New Paltz The Instruction Set: a Critical Interface Instruction set Software Hardware Which is easiest to change?

7 CSE SUNY New Paltz Instruction Set Architecture: What Must be Specified? Instruction Fetch Instruction Decode Operand Fetch Execute Result Store Next Instruction fetch-decode-execute is implicit!

8 CSE SUNY New Paltz Instruction Set Architecture A very important abstraction –interface between hardware and low-level software –standardizes instructions, machine language bit patterns, etc. –advantage: allows different implementations of the same architecture 80x86 family upward compatibility versus and Power PC –disadvantage: sometimes prevents using new innovations we are stuck with segmentation of 80x86.

9 CSE SUNY New Paltz Example ISAs (Instruction Set Architectures) Digital Alpha(v1, v3) HP PA-RISC(v1.1, v2.0) Sun Sparc(v8, v9) SGI MIPS(MIPS I, II, III, IV, V) Intel(8086,80286,80386, ,Pentium, MMX,...)

10 CSE SUNY New Paltz Organization Logic Designer's View ISA Level FUs & Interconnect Capabilities & Performance Characteristics of Functional Units –(e.g., Registers, ALU, Shifters, Logic Units,...) Ways in which these components are interconnected Logic and means by which “information flow” between components is controlled.

11 CSE SUNY New Paltz Example Organization TI SuperSPARC tm TMS390Z50 in Sun SPARCstation20 Floating-point Unit Integer Unit Inst Cache Ref MMU Data Cache Store Buffer Bus Interface SuperSPARC L2 $ CC MBus Module MBus L64852 MBus control M-S Adapter SBus DRAM Controller SBus DMA SCSI Ethernet STDIO serial kbd mouse audio RTC Boot PROM Floppy SBus Cards

12 CSE SUNY New Paltz Abstraction Both hardware and software consist of hierarchical layers Each lower layer hiding details from the above layer Principle of abstraction omits unneeded detail, helps us cope with complexity

13 CSE SUNY New Paltz What is “Computer Architecture”? I/O systemInstr. Set Proc. Compiler Operating System Application Digital Design Circuit Design Instruction Set Architecture Firmware Coordination of many levels of abstraction Under a rapidly changing set of forces Datapath & Control Layout

14 CSE SUNY New Paltz Forces on Computer Architecture ComputerArchitecture Technology Programming Languages Operating Systems History Applications

15 CSE SUNY New Paltz Technology => dramatic change Processor –logic capacity: about 30% per year –clock rate: about 20% per year Memory –DRAM capacity: about 60% per year (4x every 3 years) –Memory speed: about 10% per year –Cost per bit: improves about 25% per year Disk –capacity: about 60% per year

16 CSE SUNY New Paltz Performance Trends Microprocessors Minicomputers Mainframes Supercomputers 1995 Year Log of Performance

17 CSE SUNY New Paltz Processor Performance (SPEC) RISC introduction Did RISC win the technology battle and lose the market war? performance now improves ­ 50% per year (2x every 1.5 years)

18 CSE SUNY New Paltz Applications and Languages CAD, CAM, CAE,... Lotus, DOS,... Multimedia,... The Web,... JAVA,... ???

19 CSE SUNY New Paltz Where we are headed Performance issues (Chapter 2) A specific instruction set architecture (Chapter 3) Arithmetic and how to build an ALU (Chapter 4) Constructing a processor to execute our instructions (Chapter 5) Pipelining to improve performance (Chapter 6) Memory: caches and virtual memory (Chapter 7) Input / Output Devices (Chapter 8) Multiprocessor Architectures (Chapter 9)