Exploring Computer Operations: A Comprehensive Overview
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Presentation Transcript
Computer Operations Part 2
Many, Many Simple Operations • Computers have small instr. set • Decoder may only recognize 100 instr • About 20 kinds of operations • All other operations must be reduced to these
Cycling the Fetch/Execute Cycle • ADD is average complexity instr. • CPUs execute many such instr / sec • MIPS • FLOPS, GFLOPS, TFLOPS
The Computer Clock • CPUs are instruction execution engines, synchronized by clock • Clock speed measured in ticks / sec (Hz) • Clock cycles are short • 2 GHz => cycle time of 0.5 ns
One Cycle per Clock Tick • Perspective • Light travels about 1 ft / ns • CPUs try to start an instr. on each clock tick
One Cycle per Clock Tick • CPUs use pipelining • Overlap instr. execution • Laundry analogy
Computer’s View of Software • Executable program • Binary object file • Sequence of 4-byte groups(words) • Can be millions of words long
Computer’s View of Software • CPU executes program by • copying binary instructions into RAM • interpreting them using Fetch/Execute Cycle
Assembly language • CPU only “speaks” machine language (executes binary object files) • Near impossible to write binary code • What to do? • Need higher-level language and translation • Assembly => object code • E.g.: ADD 15, 21, 19 => 010011100…001
Assembly language • Assembly language uses letters and #s • Computer scans assembly code • Looks up words in table to convert to binary • Converts #s to binary • Assembles binary pieces into object file
Programming Languages • Most programs written in High-level programming language • Translated (compiled) to assembly • Assembled to binary
Operating Systems • Operating system (OS) • Manages resources • Most popular OS’s? • Microsoft Windows • Apple's Mac OS X • Unix / Linux
Operating Systems • Sits atop h/w • Apps • OS • Hardware • Responsible for • Booting • Process, memory, file, and device management
Programming • Programmers utilize s/w stack • Software stack • Layers of software of increasing complexity • Higher-level abstractions toward top
Integrated Circuits (ICs) • IC • “Chip” • Electrical components integrated into silicon • Smaller = faster • Speed of light
Photolithography • Photolithography: process of making IC • Si wafer covered with light-sensitive photoresistand patterned mask • Exposed to uv light which causes open areas to harden (unexposed areas are washed away leaving pattern) • Hot gases etch original layer • When remaining photoresist is removed, the pattern from mask remains
Making a CPU • Intel: From Sand to Silicon – the Making of a Chip • http://newsroom.intel.com/docs/DOC-2476#
How Semiconductor Technology Works • Silicon is semiconductor • Making chip entails controlling conductivity
How Semiconductor Technology Works Searching for red AND giant
On-Again, Off-Again • Two switches can compute logical AND • Other combinations of switches in ALU perform • AND • OR • NOT • etc.
Transistors • Transistor • Controllable switch • Key component in IC
Big Picture: Running App • Start with information-processing task • Task is performed by a program • Program consists of instr. • Instr. were written in high-level language, but have been compiled and assembled into binary code • CPU uses Fetch/Execute cycle to run instr.
Summary • Computer • CPU • ALU • CU • Memory • Storage • I/O • Fetch/Execute Cycle
Summary • Machine instructions • Programming languages • Software stack • Integrated circuits
Quiz • What part of the CPU is responsible for arithmetic and logical operations? • Memory is a sequence of cells, each of which can hold 1 ___________. • The last stage of the Fetch/Execute cycle is ____________.
