Abstraction And Technology 1 Comp 411 – Fall 2006 8/28/06 Computer Abstractions and Technology 1. Layer Cakes 2. Computers are translators 3. Switches.
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Abstraction And
Technology 1
Comp 411 – Fall 2006 8/28/06
Computer Abstractionsand Technology
1. Layer Cakes2. Computers are translators3. Switches and Wires
(Read Chapter 1)
Abstraction And
Technology 2
Comp 411 – Fall 2006 8/28/06
Computers Everywhere
∙ The computers we are used to- Desktops
- Laptops
- Embedded processors• Cars• Mobile phones• Toasters, irons, wristwatches, happy-meal toys
Abstraction And
Technology 3
Comp 411 – Fall 2006 8/28/06
Compiler for (i = 0; i < 3; i++) m += i*i;
Assembler and Linkeraddi $8, $6, $6 sll $8, $8, 4CPU
ModuleALU
A B
Cells A BCO CI S
FA
A Computer System∙ What is a computer system? ∙ Where does it start?∙ Where does it end?
Gates
Transistors
Abstraction And
Technology 4
Comp 411 – Fall 2006 8/28/06
Computer Layer Cake
∙ Applications∙ Systems software∙ Shared libraries∙ Operating System∙ Hardware – the bare metal
Hardware
Operating System
Libraries
Systems S/WAppsComputers are
digital Chameleons
Abstraction And
Technology 5
Comp 411 – Fall 2006 8/28/06
Computers are Translators
∙ User-Interface (visual programming)∙ High-Level Languages
- Compilers- Interpreters
∙ Assembly Language∙ Machine Language x: .word 0
y: .word 0c: .word 123456
...
lw $t0, xaddi $t0, $t0, -3lw $t1, ylw $t2, cadd $t1, $t1, $t2mul $t0, $t0, $t1sw $t0, y
int x, y;y = (x-3)*(y+123456)
Abstraction And
Technology 6
Comp 411 – Fall 2006 8/28/06
Computers are Translators
∙ User-Interface (visual programming)∙ High-Level Languages
- Compilers- Interpreters
∙ Assembly Language∙ Machine Language
x: .word 0y: .word 0c: .word 123456
...
lw $t0, xaddi $t0, $t0, -3lw $t1, ylw $t2, cadd $t1, $t1, $t2mul $t0, $t0, $t1sw $t0, y
0x04030201 0x08070605 0x00000001 0x000000020x00000003 0x00000004 0x706d6f43
Abstraction And
Technology 7
Comp 411 – Fall 2006 8/28/06
Why So Many Languages?
∙ Application Specific- Historically: COBOL vs. Fortran- Today: C# vs. Java
Visual Basic vs. Matlab
∙ Code Maintainability- High-level specifications are
easier to understand and modify
∙ Code Reuse∙ Code Portability∙ Virtual Machines
Abstraction And
Technology 8
Comp 411 – Fall 2006 8/28/06
Under the Covers
∙ Input∙Output∙ Storage∙Processing
- Datapath- Control
Abstraction And
Technology 9
Comp 411 – Fall 2006 8/28/06
Under the Covers
∙ Input∙Output∙ Storage∙Processing
- Datapath- Control
Abstraction And
Technology 10
Comp 411 – Fall 2006 8/28/06
Under the Covers
∙ Input∙Output∙ Storage∙Processing
- Datapath- Control
Cathode Ray Tube (CRT)The “last vacuum tube”Now nearing extinction
Abstraction And
Technology 11
Comp 411 – Fall 2006 8/28/06
Under the Covers
∙ Input∙Output∙ Storage∙Processing
- Datapath- Control
Liquid Crystal Displays (LCDs)
Abstraction And
Technology 12
Comp 411 – Fall 2006 8/28/06
Under the Covers
∙ Input∙Output∙ Storage∙Processing
- Datapath- Control
Abstraction And
Technology 13
Comp 411 – Fall 2006 8/28/06
Under the Covers
∙ Input∙Output∙ Storage∙Processing
- Datapath- Control
Abstraction And
Technology 14
Comp 411 – Fall 2006 8/28/06
Under the Covers
∙ Input∙Output∙ Storage∙Processing
- Datapath- Control
Intel Pentium III Xeon
Abstraction And
Technology 15
Comp 411 – Fall 2006 8/28/06
Implementation Technology
∙ Relays∙ Vacuum Tubes∙ Transistors∙ Integrated Circuits
- Gate-level integration- Medium Scale Integration (PALs)- Large Scale Integration (Processing unit on a chip)- Today (Multiple CPUs on a chip)
∙ Nanotubes??∙ Quantum-Effect Devices??
Abstraction And
Technology 16
Comp 411 – Fall 2006 8/28/06
openclosed
Implementation Technology
∙ Common Links?∙ A controllable switch∙ Computers are wires and switches
open
control
Abstraction And
Technology 17
Comp 411 – Fall 2006 8/28/06
Chips
∙ Silicon Wafers- Chip manufactures build many
copies of the same circuit onto a single wafer. Only a certain percentage of the chips will work; those that work will run at different speeds. The yield decreases as the size of the chips increases and the feature size decreases.
- Wafers are processed by automated fabrication lines. To minimize the chance of contaminants ruining a process step, great care is taken to maintain a meticulously clean environment.
Abstraction And
Technology 18
Comp 411 – Fall 2006 8/28/06
Field Effect Transistors (FETs)
∙ Modern silicon fabrication technology is optimized to build a particular type of transistor. The flow of electrons from the source to the drain is controlled by a gate voltage. Source DrainGate
Bulk
n+ n+
p
IDS = 0
VDS
Abstraction And
Technology 19
Comp 411 – Fall 2006 8/28/06
Chips
∙ Silicon Wafers
Metal 2
M1/M2 via
Metal 1
Polysilicon
Diffusion
Mosfet (under polysilicon gate)
IBM photomicrograph (Si has been removed!)
Abstraction And
Technology 20
Comp 411 – Fall 2006 8/28/06
How Hardware WAS Designed
∙ 20 years ago- I/O Specification
•Truth tables•State diagrams
- Logic design- Circuit design- Circuit Layout
Abstraction And
Technology 21
Comp 411 – Fall 2006 8/28/06
How Hardware IS Designed
∙ Today (with software)∙ High-level hardware specification languages
- Verilog- VHDL
Abstraction And
Technology 22
Comp 411 – Fall 2006 8/28/06
Reconfigurable Chips
∙ Programmable Array Logic (PALs)- Fixed logic / programmable wires
∙ Field Programmable Gate Arrays (FPGAs)- Repeated reconfigurable logic cells
Abstraction And
Technology 23
Comp 411 – Fall 2006 8/28/06
Death of Silicon Diversity
∙ In the future will there be more or fewer types of chips?
∙ Programmability = Flexibility∙ One chip can be programmed to perform many
functions∙ An ultra-flexible architecture might be
designed to emulate any function required∙ High-volumes might compensate for wasted
area∙ Computers are this ultimate circuit type∙ How many types of chips do we need?
- Memory chips- Logic Chips- Potato Chips (credit Anant Agrawal)
Abstraction And
Technology 24
Comp 411 – Fall 2006 8/28/06
Next Time
∙Computer Representations∙How is X represented in
computers?- X = text- X = numbers- X = anything else
∙Encoding Information
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