CS311 Computer Organization
Lecture 1:Computer Abstractions and
Technology
Fall 2020
Soontae Kim
School of Computing
KAIST
#1
The Computer Revolution
• Progress in computer technology
– Underpinned by Moore’s Law
• The number of transistors that can be placed inexpensively on
an integrated circuit doubles approximately every two years
• Makes novel applications feasible
– Computers in automobiles (Electronic Control Unit, ECU)
– Smartphones
– Human genome project
– World Wide Web
– Search Engines
– Google AlphaGo, IBM Watson
• Computers are pervasive
– Embedded systems, Internet Of Things (IOT)
#2
Classes of Computers
• Personal computers
– General purpose, variety of software
– Subject to cost/performance tradeoff
• Server computers
– Network based
– High capacity, performance, reliability
– Range from small servers to building sized
– Developed into cloud computing
#3
Classes of Computers II
• Supercomputers
– High-end scientific and engineering calculations
– Highest capability but represent a small fraction
of the overall computer market
• Cray supercomputers
• Embedded computers
– Hidden as components of systems
– Stringent power/performance/cost constraints
– E.g. Cell phone, ECUs in cars, games, TVs
– Developed into smartphones and IOT
#4
The PostPC Era
#5
The PostPC Era
◼ Personal Mobile Device (PMD)
◼ Battery operated
◼ Connects to the Internet
◼ Hundreds of dollars
◼ Smart phones, tablets, electronic glasses
◼ Cloud computing
◼ Warehouse Scale Computers (WSC)
◼ Giant datacenters
◼ Software as a Service (SaaS)
◼ Portion of software run on a PMD and a portion ru
n in the Cloud
◼ Amazon and Google #6
What You Will Learn
• How programs are translated into the machine
language
– And how the hardware executes them
• The hardware/software interface
– Instruction set architecture
• What determines program performance
– And how it can be improved
• How hardware designers improve performance
• What is parallel processing
– multicore
#7
Performance of program
• Algorithm
– Determines number of source-level statements and I/O
operations executed- algorithms, data structure
• Programming language, compiler, architecture
– Determine number of machine instructions executed per
statement – ch2, 3
• Processor and memory system
– Determine how fast instructions are executed – ch 4,5,6
• I/O system (including OS)
– Determines how fast I/O operations are executed – ch
4,5,6
#8
Architecture
§1.2 Eight Great Ideas in Computer
Eight Great Ideas invented
• Design for Moore’s Law
• Use abstraction to simplify design
• Make the common case fast
• Performance via parallelism
• Performance via pipelining
• Performance via prediction
• Hierarchy of memories
• Dependability via redundancy
#9
Below Your Program
• Application software
– Written in high-level language
• System software
– Compiler: translates HLL code to
machine code
– Operating System: service code
• Handling input/output
• Managing memory and storage
• Scheduling tasks & sharing of resources
• Hardware
– Processor, memory, I/O controllers
#10
Levels of Program Code
• High-level language
– Level of abstraction closer to
problem domain
– Provides for productivity and
portability
• Assembly language
– Symbolic representation of
machine instructions
• Hardware representation
– Binary digits (bits)
– Encode instructions and data
#11
Components of a Computer
The BIG Picture • Same components for
all kinds of computer
– Desktop, server,
embedded
• Input/output includes
– User-interface devices
• Display, keyboard, mouse
– Storage devices
• Hard disk, CD/DVD, flash
– Network adapters
• For communicating with
other computers
#12
Touchscreen
• PostPC device
• Supersedes keyboard
and mouse
• Resistive and
Capacitive types
– Most tablets, smart
phones use capacitive
– Capacitive allows
multiple touches
simultaneously
#13
Through the Looking Glass
• LCD screen: picture elements (pixels)
– Mirrors content of frame buffer memory
#14
Opening the Box
Capacitive multitouch LCD
screen
3.8 V, 25 Watt-hour battery
Computer
board
Components of the Apple iPad 2 A1395
#15
Inside the Processor (CPU)
• Datapath: performs operations on data
• Control: sequences datapath, memory, ...
• Cache memory
– Small fast SRAM memory for immediate access to data
#16
Inside the Processor
• Apple A5
GPU
#17
Abstractions
The BIG Picture
• Abstraction helps us deal with complexity
– Hide lower-level detail
• Instruction set architecture (ISA)
– The hardware/software interface including instructions,
registers, memory access, I/O …
• Application binary interface (ABI)
– The ISA + OS interface provided to app. programmers
• Implementation
– Hardware that obeys the architecture abstraction
Chapter 1 — Computer Abstractions
and Technology — 18 #18
A Safe Place for Data
• Volatile main memory
– Loses instructions and data when power off
– Mainly use DRAM (Dynamic RAM)
• Non-volatile secondary memory
– Magnetic disk
– Flash memory
– Optical disk (CDROM, DVD)
Chapter 1 — Computer Abstractions and Technology — 19 #19
Networks
• Networked computers have advantages of communication,
resource sharing, nonlocal access
• Local area network (LAN): Ethernet
• Wide area network (WAN): the Internet
• Wireless network: WiFi, Bluetooth
Chapter 1 — Computer Abstractions
and Technology — 20 #20
§1.5 Technologies for Building Processors and Memory
Technology Trends
• Electronics
technology continues
to evolve
– Increased capacity and
performance
– Reduced cost
DRAM capacity
Year Technology Relative performance/cost
1951 Vacuum tube 1
1965 Transistor 35
1975 Integrated circuit (IC) 900
1995 Very large scale IC (VLSI) 2,400,000
2013 Ultra large scale IC 250,000,000,000
Chapter 1 — Computer Abstractions
and Technology — 21 #21
Manufacturing ICs
• Yield: proportion of working dies per wafer
Chapter 1 — Computer Abstractions
and Technology — 22 #22
Intel Core i7 Wafer
• 300mm wafer, 280 dies, 32nm technology
• Each die is 20.7 x 10.5 mm
Chapter 1 — Computer Abstractions
and Technology — 23 #23
Integrated Circuit Cost
Cost per wafer
Cost per die =
Dies per wafer Yield
Dies per wafer W afer area Die area
1
Yield =
(1+ (Defects per area Die area/2))2
• Nonlinear relation to area and defect rate
– Wafer cost and area are fixed
– Defect rate determined by manufacturing process
– Die area determined by architecture and circuit design
Chapter 1 — Computer Abstractions
and Technology — 24 #24
