Lecture 1 - introduction to computer systems architecture 2018 / 2019

1. IN1006 Systems Architecture
Lecture 1: Introduction to Computer systems
Architecture
Prof George Spanoudakis
Semester 1, 2018/19

2. Credits
§ Some text and images for this lecture come from the / adapted
from recommended text book
§ Some other sources of photos / text are also for teaching
purpose only
§ Some slides and notes were adapted and developed from
contributions of Andrew Tuson, Kevin Jones, Eva Kalyvianaki
and Aravin Nathan
2

3. Learning objectives
§ History of Computers
§ Basic hardware components of a computer
§ von Neumann components of a computer system
§ Semiconductor
§ Introduction to Moore’s law and technology trends
§ Concept of Abstraction
§ Computer system in terms layers of functionality
3

4. History of Computers
§ Early devices:
mechanical calculating machines (1642 – 1945)
§ Mechanical Calculating Clock:
§ Add, subtract 6-digit numbers (W. Schickard<1635)
§ Difference Engine and Analytical Engine by
Charles Babbage (1791-1871) (the father of
computing?)
§ Analytical Engine had many of the components of
modern computers: the mill (like the ALU), the store
(like memory) and input and output devices
§ Ada Lovelace, 1st programmer à “a plan on how the
Analytical Engine would calculate numbers”
§ Analytical Engine with punched cards (C. Babbage,
J.M. Jacquard )
Charles Babbage,19th
century English
mathematics professor
designed the Analytical
Engine and it was this
design was the basic
framework of
the computers of today
Ada Lovelace was the first to
recognise that the machine had
applications beyond pure
calculation, and created the
first algorithm intended to be
carried out by such a machine.
As a result, she is often
regarded as the first to
recognise the full potential of a
"computing machine" and the
first computer programmer
en.wikipedia.org
4

5. History of Computer
1) First generation Vacuum Tube Computers (1945
– 1953)
§ Valves/Vacuum tubes
§ ENIAC 1946, the first all-electronic, general purpose
computer with 17,468 vacuum tubes: 1800 square
feet of floor, 30 tons, 174 kilowatts of power. It had
1,000 information bits of memory, about 20 10-digital
decimal numbers.
2) Second generation Transistorized computers
(1955 – 1965)
§ Transistors (1948) (televisions, radios, computers)
§ Computers are now smaller, faster and consume less
power but still bulky and costly.
§ First computers: IBM 7094, DEC PDP-1, CDC 6600
IBM Vacuum Tube Computer.
http://www.chipsetc.com/
5

6. History of Computer (cont.)
3. Third generation Integrated Circuit Computers (1965 – 1980)
§ Integrated circuits or microchip, silicon chips
§ Each IC contains dozens of transistors
§ Computers are faster, smaller and cheaper
§ IBM 360, DEC PDP-11, Cray 1
§ Multiprogramming and time-sharing (when more than one person
can use a machine at once) was also introduced.
4. Fourth generation VLSI computers (1980 – Now)
§ Very Large Scale Integration (VLSI): 10,000 components per chip
§ IBM PC, Apple Mac, …
§ 1981, IBM introduced the Personal Computer PC
5. Modern computers
§ System on Chip (SoC) when all components of a computer in one
chip
§ Laptops, tablets, smartphones, …
www.timetoast.com
Apple A4 chip built in on a smart phone
Integrated Circuit Computers
Very Large Scale Integration
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7. Computer hardware components
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8. Computer Hardware Components
§ Personal Computer
§ Main System
§ CPU, RAM, disks, etc.
§ Input Devices
§ E.g. keyboard, mouse, etc.
§ Output Devices
§ E.g. monitor, speakers, etc.
§ Input / Output Devices
§ E.g. Touch Screen, Ethernet, etc.
Photo: Dell Dimension 4300
(Source: PC Magazine)
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9. Input Devices
§ Keyboard
§ E.g. QWERTY, Dvorak…
§ Mouse
§ E.g. mechanical, optical…
§ Joystick
§ E.g. analog, digital…
§ Input sensors
§ E.g. graphics tablet, data glove…
9

10. Output Devices
§ Desktop Monitors
§ E.g. CRT, LCD, plasma...
§ Projectors
§ E.g. CRT, LCD, DLP...
§ Etc…
§ E.g. 3D displays, electronic paper,
§ laser projections…
Photo: Samsung 950b CRT
Display, LCD Display, ViewSonic
AirPanel 150, LCD Projector, DLP
Projector
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11. Input / Output Devices
§ Peripherals
§ E.g. serial, parallel, USB…
§ Modems
§ E.g. 56Kbs, broadband…
§ Wired Networks
§ E.g. Ethernet…
§ Wireless Networks
§ E.g. WiFi, Bluetooth, 3G, 4G, 5G, … Photo: Alcatel SpeedTouch 330 USB ADSL
Modem, Swann USB 56K V90 External
Modem, Sony Ericsson Bluetooth Headset
HBH-15, Netgear Wireless ADSL Modem,
Apple Airport Extreme Hub and Card, Aspen
Systems 32 Node Beowulf Cluster
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12. Main Systems
§ Anatomy of a Computer
§ Processor
§ Motherboard
§ Main Memory
§ Disk Drives
§ Expansion Cards
§ I/O Ports
§ Case Photo: A generic PC with the
outside cover removed
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13. Main Systems: Cases (Categories)
§ Computer Form Factors
§ E.g. servers, desktops, towers,
mini-towers, laptops, notebooks,
palmtops, wrist-tops, workstations,
rack-mounts 1U 2U 3U, clusters,
supercomputers…
Photo: Antec Sonata Mini Tower, onHand PC, Shuttle
XPC SB61G2, Acer Veriton 5500 Desktop, Compaq iPAQ
3670 Pocket PC, Antec 1U26ATX250 Rackmount
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14. Main Systems: I/O Ports
§ Input / Output Standards
§ E.g. mouse (serial, PS2), keyboard, VGA,
parallel printer (RS232), USB (v1.0, v1.1,
v2.0), FireWire, Ethernet (RJ45)…
§ Motherboards have a number of ports as
standard and more are often added by
expansion cards
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15. Main Systems: Expansion Cards
§ Expansion cards provide additional facilities
using high-performance internal buses:
§ 3D Graphics Cards
§ 5.1 Dolby Audio
§ Network Interface Cards
§ Development Boards
§ Etc.
Photo: ATI Radeon 9700 Pro 128Mb (3D Graphics
Accelerator Card)
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16. Main Systems: Disk Drives
§ Secondary Memory
§ Hard Disks
§ Removable Media
§ Floppy Disks
§ E.g. 3½ Floppy, Zip Disk
§ Optical Disks
§ E.g. CD-Rs, DVD-RWs
§ Solid State Disks
§ E.g. Compact Flash
§ Hybrid Drives
Photo: Western Digital 120Gb 7200 RPM
EIDE ATA-100, IBM 1Gb Microdrive®,
Iomega Zip 100Mb, Generic 1.44Mb 3½
floppy disks
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17. Main Systems: Memory
§ Main Memory
§ Volatile Program and Data Storage while
processing
§ The contents are lost with the loss of
power.
§ Integrated Circuits -- Manufactured
similarly to processors, e.g. DRAM
Photo: Intel® 4Mb DRAM (Source: Intel)
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18. Main Systems: Motherboards
§ Connects Components
§ Integrates I/O Ports
§ Processor Socket
§ Expansion Slots
§ Distributes Power
§ Memory Slots
§ Disk Interfaces
Photo of mother board with labeled components. labeled
diagram of Acer E360 Socket 939 motherboard by
Foxconn.
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19. Main Systems: Processor
§ The Processor is also known as the Central
Processing Unit or simply the CPU.
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20. The von Neumann model
§ All modern stored-program computers are based on the
von Neumann model (stored program digital computer). It
consists of five components:
1) Control Unit
2) Arithmetic Logic Unit (ALU)
3) Registers,
4) Main Memory System
5) I/O System
These computers have the capacity to carry out
sequential instruction processing.
§ A single datapath between the CPU and main memory.
§ This single path is known as the von Neumann
bottleneck
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21. The von Neumann model
§ The von Neumann model or the fetch-decode-
execute cycle:
1) Control unit fetches the next instruction to
execute from memory
2) Instruction is decoded
3) Any required data operands are fetched from
memory to registers
4) The ALU executes the instruction and puts
results in registers/mem
5) Go back to (1) for next instruction
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22. The non-von Neumann models
§ Conventional stored-program computers have undergone many incremental improvements
over the years
§ These improvements include adding specialised buses, floating-point units, and cache
memories or,
the system bus model:
§ But enormous improvements in computational power require departure from the classic von
Neumann architecture:
§ Adding processors
§ Separate buses for data and instructions (Harvard architecture)
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23. Key Processor Components
§ Registers
§ local storage of key data
§ Memory Management Unit (MMU)
§ Interface to main memory
§ Instruction fetcher/decoder
§ Fetches and decodes instruction given at program counter (PC).
§ Arithmetic Logic Unit (ALU)
§ Performs calculations/operations
§ Datapath / control
§ Controls the flow of information that allows the instruction to be
executed.
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24. Anatomy of a Pentium 4 Processor
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25. Technology of Computer Processors
§ Computers improved as the underlying technology changed:
§ The most significant factor that allowed this progress was the move to the use of
Semiconductors
Mechanical è Vacuum tube è Transistor è IC è VLSI è SoC
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26. Semiconductors
§ Semiconductors are a type of material which are
sometimes
§ Conductors – allow electricity to flow
§ Insulators – prevent the flow of electricity
§ They can switch between these two states under
external control
§ Semiconductors can be used to build transistors that
function as switches and make all the basic logic of a
computer
§ Silicon is a semiconductor material that can be
manufactured and processed efficiently and
inexpensively
This is why all modern electronics are referred to as “Silicon Chips”
Illustration: Jean-Luc Fortier Switching with
Carbon: A carbon-nanotube field-effect
transistor (FET) resembles a conventional
silicon FET - spectrum.ieee.org
26

27. An Example of a Packaged Processor
§ This is what people typically see when
they buy a new processor.
§ The pins on the bottom of the package
connect the chip to the rest of the
computer.
Photo: Packaged Intel® Pentium®
4 processors (Source: Intel)
Intel quad-core
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28. Introduction to Moore’s law
Transistor count (in IC/Silicon Chips) will double
approximately every 18 (24) months.
Gordon Moore (1965) noticed that the number of transistors
per square inch on integrated circuits had doubled every year
since their invention. Moore's law predicts that this trend will
continue into the foreseeable future
Gordon Moore
Co-founder of Intel
Shrinking transistors have powered over 50 years advancement in computing
power, but its time to find other ways to improve computing power in cloud era.
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29. 29

30. Recapitulate: Concept of Abstraction
§ Systems can be decomposed into layers
§ The process of abstraction allows layers to hide
lower level information from higher levels – in a
way that allows the higher levels to be useful and
consistent without being cluttered by unnecessary
detail
Vital concept to all of computer science
§ You don’t want to think about electron flow when
writing a games program!
(Some times you need to break the abstraction to
get things right – optimal performance of the game
requires detailed knowledge of the caching
architecture) 30

31. In summary
§ History of computers and technology trends
§ Understand the architecture of computer systems and key hardware components
§ Appreciate the layers of abstraction and its advantages
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32. City, University of London
Northampton Square
London
EC1V 0HB
United Kingdom
T: +44 (0)20 7040 5060
E: department@city.ac.uk
www.city.ac.uk/department