Transcript Computers and How They Work

Computers: How They Work
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
What is a Computer
Components of Computer
World’s First Computers
4004 – First single chip Microprocessor
Transistors in integrated circuits (ICs)
Review of MOSFET transistors (how they work and how they are made)
Basic building blocks from transistors
NANDS, NORS, Latches, Adders
Simple components using basic building blocks
Integrating the components to create a 4-bit Microprocessor
Scaling up and Moore’s Law
Machine Code and the processor’s Instruction Set – Software
Memory types (ROM, DRAM, SRAM, FLASH)
Mother Board
Hard Drive
Keyboard
Monitor
The Mouse
I/O
DSL and connection to Internet
File Compression
Demonstrations
►
►
►
►
►
►
PC Mother Boards
Plain and Etched Wafers
Silicon Ingot
ICs with lids removed
Masks
Memory




►
►
►
►
Hard Drive
Magnetic Tape
Punch Cards
CDs
Cathode Ray Tube Monitor
LCDs
Keyboard
CCD chips
What is a Computer?
►A
machine that stores
instructions and operates
on information/data.
► A calculator that executes
a stored program
(sequence of instructions)
http://www.sscnet.ucla.edu
Jacquards Loom
Circa 1804
Charles Babbage’s first attempt at
a Computer
The Analytical Engine, c. 1822
► Designed
to use Jacquard
punch cards to store and run
a program
► Mathematician,
Augusta Ada Lovelace,
created programs
► Steam Powered
► 25,000 parts
► 15 tons and 8 feet high
► Never completed
http://concise.britannica.com
Difference Engine II
► Designed
to
calculate
polynomials and
compute trig
and log
functions
► C. 1847
► Crank operated
Now on Display at the
Computer History Museum!
http://www.computerhistory.org/babbage/
Herman Hollerith’s Census Tabulator
c. 1890
►
►
Census recording performed in six weeks in 1890
Census recording took 7 years in 1880
Also on Display at the
Computer History Museum!
Holerith’s Tabulator
► Data
entered on
punch cards
► Card reader used
mercury to close a
circuit which
would advance a
dial by one ‘tick’
http://www.columbia.edu/acis/history/census-tabulator.html
ENIAC in 1946
First electronic
computer
► Designed for the
Army
► $500,000
► >17,000 Vacuum
Tubes
► 150 KW of power
► Filled multiple
rooms (700 sq. ft)
► Soldered and
constructed by
hand by the
University of Penn.
►
IBM’s Accounting Machine
Introduced in 1949
Punch cards used to store Fortran
programs up until about 1980.
► Individual
Parts
► Manual hand wiring
IBM 402
The birth of the integrated circuit
(IC)
►
►
►
1947- using silicon as a transistor is discovered
1960- TI put 10 transistors on one piece of silicon
Used in Apollo Space Program – lower power and weight
Intel 4004
The World’s first
Microprocessor, made in
1971
Computer on a chip!
It had 2300 transistors and
ran at 740 KHz.
It could execute 45
instructions.
Could execute 96,000
instructions per second
As powerful as the ENIAC
Where’s the chip?
Microprocessor
►A
logic machine that
can execute a
computer program.
► A Central Processing
Unit (CPU) integrated
into a single chip
(i.e. constructed as an
integrated circuit or IC
on a single piece of
Silicon)
http://en.wikipedia.org/wiki/Central_processing_unit
Busicom
In 1965 Gordon Moore predicted that
the number of transistors on a chip
would double every two years.
Moore’s Law
http://www.computerhistory.org/semiconductor/
Wikipedia
micron = 10-6 meters
The feature size of an integrated circuit is indicated by the width
of a "wire," measured in microns (one micron is one millionth of a
meter). Analysis and Design of Analog Integrated Circuits (4th Edition)
Components of a Computer
► Processor
► Memory
► Input/Output
Processor
Memory
(ROM, RAM,
Registers, Cache)
Output
(Monitor, speakers,
USB Drive, Printer,
DSL, Hard Drive)
USB – Universal Serial Bus
Input
(Keyboard, Mouse
USB Drive, DSL,
Touchscreen, Microphone,
Hard Drive)
DSL – Digital Subscriber Line
4004 Processor
http://en.wikipedia.org
What’s Inside a basic CPU?
(Central Processing Unit)
► ALU
(Arithmetic Logic Unit)
► Instruction Decoder
► Program Counter
► Instruction Register
► Data Registers
► Accumulator (place for storing a sum)
► Clock for sequencing operations
CPUs are made from Transistors
Transistors are tiny
switches that can
open and close
very quickly.
A negative voltage
will turn this
transistor ‘on’.
http://www.answers.com
nMOS Transistor (n-channel)
A positive voltage will
turn this transistor ‘on’.
http://www.ugrad.cs.ubc.ca
Chips can have millions
of transistors built on a
small piece of silicon.
CMOS stands for ‘Complimentary
Metal Oxide Semiconductor’. This
means CMOS chips contain both
pMOS and nMOS transistors.
http://www.britannica.com
Transistors are used to
make logic gates
http://www.iclayoutonline.com
Making the Inverter Logic Gate
Making the Exclusive OR gate (XOR)
http://www.ibiblio.org/obp/electricCircuits
Now what can be made with
NAND, NOR, & XOR gates?
1-bit adder
(Full Adder)
Multiplexer
http://users.ece.gatech.edu
A multiplexer selects
one of many sources
to send to the output.
1-Bit ALU (Arithmetic Logic Unit)
Coming
from the
Instructions
http://www.cs.umd.edu/
4004 Processor
http://en.wikipedia.org
Cascading 1-bit ALU to get a 3-bit ALU
http://www.cs.umd.edu/class/spring2003/cmsc311
Memory – A Device that
“remembers” a previous input.
Registers are the high speed memory on
the CPU chip. These registers are used
for storing data that is frequently needed.
Instructions are pre-fetched and stored in
registers too so that they are ready when
needed.
Registers
1-bit Latch (Flip Flop)
Static Ram and registers are constructed with this logic.
The state of Q is retained as long as power is on.
http://www.cise.ufl.edu
Clocked Latch
Also known as a D-Flip Flop
Cascading Flip Flops to build
an N-bit register
Now we know how to add binary
numbers and store binary data
► Use
Flip Flops to store instructions which
are coded as binary (base-2) numbers
► Use an ALU to add numbers together
► Scale this concept up to accommodate
larger numbers
► Add more functionality to the ALU
Microinstructions are coded and
stored as binary data
► Microinstructions
are the controls that
make the hardware operate
► Microinstructions are coded in 1’s and 0’s
► Microinstructions are unique to the
processor (each processor has it’s own
instruction set)
► The clock sequences operations and keeps
operations in lock step
00011011  Add C, #1
To Registers A, B, C, and D
To avoid large decoder
circuits, the codes are
broken up into fields.
In this example there
are three fields, each
field has dedicated
decoding circuitry:
1. The command
2. The data to be used
http://webster.cs.ucr.edu
2 to 4 decoders
http://users.ece.gatech.edu
Software commands Hardware
C++ high level codes gets
compiled/translated into low level
machine codes
while (amt2 <= amt1)
{
amt1 = amt1 + 100;
amt2 = amt2 + 0.05*amt2;
year++;
}
14:
while (amt2 <= amt1)
004015BB fld
dword ptr [ebp-8]
004015BE fcomp
dword ptr [ebp-4]
004015C1 fnstsw
ax
004015C3 test
ah,41h
004015C6 je
main+70h (004015f0)
15:
{
16:
amt1 = amt1 + 100;
004015C8 fld
dword ptr [ebp-4]
004015CB fadd
dword ptr
[__real@4@4005c800000000000000 (0046f0a4)]
004015D1 fstp
dword ptr [ebp-4]
17:
amt2 = amt2 + 0.05*amt2;
004015D4 fld
dword ptr [ebp-8]
004015D7 fld
dword ptr [ebp-8]
004015DA fmul
qword ptr
[__real@8@3ffaccccccccccccd000 (0046f098)]
004015E0 faddp
st(1),st
004015E2 fstp
dword ptr [ebp-8]
18:
year++;
004015E5 mov
eax,dword ptr [ebp-14h]
004015E8 add
eax,1
004015EB mov
dword ptr [ebp-14h],eax
19:
}
Fetch-Decode-Execute Cycle
► Fetch
an Instruction:
 Fetch instruction at address stored in address
register
 Increment Program Counter
 Load the Instruction Register with this
Instruction
► Decode
 Decode the Instruction
 Fetch the operands
► Execute
 ALU or other logic performs the operation
 The result is then written to memory or to a
register.
Memory Hierarchy
http://www.surriel.com/lectures/hierarchy.gif
Cache Memory
http://content.answers.com
SRAM
► Static
Random Access Memory
► Retains data in memory as long as power is on
► Uses flip flops (4-6 transistors each)
► Fast but more expensive due to more chip realestate needed for each memory location compared
to DRAM
► Used for cache memory
► Access time  10 nanoseconds
DRAM and SDRAM
►
Dynamic RAM
 Dynamic refers to the need to
refresh the data
►
Synchronous DRAM
 (Timing of memory chip is
synchronized with CPU clock)
►
►
►
Data is stored as electrical
charge in a capacitors
Capacitors will discharge
requiring that memory be
refreshed every few
milliseconds. This slows down
the DRAM
Dense therefore least
expensive form of memory
http://www.electronics.dit.ie/staff/tscarff/memory/ram.htm
10 byte DRAM
The word “random” means bytes can be accessed randomly.
Data access is not sequential like a magnetic tape.
http://www.cse.scu.edu
SIMM & DIMM
► Single
In-line
memory module
► Dual In-line
memory module
► These cards are
DRAMS
http://en.wikipedia.org/wiki/DIMM
ROM of three memory locations,
Diodes
each ‘word’ of memory is 3 bits
► Read Only Memory
► Data contents can not
be changed
► Data retained even
when power is off
► Manufactured with the
data
► Used for booting up
computer and loading
Operating System
► Device Driver software
http://www.compeng.dit.ie
Flash Memory
Type of EEPROM
(Electrically Eraseable
Programmable Read
Only Memory)
► Using Floating Gate
Transistors to store bits
► Non-volatile (power not
needed to maintain
data)
► MP3 Players are flash
drives with extra
circuitry to decode data
to analog music signals
►
http://electronicdesign.com/Articles/ArticleID/16383/16383.html
Hard Drive
50-80 GBytes
► Data
http://www.metallurgy.utah.edu/
stored magnetically
► Permanent Storage, Non-volatile memory
► Fast - Spins 4,500 to 12,000 rpm
► Dense and Inexpensive
► Data easily erased and rewritten
► Iron Oxide or very thin magnetic film applied with
a sputtering process stores magnetic data
Actuator
Actuator Arm
Platter
Spindle
Read/Write head
Multiple Platters
Head 20-50 nm from platter surface
A human hair is 100 nm
Read-Write Head
How Stuff Works
wikipedia
www.hddtech.co.uk
The voice-coil actuator controls the movement
of the actuator arm
►
►
►
►
►
►
Positions the
read/write heads
Similar to a speaker!
Uses a coil and
permanent magnet
Converts electrical
signals into mechanical
movement
In this picture, magnet
has been moved to the
left during disassembly
to expose the coil
Coil moves freely
under the magnet
http://www.storagereview.com/guide2000/ref/hdd/op/over.html
Small Tolerances
► 5-80
Mbytes/sec media transfer rate
► Scaled up to size of Boeing, tolerances are
equivalent to traveling at 65 mph at an
altitude of 1.5 mm
As an analogy, a magnetic head slider flying over a
disk surface with a flying height of 25 nm with a
relative speed of 20 meters/second is equivalent to
an aircraft flying at a physical spacing of 0.2 µm at
900 kilometers/hour. This is what a disk drive
experiences during its operation.
”
—Magnetic Storage Systems Beyond 2000, George C. Hadjipanayis
A Computer is much more than a processor
►
►
►
►
►
►
Processor Intel® Core™2
Q6600 Quad-Core (8MB L2
cache,2.4GHz,1066FSB)
Video Cards 768MB nVidia
GeForce 8800 GTX
Memory 2GB* Dual Channel
DDR2 SDRAM at 667MHz - 2
DIMMs
Hard Drive: 500GB* 7200RPM, SATA 3.0Gb/s, 16MB
Cache
Optical Drive Single Drive: Bluray Disc Drive (BD/DVD/CD
burner w/double layer BD write
Monitors 20 inch E207WFP
Widescreen Digital Flat Panel
http://www.dell.com
….