COS 109
Monday September 21
• Announcements
– I won’t be here on Wednesday (Jewish holiday); class will be taught
by Brian Kernighan
– Powerpoints (in whole or abstracted) for all lectures will appear on
the website after class
– First assignment is available on the web site as of today (and is due
next Monday September 28)
– First lab is available on the web site as of today (this is early) and is
due next Friday October 2
• Overview of today’s lecture
– Describing the first assignment
– Covering some material from Wednesday that was skipped
o Largely course overview/roadmap
o Some policy issues
• Beginning our coverage of computer hardware
About the first assignment
• Monitor your use of technology
– For a representative 4 hour period, monitor your usage of
Computers
Phones
Other devices
– How often do you use them and for what do you use them
• Extrapolate from this
– How much time you will spend on technology during your 4 years at
Princeton
– How much time Princeton students spend on technology per year
– How much time all college students in America spend on technology
per year
– Translate the time spent into another activity (walking) and measure
how far you could walk during the time spent on technology
• Extend the gas station exercise from class in a few directions
From: http://www.businessinsider.com/smartphones-in-americans-lives-2015-7
Course high level outline
• hardware (3-4 weeks)
• software (3-4 weeks)
• networks and the impact of internetworking (3-4 weeks)
• along the way
– current events, history, QR, ...
Course high level outline
• hardware (3-4 weeks)
– how computers represent and process information
– what's inside a computer, how it works, how it's built
– computer represents information
– the universality of a computer
• software (3-4 weeks)
• networks and the impact of internetworking (3-4 weeks)
• along the way
Course high level outline
• hardware (3-4 weeks)
• software (3-4 weeks)
–
–
–
–
how we tell computers how to do things
algorithms as recipes for computations
a very gentle introduction to programming in Javascript
programs that make us able to write programs, run apps, …
• networks and the impact of internetworking (3-4 weeks)
• along the way
Course high level outline
• hardware (3-4 weeks)
• software (3-4 weeks)
• networks and the impact of internetworking (3-4 weeks)
– how the Internet and Web work – protocols and routing
– threats and countermeasures: security, privacy, cryptography, ...
• along the way
– current events, history, QR, ...
Changing perceptions of the internet
Peter Steiner cartoon published by The
New Yorker on July 5, 1993
Who is paying for your free
Internet? May 21, 2012
Leaving the analog world and becoming digital
Going from analog to digital
1
0.8
0.6
0.4
A curve
0.2
0
-0.2 0 0.250.50.75 1 1.25 1.5 1.75 2 2.252.52.75 3 3.253.53.75 4 4.254.54.75 5 5.255.55.75 6 6.25
-0.4
-0.6
-0.8
-1
1
0.8
A string of numbers
0.6
0.4
0.2
0
-0.2 0
-0.4
-0.6
-0.8
-1
1
2
3
4
5
6
7
Can affect the sampling rate
1.5
1
0.5
0
0 0.4 0.8 1.2 1.6
2 2.4 2.8 3.2 3.6 4 4.4 4.8 5.2 5.6 6
-0.5
-1
-1.5
1.5
1
0.5
0
0 0.30.60.9 1.2 1.5 1.8 2.1 2.42.7 3 3.33.63.94.24.54.8 5.1 5.45.7 6
-0.5
-1
-1.5
Technologies becoming disruptive
What do all of these changes have in common?
Going digital
[ Universal digital representation ]
Music
just numbers
Pictures
just numbers
Sounds
just numbers
[ Universal digital representation ]
Music
Pictures
Sounds
Movies = pictures and sounds
TV and radio = pictures and sounds
Telephone calls = sounds (pictures for Skype)
Books and newspapers = pictures and text
Business records = pictures and text
Classified documents = pictures and text
Programs = text
. . .
specialized mechanisms replaced by uniform rep
The impact of being digital: Copyright
• music, movies, TV, games, etc., are all digital
– copies are free, copies are perfect, distribution is free
• technically, it's impossible to prevent copying
– cryptography, watermarking, etc., don't work
• legally, it's difficult to prevent copying
– sensible laws are hard to write
– laws are different in different countries
– many countries don't protect intellectual property
• warning: it's pretty easy to catch violators here
– don't download copyrighted material like movies and TV shows
Tracking copyright violations
• Google transparency report
– Google regularly receives requests from copyright
owners and reporting organizations that represent them to remove
search results that link to material that allegedly infringes
copyrights. Each request names specific URLs to be removed, and we
list the domain portions of URLs requested to be removed under
specified domains.
• Copyright removal requests received for search in the past
month
•
•
•
•
55,702,393 URLs Requested to be Removed
80,526 Specified domains
5,991 Copyright Owners
2,683 Reporting Organizations
• How many URLs are there?
The impact of being digital: Privacy
• data for shopping, banking, taxes, ..., is all digital
– public records are increasingly digital too
e.g., election contributions often include home addresses
• data is easy to collect, store, copy, analyze, sell,
and use for good or ill
• technically, it's impossible to control access
– we're vulnerable to bugs, incompetence, stupidity, theft
• legally, in USA, we don't control data about ourselves
– anyone can collect and sell anything about all of us
– laws are different in different countries
– some (but not all) countries are more restrictive
And what about Ashley Madison?
Last month, America's most prominent dating site for cheating spouses got egg
on its face after hackers stole millions of users' private information. The stolen
data reportedly included names and credit card information, photos, and sexually
explicit chat logs.
The hackers objected to Ashley Madison's morally dubious business model, and
they tried to blackmail the site into shutting down.
Ashley Madison refused to suspend its operations, so now the hackers appear to
have retaliated by releasing the stolen data online. While Ashley Madison hasn't
officially confirmed the data's authenticity, it appears to be genuine. That's
going to cause heartburn for the millions of people who have created accounts on
the site.
From http://www.vox.com/2015/7/20/9007039/ashley-madison-hack-explained
TORONTO (AP) — The hack of the cheating website Ashley Madison
has triggered extortion crimes and led to two unconfirmed reports
of suicides, Canadian police said Monday.
From: http://www.usatoday.com/story/news/nation-now/2015/08/24/police-ashley-madison-hackextortion-crimes-suicides/32269699/
Ashley and the Ivies
Has it happened to you?
• What has already been hacked?
[ Surveillance ]
• Would you wear something like an ANKLE BRACELET
so someone knew where you were all the time?
• location tracking ("loss of locational privacy")
– cell phones
– ubiquitous cameras
• government surveillance
– NSA is monitoring pretty much everything on Internet
– and on the phone system
– and in your dealings with companies
Security
• the universal network makes us vulnerable to strangers
– the Internet has no geography
– it's easy to lie about who you are and where you are
– the bad guys are usually far away
• general-purpose computers are everywhere
– "active content": web pages, email can contain programs
• leads to spam, phishing, viruses, spyware, botnets, ...
• it's impossible to control such programs
Top 10 attacks on PU on Sept 3, 2014
It's not just computers
• computers and networking are spreading into devices
• devices are increasingly powerful
• devices and systems are increasingly connected to
the Internet: "Internet of Things"
phones
games
consumer electronics
cars
planes
medical systems
telephone, power and other infrastructure systems
weapons
...
[ Big players, powerful interests ]
• there's a lot of money and power at stake
• governments, companies, criminals, little people
• jurisdiction
– countries limit Internet use (and monitor it)
Google and other search engines v China
online gambling in USA
porn in Saudi Arabia
access in lots of countries
– Amazon resisted collecting state sales taxes for a long time
• who has your data?
– Google: gmail, docs, search history, ...
GOOG has bought 27 companies so far this year
–
–
–
–
Facebook: friends, pictures, relationships
Amazon: everything you buy, read, watch, …
will they release info for profit, for subpoena, ...?
what's the answer in other countries?
[ What matters and why ]
• we are totally dependent on digital mechanisms
– we can't just turn things off
– technology won't wait while we figure out what to do
– the rate of technological change is increasing
• legal, economic, political and social systems change slowly
– and change differently in different places
• people don't change in fundamental ways
– and certainly not as fast as technology does
Wired Magazine July 21, 2015
What is wrong with this picture?
How do we talk about a computer?
• The pieces and what they do
• The architecture of how the pieces fit together
• The support for software that lets things happen
Major pieces of a computer
CPU (central processing unit)
controls and processes
Random Access Memory (RAM)
stores instructions and data
while computer is running
Disks (secondary storage)
Peripherals
store everything when computer is off perform a variety of other tasks
How the pieces fit together
CPU
mouse
keyboard
display
(processor)
Bus
Memory
(RAM)
Hard
disk
CD/
DVD
network
/wireless
(and many
others)
PC or Mac?
• Why?
• How does this compare to the broader world?
• iPhone or Android?
Different models -- PC vs Mac: who has what?
Worldwide
~90% Windows
Princeton
students
administration
75% Mac
50-60% Windows
[ PC vs Mac: what operating system do people use? ]
[ PC vs Mac: a comparison? ]
•
•
•
•
which is better?
why does Windows have ~ 90% of market?
Why is Princeton different?
what's different? what's the same?
– what does "Intel inside" mean?
• distinguish between hardware and software
• why do they keep getting cheaper and faster?
– how fast is that?
– do they?
Numbers
•
•
•
•
•
•
•
Kilo
Mega
Giga
Tera
Peta
Exa
Zetta
1,000
1,000,000
1,000,000,000
1,000,000,000,000
1,000,000,000,000,000
103
106
109
1012
1015
1018
1021
•
•
•
•
Milli
Micro
Nano
Pico
.0001
.0000001
.0000000001
.0000000000001
10-3
10-6
10-9
10-12
• Googol
• Googolplex
10100
10googol
210
~ 220
~ 230
~ 240
~ 250
~ 260
~
2019 freshman SCI computers
Apple Macbook Pro 13" Retina
•2.7 GHz Intel Dual Core i5 processor
•13.3" retina display
•Intel Iris Graphics 6100
•8 GB memory
•256 GB PCI-e Flash Storage
•Ethernet and VGA Adapters included
•Mac OS X 10.10 Yosemite
Dell XPS 13
•5th Generation Intel Core i7-5500u processor (4M Cache, up to 3.0 GHz)
•13.3 inch UltraSharp QHD+ (3200x1800) Infinity Touch Display
•UMA Graphics
•8 GB memory
•256GB Solid State Drive
•Backlit Keyboard
•Ethernet and VGA adapters incl.
•Windows 8.1 Pro
2011 freshman offering:
2019
vs.
Apple Macbook Pro 13" Retina
•2.7 GHz Intel Dual Core i5 processor
•13.3" retina display
•Intel Iris Graphics 6100
•8 GB memory
•256 GB PCI-e Flash Storage
•Ethernet and VGA Adapters included
•Mac OS X 10.10 Yosemite
Dell XPS 13
•5th Generation Intel Core i7-5500u processor
(4M Cache, up to 3.0 GHz)
•13.3 inch UltraSharp QHD+ (3200x1800) Infinity
Touch Display
•UMA Graphics
•8 GB memory
•256GB Solid State Drive
•Backlit Keyboard
•Ethernet and VGA adapters incl.
•Windows 8.1 Pro
2011
What you get in processors
Processor
I7-5500u
Core 2 Duo
Release Date
January, 2015
July, 2006
Cost
$393
$183
Size
4 cm x 2.4 cm
3.75 cm x 3.75 cm
Transistor count
1.38 billion
295 million
Line thickness
14 nm
65 nm
Power requirement 15 watts
Includes
65 watts
Caches,graphics,
• Thicknesses
– 17,000 nm --- minimum width of human hair
– 70,000 – 180,000 nm – thickness of paper
Motherboard (~1998)
Backplane (~1998)
Functional design is not physical implementation
• block diagram is "architectural" or "functional" or "logical" design
– gives components, shows how they are connected, maybe what they do
• physical construction is how it's built
– usually many different ways to build same functional or logical design
– will all behave more or less the same (same functions)
• important general rule: the logical / functional organization does
not describe a physical implementation
– logical abstracts away irrelevant physical details
Evolution of hardware
•
•
•
•
•
•
fewer components (more going on inside that you can't see)
more connections to outside (with finer, closer wiring)
buses getting wider (more parallel wires)
CPU chips have more pins, bigger heat sinks (but same size?)
less handwork (automated assembly)
changing countries of origin (and fewer?)
Wrapup on components
• the logical or functional components of computer hardware
• how they fit together, what the numbers measure
• some neat Greek/Latin/... prefixes:
– (femto, pico,) nano, micro, milli,
kilo, mega, giga, (tera, peta, exa)
• what the basic physical pieces look like
• one logical organization can have different physical forms
• logical organization hasn't changed much in 60+ years
• physical form has changed rapidly for the entire time
– many tradeoffs among physical forms (size, weight, power, …)