Midterm Review25 February 2008

What does a Computer Do Well? Intelligence amplifier

amplifies our ability to perform mental activities “power tools” for the mind Can process much more information

Does repetitive tasks quickly and correctly Check things more quickly Removes people from boring tasks

Manipulates forms and data

What a Computer Does

Very simple machine: executes exactly what it is told

Executes instructions that define algorithms Instructions stored in the computer are the software

We can change them Instructions deal with holders of data, not the data

itself Gives them the ability to deal with any data

Makes computers the most adaptable tool

Logical organization of computer system

Inputs

CPU

MemoryOutputs

Programs &Data/info in use now

StorageLOTS of programs and data files stored here

programsdata

information

What is stored in the Computer?

Bits: ones and zeroes Why? Easy to build

To make managing information easier, stored in fixed size packets: Bytes (8 bits), Half words, Words, ...

Storing Numbers:Binary Positional System

10

=0 0 0 0=

0 0 1 0=

8 4 2 1

=0 0 0 1

0 1 0 0=

=0 0 1 1

0

1

2

3

4

Data Types Computer doesn’t know what the bits

represents or what format is being used Computer assumes that the instructions know

the format of the data

Data Types Numbers: integers and floating point numbers (scientific

notation) Why do we need floating point numbers?

Text: Unicode, double byte Languages and symbols (Word insert symbol)

Pictures: pixels A very fine needlepoint How to represent color?

Sound: different formats Instructions

The Internet What is it?

The infrastructure that connects identified computers Links = the wires Routers = the boxes that connect them

World Wide Web Computers that contain information to be shared Servers

How Networking Works Need to know where to go and how to et there

Who identified by IP address Every machine that is connected to the network has one

Routers know how to get there But IP addresses aren’t user friendly

Give names instead Domain Name Server does the mapping

Benefits and Risks Most benefits are obvious

Productivity tools Medicine Education Assistive technologies …

But with benefits come risks…

Risks

Software failures Networking breaches Technology often evolves faster than our

ability to handle Try to do everything with technology

Software Problems Usability

Bad Design

Reliability Programming Mistakes

Why is it so hard? Why can’t we get it right?

“Our civilization runs on software, yet the art of creating it continues to be a dark mystery, even to the experts.

And the greater our ambitions, the more spectacular we seem to fail.”

Scott Rosenberg, “Dreaming in Code”

Is this a Problem?

Help you achieve WHAT you want, in less time, with minimal effort….

Do ALL that you need …

Easy to learn (intuitive)

Easy to remember

Standardized

Characteristics of a Useful Tool

Why are bugs hard to find? The error can appear in another program

Device drivers, memory management

The error may only occur occasionally May require multiple conditions to occur

User Interface Bug Afghanistan War (December 2001)

Friendly fire kills 3 injures 20 when satellite-guided bomb landed on a battalion command post

Use of GPS Receiver to determine coordinators Change battery Own location came up, not the one that had been

entered

Lots of Examples of Software Bugs

Therac 25 FBI Virtual Case File Rocket launches, ...

Networking Problems Data can be read Data can be lost Data can be changed Data can be sent to someone else

People assume they know who owns the site

Easy-to-discuss RISKS

• Technostress

• Multitasking

• Sidetracking

Kling Analogy First viewed as a clean technology Easy to See the Benefits

Easy to identify Want to see them

Is it possible to identify every side effect or impact?

What about unintentional side effects? Ethical responsibility to try to look at

consequences

Role of Ethics Framework to evaluate and reason Philosophical study of morality Ethical issues must be voluntary and related

to morality Fundamental purpose of morality: to advance

the common good Core values

Ethical Theories Ethical relativism

Individual (or subjective) Cultural

Normative ethical theories Deontological

Kantianism Contractualism

Teleological Utilitarianism Just consequentialism

Normative Ethical Theories Deontological: based on the sense of duty

Right because of the act Teleological: based on the result

Right because of the result

Deontological Theory What is it?

Based on our duties and responsibilities Actions are fundamentally right or wrong

Examples Kantianism (Kant) Contractualism (Hobbes, Rousseau)

1588-1679

1724-1804

1712-1788

Kantianism: Ethics of Duty Duty as freely imposing obligation on one’s

own self Duty is internal We impose duty on ourselves

Kant’s Categorical Imperatives Universality: “Always act in such a way

that the maxim of your action can be willedas a universal law of humanity.”

Respect: “Always treat humanity, whether in yourself or in other people, as an end in itself and never as a mere means.”

Strengths of Kantianism Rational Produces universal moral guidelines Treats all people as moral equals

Strengths and Criticisms Strengths

Rational Produces universal moral guidelines Treats all people as moral equals

Criticisms Moral minimalism: requirements are not heartfelt Moral alienation: alienated from feelings No way to resolve conflict between rules Allows no exceptions

Contractualism Social Contract Theory: duty not to interfere

with others’ rights Morality consists in the set of rules,

governing how people are to treat one another, that rational people will agree to accept, for their mutual benefit, on the condition that others follow those rules as well.

James Rachel, The Elements of Moral Philosophy

Rawls’s Principles of Justice Each person may claim basic rights and

liberties as long as these claims are consistent with everyone else having a claim to the same rights

Social and economic inequalities must Be associated with positions in society to which

everyone has an equal opportunity Be of the greatest benefit to the least-advantaged

1921-2002

Strengths and Criticisms Strengths

Framed in terms of rights Explains acting out of self-interest when there is no

common agreement Provides framework for moral issues dealing with

government Criticisms Doesn’t address actions that can be characterized

multiple ways Doesn’t address conflicting rights

Term Projects A thesis needs to be a statement that you are

willing to defend It should not be a black or white statement

Rework for Monday

Teleological Theory What is it?

Something is good based on its consequences Primary example: Utilitarianism

Jeremy Bentham

John Stuart Mill

1748-1832

1806-1873

Utilitarianism Greatest Happiness Principle Compute the costs and benefits

Simple calculation: do positives outweigh the negatives?

Two forms Act – judge the consequence of a specific act Rule – judge the consequence of the generalized

rule

Strengths and Criticisms Strengths

Focus on happiness Down to earth Appeals to many people Comprehensive

Criticisms Ignores our sense of duty Range of effects that one must consider Requires that we balance very different aspects Unjust distribution of good results

Just Consequentialism James Moor (Dartmouth) Consider consequences of action… but

combine w/deontological ideals

Consider duties, rights, and justice

Protect against unnecessary harm (suffering), where harm = loss of core values life, happiness, abilities, security, knowledge, freedom,

opportunities, resources

Applying Just Consequentialism

A decision or action is ethical if It does not cause any unnecessary harm to

individuals and groups

Supports individual rights

Fulfills duties

Beyond Ethics Regulators in Physical Space (Lessig)

Law (sanctions) Social norms (behavior) Market (cost) Architecture (self-enforcement)