What is Computer Science

1
What is Computer Science?

• Amit Jain
• Associate Professor
• Department of Computer Science
• College of Engineering
• Boise State University
• Consulting Scientist
• Balihoo, Inc

2
Introduction

• Computer science, like Engineering, builds upon
  a foundation of Mathematics and Science.
• Both computer science and physics are about how
  the world works at a rather fundamental
  level. The difference, of course, is that
  while in physics you're supposed to figure out
  how the world is made up, in computer
  science you create the world.
• Computer Science and Engineering deal precisely
  with the notion of how to. Science and
  Mathematics deal precisely with the notion of
  what is.
• Computer Science in turn now drives the research
  and practice in science, mathematics and
  engineering.

3
Introduction (continued)?

• Computer Science involves finding how to
  decompose problems into manageable parts and
  how to work on those parts.
• Computer Scientists often use computer
  programming languages to write the steps for
  solving a problem, but the crux of the work is
  spending time discovering the steps needed to
  solve a particular problem.
• The computer revolution is a revolution in the
  way we think and in the way we express what
  we think.
• A computer language is not just a way of getting
  a computer to perform certain operations but
  rather it is a novel formal medium for
  expressing ideas about methodology.

4
Major Areas of Computer Science

• Algorithms and Data Structures
• Programming Languages
• Systems Operating Systems, Architecture,
  Databases and Networking.

5
Recursion

• Define a b as
• if a is 0 then b
• else (decrement a) (increment
  b)?
• An implementation in the programming language
  Scheme
• (define ( a b)?
• (if ( a 0)?
• b
• ( (dec a) (inc b))))?

6
Hole in my Bucket

• There's a hole in my bucket,
• dear Liza, dear Liza,
• There's a hole in my bucket,
• dear Liza, a hole.
• Well fix it, dear Henry,
• dear Henry, dear Henry,
• Well fix it, dear Henry, well fix it.
• With what shall I fix it, . . .
• With straw, . . .
• The straw is too long, . . .
• Well cut it, . . .

With what shall I cut it, . . . With an
axe, . . . The axe is too dull, . . . Then
sharpen it, . . . With what shall I sharpen
it, . . . With a stone, . . . . The stone
is too dry, . . . Then wet it, . . . With
what shall I wet it, . . . With water, . . . .
In what shall I fetch it, . . . With a
bucket, . . . There's a hole in my bucket, . .
.
7
Algorithm Example

• Computer 2n
• Approaches The simple way versus recursive
  doubling.

8
Software Engineering Example

• The Linux Operating System kernel
• Version 2.6.22 7.44 million lines of code, 26356
  files, about 100,000 developers
• The Space Shuttle
• 2.5 million parts, 230 miles of wire, 4.5 million
  lbs, 18,000 NASA employees.

9
Computer Science Careers

• Wide variety of careers Software companies,
  Engineering companies, Biomedical companies,
  Investment companies etc.
• NASA, NSA, Google, Wall Street, Bioinformatics,
  Intel, Microsoft, Facebook, Twitter.
• Boise Metro Area over 200 software companies

10
History

• Charles Babbage (1791-1871). Designed the first
  programmable computer (around 1822) called the
  Difference Engine. It had 25,000 parts,
  stood 8 feet tall and weighed fifteen tons.
• Countess Lovelace Ada (1815-1852). Collaborated
  with Charles Babbage. She was the first
  programmer! She understood and articulated
  the promise of a general purpose computer.
• Alan Turing (1912-1954). Defined the notion of a
  general purpose computer precisely. Led a team
  to build one of the first computers in the
  1940s..
• Von Neumann (1903-1957). One of the earli
  pioneers who also led a team to build a
  digital computer in the 1940s.

11
References

• Is Computer Science Science? By Peter J,
  Denning, Communications of the ACM, April
  2005, Vol. 48, No. 4.
• Just for Fun The Story of an Accidental
  Revolutionary by Linus Torvalds and David
  Diamond, HarperCollins, 2001.
• What is Computer Science? By James Thornton,
  http//jamesthornton.com/wp/display/350/