• Exactly What is a Computer?

• What are the Components of a Computer?

• A Peek Under the Hood

Hard to Define:

Thermometer, Slide Rule, Hand Calculator, Human = Computers?

Our Text: "A computer is a device capable of performing computations and making logical decisions at speeds millions, and even billions, of times faster than human beings can"

CX 121 text: "A Computer System consists of hardware and software that work in concert to help us solve problems."

Brookshear: "Computer Science is the discipline that seeks to build a scientific foundation for such topics as computer design, computer programming, information processing, algorithmic solution of problems, and the algorithmic process itself."

Britannica: "any of various automatic electronic devices that solve problems by processing data according to a prescribed sequence of instructions."

Fundamental Idea: Algorithm (list of instructions, recipe)

We will be studying digital devices that can store and execute algorithms.

Algorithm: The instructions

Application: An algorithm that can be "executed" or "run" directly on a computer(Word, Excel, Photoshop)

Document: File produced by application.

The instructions that comprise an application are expressed in a computer’s native language

Everything a computer does is expressed in terms of bits.

0’ and 1’s can be implemented easily mechanically or electronically.

It’s hard for us to write directions in binary.

Humans use a high level Programming Language: English-like set of words.

Two Kinds of Translators

Interpreters (line by line)

Compilers (full translation of entire program)

Programming Languages

FORTRAN (~ 1957)

COBOL (~ 1959)

BASIC (~ 1965)

Pascal (1971)

C (1972)

C++ (early 1980’s)

Java (1995)

Javascript

Hardware and Software

1. Some applications do not fit or they function poorly in restricted RAM (browsers, word processors)

2. Keep several applications open at the same time.

3. Some tasks will be faster (playing a movie or song, printing long document)

Buying RAM Chips

Single Inline Memory Modules : SIMMS

Double Inline Memory Modules: DIMMS

The Basic Diagram

The main logic board s often housed in a box-like system unit. The remaining peripheral devices (monitor, keyboard,..) are connected to the logic board through ports that are visible at the back of the system unit. The main logic board often contains slots where additional cards can be inserted. (video capture card, ethernet card).

A program must reside in RAM to be executed. So does the data on which the program operates. Changes stay in RAM unless written (SAVED) to the copy in storage.

The modern computer market is dominated by IBM PCs or IBM PC Clones.

Over 75% of the computers sold today are PCs or PC clones. IBM itself

has about 10% of the microcomputer marker.

Dell, Compaq, Packard Bell, NEC, Tandy... have over 65%.

The IBM and IBM clones use CPUs from the Intel Corporation.

Apple Macintosh computers and IBM RS/6000 computers use CPUs from Motorola.

Programming Language

How does ROM differ from RAM?

How does "storage" differ from "main memory"

Where must a program reside while it is being executed?

Where does the actual execution take place?

How does a "hard disk" differ from a "floppy disk"?

Why are "hard disks" better than "floppy disks"?

How does a CD-ROM differ from a hard disk?

Why is nice to have lots of RAM?

Supercomputers Governments

Mainframes Large Businesses

Minicomputers Colleges

Microcomputers Individuals

Workstations

Laptops

Notebooks

Palmtops