Def: A computer is a machine that performs calculations automatically.

The First Special Purpose Calculators:

    The Abacus: The first mechanical computers were invented over 2000 years ago: The abacus can be used to add, subtract, divide, and multiply. The abacus can be used for square-roots and cubic roots.

    Blaise Pascal developed the first digital calculator in 1642. It used radial dials with gogs that flipped through numbers by digit.

The Difference Engine:

    In 1847-1849 Charles Babbage built the first prototypes of portions of the Difference Engine, and Edvard Schuetz constructed the first working Differencing Engine 1855. This mechanical digital calculator was designed to tabulate polynomial functions. Logarithmic and trigonometric functions are easily calculated from polynomials, so this machine was more useful than previous calculators. This machine was powered by cranking a handle!s

The Fisrt Digital Computers:

    In 1939 John Vincent Atanasoff utilized capacitors to store electric charge that could represent numbers in the form of logic 0s and logic 1s (on and off, or charge and no charge). The input was on punched cards. The output was burned spots which had different electrical resistance than the rest of the cardboard and could automatically be readback into the machine.

    Alan Turing and coleagues with the Allied Forces in 1943 developed COLOSSUS, the worlds first programable computer in order to break the German code the "Fish", which was much more complex than the famous ENIGMA Code. This machine was comprised of 1800 vacuum tubes.This machine could perform several different algoriths. This machine was ~10000 cubic feet in volume and ~3 tons.

    From 1944 to 1952 the first "stored program computer", EDVAC, was developed. The idea was to have the program/algorithm already stored on the computer.

Improvements:

    In the 1950s the transistor developes into an integrated circuit. These are made from materials known as semiconductors. Transistors were much cheaper and smaller than vacume tubes. The integrated circuit placed multiple transistors on the same piece of semiconductor, which made computers even smaller.

    In 1970 the first Random Access Memory (RAM) was developed. This ment that the computer could store information without outputting and inputting it back in.

    From 1973 on computers have been sold to individuals and companies.

    In 1975 Bill Gates and Paul Allen founded Microsoft.

    In 1976 Apple I and in 1977 Apple II microcomputers were released. On these early computers no software came for them, so users had to develope their own. (My first computer was an Apple IIC in 1983).

    In 1984 Apple release a "Graphical User Interface" GUI computer with multitasking capabilities: Macintosh. That same year Microsoft released the beta version of an equivalent program, Windows with similar capabilities. Windows wasn't released officially until two years later.s

    In 1985 Home desktop publishing was possible with a GUI interface with PageMaker program for Mac. The same wasn't developed for windows until 1987.

Modern Computers: Modern computers have the following parts:

  • CPU: Central processing unit, or processor. This where the calculations are actually done.
  • Inputs: Keyboard, Mouse. These are the major inputs that provide the user ways to control the computer.
  • Outputs: The monitor is the main output device for computers.
  • Disks: The computer relies on stored memory on various forms of disks. Hard disk (internal or external), CD, DVD, Flash, ...
  • Peripheral Components: Extra components for input and output such as printers, modems, scanners, digital cameras, sound cards.

Software: Software is the information that the computer uses to accomplish tasks. Software must be accessed before it is used. Software must be converted from instructions into a program that completes the tasks.

    Publishing: These programs are useful for publishing results. Examples of software packages we will use are:

    • Word Processing: Word processing tools, such as Microsoft Word or LaTek (generally older scientists only) are useful for writing documents.
    • Spread Sheet: It is handy to have a program that can easily manipulate tables.
    • Illustration: It is useful to have a program that helps touch up, or even make illustrations, such as Adobe Illustrator & Photoshop:
    • Presentation: In the sciences we advertise our science and learn from others by way of presentation. It is useful to have experiences with presentation making software like Powerpoint.
    Programming: Most geoscientists use some form of accademic software for research at some point in their research. It is useful to be able to program in order to understand what the software is doing, and how to fix it if the software isn't working.
    • Fortran: An early programming language that is easy to use, but limited in GUI interfaces.
    • C/C++: This language is generally more versatile than fortran, but has less legacy code left over from previous generations.
    • Java: This is a web based extension of C++. It has advantages that it is more portable than other programs.
    • Matlab: This language is actually a scripting language that requires another program to run it. It is extremely user friendly, but slow and limmited for hard-core computing.
    • HTML: This is a formatting language. Programs such as Internet Explorer and Safari interpret the language and display the results. Everyone should have a web page. It makes you accessible to the outside world. It increases interaction among scientists.
    Free Geoscience Programs:
    • GMT: Generic mapping tool (Unix Based) is useful for creating maps and various plots.
    • SAC: Seismic Analysis Code (Unix Based) is useful for data analysis (for seismologists and non-seismologists).

Data & Storage: Disks are used to store information. Information is stored in files, whose size are measured in bytes. A byte is composed of 8 bits. Bits are 1s or 0s (or ons & offs). One byte is about 1 character (letter "L", number "120", symbol "@" ... ).

    Practicle Sizes:
    • kilobyte (KB): 103 bytes.
    • megabyte (MB): 106 bytes.
    • gigabyte (GB): 109 bytes.
    • terabyte (TB): 1012 bytes.

    Different types of disks hold different amounts:

    • CDs: 650 Mb (Good for quick backup)
    • DVDs: 4 Gb (Good for backup)
    • Hard Disks: Up to 10 Tbs (Typically < 500 Gb).
    • USB Tumb: ~250 Gb (Useful for sharing at conferences)

NOTE: IT IS VERY IMPORTANT TO BACK UP YOUR WORK BECAUSE ALL FORMS OF DISKS ARE SUBJECT TO FAIL. MURPHY'S LAW: ANYTHING THAT CAN GO WRONG WILL! (AND USUALLY AT THE WORST TIME POSSIBLE).

Health & Safety: Using computers regularly (as we all do in the sciences) is inherantly bad for your health. Be careful not to damage yourself. The damage you do now may not be reparable later. Follow the following tips to minimize personal damage:

    • Relax: Computers are here to help us, not make our lives more stressful. The most harmful part about computers is stress!!!!
    • Don't slouch! Your mother is right, sit upright and correct your posture. If you don't your back will begin to hurt! Make sure that your monitor is at eye level, and the mouse and keyboard are not too high or low.
    • Monitor Size: Don't strain your eyes too much. decrease the resolution if need be. Straining your eyes can cause focusing problems. You may need to get glasses or bifocals if you continue to squint.
    • Time Out: It is good policy to take breaks from your computer to stretch muscles and give the stess, eyes, and mind a break.
Last edited on August 29th, 2006 by Jesse F. Lawrence.