221 lines
9.2 KiB
Plaintext
221 lines
9.2 KiB
Plaintext
IF YOU HAVE NEVER USED A COMPUTER BEFORE:
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Welcome! Computers have been around since the Chinese Abacus.
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They are here to stay. There is a certain feel and flow to the
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logic which directs their activities.
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Electronically all computers work about the same. The one you
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are using is called a MICROcomputer. This is due to its size.
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Larger computers include MINIcomputers and Mainframe computers.
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RAM
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---
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Think of a computer as a human brain. Your brain is a memory sponge.
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It contains a lifetime of memories which cause us to act or react
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based on inputs. Inputs come via our 5 senses. If you see and smell
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a steak burning on the grill (inputs) you know how to react based on
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previous experiences (memory - go out to eat).
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The computer's brain is comprised of a large memory area called Random
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Access Memory (RAM) and a calculating portion called the Central Processing
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Unit (CPU). The CPU and RAM work together as the computer's "brain". Each
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day when we start up the computer one of the first tasks will be to fill
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RAM with instructions to give it an ability to perform work. This work may
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be in the creation of documents or tracking accounting data (more information
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on CPU is found under the HARDWARE section).
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You control which instructions will go into the computer's brain.
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You control which sets of experiences you will provide the
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computer. Once in RAM, the computer will evaluate inputs from
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many devices and react. The most typical input device is a
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keyboard. As you type commands, the computer evaluates them and
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based on the set of instructions within its RAM, will follow some
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action - perhaps print a document, calculate, or send information
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over a telephone line.
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At some later point you may empty the computer's brain and
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install a different set of instructions, thus giving it a
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different ability.
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Unlike a human, the computer requires electricity to keep the
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information within RAM. Each time the computer is turned off,
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all information within RAM is lost. RAM is a temporary memory.
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To save instructions for use at a later date, a storage device is
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required. Computers use many such devices. Your computer uses a
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Floppy Disk and/or a Hard Disk. Both are similar.
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DISKS
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Think of these disks as cassettes. You can record information on
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a cassette which can be replayed indefinitely and if desired,
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recorded over. Floppy and Hard Disks operate in a similar fashion.
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We record (Save) something we have created - like a document - onto the
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disk. Then, hours, days, or months later we are able to play back
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(Retrieve) the document into the computer to alter or print out. Just
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like cassettes, the Floppy and Hard Disks do not require electricity to
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retain their information.
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Hard Disks and Floppy Disks are similar. Hard Drives have a larger
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capacity for file storage, are faster and are less likely to fail due
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to the protected environment from within which they operate.
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RAM is called volatile memory because of the electricity
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requirement. Floppy and Hard Disks are called non-volatile
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memory because they will retain their information without the aid
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of electricity.
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A computer system includes computer hardware, software and
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people. A computer is a device capable of solving problems
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or manipulating data by accepting data, performing prescribed
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operations on the data, and displaying the results.
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HARDWARE versus SOFTWARE
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------------------------
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HARDWARE: Physical equipment such as electronic,
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magnetic, and mechanical devices (monitor, keyboard,
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printer, microchip boards,...). Includes INPUT/OUTPUT
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DEVICES which allow the operator to communicate with the
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computer and vice versa.
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SOFTWARE: Sets of programs (stored sets of
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instructions) that govern the operation of computer system
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and make the hardware run. These programs (instructions)
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tell the hardware how to perform a particular task such as
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word processing, games, database management, etc.
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Software refers to the instructions that are used to enable
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an otherwise dead machine to understand your inputs and
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transform them into desired outputs.
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Computer hardware by itself has no personality; this is
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determined by the software. Word processing software turns
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the computer into a word processor, accounting software turns
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the computer into an accounting tool, etc.
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The computer requires two types of Software:
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DOS - Disk Operating System
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Application Software - Word Processing, Spreadsheet, Games,
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Database Management, Accounting, Payroll, etc.
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DOS (Disk Operating System)
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---
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All computers require an operating system and the one IBM
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PC's use is referred to as DOS (sounds like floss). DOS is
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software that allows the terminal, printer, computer and mass
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storage systems (floppy disks) to work together as a unit,
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and controls the execution of programs. It also allows you
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to perform housekeeping chores in regards to managing disks
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and files.
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Therefore - DOS: 1. Links Hardware
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2. Enables File Management
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PROPER HANDLING OF DISKS - DISKS NEED CARE!
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------------------------
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- Never touch the mylar surface - Do not bend the disks
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- Always store in their protective sleeve
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- Hold the disk by its label or any part of the sleeve
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- Avoid bringing disks near magnets (TVs, telephones,..)
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- Do not leave in hot or cold areas (radiators, car-dash, in
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car during winter, etc.)
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- Use felt tip pens if possible when labeling. Ball points
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can crease the mylar.
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Note the write-protect notch on the disk. If this is covered
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by tape or non-existent, data cannot be "written" to the disk.
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However, data can still be "read" from the disk.
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It is a good idea to always save data and programs on two
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separate disks in case one is destroyed. Even with the most
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cautious of care, the delicate Floppy Disks sometimes fail
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for no apparent reason.
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HISTORY:
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The first computational device was the abacus. This has been
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in continuous use for thousands of years. During the 1600's the
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Pascal adding machine was developed. This was a mechanical
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device which laid the groundwork for today's odometers and
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gas meters. The 1800's saw many machines developed that were
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controlled by punch cards - weaving looms, etc. The
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theoretical basis for electronic circuitry was developed in
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the mid 1800's.
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The first electronic computer was developed in 1942 at Iowa
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State College. From this point forth there were numerous
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firsts as computers became less mechanical, smaller, faster
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and cheaper. IBM began dominating the computer market by the
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mid-1950's and still does today in the mainframe (very large
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computer installation) market. Digital Equipment Corp.
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(DEC) became a significant competitor by the mid-1960's. DEC
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is generally considered technically better (faster, smaller,
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etc.) than IBM but still only has a fraction of the total
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market due to marketing snafus. Today the Cray Supercomputer
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is the fastest in the world, is manufactured in Wisconsin,
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and is set in a vat of liquid helium to increase the
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conductivity for faster operation.
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TIME vs SPEED
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Method of Calculation Approximate Speed
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Human (manual calculation) 1 each 60 seconds
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Burroughs E101 (1954) 4 per second
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IBM 1130 (1964) 600,000 per second
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DEC PDP 11 (1974) 1,000,000 per second
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Cray supercomputer 13,000,000 per second
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The Personal Computer is defined by its size, cost
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applications for small business and the home. The first one
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appeared in January 1975 and was the Altair 8800 kit. Only
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hobbyist bought these. Then the Radio Shack TRS 80 and Apple
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computers hit the market as the first pre-assembled
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microcomputers.
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Market growth remained sluggish until two business students -
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Dan Bricklin and Dan Fylstra developed a program to run on
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Apple computers to handle the tedious recalculations in their
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school assignments. This program was called VisiCalc and is
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the forerunner to the spreadsheet program Lotus 123.
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With VisiCalc as a useful tool, Apple sales took off. Apple
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became the standard because all programs were written for
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Apple. Today we still see Apple dominate the school market.
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In 1981 IBM introduced its PC which is unable to run Apple
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software. Unlike Apple or other IBM products, the IBM PC had
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an open architecture which means the technical details of how
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it operated were published right along with the product's
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introduction. This permitted hundreds of companies to write
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software (programs) for the IBM PC as well as a variety of
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accessories. Adding IBM's sterling reputation, the open
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architecture did enable rapid market penetration. The
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microcomputer was no longer a toy, it was a business tool.
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The open architecture however, also allowed for the
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generation of a host of lower cost compatible computers.
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IBM had traded quick initial market entry for eventual erosion
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of market share. In both instances, we the consumers
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benefit.
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***** END OF FILE: Press <ESC> to return to Main Menu *****
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