Wednesday January 13, 1999

General Computer Concepts

Data vs. Information

Data is raw facts such as ages, birthdates, etc. pertaining to some entity.

Information is the outcome when data is transformed into something meaningful. For example, if we make a comparison about the ages of people in a certain group and are able to make a conclusion then that conclusion is considered information.

The computer is what we use to transform data into information.

The four major functions of a computer

Input
Output
Processing
Storage

Definitions

Hardware - The physical components of a computer system
Software - The programs which control the hardware
Data - Raw facts
Information - Raw facts processed into a meaningful form

A computer transforms data into information.

Input

Keyboard
- Enter Key
- Function Keys
- Navigation Keys
- Insert/Delete, Backspace Key
- CTRL, ALT, DEL / Escape Key
- Start Button Key
Mouse
- Left Button
  - Double-Click
  - Click
  - Point
  - Click and Drag
- Right Button
  - Quick Menus

Processing

Recall that processing inside of a computer takes place in the CPU ( Central Processing Unit)

Some of the responsibilities of the CPU are

Interpreting Instructions
Arithmetic and Logic Operations
Controlling Input and Output Operations

It is necessary sometimes for the CPU to store data temporarily. Therefore, computer memory is an important consideration. There are two types of memory inside a computer.

ROM - Read Only Memory - Non-volatile - is not erased when the power off
RAM - Random Access Memory - temporary memory - volatile - is erased every time the power is turned off.

Output

Monitor
Printer
Speaker

Storage

Units of Storage
- Bit - binary digit - 0 or 1 - the smallest unit of data
- Byte - 8 bits
- Kilobyte (KB) - 1024 bytes
- Megabyte (MB) - approximately 1 million bytes
- Gigabyte (GB) - approximately 1 billion bytes
- Terabyte (TB) - approximately 1 trillion bytes
A file is a collection of data. Files can be created, edited, and saved.
Data can be moved between files using the Cut/Copy/Paste feature. The clipboard is a temporary storage area. Cut removes the current data and copies it to the clipboard. Copy makes a copy of the current data on the clipboard. You can then use paste to remove the data from the clipboard to the destination.
Files can be stored externally on disks
- Some common types of disk are DS/HD Double-Sided/High-Density
- The disks are called floppies because the first ones were physically floppy.
- In order for a floppy to be used, it must be formatted.
- When formatted, a floppy is divided into tracks and sectors. Recall that a track is a circular section of the floppy, and a sector is a pie-shaped wedge of the floppy. The intersection of a track and a sector is called a track sector. Depending on the operating system, a cluster is from 2 to 8 track sectors. A cluster is the smallest unit of physical storage on a floppy. The recording density determines how much data can be stored on the floppy.
- Also created when a floppy is formatted is a root directory and FAT (File Allocation Table). A FAT is a special area of the floppy that contains information such as name, size, last date modified, and location of clusters contained in a file. It also contains information about bad clusters.
In Windows 95, the letters A and B normally designate floppy drives on the system, and the letter C normally is reserved for the hard drive. A hard drive is a fixed drive. D is either used for either a hard drive or a CD-ROM drive.
Peripherals are devices which are connected to a computer such as a printer.

Computer Software

Applications Software
- Word Processing
- Spreadsheet
- Database
- Graphics
- Communications
System Software
- Operating System
  - OS2
  - MS-DOS
  - Windows 95
  - Windows 98
  - Windows NT
  - UNIX
- The purpose of an operating system
  - Boots Computer
  - Provide an interface between a user and the computer
  - Coordinates Access to Devices
  - Runs Programs
- Virus Protection - Recall that we need to be aware there is a threat of computer viruses. There exist software packages which will detect and remove known computer viruses.
Program files contains instructions that tell the computer what to do.

Windows 95

Microsoft Windows 95 is one of the most popular operating systems for home and office computers. The release date of this product is reflected in its name. It is the operating system which we will use this semester.

Start Button

Programs - contains a menu of all the executable programs on the hard drive. Some of the important programs are applications programs like Microsoft Word or Netscape Communicator, Accessory programs like Notepad, and an MS-DOS Prompt
Documents - contains a list of all recenlty opened documents
Settings - shortcut to Control Panels, Printers, and Taskbar
Find - allows us to search the entire hard drive or any part of the hard drive for certain files. We may use wildcards if we are not sure of the name
Help - contains a list of all tutorials on the hard drive, an index of all help topics, and an advanced index
Run - allows us to run an application just as we would at an MS-DOS Prompt
Shutdown - brings up a menu that allows us to either shut the machine down, restart the machine, restart the machine in MS-DOS mode, or close all programs and log on as a different user. The proper way to shut down a Windows 95 session in a networked environment is to close all programs and log on as a different user.