Basically, a computer is a device capable of manipulating numbers and data. The hardware can do basic math functions and comparisons. By telling the hardware what combinations of these to perform in what order the computer can appear to perform many more complicated tasks.

The series of instructions that do this is called software; the lifeblood of the computer.

Some software actually controls the computer. This software is usually called the operating system. Other software performs tasks for you (e.g., text editing, graphics). These are applications.

Some applications require specific types of hardware. When buying software it's important to know what it requires in order to run and be certain you have the necessary equipment.

This is why it's important for you to know some of the basics before you get involved with computers. At least learn to speak the language.

Bits and Bytes

One of the most frequently heard terms when dealing with computers is byte or its derivatives: kilobyte, megabyte, and gigabyte.

The computer operates using digital electronics. Basically, this means that the computer works with circuits that are either on or off. Math and comparison operations in the computer are performed using mathematics developed around these two states. There are only two numerals used in this mathematics: zero and one (to go with the two states of the hardware: off or on). So, in binary, you count:

0 1 10 11 100 101 110 111 1000 1001 etc.

If you get to a binary number with eight numerals in it you can use that number to represent 256 items. For a variety of reasons the computer industry uses these eight digit numbers in a special way and has given them a special name: the byte (pronounced "bite").

Each byte represents a single character in the computer (a character can be a letter, single number, or one of several special symbols).

Virtually every computer quantity you will encounter is counted in bytes.

The amount of memory in the computer is typically stated in millions of bytes, or megabytes. It used to be measured in thousands of bytes, or kilobytes. (Memory is used to hold software instructions and data on a temporary basis.)

The amount of permanent storage space (hard disk size) is typically stated in megabytes or, in some cases, gigabytes (billions). A hard disk is where software is stored when not in memory telling the computer what to do.

Just so you know...a kilobyte is not exactly 1,000 bytes. Because of the way binary numbers are counted, a kilobyte is really 1,024 bytes. This is why the actual number of bytes you see for memory or on a disk is never an even number (the same goes for megabytes and gigabytes).

What other measures will you likely encounter?

The CPU

The Central Processing Unit (CPU) is the computer chip that controls activity within a computer. The more things the computer has to do, the more powerful the CPU has to be. Some indications of this power are:

• The speed at which it operates. This is usually expressed as an operating frequency (e.g., 66MHz - 66 million Hertz). Faster is often more powerful (but not always). [Note: The examples date the tutorial. CPU speeds up to 2GHz and above are now available.]
• The size of its address bus. This figure is usually expressed as a number of bits (e.g., 16, 32, or 64 bits). The larger the number the more memory the CPU can control and the faster information can be moved from memory into the CPU for processing.
• The makeup of the CPU (i.e., CISC or RISC). Most PCs use a CISC
  (CISC = Complex Instruction Set Computer) CPU but RISC chips
  (RISC = Reduced Instruction Set Computer) are coming. Which is best depends on the operating system.

Makeup of a Computer

Computer hardware can be broadly categorized into five areas which interact with one another:

• Input
• Output
• Central Processing Unit
• Memory
• Secondary Storage

Input and output are ways of getting information into and out of a computer. The keyboard and mouse are input devices and your monitor and printer are output devices. There are many other devices and some even operate in both modes (e.g., a modem can take information from another computer and input it to yours as well as send information from your computer to another).

The CPU we've talked about. Memory is where software and data is stored while the computer is operating. Secondary storage can be floppy and hard disks where software and data are permanently stored.

Secondary Storage

There are two common secondary storage solutions: floppy disks and hard disks.

In both cases, the information is stored on magnetic media similar to cassette tape. Instead of a long strip, the media is cut into a disk shape. The disk spins and the read/write head is attached to an arm that moves radially in and out. The information is thus stored on the media as a series of concentric circles; one circle for each place the read/write head stops. These circles are called tracks on floppy disks and cylinders on hard disks (hard disks usually have more than one platter, stacked on top of one another so tracks on top of one another form cylinders).

Depending on the density of the data, type of media, and several other factors you can expect to store amounts as small as 360 kilobytes to many hundreds of megabytes or even gigabytes on one device. Disks vary widely in performance. They are also subject to failure. It's therefore very important that you make multiple copies of your important data. You never know when a disk will fail.

Keyboard and Mouse

The keyboard and mouse are the two most popular input devices for a personal computer today.

The keyboard is used like a typewriter to enter both commands and data. You will usually find several extra keys you won't find on a typewriter. The Control (CTRL) and Alternate (ALT) keys work like the Shift key in that when you press and hold either of these and then press another key you have modified the characteristics of the other key. In manuals you'll often see either Alt-X or Alt+X. This means you should press and hold the ALT key down while also pressing the X key. Sometimes these are used in combination (e.g., Ctrl+Alt+X). It sometimes helps to be a contortionist to issue these commands.

To make command entry easier, the mouse was introduced. A mouse is a device that rolls on the table and its motion and position is translated by the computer to a cursor on the screen. As you move the mouse the cursor moves in relation. You activate commands by placing the mouse cursor on top of them and then pressing one of the mouse buttons. Usually, the left button activates a command.

Video

Most computer output is to a video display as either characters or graphics or some combination of the two. Typically, displays are in color, although some portable computers still show only two colors. [Rare now]

The most versatile color display is the CRT (cathode ray tube) monitor. This device operates much like a television set although many of today's monitors work with digital data while TV sets continue to work with analog signals.

Portable computers typically have a display based on liquid crystal (LCD) technology. In these, the various picture elements (pixels) are turned on and off by placing an electrical signal across the material thus changing its ability to transmit light. This transition is not as rapid as it is with a CRT so LCD displays will typically be a bit washed out and may not show fast motion very well. Active matrix LCD displays and other technologies are solving this problem and making it easier to get color on the flat liquid crystal display.

In addition to type of display you should also know about resolution...

Video Resolution

Video displays are typically not square. The technology allows you to have more pixels horizontally across the screen than you have vertically on the screen. In early displays this became obvious when you attempted to draw a circle on the screen and it came out as an oval. Modern standards assure that when you draw a circle the display shows it as a circle.

The most common resolution as this is being written [1994] is the VGA 640x480 standard. It is being supplanted by Super VGA at 800x600, although there is no defined standard for this resolution. Other resolutions being sold include 1024x768 and 1280x1024. These latter are more often used in higher power engineering computers as you really need an expensive, large monitor if you are going to use them effectively.

Since many of the resolutions above VGA (640x480) are non-standard, the important thing to find out is if the software you buy for the computer will run with the particular video display hardware in your machine. If not, your hardware vendor may have a new software driver that will make the software and hardware work together.

Printers

Despite the promises of a paperless office, the printer is still a major output device for computers. There are many printer technologies on the market but the two that are most popular at the time this is being written [1994] are:

• Ink jet. The ink jet printer "shoots" individual dots of ink to the paper, calculating the location of each dot in order to form individual characters or dot graphics. When using these, a good paper is necessary to avoid smearing.
• Laser. The laser printer is noted for producing a page of text at a time. In this printer a laser scans a photoactive plate building up an image of the printed page. Like in a copy machine, the plate is dusted with toner which sticks to the exposed areas. Paper is then placed in contact with the plate, transferring the image to the paper. A final heat bonding seals the toner to the paper. This all takes just a few seconds.

Interfaces

Not everything is built into a computer. You will often have to connect devices to it. You do this through an interface. There are two types of interface: parallel and serial.

Their names describe the functions. In a serial interface each bit is sent to the device individually. A parallel interface sends all eight bits in a byte at once. They will not intermix. Parallel is faster than serial. A computer has only so many of each.

Modem

The telephone system developed as an analog system. While the central switching offices have mostly changed to digital, the actual phone instrument you speak into is still analog.

Thus, until the entire phone network from end to end becomes digital a computer that needs to "talk" to other computers over phone lines will need to convert its digital signals into analog and back again.

The device that does this is called a modem; short for MOdulator/DEModulator.

In use, your computer sends digital signals to a modem via its serial interface port. The modem converts these signals to tones and sends them over the phone lines. Another modem converts the tones back to digital data and inputs it to another computer via its serial port. Responses come back along the same path.

Because the phone lines have limited capability to carry tones, data encoding and compression schemes are used to get high data rates.

Networks

Another way computers "talk" to one another is via a network.

Networks are completely digital and therefore can be very fast for transferring data. The computers in a network can be connected via a variety of media: cables, wires, fiber optic cables, or radio waves. Even high-speed digital telephone connections can be used.

One of the original uses of networks was to share high-cost items.
Via a network, many computer users could print to a single high-quality printer.

Networks are now additionally used to share applications (the software is installed on a special network computer and everyone can use it from that computer); and for electronic mail (messages delivered via the network).

Networks are evolving to include many data sharing tasks more often delegated to mainframes not too long ago. The technology for this is called client/server. Expect to see that term more and more often.

Expansion

In addition to the serial and parallel interfaces, most desktop computers have an expansion bus consisting of slots into which you place cards that perform specialized tasks. Some of these might be: high-resolution video, sound, network interface, modem, TV video processing, or many others.

Another expansion card you can put into your computer is a SCSI card (SCSI = Small Computer System Interface). This card gives you additional expansion capability for items such as high-capacity hard disk drives, scanners, and other items that use the SCSI interface. Up to seven devices can be connected to a SCSI interface.

An upcoming expansion interface is called the local bus. There are two local bus types: VL-bus and PCI. The VL-bus runs directly off of the CPU and, to some extent, has to be designed around the CPU. The PCI local bus is an upcoming standard that uses a special chip that sits between the CPU and the bus. Interface cards connected to the local bus have the potential of operating much faster then those connected to the expansion bus mentioned above. [As time has proven, PCI won.]

Booting a Computer

Now that you have some understanding of the hardware and what software is, including an operating system, let's start a computer and watch what happens. Because it almost literally pulls itself up by its bootstraps, the process of starting a computer is called booting.

When you turn a computer on it first uses a bit of software built into it to check itself. This is called a power on self-test (or POST). You may see results of that on the screen (memory checking and other messages).

When finished with the POST, control of the computer is turned over to a special location on its hard disk: the boot sector. In here is a small program which when loaded into the computer's memory loads the components of the operating system from the disk. Once these are in memory, control is turned over to them. After the operating system sets itself up, control of the computer is turned over to you.

At this point you will either see a command prompt similar to C> or some form of graphic front end (e.g., Microsoft Windows).

Files

For the rest of this tutorial we'll assume you've started the computer and have been left at the DOS prompt. Here we'll show it as C> although yours might look like C:\> or something else (you can customize the prompt). [If you want to skip the DOS discussion section of this summary click here.]

DOS commands are issued at the prompt C>. Whatever you type after that prompt that is assumed by the computer to be a command you want executed. The actual software instructions that respond to the command are either part of the DOS file COMMAND.COM (these are called internal commands) or executable files on the disk (external commands).

All programs and information stored on the disk are in files. Each file is given a name. The name of a file has two parts given in the form: FILENAME.EXT

The first eight characters are the rootname, the period divides the two parts, and the last three characters are the extension. Filenames that end in .BAT .COM or .EXE represent external commands or application programs.

Disk DIRectories

One of the first things you might want to do is to see what's on the disk. You do that with the DIR (directory) command.

In its simplest form type DIR at the command prompt:

C>DIR

Volume in drive C has no label
Volume Serial Number is C2F5-45BC
Directory of C:\DOS

COMMAND COM 52925 03-10-93 6:00a
FORMAT COM 22717 03-10-93 6:00a
...
QBASIC EXE 194309 03-10-93 6:00a
18 file(s) 325190 bytes
83968 bytes free

DIR tells you what files are on the disk, how big they are, and when they were created. Also, the number of files, the total space they take, and what free space is on the disk are listed.

Like most commands, DIR has options you can use to customize what you see. The more advanced tutorial has details.

Below are three more internal commands you can execute at the DOS prompt. You'll likely use CLS quite a bit and the other two infrequently at best.

• CLS Clears the screen and puts the cursor in the home (upper left) position.
• VER Shows the DOS version number on the video display. You are shown the one-digit version and two-digit revision.

MS-DOS Version 6.00

• VOL Displays a volume label, if one exists. The label is a name you have given to the disk when it was formatted. It is used for identification purposes. (The serial number is put on the disk by DOS when you prepare a disk for use.)

Volume in drive C is HANDBOOK
Volume Serial Number is 2C35-16F9

Date and Time

DATE and TIME (These commands can change the hardware clock.)

These two commands show and/or set the system date and time. When the computer boots DOS looks for the date and time in a hardware clock. If DOS can't find a clock or its battery has run down, the default values will be 1-1-80 for the date and 00:00:00.00 for time.

You can enter the date as month/day/year with hyphens or slashes, i.e., 3/1/94 or 3-1-94 are acceptable dates.

Do not enter the day of the week, even though it shows on the screen. The computer will calculate it for you. A two digit year assumes dates between 1980 and 1999. In 2000 you will have to start putting in all four digits.

In early versions of DOS, the time setting requires a 24-hour clock, i.e., any time after noon has to have 12 added to it, for example 3:00pm has to be entered as 15:00. With version 4.0 and later you can also enter 3:00p.

Rest of DOS

The commands shown above were described more as simple examples of the general nature of DOS commands. There are a considerable number of DOS commands that have a wide variety of functions.

A few more examples are shown in the intermediate set of tutorials.

A complete description of each DOS command up through DOS 6.0 is provided in the advanced part of this tutorial set. The commands are outlined with all optional parameters; notes which describe special features of the commands are given; and a few examples of proper use are given.

CONFIG.SYS

When a computer is designed there is no way to design in all of the various functions a given user might need. The device is simply too flexible. For that reason, the hardware is flexible through expansion slots and ports and the operating system can be expanded by attaching modules to it. When you add hardware you typically also have to add a driver to the operating system for it to recognize the hardware. These drivers are typically added via DEVICE statements in your CONFIG.SYS file.

When DOS starts, it loads itself then loads the drivers and executes the statements in the CONFIG.SYS file.

With DOS 6.0 a "clean boot" feature was introduced. Press the F5 key during the boot process and CONFIG.SYS will be ignored. This is useful as it is possible to have your computer lock up and stop working if two drivers interact. You may not know this ahead of time. In the past the only recourse you had was to find a floppy disk to boot from.

CONFIG.SYS is a powerful way to modify DOS. Use caution.

AUTOEXEC.BAT

When DOS is finished setting itself up it looks for and runs (if found) the batch file AUTOEXEC.BAT. This file is not required by DOS; it's available to you to place whatever commands you want into the file in order to further customize DOS to your benefit or run commands you would have to type every time you start your computer.

AUTOEXEC.BAT differs from CONFIG.SYS in that the latter actually adds software which functions as part of the operating system. The batch file simply executes commands and programs for you. It's the same as if you typed those commands or program names at the DOS prompt. The AUTOEXEC.BAT file allows you to have your computer boot directly into your favorite program or a graphical environment such as Microsoft's Windows if that's the way you wish to customize your environment.

As with all batch files you can have a fairly extensive AUTOEXEC.BAT file, including branches. Indeed, with DOS 6.2 you are capable of easily placing jumps into both CONFIG.SYS and AUTOEXEC.BAT or, for debugging purposes, causing each to stop after every command so you can see what happened in detail (press F8 instead of F5).

Memory Management

Optimizing your use of memory is not an easy task. It is not for the faint of heart and it's handy if you enjoy experimenting. Memory management techniques apply only to computers with an 80386, i486, or Pentium CPU. To optimize memory use you must juggle use of several areas by your programs and drivers:

The High Memory Area (HMA)
Reserved Memory or Upper Memory Blocks (UMB)
Conventional Memory

Unless directed otherwise by a memory manager, DOS, all drivers and any running programs will use conventional memory. Some of these, particularly drivers, can be moved into unused areas in the upper memory blocks. DOS typically takes the HMA. This leaves much more conventional memory free for programs. Some of those will use either extended or expanded Memory memory (if available) to reduce their use of the valuable 640K conventional memory.

Memory manager drivers come with DOS or as third party software.

Why Organize Files?

Imagine what would happen if you dropped your paperwork randomly into a file cabinet; then, after a couple of years, tried to find a single piece of paper. You'd have to search through the entire cabinet to find it if you had no better organization. If, instead, you set up drawers for general topics and file folders for specific items it would be much easier to find a single piece of paper. The same holds true for your hard disk drive.

Some programs have 20 or more files associated with them. Imagine dumping all the files for several programs into a single place on your hard disk and then trying to find all the files that belonged to a single program at a later time. It would be very difficult to do.

Just like a file cabinet, you can divide a hard disk into different storage locations so files that are related can be stored together. Such a storage location is called a directory or subdirectory and the organization of directories on your disk is very much up to you. The structure is like an upside down tree and can be wide and shallow or narrow and deep; or anything between.

Subdirectories

You've seen why a subdirectory structure would be helpful. Let's take a quick look at the rules for subdirectories:

• The base directory on a disk is called the "root" directory.
• The root directory can only have a fixed number of files, depending on the size of the disk.
• Subdirectories have no limit on the number of files they can hold (but remember for organizational reasons you don't want to dump lots of files into a single subdirectory).
• Subdirectory names have the same rules as file names (8 character rootname and 3 character extension) although it's easier to work with them if you don't use an extension and keep the names short.

The wide structure for a disk is usually easier to work with as some commands require you to type out the entire pathname to a file and this is easier to do if that pathname is not too long as it would be with a narrow structure.

Managing Subdirectories

Three commands are typically used to manage subdirectories:

• MD or MKDIR - Makes subdirectories. When you need a new subdirectory, the MD command is what you would use. Just tell DOS what directory to make and it's done.
• CD or CHDIR - Changes from one subdirectory to another. As you move from program to program you will change directories to the one the new program resides in. This command allows you to do this.
• RD or RMDIR - Removes subdirectories. When you no longer need a subdirectory for storing files it is prudent to remove it so as not to clutter the disk. This command does this so long as the directory has no files in it.

If you are not certain what subdirectories are on your disk and don't want to issue a DIRectory command for each one to explore the disk you can use the TREE command to show the complete structure of a disk. With options, the TREE command can even show you all the files on your disk.

Path

Unless you tell DOS otherwise, when you issue a command DOS will look for the file that represents that command in the current directory. There are, however, many times when you don't particularly want to go to the trouble of changing to the directory in order to run a command. Imagine, for example, having to change to the DOS directory every time you wanted to run a DOS command that wasn't built into the COMMAND.COM program. DOS solves this problem with the PATH.

The PATH is nothing more than a list of directories, set apart by semicolons. When you issue a command DOS still looks first in the current directory. If the command is not found there each directory on the PATH is searched in turn. The first program found in any of those directories that matches the command issued will be executed. This allows you, for example, to run your word processor with any location on the disk defined as current. Utility programs are another common program type to put on your path.

The PATH information is stored in the DOS environment space and might look something like: PATH=C:\DOS;C:\WINDOWS;C:\UTIL;C:\BATCH;

What is a Batch File?

A batch file is a construct designed to make complex DOS processes simple. Many things you do in DOS require several commands to properly perform the task at hand. If these commands could be automated the task would be made easier as only a single command would have to be issued. A batch file does this. It's nothing more than a line by line list of the DOS commands necessary to perform a task or series of tasks. In the proper format, this file of commands can be executed, one at a time, by giving one command (the batch file name) to DOS.

In addition to standard DOS commands and program names, there are special commands that allow you to effectively write small programs within batch files. You can branch to different commands based on test results, perform functions a number of times with a single command (iteration), and transfer control to other batch files.

Batch files are executed just like any other command or application program. Programs and commands have the extension .EXE or .COM while batch files have the extension .BAT. They are all executed by typing the rootname at the DOS prompt.

Making a Batch File

You create a batch file with any text editor (not a word processor which puts in special formatting codes). Each line contains a command (only one per line). The file is given a name with the extension .BAT.

Typing the rootname at the DOS prompt runs the file.

The most common, and best known, batch file is AUTOEXEC.BAT. This file runs when DOS starts and it gives you the opportunity to execute a variety of commands automatically at that time.

Like any good program, any complex batch file should be well documented with remarks describing what each command or logic call does and why it's there. The REMark command will allow this and it should be used freely.

Batch files can also be made to accept command line parameters for additional flexibility. This allows you to construct a batch file you feed information to in order to change its operation.

Some Batch Commands

This screen and the next summarizes various batch commands. See the more advanced tutorials for details and specific examples.

• @
  In DOS 3.3 and later you can selectively cause lines in a batch file from being displayed. To cause this, place an "@" sign in front of the line in question.
• CALL Filename
  Calls a second batch file from within a parent.
• ECHO ON -or- ECHO OFF -or- ECHO <Message>
  Turns command display on or off, or displays a message to the screen.
• FOR %%Variable IN (Set) DO Command
  Allows use of a single batch command for several different variables.
• GOTO Label
  Jumps to locations within a batch file.
• IF Condition Command
     Condition is ERRORLEVEL # -or-
     String1 == String2 -or-
     EXIST Filename
  Permits conditional execution of commands.
• PAUSE
  Halts execution until the user presses a key.
• REM Message
  Displays a message to the screen if ECHO is on.
• SHIFT
  Shifts command line parameters to the left by one.

The combination of these commands plus programs and utilities gives DOS a fair amount of flexibility. Like anything else, however, you need to do some work to make it happen.

Classes of Software

There are several classes of software, largely distinguished by the method of distribution and what you are allowed to do with it:

• Shareware
• try before buy software
• freely distributed
• Public domain
• use or change without payment
• freely distributed
• Commercial
• buy before try software
• usually sold in stores or by mail-order

Some people confuse shareware and public domain software. Please don't be one of them. Shareware is fully copyrighted software that is freely distributed with the understanding you will pay for it if you use it. Public domain software has no associated payment obligations.

Distribution Methods

As you've seen, there are several types of software. Each of these has its own distribution method; although some of these methods overlap.

Commercial software will typically be found in a computer store or be sold via a mail-order catalog. The distribution media is typically floppy disk although for some programs the CD-ROM is becoming popular.

Shareware has a wider distribution network. Some may be found in computer stores beside commercial software; some may be found on racks in a variety of general merchandise stores; disk vendors that sell by mail are another source; bulletin board systems are another source. The stores and vendors typically provide floppy disks with one or more programs on them. Files are directly transmitted via the BBS outlets. Finally, some vendors are starting to distribute this software form via a CD-ROM. Several hundreds of megabytes of software can be placed onto a CD-ROM disk. [Don't forget to register shareware you use.]

Public domain software uses shareware channels. Don't confuse the two.

Can I Copy It?

In a word. . . . .it depends.

Software, like a book, is covered by basic copyright law. These laws vary somewhat from country to country but the basic thrust of copyright is to protect a work. The holder of a copyright is allowed to place almost any restriction they wish on what users can do with the copyrighted material. The usual vehicle used to do this is a "license to use." These licenses are included with the software.

Because each software vendor uses a different license there is no general rule you can apply to copying software; it all depends on what the license says. Some examples are shown below. Use caution.

• You can make copies and install on several computers so long as the software is not in use on two of those simultaneously.
• You can only make a single backup copy.
• You can make no copies and must register the software to run on a single machine by serial number.
• [Make up your own -- it probably exists somewhere.]

Word Processing

Word processing is possibly the most often used computer application. The computer is an excellent tool for both creation and management of documents. You never have to commit to paper until all is perfect.

Some of the features of a word processor that make it more powerful than a typewriter are: word wrap, editing tools, search and replace, layout information, spell checking, thesaurus, automatic footnote tracking, columns, content tables, indexes, and mail merge.

Early word processors were character-based with only the option of previewing the page in graphic mode. Most modern word processors have an actual graphic editing mode. As you type you see exactly what the document will look like on the printed page. While a nice feature, graphic editing can be a problem if you type fast and have a slow computer. Because of the resources a graphic editor takes a fast typist can sometimes overtype the computer's ability to respond. If in doubt, test the program you plan to use in its various modes.

A word processor will probably be your first software purchase.

Spreadsheets

The original spreadsheet programs were designed to essentially mimic accounting paper, with its rows and columns, on the computer screen. The row/column intersections are called cells and each cell could contain either a label, a number, or a formula which relates that cell to any others on the worksheet. A variety of math and logic functions are available for use in these formulae.

Rows are typically designated by numbers and columns by letters so a cell will usually have a designation like C25. Most spreadsheets allow assignment of names to a cell to make it easier to use. The "magic" of a spreadsheet is that for every change you make all the formulas are recalculated instantly and the new values displayed. This allows you to easily perform "what if" calculations.

Most modern spreadsheet programs allow you to compartmentalize your data, placing like data onto small worksheets and then relating those worksheets together. Some programs also allow you to link the worksheet to other data sets (e.g., database files). With many other formatting options, spreadsheets can be used for most any task.

Database

While virtually all computer applications store data in some form a database program is specifically designed for data storage and, more importantly, quick retrieval. When dealing with databases you'll hear the terms record and field. Taking a name and address as an example, a record would be the full name/address information for one individual (e.g., Computer Knowledge, PO Box 5818, Santa Maria, CA 93456). A field would be one of the elements in that record (e.g., Computer Knowledge or 93456).

There are a variety of database organization methods. Most involve a method known as relational where instead of a single large database the data is stored in many smaller files with links between them. As an example, a customer address file might be linked to an account file via a unique customer number. This makes it unnecessary to change a large number of records when the customer address changes.

Network database applications are being designed with client/server architecture in mind along with storage of large objects such as video clips and audio information.

Conclusion

This concludes the summary of the tutorials. A large number of topics have been covered at an introductory level. You might consider that you now have enough knowledge to be dangerous.

You should be able to read the intermediate and advanced tutorials and not have too much trouble with terminology. If not, consider going back through the summary again. If you need to review just a specific section, use the navigation links to jump to a screen where you can then move to individual pages.