In the Beginning: Computer Technology for New Users
Part 3: Let's Get Knowledge!

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Now that you have decided what your computer will do and you have set up your work space it is time to buy your "precious." For some of us who have been with computers for a time it is our right hand servant or the other love of our lives. What system do you buy? How do you decide? How much should you spend? So many questions that need answering but it is not as hard as it might seem. The hard part was deciding on what you wanted the computer to do and getting it down to the unit that will do that job the best. This was done in part one of our series. For some it was a PC (Personal Computer or what the old timers call an IBM compatible computer). Others have decided to buy a Macintosh or Apple computer. Others may have gone in an entirely different direction all together.

Generally business and home users not into high speed and high volume computing will usually chose a PC type computer for their use. Those heavy into graphics and ease of use probably chose an Apple or Macintosh computer. They love the easy to use graphical interface that is part of that operating system. The vast majority of new users will have chosen one of the above listed machines. We will write about the users going the PC route and keep our article focused in that area.

There are many varied types of PCs in the world today. They range from pocket PC units to large tower units almost as high as a regular work desk. Some computers have limited computing capability (look at the two Mars Lander's computing units) and others have large amounts of power to spare up into the Mega to Giga byte range. We will explain Mega, Giga, and byte shortly. For the most part you want to purchase a unit that will meet your present needs as well as your anticipated needs for the next five (5) years. Five years is used because computing changes so fast that it may be necessary to completely change your entire computer system at about the five year mark (do not worry it is not always necessary to do that).

At this point the problem is where do we begin. It is probably best to start with technical terms and learn some of the jargon you will hear if you have not already heard it. The most common terms in use follows:

The two most common terms you will hear in computer jargon today will be bits and bytes. For some people, it has become a confusing set of terms misused often in the computer world. The term bit is an acronym for Binary Digit, which is the smallest unit of data that a computer can represent. A bit can only represent one of two states--on or off or more accurately one or zero. This is the only thing that is going on in a computer the moving and storing of ones and zeros in a combination easily understood by the computer. A single bit by itself does not carry much information (none really), but when strung together in a series of bits, information can be ascertain. When eight bits are strung together as a unit of information, you have a byte.

Eights bits grouped together (byte) as a unit usually represents a single character in the computer. These characters are numbers, uppercase and lower case letters of the alphabet (any language), punctuation marks, and special symbols. Combining ones and zeros together in certain different combinations will provide information that is represented by 256 individual characters useful for human manipulation. The various combinations form various patterns called coding schemes.

The two most popular coding schemes are ASCII (pronounced ASK-ee) (American Standard Code for Information Interchange) and EBCDIC (pronounced EB-see-dic) (Extended Binary Coded Decimal Interchange Code) used in the United States. Because Asian and other languages are so extensive in there use of the alphabet a different coding scheme is used called Unicode, which can represent all of the current world's languages. Using coding schemes allows humans to interface easily with a computer.

Probably the next most often heard terms are speed, hertz, kilo, mega, and giga. Speed usually refers to many different things. The most important of which is the rate at which the system clock times all computer operations. The timing that the system clock performs is a constant electronic pulse or cycle that is maintained to allow the computer to execute instructions. Most computers today can execute more than one set of instructions per clock cycle. Today's clock speeds are usually designated as hertz which is defined as one cycle per second. A manufacture will designate how fast its system clock runs by stating it by the number of hertz the system clock will pulse to the computer CPU (Central Processing Unit). The numbers are fairly large and are usually stated in Megahertz or Gigahertz. Mega stands for one million, so one megahertz is one million cycles per second. The same relates for giga which is one billion, so one gigahertz is one billion cycles per second. Therefore a one megahertz processor is slower that a one gigahertz processor. What this means is that a CPU with a higher processor speed can process more instructions per second than one with a lower clock speed.

Next most popular set of terms are memory, ROM, RAM, floppy or floppy disk, and hard disk. The instructions that make the computer work need a place to stay or reside and it is called memory. Memory is a temporary storage place for instructions, data, and information. Primary memory or more accurately primary storage is located in one or more chips on a circuit board in the computer. Here memory stores three basic items: system software that controls the usage of the computer and its equipment, application software that is used to carry out specific tasks, and the actual data that will be processed by the application programs. When both data and programs are stored it is called the stored program concept.

Memory has specified areas or locations called addresses. Those addresses are unique numbers that identifies a location for each byte (8 bits in order) in memory. To access any data or set of instructions residing in memory the computer must reference a specific set of addresses that contain the necessary bytes of stored data or information. The amount of storage a given piece of memory contains is designated by multiples of 1,024 bytes. To simplify things 1,024 bytes is referred to as one kilobyte or 1KB (note capital "B" not lowercase "b") or K. An example would be if you stored 100 KB, you are storing 100,000 bytes. Similar if you have one megabyte (MB) you have one million bytes and if you have one gigabyte (GB) than you have one billion bytes. For those into complete accuracy 1 MB equals 1,048,576 bytes and 1 GB equals 1,073,741,824 bytes (for those who know their math the actual figures are calculated in powers of two).

Within a computer system are two major types of memory called volatile memory and nonvolatile memory. Volatile memory loses its contents once power to the computer is removed or turned off. Nonvolatile memory will not normally lose its contents with the removal of power. One type of nonvolatile memory is called ROM (Read Only Memory) which is a set of chips that store data that can only be read. The stored data in these chips never change and usually contain data or instructions for the computer to follow at start up. ROM will usually contain the basic input/output system or BIOS (Pronounced Bye-OHSS). BIOS is a sequence of instructions that the computer follows to load its operating system and any other files that are needed at the time the computer is first turned on. Some other devices may contain ROM chips or memory storage units and they are used for various functions such as storing fonts. Fonts are a name assigned to a specific design of characters.

The most common form of memory that is discussed is RAM or random access memory. This is an example of volatile memory which is read or written to by various devices in or connected to the computer. When the computer is powered on, certain operating system files load from a storage device and write to specific areas of RAM. As long as the computer is powered you can add to or remove or read data in RAM. When you use your computer, information is changing in RAM but the moment you lose power or turn off the computer all the data stored in RAM is lost forever. Because data can be lost in RAM, it is necessary that you save your data or copy it to another memory device that will not lose its contents when power is removed, such as a hard disk or floppy.

There are two basic types of RAM chips, dynamic RAM and static RAM. Dynamic RAM chips (DRAM) are sometimes called main memory in the computer and are the most common. A DRAM chip must constantly be re-energized or it will lose its contents. A RAM chip that does not need to be re-energized as often as the DRAM chip is called static RAM (SRAM). These chips are faster but more expensive than DRAM chips and usually used for cache in a computer. Cache is a specific type of memory that improves processing time by storing the contents of frequently accessed RAM locations. There are two types of cache, memory cache and disk cache.

You may hear about something called a SIMM (single inline memory module) or a DIMM (dual inline memory module. The SIMM are the pins on opposite sides of the circuit board connecting together to form a single set of contacts. DIMMs are the pins on opposite sides of the circuit board that do not connect and form two sets of contacts. SIMMs and DIMMs are typically used for SDRAM chips.

Earlier we mentioned hard disk and floppy, these are another form of memory but instead of being chips they are much larger and bulkier. A floppy disk is a portable storage medium usually consisting of a thin, circular, flexible plastic disk with a magnetic coating enclosed in a square-shaped plastic shell. The floppy disk is written to or read by a floppy disk drive. In some laptop computers this drive is removable and can be replaced with another type of drive. Most floppy disks are very limited in the amount of data that they can store so a hard disk is usually used to store large amounts of data.

A hard disk or more properly a hard disk drive consists of several inflexible, circular platters that stores data electronically. Each platter records data magnetically on both the upper and lower surfaces. Data is written or read from both surfaces of a platter with a moving read/write head that is enclosed within an airtight, sealed case. Data is stored in cylinders, sectors, and tracks.

This article has spoken of storage and memory as one but all storage devices are not memory devices. For complex or large storage needs another medium is used called a compact disc or CD or sometimes call an optical disc. Normally a CD is a flat, round portable, metal storage medium about 4.75 inches in diameter. These storage devices are so common they not only store computer data but they also store audio and video information. The CD drive will only ready one side of the CD with the other side usually used for a label or identifying what is on the CD it self. A CD drive differs from the other storage drives in that the CD will sit in a try and a button is used to move the tray in and out. Remember to keep the label up when placing the disc in the tray. Information is stored on a CD in a single spiral track of pits (indentations) from the center of the disc to its outer edge and land (flat areas). The track is evenly divided into sectors the same as on a disc.

Compact disc are available in a wide variety of formats CD-ROM, CD-R, CD-RW, DVD-ROM, DVD+R, DVD-R, DVD+RW, and DVD-RW. CD-ROM or compact disc read-only memory is either silver or gold in color and is basically the same as an audio CD. This type CD is written to only by the manufacture and can only be ready by the computer user. You can not change or modify the contents on the CD. These discs hold about 650 MB of data. The drives that play the CDs are listed in transfer rates of X that is from 2X to 75X. The higher the number the faster the drive reads the data to the computer.

When you have "-R" it means that the CD is recordable in more than one session but once a section has been recorded you can no longer write over the initial recording. You can read from a "-R" type disc as many times as desired. Most CD-ROM can read a "-R" disc. If you have a CD recorder it will usually indicate that it will record at one speed and read at another speed and is given as 8/24 for example. The slower speed is the write rate and the faster speed is the read rate for that device. The higher the rate usually means the more expensive the CD device will cost.

When you have a "-W" it means that the CD is rewritable and you can erase the disc and write on it multiple times. When you see CD-RW the CD will act like a floppy or hard disk by allowing you to write and rewrite data on the disc multiple times. These drives have special software that will allow the writing on special "RW" discs. The speeds are usually listed in three units separated by slashes such as 12/4/32. The first listed speed is the write speed, the second speed is the rewrite speed, and the third speed is the read speed for the unit. Normally a CD-RW can only be read by a multiread CD-ROM drive.

A DVD-ROM disc is a digital video read only memory type disc. These discs have extremely high storage capacity ranging from 4.7 GB to 17 GB and much higher quality than a regular CD. In order to read a DVD type disc you will a DVD-ROM drive or player. Even though a DVD disc and a CD disc look the same there is a slight difference in the way it achieves a higher storage capacity. Some DVD units pack the pits closer together to give a higher density to the data storage. Another method uses two layers of pits and land area with the first or lower layer of pits semitransparent. By making two layers of information you can double the capacity of the disc. The last method is to use both sides of a DVD disc. To ready both sides of the disc you will have to turn the disc over to read the other side.

With DVD you have two types of RW setups. One is minus and the other is plus. The plus is mostly use for movies and audio recording and playback while the minus is used for data storage and playback. The cost for the two types of discs are also different with the +RW slightly higher than the -RW format. Usually the DVD drive can read both types but the quality may differ with brands.

There is another type of memory called flash memory and is another type of nonvolatile memory that you can erase electronically and reprogrammed. This memory is a removable device instead of a chip used in personal devices or small type devices. Flash memory allows the transfer of data from one type of device to a compute without the use of cables or cords. Devices such as handheld computers, digital cellular telephones, printers, digital cameras, automotive devices, pagers, and others make use of flash memory.

Most memory devices such as disk drives, CD and DVD drives, and some other drive devices have a light to indicate when that device is in use. It could be green or red in color to indicate when the device is "on" or when a particular device is in use. The light for these devices are on the device itself or on the front of the computer panel unit. Some lights will flicker to indicate that a particular device is either reading or writing to the disc in the drive. This is a reminder to wait before shutting down the machine (turning it off) or in trying to remove disc from the drive. Remember always wait for the drive light to go off before taking the disc out of the drive. It is also good practice to wait until the drive light is off to turn the computer off.

On some new machines you will see two buttons close together, one is for turning the machine on or off and the other is for resetting or warm booting the machine. Booting is process of starting or restarting the computer. If the computer has already been off and you are just starting the machine you are cold booting your computer or performing a cold boot. When your computer is already running or in use but you need to restart the machine that is a warm boot. Warm boots are done in Windows from the keyboard, options from a menu in a program, or from pressing a Reset Button on your computer. When you boot a computer, you are loading the core of your operating system call the kernel and other frequently used instructions from the operating system into the computer's RAM. This happens to help manage your computer's various devices and make sure the computer will operate correctly. You know your system is on because one or more lights are on or flickering and in some cases the computer "on" light is also lit.

Using the computer you will hear such terms as monitor, LCD, CRT, and DPI. Humans to work with a computer need various types of input and output devices so that they can easily understand what is happening with their computers. One type of output device that will visually convey text, graphics, and video information for human ease of use is a display device or a visual output device. Visual display devices have a screen or a surface used to project an image. The most commonly used visual display device is a monitor. Simply put a monitor is a box or case that houses the screen or projection surface. There are three basic types of monitors, CRT, LCD, or plasma.

The CRT monitor is similar to a television set. It has a cathode ray tube (CRT) that has tiny dots or pixels (acronym for picture element) coating the screen. Each pixel consists of three elements red, green, and blue phosphors (if a color CRT). An electron bean passes over each pixel and causes them to glow and produce an image on the screen. The same happens in your television set but in a slightly different manner. Just like your television, you measure the CRT monitor diagonally. The larger the measurement the more viewing area that monitor has. A large monitor allows the computer to display more information on the screen all at once, help make it easier to use a computer, and will help increase productivity.

Another visual display is the LCD monitor or LCD (liquid crystal display) display. The LCD uses liquid crystals between two sheets of material whereby an electrical signal passes through the crystal to block some light waves and allow others to pass creating the visual image on the viewing panel. LCD monitors and displays can also go by the name flat-panel displays and are very distinctive in looks. LCD units have a smaller footprint (area taken up when sitting on a resting surface) and are measured the same as a CRT. These displays are more popular in portable devices such as PDA's and laptop computers. They are also gaining in favor with desktop users.

Plasma monitors are similar to LCD's but substitute a layer of gas for the liquid crystal and emits ultraviolet light to cause the pixels on the screen to glow and form a visual image. Plasma displays are generally larger than LCD types and are very costly in comparison. Plasma is more common with television displays than with computer displays except at large conventions mainly because of the cost. Again, the measurement for a plasma display is diagonal.

One important aspect when talking about monitors is the resolution for that monitor. Resolution describes the clarity or sharpness of the visual image produced by the monitor. Normally you define resolution by DPI, dots, or pixels per inch. The more dots or pixels per given area of screen the better is the resolution and the smother the image is to the viewer. There is one problem, as the resolution increases the visual image on the screen decreases in size. That is why on smaller monitors high resolutions make the screen almost un-viewable. It is better to use high or very high resolution (1280 X 1024 or higher) on large monitors.

New computer users need to know one more thing about their monitor and that is the refresh rate. The refresh rate at times called the vertical frequency or vertical scan rate is the speed at which the monitor will redraw its images across the screen. You want to make sure the refresh rate is fast enough to prevent screen flicker or fading of the screen image. The measurement of refresh rate is in hertz (cycles per second) and you will have to set the rate that is best for your monitor size and resolution.

Now you must feel enlighten and smarter than ever before. With some of the most used technical and nerd terms in your vocabulary you can handle anyone trying to give you a snow job. When you want to buy any piece of equipment or need advice you can talk intelligently and understand what it is they are saying to you.

Our next article will cover more on computer usage. If you have any questions or would like a better explanation of what was covered in this article please contact the Vice-president of the NOPCC at vp@nopc.org.

Ashton C. Mouton, Jr.

© 2004 Ashton C. Mouton, Jr.
All Rights Reserved

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