Here are the basics you should know when buying a
computer.
Components of a Computer
Disk Drives
Input Devices
Output Devices
Protect Your Investment
There are many different kinds of computers to choose from and finding the one that is right for you and fits your budget
can be difficult. The purpose of this
page is
to describe the parts of the computer and the benefits and pitfalls of these parts so that you can make an educated decision on your computer purchase. This
page is designed to assist you in buying a home
computer and will not cover portable computers or laptops. It will also mainly talk about the PC rather than Macintosh, as I feel that the PC is a better choice.
PC vs. Macintosh
- The two major types of computer systems are PC’s (also known as IBM compatibles) and Macintosh. There are advantages and disadvantages of both. The Macintosh is generally
more user friendly than the PC and many schools are using the Macintosh. This is the main reason that many people buy Macintosh. Since children use the Macintosh in school their parents decide to buy a
Macintosh for their home. Macintosh is also popular in the advertising and graphic arts market. Many advertising agencies and graphic artists use the Macintosh because of the easy operating system and graphics
software available for Macintosh.
My preference is the PC. The PC is more widely used in the home and business, and there is much more software available for the PC compared to the Macintosh.
Where To Buy Your PC
- Computers are available from a variety of sources. The first place you would think to look are the big retailers, such as Best Buy, Circuit City, CompUSA, or others. The
big retailers offer a variety of different computer choices and can be easy to shop at. You pick the computer you want, pay for it, and walk out the door. Another reason to shop at a big retailer is
convenience, especially if you have a problem and you need to return or exchange your computer. You can also find good deals and sales at the big retailers.
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Another way to buy a computer is through a mail order company or directly from the manufacturer. With a mail order company you may have to wait a little longer to get you
computer, but this is not always bad. When you order a computer you can get the exact computer that you are looking for. You can customize your order so that you get all the things you need in a computer. One
down side to ordering a computer through the mail is if you have a problem, you may have to send it back, and wait for a replacement.
The other alternative is to by a no name clone. There are many people out there who are building computers to sell locally. Since this is how these people make a living the
customer service is likely to be top notch. Like mail order you can usually get exactly what you want put installed in your computer. You will usually end up getting better components through these small
computer retailers.
There are many different brands of PC's available, and different computer sellers carry different brands. The prices from the three different computer sellers is likely to
be competitive. Of course, as with any product, you get what you pay for. A cheaper computer may contain cheaper parts that are more likely to fail. If your computer should fail or stop working it is important
to know how to get help. Two things to check for with any purchase, that many people overlook are: 1) Does the manufacturer have a toll free technical support phone number? 2) Does the company charge a fee for
using the technical support? These are very important, if you ever have any problem with your computer.
A computer is a complex machine that contains many different components. When buying a computer, you should know what these parts are and what they do. This will help you
to know what to look for in a quality computer.
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CPU
- The CPU, or central processing unit, is the brain of the computer. The CPU controls all the action that occurs inside the computer. CPUs come in different types and speeds.
Intel, Cyrix, and AMD are the three main manufactures of CPUs. Intel is the market leader, and will probably stay that way for quite some time. The Cyrix and AMD offerings are usually comparable to the latest
Intel CPUs, however, performance is usually slightly below that of Intel. I recommend buying one step behind the latest technology. It is here that you will find the best value for your money. The newest
technology is always the most expensive, and when a new chip comes out, the previous model always drops in price. I would not buy anything more than two steps behind the latest technology. Technology changes
quickly, and you don't want to buy a computer that will become outdated to quickly.
Processor (CPU) Types
- This section gives specific information regarding CPUs, and has a tendency to get outdated within a few months. The general advice given in the previous section (CPU) is
more general and therefore more timeless.
The 386 is outdated. It can still run some very basic and very old software, but most of the new software will not run on it. This is here mostly for reference, I would not
recommend buying a 386 computer.
The 486 is the next step up. A 486 is also, for the most part, outdated. It will still run some of the software available now, but a lot of the newer software requires much
more from the processor. There is a wide range of 486's available. The top of the line is competitive with the Pentiums, while the bottom of the line is closer to the 386. I would not recommend buying a 486
computer.
The 586 seems to be just a hopped up 486. They are only marginally better than a 486DX4.
The Intel Pentium, AMD K6, and Cyrix 686 are the next step up. These were the top of the line processors for quite some time. These CPUs are still functional and will still
run most software available. Soon however, these will become outdated as software is produced that will take advantage of the new hardware available. MMX was a technology later added to this level of CPU. It
provided enhanced video and sound capabilities, but was short lived as newer processors were soon introduced. I would not recommend buying Pentium, K6, or 686 computer.
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The Intel Celeron and Cyrix MediaGX are the next level of CPU. This level of CPU was created mostly for home users to provide an inexpensive alternative to the newer
processors. This is the lowest level of CPU that I would buy.
The Intel Pentium II, AMD K6-2, and Cyrix MII are one level behind the newest technology. This is where I believe you get the bang for the buck. This is the level of CPU
that I recommend buying.
The Intel Pentuim III and the AMD K6-III are the latest and greatest technology in CPUs. They are the fastest and most powerful CPUs currently available. This also means
that they are the most expensive.
SX, DX, DX2, DX4
- SX, DX, DX2, and DX4 are terms you won’t see much anymore. They are used to refer to the different varieties of 486. The 486SX is basically a 386 that runs faster. The
486DX is a true 486. The DX means that the chip contains a math co-processer. The math co-processor speeds up mathematical computations, and therefore makes the computer run faster. There are different speeds
of processors for any of the chips available. The DX2 runs at two times the speed of the DX chip, and the DX4 runs at three times the speed of the DX.
Processor Speed
- The speed of the chip is indicated after the brand of the chip. For example a Pentium II 400 runs at 400 MHz. MHz stands for Megahertz, which put simply, is how fast the
computer runs. The higher the Megahertz, the faster the computer. There are many speeds available. For the Pentium the speeds range from 60 to 266 MHz. The MMX processors, made by different manufacturers, range
from 200 to 266 MHz. The Pentium II ranges from 233 to 450 MHz. The Pentium III ranges from 450 to 1000 MHz. New, faster processors are always in development, and as faster processors become available many of
the slower processors are phased out.
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Which Processor is Best
- A basic rule of thumb is to buy as much processor as you can afford. If you can afford a CPU with the newest technology, then by all means, buy that. The processor is the
hardest and most expensive part of a computer to upgrade. Most of the other components can be easily upgraded. This means that the most important decision in buying a computer is choosing the processor. Of
course, you may not need the fastest processor available. If the only thing you are using your computer for is typing school papers, then a 486 will do just fine. If you are going to use it for playing
multimedia games, designing graphics, or running multiple applications, then you should get at least a Pentium. As stated previously, the best value is usually one level behind the newest technology.
RAM (Memory)
- RAM, Random Access Memory, is commonly referred to as memory. Memory is measured in Megabytes, abbreviated MB. This is the second most important decision for your PC
purchase. RAM is used by the computer as a temporary storage area for the things it is using. Any data that you are using or inputting is
temporarily stored in the RAM, where it can be manipulated and used by
the computer. With RAM there are three things to consider: How much, what size simm, and what type.
As for how much, more is better. The more RAM you have, the faster the computer can perform tasks. RAM is usually used in blocks of four. The minimum amount of RAM you
should have is 16 megabytes. The standard now is 32 megabytes. As computers improve, they seem to need more memory, and 64 megabytes will surely be considered standard in the future. RAM is easily upgradeable,
so if you can’t afford 64 megabytes now, then get 32 megabytes and upgrade later.
DIMMS vs. SIMMS. The amount of memory is not the only consideration when purchasing RAM. RAM comes packaged on a small board called a simm (single inline memory
module) or a dimm (dual inline memory module). Most new computers use 168 dimms. Some still use 72 pin simms, but these are on their way out. Some older computers including 386's and 486's use
32 pin simms. The 168 pin dimm is better and is now the standard.
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EDO vs SDRAM. There are several different types of memory: Parity, Non-Parity, EDO, and SDRAM. Parity and non-parity were the standards before EDO. These were
used in 486's and the first generation Pentiums. Then EDO became the standard and is still widely used. EDO stands for extended data output. Parity, Non-Parity, and EDO are manufactured as 72
pin simms. EDO is on it's way out and SDRAM is the current standard. Most new computers will contain SDRAM. SDRAM is manufactured as 168 pin dimms. SDRAM stands for Synchronized DRAM.
Synchronized means that it is synchronized to interact with the CPU at specific intervals. This means that it doesn't have to wait for the CPU to be ready since it has time scheduled to communicate with
the CPU. Basically, SDRAM is just faster.
Bus Speed. There are currenlty two different bus speeds, 66MHz and 100MHz. The 100MHz is becoming the standard. The faster the bus, the faster the
CPU can communicate with other parts of the computer. The SDRAM is the only type of memory that can take advantage of the 100MHz system bus.
Cache
- Cache is another type of memory which is similar to RAM. Cache is used by the computer to move data between the RAM and the CPU faster. The standard amount of cache
installed on most computers is 256 kilobytes. The next step up is 512 kilobytes, more is better. Cache is available in two different types, asynchronous and synchronous. Asynchronous cache is not synchronized
with the processor. This means the processor has to wait for the data in cache to be ready before it can be retrieved. Synchronous cache is synchronized with the processor, and therefore there is no delay
between the cache and the processor. In general the difference would be very hard to notice, but go with synchronous if you have the choice.
Motherboard
- The motherboard is the circuit board which everything in the computer plugs into. The CPU, RAM chips, and Cache all plug into the motherboard. Three main considerations in
a motherboard are bus type, number of expansion slots, and number of RAM slots. Bus types can be a rather complex subject but just remember that a PCI bus is better than a VESA local bus. The Pentium and 686
use the PCI bus. Most 486’s use the VESA local bus while some high end 486’s and most 586's will have a PCI bus. All computers come with several PCI slots and several ISA slots. The ISA bus is
an older type of bus, but is still widely used for different type of expansion cards (ie. sound cards and modems). Expansion slots are used for holding cards, such as video cards or sound cards. RAM slots
are where the RAM chips plug into. With both types of slots more is better. The more slots you have, the more room you have for expansion. This is a very basic description of the motherboard, but it should give
you enough information so you know what to look for.
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Case
- One of the smaller and easier choices in your computer system is the type of case to get. The two types of cases are the tower and the desktop. The type of case you get
depends on the amount of room you have for it. A desktop case fits nicely underneath the monitor, but takes up more space on the desk. The tower case can be put on the floor to clear up some room on your desk.
Tower cases usually have an extra disk drive bay, but unless you are planning on adding several more drives, this is not a big concern. Basically, it is just a matter of preference.
Disk drives are a very important part of the computer, but choosing them is relatively easy. There are several types of disk drives: Hard drives, Floppy disk drives, CD ROM
drives, Tape backups, and Zip drives.
Hard Drive
- The hard drive is where most of your programs will be stored. The hard drive is inside the computer, so you won’t be able to see it, but it is a very important part of a
computer. Hard drives come in many different sizes, up to about 16 gigabytes. The standard size for a hard drive now is around 4 gigabytes. You should not get a drive with less than 2 gigabytes. The more
programs you have, the more disk space you will need. Once again, more is better.
Floppy Disk Drive
- Every computer comes with a floppy disk drive. They are the main way of putting information on to the hard drive. They also allow you to save information on a disk, which
is an easy way to transport files and data between different computers. There are two different sizes of floppy drives. The 5.25” floppy disk is not used very often any more. It has been replaced by the
3.5” disk, which is smaller and can hold more information. A 3.5” high density disk can hold 1.44 megabytes of data.
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CD ROM Drive
- Most computers now come standard with a CD ROM drive. Most programs and games now come on CD. Many programs are being put on CD’s because they can hold over 500 megabytes
of data on a single disk. A CD ROM drive reads data from a CD that looks much similar to a music CD, except it holds data rather than music. Much like music CD’s, CD ROMs cannot be written to, so you cannot
save information to a CD ROM. CD’s make it possible to add sound and video to games and programs. The CD ROM drive comes in several different speeds. Speeds vary from double speed to 32X speed. A double speed
CD ROM is the minimum. It is still functional but the video and sound are more likely to be a bit jumpy. The faster a CD ROM can read a CD the smoother the video and sound becomes. Faster is better, but for
most users an 8X speed will work just fine. CD writers are now available. CD writers allow you to write information to a CD. You have to buy blank CD’s to write to. Once written, these CD’s can be read by
any CD ROM drive. This may sound like a good solution to your storage problems, but they can be tricky to use. You may waste a few CD’s while learning how to use it.
DVD Drive
- The latest in mass storage is the DVD drive. DVD stands for digital video disk. The DVD technology is still developing. A dual layer, dual sided version of this disk can
hold up to 17 gigabytes. The current version, which is single layer, single sided holds 4.7 gigabytes. Since this technology is still relatively new, there are not a lot of products that support it. DVD will
soon replace the CD.
Tape Backup Drive
- A tape backup drive is mainly used for backing up all of the files on your hard drive. They can hold a lot of information, but they are not much good for anything except
backing up files. The reason for this is that it is slow to access data from a tape. It is a very easy way to back up your hard drive. It is very useful if you have important files that need to be saved in case
your computer crashes. Most computer systems do not come with tape drives because most people don’t have a large amount of data that needs to be backed up.
High capacity removable storage
- The Iomega Zip Drive is removable storage similar to a floppy drive. A Zip disk can hold about 100 megabytes of data. It is faster than an ordinary floppy drive but slower
than a hard drive. This is a good alternative to the tape backup if you do not have a lot of files to backup. A Zip disk can hold an entire program, yet it is not much bigger than a floppy disk. This is
definitely a good way to back up your important programs. A Zip drive is not a necessary part of the computer, but it is something to think about getting. The Iomega Jazz drive is similar to the Zip
drive, but it's disks can hold more data. There are two types of Jazz drives and disks. The 1 gigabyte Jazz drive is being replaced by a 2 gigabyte Jazz drive. These drives are rather
expensive but you get a lot of storage.
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The SyQuest EZFlyer is similar to the zip drive. It holds 230 megabytes of data on a removable disk. It is almost as fast as a hard drive. This is it's main advantage over
the zip drive. From what I have seen, the zip drive is more popular than the EZFlyer. The next step up from the EZFlyer is the SyQuest SparQ which holds 1 gigabyte of data. The next step up
from the SparQ is the SyQuest SyJet which holds 1.5 gigabytes of data. All of the SyQuest drives are based on hard drive technologies which means they are faster than the Iomega products which are based
on floppy drive technologies.
Another product to note is a CD rewritable. It is a CD drive that can read and write to a CD. These CD's are a little different from the normal CD ROM disks, but can hold
about the same amount of data. They are still rather expensive, but you can expect the price to come down in the future.
Input devices are parts of the computer that let you input information and data into the computer. The keyboard, mouse, and joystick are examples of input devices. Scanners
and cameras are also input devices, but are not used as often. Disk drives and modems can also be used as input devices.
Keyboard
- Using the keyboard is the primary way of inputting data into many of your programs. I am sure you know what a keyboard is so I will not go into much detail to describe it,
but I will tell you of a few different kinds of keyboards. Keyboards are usually described by the number of keys they have. The standard keyboard is referred to as a standard 101 keyboard. The 104 or Windows 95
keyboard comes with special keys for Windows 95. This keyboard comes standard on most computers. There are also ergonomic keyboards. These keyboards look like they are broken in half, and are supposed to make
typing less stressful on your wrists. Some keyboards come with a built in trackball or finger pad. Picking a keyboard is just a matter of preference. For most everybody, the standard 101 keyboard will work just
fine.
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Mouse
- The mouse is a very important input device because it makes getting around in your computer easier. The mouse controls and arrow which can be moved anywhere on the screen.
The mouse is good for doing tasks such as moving and pointing to objects on the screen. There are several types of mice, and several input devices similar to mice. Alternatives to the mouse include: the
trackball, touchpad, and touchscreen.
A mouse can have two or three buttons. A two button mouse is usually standard. It will accomplish any task that a good mouse should. I prefer the three button mouse. The
software that comes with a three button mouse will allow you to easily program the middle button to do certain tasks. I use my middle button as a double click. Pushing the middle button once is much easier than
trying to double click the other button. This would also be good for children, who seem to have a hard time with the double click.
Another thing to note about your mouse is how it plugs into the computer. A serial mouse plugs into a 9 pin serial port in the back of the computer. Most computers now come
with an input for a bus mouse, also referred to as a PS/2 mouse. The PS/2 mouse has a round connector similar to that of the keyboard. This mouse is a better choice, because more computers are using it now.
The trackball is very similar to the mouse, except the ball is on top instead of underneath. You move the ball with your thumb or palm. This is sometimes easier for
children to use because they can let go of the ball to click the buttons. This is good because the arrow will not move when you try to click on something. With the mouse, if you let go of it to click a button,
it will usually move. Choosing between the mouse and the trackball is just a matter of preference.
The touchpad and touchscreen are very similar. For both you use your finger to move the cursor on the screen. With the touchpad you move your finger on a pad. With the
touchscreen you move your finger directly on the screen. These may be fun additions to your computer, but I prefer the mouse or trackball.
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Joystick - The joystick is a must for all the PC gamers out there. If you are going to be playing a lot of games on your computer then you should probably get a joystick. Most games
will work with a mouse, but the joystick is usually easier to use. If you plan on playing flight simulator games, then the joystick is a necessity. Flight simulators are much easier to use with a joystick. Game
pads similar to Nintendo or Sega are also available. Joysticks can range in price from about 20 dollars to over 100 dollars. You can usually get a very good quality joystick for around 50 dollars.
Scanners
- Scanners are useful if you need to copy written page or pictures directly into your computer. Most people do not really need this, but it can be a fun extra. If you are
using your computer for business, a scanner could be more useful. There are three basic types of scanners: Hand scanners, Page scanners, and Flatbed scanners. Both types come in black and white or color, with
color being more expensive. A hand scanner is held in the hand and dragged across the page being scanned. A page scanner feeds paper through it similar to a printer, but instead of printing, it scans in
whatever is on the paper. A flatbed scanner looks and works like a copy machine. You put the object to be scanned in the scanner, then it scans it into the computer. If you are just using a scanner for fun,
then the inexpensive hand scanner is the way to go. It you are using a scanner for business then a flatbed scanner will probably be more useful.
Cameras
- Cameras that hook into the computer can take pictures or record movies and save it in the computer. You can buy small cameras that plug right into the computer or you can
buy an adapter to hook your video camera into the computer. Once again, cameras are usually just a fun extra. They can however be useful. They can be used for videoteleconferencing or for putting pictures on
cards or even T-shirts.
Output devices are the parts of the computer that let you see what you are doing. The two main type of output devices are the monitor and the printer. Disk drives and
modems and sound cards could also be considered output devices.
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Monitor
- Several different sizes of monitors are available. Most computers come with a 15 or 17 inch monitor. 15 inch is a little small, 17 inch is a better size. 19 or 21 inch
monitors are also available, but cost quite a bit more. Which size to choose just depends on your personal preference. Be sure your monitor is a Super VGA (SVGA) and displays 256 colors. Most monitors sold meet
this requirement. One other thing to look for is the dot pitch. Be sure that it has a .28 inch dot pitch or lower. Basically the dot pitch describes how sharp the picture will be. The lower the number on the
dot pitch, the sharper the image will be. The last thing to consider for monitors, is interlaced or non-interlaced. Interlaced monitors are not a good choice. Interlaced monitors project every other line to the
screen, then go back and fill in the other lines. This repeats over and over. This can cause the screen to flicker. The non-interlaced monitor is a better choice because it projects every line to the screen in
order. This produces images with no flicker. Many retailers do not include the price of the monitor in the price of the computer system, so be sure to check to see if the price of the computer system includes
the monitor.
Video Card
- The video card is the part of the computer that sends the images to the monitor. As with the monitor be sure to get a SVGA video card. Video cards are also referred to as
video accelerators. Video cards usually contain their own memory chips. This memory helps the computer to load images faster. A video card should contain at lest 1 megabyte of memory, but 2 megabytes is
becoming standard. 4 megabytes is quite a bit more expensive, but is even better. There are two types of memory available on video cards: DRAM and VRAM. All you need to remember is that VRAM is better than
DRAM.
Printer
- A printer is a very useful tool to have. A printer allows you to make hard copies of your documents. There are basically three different kinds of printers available: Dot
matrix, Ink jet or Bubble jet, and Laser printer.
The dot matrix printer is the least expensive printer to buy and maintain. The dot matrix printer consists of head with a row of pins that strikes the ribbon as it moves
across the page. There are two types of dot matrix printers: The 9 pin and the 24 pin. The 9 pin is low quality and is not used much today. The 24 pin prints in relatively good quality and is the most popular
type of dot matrix printer. A dot matrix printer cannot give you the same high quality as that of an ink jet or a laser printer. If you are printing on multilayer forms, then you will have to use a dot matrix,
as the ink jet and the laser printer will not work for this task. Dot matrix printers are still popular because of their low cost.
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Ink jet or bubble jet printers are the next step up. Ink jet printers squirt little droplets of ink onto the paper. The ink dries almost instantly and the quality is almost
as good as a laser printer. Ink jet printers are the most feasible for printing in color. Ink jet printers can print good quality color pictures. Some dot matrix printers can print in color, but the quality is
not nearly as good. Ink jet printers are more expensive than dot matrix printers, but less expensive than laser printers. The cost of maintaining them is also between the two. A color ink jet printer would
definitely be my choice of printers.
Laser printers produce the best quality print. The mechanics of a laser printer is rather complex. The printer must control a laser beam, control the movement of the paper,
sensitize the paper so that is will accept the toner that makes up an image, and then fuse that image to the paper. Laser printers are the most expensive of all the printers. They cost more to buy and to
maintain, but since they offer such good quality, they are usually the top choice of businesses.
Sound Card
- Most computers comes standard with a sound card. A sound card allows your computer to reproduce music, sounds, and voice. This is a definite necessity if you are going to
play multimedia games. If you are just using your computer for business, then you may not need a sound card. The market standard for sound cards is the Sound Blaster. Be sure to get a computer with a Sound
Blaster compatible sound card. There are also different quality of sound cards. Most computers now come with 16 bit sound cards. The next step up would be a 32 bit sound card. Some sound cards have a wave
table, which means that it reproduces actual instruments rather than synthesized sound. Most sound cards also have an input for a microphone so that you can record your own voice. My choice would be the Sound
Blaster awe32. This is a good quality sound card and it should work with almost all of your games.
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Modem
- The modem comes standard on most computers. If you want to send faxes or get on the internet, then this is what you need. The modem allows the computer to communicate with
other computers through the telephone lines. Most modems come with faxing capabilities. Modems are available in different speeds. The standard speed is 56.6 Kbps. Kbps stands for kilo bauds per second, which is
just the speed of the modem. The 56.6 modem is also refered to as V.90. This is the name for the standard on which all 56.6 modems are built. The 56.6 Kbps modem replaced the 33.6 Kbps modem as the
standard. 33.6 and 28.8 modems are still widely used, but if you spend a lot of time on the Internet, you'll appreciate the speed of the 56.6. The 14.4 modem is now outdated. It's just too
slow for most people. Another choice you have with modems is external or internal. If you buy a new computer it should come with an internal modem. Internal means that it goes inside your computer,
external means that is plugs into your computer and sits on the desk. Internal modems are usually less expensive than external modems. The quality between the two is about the same, so it is just a matter of
preference.
With all the money you put into your computer system, it would be tragic to be destroyed by a power spike. A surge protector is an easy and inexpensive way to protect
against this. A surge protector will blow a fuse if it gets hit by a surge of electricity, thus protecting your computer from being fried. If you are using a modem, be sure to get a surge protector with a
telephone jack included. A surge protector is not complete insurance, however. If you get a direct lightning strike, a surge protector will not do much good. The only sure protection against lightning strikes
is to unplug your computer and modem during thunderstorms.
Another alternative is a UPS. UPS stands for uninterrupted power supply. It protects against surges and power outages. It contains a battery backup which will keep your
computer running for a short time after the power goes out. This is something you will be thankful for after you have typed about ten pages and the power goes off. You will have enough time to save your work
and turn off the computer before the battery runs out.
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