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Last month, we covered how to choose a motherboard and CPU chip. This time around, we'll discuss two of the most important subsystems to be found in modern PC's: hard drives and video graphics.
Virtually all PC's in use today have some form of mass storage device. By far the most common of these is the fixed disk, or hard disk, drive. The name "hard disk" or "fixed disk" distinguishes these drives from the so-called "floppy disks," which will be covered in a later installment. It also refers to the fact that, in contrast to floppy disks, these disk drives have recording media that are "fixed" in their location -- that is, they are not designed to be removed from the computer.
In order for the computer to make use of a hard disk drive, it must have some means of communicating with it, so that the needed information can be stored, retrieved, and transferred to other parts of the computer when called for. This is done by means of a special expansion card called a hard disk controller card.
Several types of controller cards are in use in modern PC's. By far the most popular, and therefore the least expensive, are known as IDE, which stands for "Integrated Drive Electronics." This term indicates that most of the needed electronic circuitry for controlling the drive are actually integrated," or built, into the drive itself. That being the case, the "controller card" merely acts as an interface which allows the drive to exchange data with the rest of the computer system.
In many cases, the IDE interface is actually built or "integrated" into the motherboard itself, or is combined with other types of controller circuitry into what is called a "multi-I/O card." More coverage will be given to these cards in our next installment.
In the last year or so, an "Enhanced IDE" standard, also known as "ATA," has become popular for use in high-speed, multimedia PC's such as the one we're putting together for this series. These drives, as the name "Enhanced IDE" suggests, are faster than regular IDE drives, particularly when used with a VESA Local Bus or PCI Bus PC.
To enable these drives to operate even more efficiently, some hard disk controllers use what is known as "caching" -- that is, they store frequently used information in special memory units installed on the card itself. In addition to permitting faster operation, these controllers cut down the number of times that the drive has to actually "seek" and retrieve information. This, in turn, lessens wear and tear on the mechanical parts of the drive, thereby prolonging its useful life.
Most caching controllers use memory chips or modules identical to the main memory units installed on the motherboard. This allows the user to add more memory to the card as needed to insure the fastest, most efficient operation possible.
Let's say that, because caching controllers are somewhat more expensive than regular IDE controller cards, we've decided to use a regular, or non-caching, controller, in the form of a "multi-I/O card" such as I mentioned earlier. With that out of the way, the size of the hard drive must now be considered.
Time was when a 20-megabyte or 30-megabyte hard drive was considered sufficient. That, however, is no longer the case. As software packages have become more powerful and sophisticated in response to user demands, they have also become far larger, and so have the data files they often create. Nowadays, programs take up 8 or 10 megabytes of hard disk space quite routinely. Such being the case, the most commonly used hard disk drives now hold in the range of 540 to 560 megabytes. Depending upon where you shop, you can now obtain a 540-megabyte hard disk drive for well under $200. We'll use one of these for our example system.
With our mass storage needs taken care of, let's now turn our attention to video graphics. From their inception, personal computers have utilized some form of video system or terminal to display information. At first, monochrome screens, using green or amber letters on a black background, were considered sufficient. These days, however, multi color graphics are widely used by most software packages -- indeed, many of them specifically require it. In fact, some software will not even operate on a PC that does not have color graphics capability of some kind.
By far the most popular color graphics standard in use today is known as "VGA," which stands for "Video Graphics Array." An extended version of this standard, providing more colors and higher resolution, is known (logically enough!) as "Super VGA." Because of the heavy demands that VGA graphics make on the PC system as a whole, not only does VGA require a separate card, but, increasingly, they too make use of VESA Local Bus or PCI Local Bus to improve performance.
In addition to the controller card, the actual selection of the color monitor itself must be carefully considered. As a rule, for most home PC's, a 14-inch monitor is the minimum acceptable size, and 15 inches is even better. While there are much larger color monitors available, they are also much more expensive. For this reason, larger monitors are primarily reserved for use in highly technical or corporate environments.
Some of you might wonder why a regular color TV could not be used. The answer is that the video circuitry in TV's is designed along entirely different lines than those for a computer monitor. While "VGA-to-TV" converters are available, in most cases a regular color monitor is a far better and less costly investment.
In choosing a color monitor, there are several factors to consider. We've already discussed the size of the monitor, so let's go on to the next factor: the "dot pitch". In a color monitor (and in color TV's, too, for that matter), the picture is displayed on the screen in the form of thousands of tiny dots. The smaller these dots are, the clearer and sharper the picture will be, and therefore easier on the eyes. This is usually referred to as "dot pitch," and is measured in hundredths of a millimeter. The lower the "dot pitch," the higher the resolution, and therefore the better the picture. For a true multimedia PC such as we're discussing, a "dot pitch" of not more than .28 millimeters is the minimum, and .25 millimeters is better.
All computer monitors, whether color or monochrome, give off small amounts of radiation in the course of their operation. While there is still debate as to the exact amount that is safe, the Swedish government has taken the lead in setting stringent standards for monitor radiation. These guidelines are collectively known as "NMPR-II," and an ever-increasing number of manufacturers are following them. In our example PC, we should certainly look for a monitor that is "NMPR-II compliant."
Finally, we should look at a monitor's energy consumption. Computers require a significant amount of energy to operate, especially color monitors. Within the last two years, the U. S. Department of Energy has taken a hard look at this subject, and has established the "Energy Star" standard. This guideline calls for special circuitry in the monitor to "blank out" -- that is, to temporarily turn off -- the picture if the computer is not used for a certain length of time. Since "EnergyStar" monitors are rapidly becoming more common, there is every reason to choose a monitor of this type, especially since there is little, if any, difference in price. Here, again, is where such magazines as "PC Catalog" and "Computer Shopper" really shine, as they can help you shop around to get the best value for dollar spent. In this case, a 15-inch Super VGA color monitor, with both "NMPR-II" and "Energy Star" compliance, can be had for less than $300, while a VESA Local Bus color graphics card (also known as an "accelerator" card) can be bought for under $100, including 1 megabyte of memory.
In our next installment, we'll cover floppy disk drives, multi-I/O cards, and memory.
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