All right, class, it's time for Technobabble 102.
Back in Technobabble 101, you learned how to sling around the basic jargon you'll need to buy a PC -- and, it is hoped, understand a little of it. Today, we'll move onto more advanced topics.
First, we'll talk about cache memory. You'll see it advertised a lot, as in a "386/33 with 64K cache." From our first lesson, we know that the store is selling an IBM-compatible computer with an 80386 processor running at a speed of 33 megahertz.
The cache refers to a little trick that manufacturers have developed to coax extra performance from 386 and 486 computers.
A cache is simply a temporary storage area. Today's advanced microprocessors can crunch data much faster than they can fetch it from your computer's main memory. Standard memory chips are too slow, largely because their contents must be continually refreshed.
To get around this problem, computer makers can design their products with a small cache of expensive, high-speed, static memory chips that don't have to be refreshed. Caches range in size from 64K to 256K.
When your computer fetches a byte of data from memory (which it spends a lot of time doing), a cache memory controller will actually read a big chunk of data from the neighborhood of the byte it needs and put the whole thing in the cache.
The theory is that the next byte of data the computer needs will be somewhere near the last byte. If that byte is in the cache, the processor can get to it much faster than it would if it had to venture out into main memory.
Caching can speed up your computer considerably, but you'll pay cash for cache -- a $100 to $300 premium, depending on the size of the cache and how much the manufacturer wants to gouge you.
Now to the next Technobabble topic -- disk drives. Any computer you buy will have at least two, a hard disk and one or more floppy drives.
Many new users confuse disk drive storage with the computer's memory. A computer's memory temporarily stores programs and data. These disappear when you turn off the power. Your disk drives store programs and data permanently -- or until you erase them.
Floppy drives use removable disks made of flexible plastic. Hard drives contain a fixed metal disk which is much faster and stores a lot more. Once you've copied your programs from a floppy disk to a hard drive, you'll only need the floppy to make backup copies of your data or share information with another computer user.
Floppy drives are measured by their size and capacity. Modern floppy drives come in two sizes, 3 1/2 -inch models whose disks store 1.4 megabytes of data and 5 1/4 -inch models that store 1.2 megabytes. All floppy drives operate at the same speed -- slow.
While the industry is moving rapidly toward 3 1/2 -inch drives, it's best to get both sizes so you can communicate with anyone. Adding a floppycosts $50 to $100.
The physical dimensions of a hard drive aren't important, but its capacity and speed are. Capacity is rated by the megabyte. A byte is the amount of space it takes to store a single character (such as the letter "A"), and a megabyte is roughly a million bytes.
Forty megabyte drives are frequently installed on low-end computer systems. Since a 40-meg drive will hold the equivalent of 65 average novels, you might think this is plenty. Unfortunately, a graphics- based operating environment such as lTC Microsoft Windows, and the programs it uses, will eat a 40-meg drive for breakfast.
Even computer games typically claim four or five megabytes of real estate. That means you'll be a lot more comfortable with an 80-meg drive, or a larger one if you're interested in graphics applications such as desktop publishing.
Hard drives are also rated by the speed at which they transfer data to your computer's memory. This is critical. Faster is always better, since programs frequently access the drive and may actually use disk space as a substitute for internal memory.
Drive speed is measured in the number of milliseconds (ms) it takes to find an average piece of data. Lower numbers are better than higher numbers. Fast drives today have 15 to 20ms speed ratings. Older designs may have 28 or even 40ms ratings. Buy the fastest you can afford.
Finally we'll deal with your monitor and graphics adapter. Most IBM-compatibles are advertised today with a "VGA" or "SVGA" monitor. This little piece of Technobabble refers to IBM's Video Graphics Array, the circuitry IBM developed for its PS/2 line of computers in 1987.
Monitors and graphics systems are judged by their resolution and the number of colors they can produce.
Resolution is measured by the number of little glowing dots, or pixels, that form the matrix of your screen.
Basic VGA systems have 640 pixels horizontally by 480 vertically. This is known as 640x480 resolution, which produces very comfortable text and decent graphic displays.
VGA monitors can produce 16 colors at 640x480 resolution, or 256 colors at 320x200 resolution.
For desktop publishing and other critical graphics applications, manufacturers have developed "super" VGA adapters and monitors, or SVGA equipment. These can produce resolutions of 800x600, or even 1,024 by 768 pixels.
Unfortunately, there's no hardware and software standard for these high-performance systems, which means the hardware makers have to supply special software, called "drivers," that work with specific programs such as Windows, Lotus 1-2-3 or Word Perfect.
So there you have it, a short course in Technobabble. Now you can go out and trade jargon with anybody. Just don't expect the salesman at Honest Ed's Computer Warehouse and Garden Supply Center to understand it. He was probably selling fertilizer last week.