GB, MB, GHZ, Oh My!, Making sense of computer specs
When you go to buy a computer, there are dizzying array of
"specs" to consider - how many GHz, MB, GB - does the new
computer have? Hi I'm Jeanna Matthews and this is Common Sense Computing.
The GHz rating on a computer tells how fast a computer can execute the
instructions it is given. 1 GHz means that it can execute 1 billion cycles
per second. Each computer instruction - like adding two numbers - takes a
specified number of cycles. Thus a machine with a higher GHz rating will
execute instructions faster.
However, this does not mean that a 2 GHz machine will seem two times
faster than a 1 GHz machine because computers don't just execute
instructions. In fact, computers spend a good deal of their time just
waiting - waiting for data to come in over the network, waiting to read
data off the disk or waiting for people to click on their mouse. Imagine if
you spent each hour, working for 10 minutes and waiting for 50 minutes. How
much would it help if you worked twice as fast but waited just as long?
The MB of memory rating for a computer tells how information a computer
can "think" about at once and the GBs of disk rating tells how
much information a computer can store "permanently". This is like
the difference between the number of projects you can have spread out all
over your desk at once versus the number of projects you can have filed
away for future reference.
If you want to work on many things at once - like running a word
processor, and a web browser and a photo editor and a game all at once -
then you need a big desk or more MB of memory. If you want to store lots of
information permanently - like music or video files, then you need a big
file cabinet or more GB of disk.
Fortunately, all these specs - speed, memory size and disk size - have
improved dramatically since the earliest personal computers. For example,
the Apple Macintosh II introduced in 1987 was only 16 MHz and had only 1 MB
of memory and 40 MB of disk. PCs today execute 500 times faster, have 250
times more memory and 1000 times more disk space.
Still even the newest computer is a lot more like us than you might
think - when it works twice as fast it doesn't always get done in half the
time and it has a lot more work stored away than it can get to today.
For common sense computing, this is Jeanna Matthews.
Copyright (c) 2004 - Jeanna
Matthews
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