Information Technology Reference
In-Depth Information
Another consideration regarding speed follows from the discus
sion in Chapter 1. In that discussion, we noted that computers process
data though the interaction of many components. In such a context,
increasing the speed of one component may not make much difference
unless other components can take advantage of that faster speed.
We need, therefore, to consider what elements are limiting our
work when we are trying to achieve significant speedup. A faster
bus or CPU may not help, for example, if the system is waiting for us
or if the machine spends most of its time accessing data on CDs or
disks. On the other hand, if much of our processing involves waiting
for a disk for the storage and retrieval of data, then getting a faster
disk might speed up our entire processing in a significant way.
More Graphics: One of the main areas for computing expansion
in recent years has involved usage and processing of images (e.g.,
pictures). These enhancements require both faster processors and
considerably more storage space. As we discussed in Chapter 2,
graphical images require the computer to determine colors and in
tensities for each pixel. Because pixelbypixel storage requires
much space, pictures may be stored in a condensed format, and the
computer then determines the expanded pixel information. Image
processing, therefore, requires either the storage and retrieval of ex
tensive graphical information or computation (or both).
In many cases, the use of graphics enhances the usefulness of
computers, and expanded use of images is most welcome. Recently,
however, the increase in general use of digital images has demon
strated that images' demands on both storage and processing capa
bility have their costs as well. Considering storage first, a highreso
lution picture may require between 0.1 and 0.5 million bytes
(megabytes) of storage; some pictures may require even more. Even
lowresolution graphics may consume 0.05 megabytes.
In the mid and late1990s, before the extensive use of graphics,
personal computers often had just 30 or 40 megabytes of storage
overall. As computer users began to save pictures, and as the World
Wide Web provided an easy way to obtain pictures, older comput
ers ran out of space—often quickly. Computers that had seemed re
markably powerful and large no longer were adequate, and ex
panded machines were needed. Further, processing of graphical
images could require extensive computation, taxing the CPUs that
may have seemed speedy just a few years before. Although this may
