Information Technology Reference
In-Depth Information
Appendix A
Discussion of Terms
,
a reference topic of synonyms, antonyms, and equivalent words. Writers
use this reference to select words with the right weight and shade of
meaning, thereby improving their writing considerably. Scientific terms
and expressions in professional usage appear far better defined and precise
than normal English words: a glossary of terms is considered sufficient.
This appendix discusses terms that systems professionals often use, and
also confuse. The idea is not to arrive at a particular definition, but rather
to explore ideas underlying multiple definitions or interpretations.
Since 1852, English speakers have been able to consult
Roget's Thesaurus
Logical versus Physical
Practically everything has a physical basis. The most complex programs,
and the smallest signals in the brain, run on physical devices. In discussing
systems, the difference between logical and physical is often between
high level and low level, between modeling and implementation (Figure
A.1). In most situations, the difference is obvious or fairly clear. For
Logical
Physical
Why is logical better?
Figure A.1
Logical versus physical.
313
