ware and software. Minor differences can cause old programs to crash and make data in old files unreadable. Even though the need for such modifications can be reduced by designing fiber optic systems with interfaces that look just like electric ones, it would not make most efficient use of fiber transmission capacity and would increase costs. 2) Limitations in Local Area Networks In Local Area Networks, fiber optics is not used as widely as one would expect. One reason is the implementation requires great deal of changes in current networks and systems. This requires a lot of time and effort which the management is not willing tosacrifice. People are comfortable with what they have and don't want to change. Although most problems regarding program changing can be solved, the solutions to it will take much longer than expected. Thus, any new program has to be a big improvement over theold one to justify a significant change (although the great improvement usually means that the old program does not work). Another fundamental problem in fiber optic LANs is the change in technology. The hardware and software to make LAN run efficiently add up to an expensive package. If many terminals in a building must be in constant touch with each other and a variety ofother hardware, such as printers and storage devices, LAN will be cost efficient. However, if the real need is to keep the terminals in touch with a mainframe computer, it would be cheaper to run cables between them and the mainframe. If the terminals need to talk to each other, ordinary telephone lines could very well be used as telephone lines are much cheaper than fiber optics. 3) Economic Evaluation The major practical problem with fiber optics is that it usually costs more than ordinary wires. All costs elements involved in economic evaluation can be grouped into two main classes; which are investment costs and operation costs. The investment costsusually includes expend...
