Telecommunications Protocols, Second Edition
The Big Picture of Telecommunications Networking - Today and Tomorrow
TABLE OF CONTENTS Telecommunications Protocols, Second Edition
Chapter 3: LANs to WANs
Section 3.1: Evolution to Distributed Processing
The first computers were not only very large in size, but they were also fairly limited in capacity and power. In comparison, today's desktop workstations carry far more processing power than many of the mainframes of the past. As the electronics industry miniaturized components, computers got smaller and more powerful.
Mainframes continue to prosper today, despite the increase in desktop applications. The fact is, there are some jobs that are just not suitable for desktop computers. Applications requiring access by many users at once are prime candidates for mainframe systems.
Section 3.1.1: An Overview of Mainframes and Their Applications
The mainframe computer uses centralized processors and applications that are resident within the mainframe memory. The central processing unit is actually many processors working together. All users accessing the mainframe must share time with the central processing unit. The more users who are logged onto the mainframe system, the fewer available time slots. This means that users have to wait longer for processor access.
Think of airline reservation systems. This is a perfect example of a mainframe application. Travel agents as well as ticket agents at airline counters around the world must have access to the same information. This means the information must be collocated within the same computer system, and the agents must have access to this information simultaneously.
The fact is, they are really time-sharing. The central processing unit can only process one transaction at a time, so the busier the airlines get,...
Copyright The McGraw-Hill Companies, Inc. 2000 under license agreement with Books24x7
