Mainframe Vs. Client Server

by Alan Hughes
A technician services a computer server

A technician services a computer server

Client-server systems have grown in computing power over the years due to improvements in computer processor architecture. However, they deliver a lower processing capability than their mainframe counterparts due to the architecture of the overall computing system. When you need high-volume transaction processing, a mainframe delivers over the lesser abilities offered by client-server systems.

Acquisition Cost

Mainframe computers are typically priced in the millions of dollars, while client-server systems have entry points in the thousands. The less expensive systems make it possible for smaller organizations to break into the computing world for a lower cost. However, larger companies, such as banks, insurance firms and payment processors, have the funds to bankroll the much-needed transaction processing power of a mainframe.

Maintenance Cost

As is the case with the cost of acquisition, the cost of maintenance and other ongoing costs are also lower for a client-server system. For instance, mainframe software companies often charge about 20 percent of purchase price for annual software maintenance. In a client-server environment, this cost is much lower. Support costs in the form of technical personnel are also lower with client-server systems, with client-server engineers earning about one-third less than mainframe systems programmers.

Operating System Differences

Most client-server systems run familiar operating systems such as Windows Server and Linux. The complexity of mainframe operating systems is much higher than client-server systems, driving much more sophisticated hardware and software applications. Client-server operating system companies depend on hardware manufacturers to write interfaces for the OS, while mainframe companies typically provide all the interfacing software written into the OS. Multitasking is similar in mainframe and Windows/Linux/Unix operating systems, with all capable of performing preemptive multitasking, making it appear that the computer is running many tasks simultaneously.

Operating Environments

While many servers are just fine in a relatively cool, clean room, mainframe computers require more specific controls, particularly in the areas of temperature, humidity, fire suppression and cleanliness. Mainframes are usually supported by uninterruptible power supplies for continuous operation and consume a lot more power than their smaller client-server counterparts. A cool room with adequate fire protection and a lockable door can easily house, cool and protect a number of client-server systems.


Modern mainframe computers are smaller than their predecessors that took up an entire room, but they are still typically the size of a refrigerator or larger. Client-server machines, on the other hand, are usually about the size of several stacked shoe boxes. The smaller footprint of a client-server machine contributes to lower environmental requirements, as well as lower power consumption.


Client-server operations are sometimes a bit more relaxed than mainframe operations. Client-server users are typically small to medium companies that do not need the processing power or strict environment of a mainframe. Mainframe users are typically large companies, such as insurance companies, large financial institutions and health organizations. Due to the high security requirements of such institutions, operations are normally strict and follow a set series of events to ensure procedural compliance.

About the Author

Alan Hughes has more than 30 years of experience in IT including mainframes, programming, client/server, networks, project management, security, disaster recovery, information systems and hardware. He holds a master's degree in applied computer science and several certifications. He currently teaches information technology at the university level.

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