mainframe

(redirected from mainframe computer)
Also found in: Dictionary, Thesaurus, Medical, Financial, Acronyms, Wikipedia.
Related to mainframe computer: personal computer, Mini Computer

mainframe

1. 
a. a high-speed general-purpose computer, usually with a large store capacity
b. (as modifier): mainframe systems
2. the central processing unit of a computer

mainframe

(computer)
A term originally referring to the cabinet containing the central processor unit or "main frame" of a room-filling Stone Age batch machine. After the emergence of smaller "minicomputer" designs in the early 1970s, the traditional big iron machines were described as "mainframe computers" and eventually just as mainframes. The term carries the connotation of a machine designed for batch rather than interactive use, though possibly with an interactive time-sharing operating system retrofitted onto it; it is especially used of machines built by IBM, Unisys and the other great dinosaurs surviving from computing's Stone Age.

It has been common wisdom among hackers since the late 1980s that the mainframe architectural tradition is essentially dead (outside of the tiny market for number crunching supercomputers (see Cray)), having been swamped by the recent huge advances in integrated circuit technology and low-cost personal computing. As of 1993, corporate America is just beginning to figure this out - the wave of failures, takeovers, and mergers among traditional mainframe makers have certainly provided sufficient omens (see dinosaurs mating).

Supporters claim that mainframes still house 90% of the data major businesses rely on for mission-critical applications, attributing this to their superior performance, reliability, scalability, and security compared to microprocessors.

mainframe

A state-of-the-art computer for mission critical tasks. Today, mainframe refers to a class of ultra-reliable servers from IBM that is designed for enterprise-class and carrier-class operations.

However, in the "ancient" mid-1960s, all computers were mainframes, since the term referred to the "main" CPU cabinet. The first mainframe vendors were (alphabetically) Burroughs, Control Data, GE, Honeywell, IBM, NCR, RCA and Univac, otherwise known as "IBM and the Seven Dwarfs." After GE and RCA's computer divisions were absorbed by Honeywell and Univac respectively, the mainframers were known as "IBM and the BUNCH."

IBM Is the Mainframe Vendor
For decades, IBM was the dominant vendor in the mainframe business. Although many tried to compete by offering compatible machines, they no longer do (see IBM-compatible mainframe). HP, Unisys, Sun and others make machines that compete with IBM mainframes in many industries but are mostly referred to as servers. In addition, non-IBM mainframe datacenters have hundreds and thousands of servers, whereas IBM mainframe datacenters have only a few machines.

There Is a Difference


One might wonder why mainframes cost hundreds of thousands of dollars when the raw gigahertz (GHz) rating of their CPUs may be only twice that of a PC costing 1,000 times less. Here's why:

Lots of Processors, Memory and Channels
Mainframes support symmetric multiprocessing (SMP) with several dozen central processors (CPU chips) in one system. They are highly scalable. CPUs can be added to a system, and systems can be added in clusters. Built with multiple ports into high-speed caches and main memory, a mainframe can address thousands of gigabytes of RAM. They connect to high-speed storage subsystems that can hold petabytes of data.

Enormous Throughput
A mainframe provides exceptional throughput by offloading its input/output processing to a peripheral channel, which is a computer itself. Mainframes can support hundreds of channels, and additional processors may act as I/O traffic cops that handle exceptions (channel busy, channel failure, etc.).

All these subsystems handle the transaction overhead, freeing the CPU to do real "data processing" such as computing balances in customer records and subtracting amounts from inventories, the purpose of the computer in the first place.

Super Reliable
Mainframe operating systems are generally rock solid because a lot of circuitry is designed to detect and correct errors. Every subsystem may be continuously monitored for potential failure, in some cases even triggering a list of parts to be replaced at the next scheduled maintenance. As a result, mainframes are incredibly reliable with mean time between failure (MTBF) up to 20 years!

Here to Stay


Once upon a time, mainframes meant "complicated" and required the most programming and operations expertise. Today, networks of desktop clients and servers are just as complex. Large enterprises have their hands full supporting thousands of PCs along with Windows, Unix and Linux and likely some Macs as well.

With trillions of dollars worth of IBM mainframe applications in place, mainframes may hang around for quite a while. Some even predict they are the wave of the future!


Mainframe System
Mainframes provided the computing power for major corporations for more than 50 years. Sperry Rand (Univac), IBM, GE, RCA, NCR, Burroughs, Honeywell and Control Data were the first companies to make mainframes in the U.S. This picture was taken in the mid-1970s. (Image courtesy of Unisys Corporation.)






UNIVAC Mainframe
Mainframes provided the computing power for major corporations for more than 50 years. Sperry Rand (Univac), IBM, GE, RCA, NCR, Burroughs, Honeywell and Control Data were the first companies to make mainframes in the U.S. This picture was taken in the mid-1970s. (Image courtesy of Unisys Corporation.)
References in periodicals archive ?
Various questions were asked concerning availability of microcomputers versus mainframe computers, sources of computer learning, and selected demographics.
In addition to these in-house functions, HCSO's mainframe computer shares databases with the local clerk's office for traffic tickets, the Department of Highway Safety and Motor Vehicles for vehicle registration information, and the Florida Crime Information Center and the National Crime Information Center databases for criminal information.
Licensing UMI databases allows a library to fix its electronic reference costs, while using mainframe computer power to retain many of the features of online searching.
The picking process begins in the mainframe computer where a pick list is generated based on customer orders.
The case materials were computerized by Berven and Scofield (1980) by means of a BASIC program written for the UNIVAC 1110 mainframe computer (Berven & Scofield, 1980).
Statistical Software Frees Students From Mainframe Computer
The Rock River Water Reclamation District is looking to install one (or more) Integrated Facility for Linux (IFL) processors in its IBM zEnterprise z114 A01 mainframe computer system.
(IBM), one of the world's largest technology companies, on suspicion that the company has abused its dominant position in the mainframe computer markets.
Unless you are using a mainframe computer, the level of risk to data loss and theft from unauthorized access is growing daily.
The problem in the carrier's mainframe computer caused hundreds of flights to be delayed when the reservations system crashed.
The company, which designs and distributes women's quality footwear and accessories to major department stores, had a mainframe computer and a lot of internal complaints about its computer system.
1 POLICE-L is managed using LISTSERV list management software running on an IBM 3090 mainframe computer. For more information about LISTSERV, visit http://www.lsoft.com/ on the World Wide Web.