Definition: computer system

The complete computer made up of the CPU, memory and related electronics (main cabinet), all the peripheral devices connected to it and its operating system. Computer systems fall into two categories: clients and servers.

Clients are the user's laptop and desktop computers, tablets and smartphones, while servers share their data and applications with multiple users. Servers range from entry-level rack mounts to mainframes. See rack mounted and mainframe.

A computer system is sized for the number of users it handles simultaneously, the type of work performed (office, engineering, etc.) and the volume of data that must be stored.

Platform
Every application is written to run under a specific CPU/operating system environment. The largest client platforms are x86/Windows, x86/Mac, ARM/Android and ARM/iOS. The largest server platforms are x86/Linux and x86/Windows. See platform, x86 and ARM.

Number of CPU Cores
The more CPU cores, the more simultaneous processing. Modern desktop computer CPUs have two, four or eight processing cores, and servers can have from two to 64 or more. In addition, multiple machines can be tied together to work as one (see clustering). See SMT and multicore.

Clock Speed
The gigahertz (GHz) rate of the CPU determines internal processing speed. See MHz.

Disk and Memory
The disk capacity determines the amount of information immediately available to all users. A computer's memory capacity determines how many applications can run efficiently at the same time.

Fault Tolerance
The use of redundant processors, peripherals and power supplies provide continued operation in the event of hardware failure. See fault tolerant.

Multiuser Computer System

This is a mainframe; however, except for the tape drives, every system contains similar components, which can all be built into a desktop or laptop computer.