Over Five Types of Computers Explained and Compared

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  • DevynCJohnson
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    A computer is a general multi-purpose device that can be programmed. These devices process mathematical and logical operations using a Central Processing Unit (CPU). There are five main types of computers. All five types (including sub-types and others) have four components in common - Central Processing Unit (CPU), memory, Input/Output (I/O), and storage. However, each type (or class) has its differences, advantages, disadvantages, and uses.


    Microcomputers or Personal-Computers (PC) are the smallest of all computer types. Microcomputers use microprocessors which are CPUs on a single Integrated Circuit (IC). Some microprocessors have multiple CPUs on a single chip (multi-core processor). The use of microprocessors reduces power consumption and manufacturing cost. Small integrated components make microcomputers physically small, relatively inexpensive, and accessible to individuals.

    Some operating systems for PCs include Solaris, Linux, Microsoft's Windows, *BSD, Minix, Android, OSX, and much more.

    Microcomputer Sub-Types

    • Stationary
      • Carputer (In-car computers) - a PC built into a car's dashboard
      • Desktop - physically small computer that can fit on a desk
      • Gaming Computer - high-quality desktop (or game console) with better graphics and hardware
      • Home Theater PC (HTPC) - Digital Video Recorder (DVR) + PC
      • Industrial PC - an x86 PC for industrial automation and a substitute for a PLC
      • Nettop (Mini-PC) - inexpensive low-power desktop with a small form-factor
      • Single-Unit PC - a desktop with all components (monitor, keyboard, etc.) in one case
      • Workstation - high-quality networking desktop
    • Portable/Mobile
      • Desktop Replacement Computer (DTR) - smaller than a desktop, but more powerful than a laptop
      • Laptop (Notebook) - small and lightweight (including the battery) enough to fit on a person's lap
      • Netbook (Subnotebook) - smaller, less expensive, and less powerful than a laptop
      • Palmtop - IBM-compatible palm-sized PC
      • Pocket PC - non-IBM-compatible palm-sized PC
      • Smartbook - contains features of both netbooks and smartphones
      • Smartphone (Phablet or Superphone) - a mobile telephone with PC features
      • Tablet (Slates or Booklets) - a touchscreen computer with dimensions resembling a thin book
      • Ultra-Mobile PC (UMPC) - smaller than a tablet PC, but as powerful as a laptop; non-IBM-compatible
      • Wearable Computer (Smart-watch) - wrist-watch sized PC
    • Advantages -
      • Publicly accessible to individuals/citizens
      • Relatively inexpensive
      • Small and typically easily portable
    • Disadvantages -
      • Less powerful than other computer types
      • Less reliable than other computers
      • More error-prone than other computers
    • Uses -
      • Education
      • Gaming
      • General networking
      • General residential and commercial computing


    Mainframes are powerful computers that can process extensive amounts of data and are highly reliable. The processing speed of mainframes is measured in MIPS (Million Instructions Per Second). Mainframes support strict backwards-compatibility with older software.

    Some operating systems for mainframes include z/OS, Linux (Linux/390, zLinux, and others), z/VSE, z/VM, OpenSolaris for System z (defunct), UTS (Unix for mainframes), Microsoft Windows Server 2008, and others. Most mainframes are made by IBM and use an architecture called "z/Architecture". Many mainframes are called "zSystems" because of their architecture. The z13 mainframe (made by IBM in 2015) uses a 5GHz octa-core processor (called "z13") and can support up to 168 processing cores. Most mainframes used in the 2010s are 64-bit.

    • Advantages -
      • Fast I/O operations
      • Highly reliable and stable
      • High integrity and fault tolerance
      • Long uptime (some up to a decade)
      • Less error-prone than other computers
      • Hot-swap system capacity without system disruption
      • Better virtualization than other computers
      • Best computer for transaction processing
      • Can store and manage large volumes of data
      • Supports files in the terabyte range
    • Disadvantages -
      • More expensive than other computers
      • Require a cool environment
      • Consumes large amounts of energy, but less than supercomputers
      • Less processing speed than a supercomputer
    • Uses -
      • Processing large quantities of data
      • Transaction processing
      • Bulk data processing
      • Applications that must not experience down-time
      • Database storage and processing


    Supercomputers are computers with the best processing speed and precision available at the time. The processing speed of a supercomputer is measured in FLOPS (FLoating-point Operations Per Second) or TEPS (Traversed Edges Per Second). As of 2015, some supercomputers perform up to quadrillions of FLOPS. While mainframes are perfect to large volumes of I/O operations or transaction processing, supercomputers are made for processing and calculation speed. Supercomputers may use hundreds of thousands of processors (both CPUs and GPUs) while mainframes may use one or a few multi-core processors.

    Operating systems for supercomputers include Linux, *BSD, IBM AIX, PUMA O/S, UNIX, UNICOS, eOS, Cray Operating System (COS), Cray Linux Environment (CLE), Microsoft Windows HPC Server 2008 and others.

    FUN FACT: China's Tianhe-2 supercomputer calculates at 33.86 petaFLOPS (PFLOPS).

    • Advantages -
      • Fastest calculation and processing speed
    • Disadvantages -
      • More expensive than most computers (including mainframes)
      • Not as reliable or fault-tolerant as mainframes
      • Smaller life-span (<5 years)
      • Large energy consumption (Tianhe-1A consumes 4.04MW; 4MW at $0.10/kWh is $400/hour)
      • Requires intensive cooling
    • Uses -
      • Engineering and scientific calculations
      • Scientific modeling and simulations
      • Government and Military uses
      • Quantum mechanics
      • Weather forecasting and climate research

    FUN FACT: In 2015, IBM (International Business Machines Corporation) has been the largest producer of supercomputers and mainframes for years.

    Programmable Logic Controller

    Programmable Logic Controllers (PLCs) are environmentally resilient hard-real-time systems commonly used for industrial automation. PLCs can withstand a wider temperature and humidity range than other computers. PLCs can be programmed using Ladder-logic, State-logic, or ported dialects of microcomputer programming languages (like C and BASIC).

    PLCs may use firmware instead of an operating system. However, there are some real-time operating systems available for PLCs such as OS-9 and VxWorks.

    • Advantages -
      • More resilient to the environment than other computers
      • Easy to program and utilize
      • More reliable than microcomputers
      • Faster boot-time than most computers
    • Disadvantages -
      • More expensive than microcomputers
      • Not as powerful as microcomputers
      • Limited memory
    • Uses -
      • Industrial Automation
      • Computing in harsh environments

    Programmable Automation Controller

    Programmable Automation Controllers (PACs) are similar to Programmable Logic Controllers (PLCs), but PACs have more features and are designed for more complex automation systems. PACs are like PLCs with added PC features.

    • Advantages -
      • More resilient to the environment than other computers
      • Easy to program and utilize
      • More powerful than a PLC
      • Support for SQL databases (unlike PLCs)
      • Support for USB logging (unlike PLCs)
      • USB programming (unlike PLCs)
      • More communication ports than PLCs
      • Larger I/O capacity than PLCs
    • Disadvantages -
      • More expensive than PLCs and microcomputers
      • Not as powerful as microcomputers
      • Harder to program and utilize than a PLC
    • Uses -
      • Industrial Automation
      • Computing in harsh environments


    There are some other obsolete, hybrid, and other miscellaneous types of computers.


    Minicomputers (or Midrange Computers) are computers that are bigger and more powerful than microcomputers, but not as great as mainframes. The term was seldomly used after the 1990s due to microcomputers becoming more powerful. Some high-quality microcomputer servers may be called "minicomputers". However, this term is considered obsolete.

    • Advantages -
      • Faster than microcomputers
      • Less expensive than mainframes
    • Disadvantages -
      • More expensive than microcomputers
      • Not as powerful as a mainframe
    • Uses -
      • Obsolete


    Gameframes are computers that have features of both mainframes and supercomputers. Such systems have fast processing speed and I/O throughput. Gameframes are typically used as gaming servers.

    • Advantages -
      • Faster than microcomputers
      • Host games with hundreds of players
      • Almost as fast as a supercomputer
      • Almost as much I/O speed as a mainframe
    • Disadvantages -
      • More expensive than microcomputers
      • Not quite as powerful as a supercomputer
      • Not quite as much I/O operations as a mainframe
    • Uses -
      • Game servers
      • Massive online multiplayer gaming

    Hybrid Computer

    Hybrid Computers have features of both analog and digital computers.


    Minisupercomputers were computers that were not quite as powerful as supercomputers, but faster than microcomputers. Minisupercomputers used array processing CPUs and were used from the mid-1980s to the mid-1990s. Minisupercomputers are now obsolete.


    "Nanocomputer" is an unofficial term for System-on-a-Chip (SoC) systems that are about the size of a credit-card. Examples include the Raspberry Pi, Odroid, Arduino, Banana Pi, Cubie-board, BeagleBoard, Pyboard, and others.

    Quantum Computer

    Quantum Computers are theoretical computers that use quantum-mechanical phenomena to perform processing operations. Quantum computers intend on using qubits rather than bits.


    Biocomputers (or Biomolecular Computers) are experimental/developmental systems that are intended to use organic molecules for data processing and storage rather than semi-conductors (like nearly all computers use). Transcriptors (biological equivalent of transistors) have been successfully made by a Stanford University bioengineer team (led by Drew Endy) in March 2013. Some sub-types of biocomputers include DNA computers and peptide computers.

    Many other unconventional computers are available, in development, or theorized such as Chemical Computers, Stochastic Computers, Chaos Computers, and Optical Computers.

    Further Reading

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