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Computer Acronyms and Abbreviations

An acronym is an abbreviation where each letter stands for a word. For example, TLA is a Three Letter Acronym. (TLAs are very common.)

Note that the Internet is made of lots of different things, such as the WWW, usenet groups, email, FTP, etc.

Units for data storage are at the bottom of the page.

  • ATA – Advanced Technology Attachment (originally AT Attachment, after the PC or AT type of computer), a type of hard disk bus. Also known as IDE, and now often called PATA (Parallel ATA) to distinguish it from SATA.

  • ATAPI – AT Attachment Packet Interface, a form of ATA, extended to use with CD-ROM drives and floppy drives instead of just hard disks.

  • CD – Compact Disc. (Or compact disk with a k – both are widely used. At time of writing, Google has 1,600,000 results for "compact disc", and 1,320,000 results for "compact disk".)

  • CLI – Command Line Interface. A text-based method of using a computer without a graphical environment or mouse (although a mouse may still be useful for copyng previous instructions). An example is a Linux terminal window. Compare with GUI.

  • CPU – Central Processing Unit. The main brain of a computer, where most of the "thinking" is done. It accepts both instructions and data, and issues processed data and sometimes instructions for other parts of the computer.

  • CRT – Cathode Ray Tube, the technology behind most older monitors and televisions. It is only in the last year or two that LCD screens have become cheap enough to replace CRTs as the main sort of computer monitor.

  • CSI – Camera Serial Interconnect. A camera interface specified by the MIPI Alliance (see MIPI below) used on Raspberry Pi and other SBCs.

  • DSI – Display Serial Interconnect. A display interface specified by the MIPI Alliance (see MIPI below) used on Raspberry Pi and other SBCs.

  • DVD – Digital Versatile Disk (or sometimes Digital Video Disk). They are "versatile" because they can be used for more than just video.

  • EIDE – Enhanced IDE.

  • eMMC – Embedded Multimedia Card. A particular storage format a bit faster than SD cards.

  • FPU – Floating point unit. Provides hardware acceleration of maths involving floating point numbers (rather than integers).

  • FTP – File Transfer Protocol. Used for uploading or downloading files over the Internet.

  • GPU – Graphics Processing Unit. Provides hardware acceleration for image processing. Also assists video playback thanks to fast buffering (storing things in memory which can be accessed very quickly).

  • GUI – Graphical User Interface. A visual-based way of using a computer, normally using a using a mouse or trackpad. Compare with CLI.

  • HDD – Hard Disk Drive. (Also HD for hard disk or hard drive.)

  • HTML – Hypertext Markup Language. The way web pages are encoded for bold, italics, etc.

  • HTTP – Hypertext Transfer Protocol. Used for downloading HTML pages, pictures, etc, on the WWW.

  • IDE – 1. Integrated Drive Electronics. See ATA.

  • IDE – 2. Integrated Development Environment. An all-in-one program allowing programming and testing.

  • LAN – Local Area Network. A small network, based in just one house or building. Two computers in the same home sharing a single printer is an example of a LAN.

  • LCD – Liquid Crystal Display. This is what powers the screens of most calculators, digital watches, and flat panel displays. In the last year or two LCD monitors have replaced CRTs as the price of them has dropped markedly.

  • LED – Light Emitting Diode. An electronic device that gives off light, and will pass current in one direction only. They are often used to indicate that something like a hard drive is being used, or simply that a device is turned on. In more recent years LEDs have become bright enough that they are now also being used for decoration, such as lighting up the inside of a computer while using a transparent case.

  • MIPI – Mobile Industry Processor Interface. Used for CSI and DSI.

  • Modem – from MOdulator/DEModulator, from what it does to convert the digital computer signal to/from the analogue telephone signal.

  • NPU – Neural Processing Unit, also called AI accelerator. It provides hardware acceleration of neural network processing. These are quite a new development. Can also stand for Network Processing Unit.

  • POP – Post Office Protocol. Used for email over the Internet. A POP account is an email account on a mail server. It is checked for new email by an email program like Mail, Eudora, or Outlook Express.

  • RAM – Random Access Memory. Much more convenient than heap or stack memory, which can only write to or read from the top of the stack. RAM means data can be written to or read from anywhere in the memory.

  • ROM – Read Only Memory.

  • RTC – Real-time Clock, a device which keeps track of the time when the computer is turned off. It needs a battery backup.

  • SATA – Serial ATA, a type of hard disk bus.

  • SBC – Single Board Computer. A computer built to have processer, memory, storage, etc all on a single printed circuit board. The Raspberry Pi is the most well known range of single board computers.

  • SCSI – Small Computer System Interface. A type of hard disk interface, not used much any more. There are several different sorts, and they used to be common enough that I made an article about the different connectors.

  • SoC – System on Chip. A single integrated circuit containing the combined CPU, GPU etc needed for a computer.

  • USB – Universal Serial Bus. An inexpensive way of attaching peripheral devices. USB was invented by someone working at Entrega, bought by Intel, and popularised by Apple when they used it for their iMac.

  • VFP – Vector Floating Point, part of a computer's main processor that handles floating point calculations with vectors.

  • WAN – Wide Area Network. A large network, over several buildings, or even the whole world. The Internet is an example of a very big WAN.

  • WWW – World Wide Web. Just part of the Internet – there is a lot more to the Internet than just the Web.


  • kb – kilobit. 1,000 bits or 125 bytes.

    kB – kilobyte. 1,000 bytes.

  • KB – might be either kilobyte (actually kB) or kibibyte (actually KiB), so it is either 1,000 bytes or 1,024 bytes depending on the context.

  • KiB – kibibyte, always 1024 bytes (210 bytes). The prefix "kibi" comes from kilo and binary.

  • Mb – megabit. Ethernet speeds are often specified in megabits per second (Mb/s or Mbps) not megabytes per second.

  • MB – megabyte. 1 million bytes. The days of 1.44 MB floppy disk drives and 20 MB hard drives are long gone.

  • MiB – mibibyte. 1,048,576 bytes (220 bytes).

  • Gb – gigabit. High speed interfaces are often specified in gigabits per second (Gb/s or Gbps or Gbit/s) not gigabytes per second (GB/s). To convert to GB/s, for USB 3 Gen 1 divide by 10 (there are two parity bits for each 8 bits); or for USB 3 Gen 2 divide by 8.25 (4 parity bits for each 128 bits).

  • GB – gigabyte. 1 billion bytes. The days of being able to buy 20 GB hard drives have also gone, although some 20 GB hard drives are still in use, especially in very old laptops.

  • GiB – gibibyte. 1,073,741,824 bytes (230 bytes).

  • TB – terrabyte. 1 trillion bytes. The smallest available (spinning disk) hard drives are now 1 TB. Solid state drives are still available in smaller sizes.

  • TiB – tebibyte. 1,099,511,627,776 bytes (240 bytes).

  • PB – petabyte. 1 quadrillion bytes.

  • PiB – pebibyte. 1,125,899,906,842,620 bytes (250 bytes).