Raspberry Pi Glossary

What's inside

A/mA

Ampere/milliampere, the base unit of electrical current.

API

Application Programming Interface, a set of subroutine definitions, communication protocols, and tools used for building software.

Arm

A series of instruction-set architectures and processor microarchitectures, mostly developed by Arm Holdings based in Cambridge, UK.

Armv6

The instruction set architecture used on the first Raspberry Pi (Pi 1) and the Pi Zero range.

Armv7

The instruction set architecture used on the Raspberry Pi 2 range.

Armv8

The instruction set architecture used on the Raspberry Pi 3 range; very similar to Armv7 in 32-bit mode.

balenaEtcher

A graphical tool for programming SD cards ready for use on our devices; available for Linux, Windows, and Mac. Now superceded by Raspberry Pi's own imaging tool, which can be downloaded here.

Bare metal

Programming the Raspberry Pi without using an operating system.

BCM2835

The SoC used on the Raspberry Pi 1, Compute Module 1, and Raspberry Pi Zero range; see our official documentation.

BCM2836

The SoC used on the original Raspberry Pi 2; see our official documentation.

BCM2837

The SoC used on the Raspberry Pi 3, Compute Module 3, and Raspberry Pi 2 version 1.2; see our official documentation.

BCM2711

The SoC used on the Raspberry Pi 4B; see our official documentation.

BLE/BTLE

Bluetooth Low Energy, a low-power version of the Bluetooth wireless communications protocol.

BT

Bluetooth, a short-range, low-bandwidth, wireless communication protocol often used for mobile devices.

CODEC

Coder/Decoder, hardware or software blocks that encode and/or decode video or audio data.

Compute Module

A Pi variant aimed at commercial customers; uses a different form factor, facilitating use inside other products.

config.txt

A file located on the boot partition of a Raspberry Pi's SD card that is parsed at boot time in order to enable, disable, and manage operating system features which cannot be changed after booting; see our official documentation.

CSI

Camera Serial Interface, a hardware interface for connecting cameras to SoCs.

DHCP

Dynamic Host Configuration Protocol, a network management protocol which dynamically assigns an IP address and other network configuration parameters to each device on a network.

DPI

Parallel Display Interface, an up to 24-bit parallel RGB interface via the Raspberry Pi's GPIO pins.

DSI

Display Serial Interface, a hardware interface for connecting LCD panels.

Device Tree (DT)

A data structure for defining hardware.

Device Tree source (DTS)

A human-readable source file to be compiled into a DTB.

Device Tree blob (DTB)

A binary file containing a Device Tree; the result of compiling DTS files.

dt-blob.bin

A binary file containing initial GPIO configuration that is read by the firmware at boot time; despite the name, this is not Device Tree blob (although it is compiled by the Device Tree tools).

DVI

Digital Visual Interface, a video interface for connecting a source device to a monitor or display; electrically compatible with HDMI, so a simple adapter can convert from one to the other (excluding audio, which DVI does not support).

Etcher

See balenaEtcher.

FAQ

Frequently Asked Questions! See our FAQ.

Firmware

Software that runs on a particular hardware device, for example a wireless chip or dongle; distinct from the usual software running on the Raspberry Pi in that it is usually a fixed binary blob of data that is loaded on to the device at startup; on the Raspberry Pi, the VC4 GPU requires firmware to be loaded to it at startup in order boot up and run the entire system.

GNU

The GNU Project is a free software mass collaboration project, which has produced huge amounts of software that is used on the Raspberry Pi, including Linux itself.

GPIO

General Purpose Input/Output, the programmable pins on the Raspberry Pi.

GPU

Graphical Processing Unit, a hardware device for handling graphical (and related) tasks at high speed; on the Raspberry Pi range up to the Pi 3B+, this is called the VideoCore4 (VC4), and is built into the SoC. On the Pi 4, a newer and faster version called VideoCore6 (VC6) is used.

HAT

Hardware Attached on Top, a specification for designing devices to attach to the Raspberry Pi; see the launch announcement.

HDMI

High-Definition Multimedia Interface, a standard interface for transmitting uncompressed video and compressed or uncompressed audio data from a source device to a display device.

HDCP

High-bandwidth Digital Content Protection, an optional encryption mechanism used for HDMI or DVI transmission.

Headless

A headless Raspberry Pi is one that does not have a display device, keyboard or mouse plugged in. Access is usually via a network connection, using a remote access protocol like SSH or VNC.

HVS

Hardware Video Scaler, a hardware block in the VC4 or VC6 GPU on all Raspberry Pi models that is used for manipulating and displaying bitmaps.

I2C/I2C/IIC

Inter-Integrated Circuit (pronounced I-squared-C), an electrical protocol used for attaching lower-speed peripheral ICs to processors and microcontrollers in short-distance, intra-board communication.

I2S

Inter-Integrated Circuit Sound, an electrical serial bus interface standard used for connecting digital audio devices together.

ISP [Imaging System Pipeline]

A set of hardware (and sometimes software) stages that processes images from a camera into a high-quality result; the Raspberry Pi has a built-in hardware ISP that processes images captured from a camera attached to the CSI port.

ISP [Internet Service Provider]

An organization that provides services for accessing, using, or participating in the Internet; see Wikipedia.

LAN

Local Area Network, an Ethernet- or wireless-based communication network in a localised area, for example a house or office.

LED

Light-Emitting Diode, a semiconductor device that produces light using electricity.

Linux

The main operating system used on the Raspberry Pi; the particular customised distribution for the Raspberry Pi range is called Raspbian; third parties have also produced their own distributions.

MSD

Mass Storage Device (amongst other things), such as an SD card or hard disk drive.

MQTT

MQTT stands for MQ Telemetry Transport, a lightweight and simple machine-to-machine protocol often used for IoT devices; see the MQTT website.

NAND

A NAND gate is a logic gate, specifically an inverted AND gate; can also refer to a type of flash memory that uses NAND logic.

NOOBS

New Out of Box software, easy OS system image installation for the Raspberry Pi range; note: NOOBS is no longer developed by the Raspberry Pi team, see PINN instead.

OTP

One-Time Programmable, a type of memory that can only be programmed once, and retains the programmed data after power off; used for serial numbers etc.

Overlay

A boot-time or run-time patch to a Device Tree allowing a degree of configuration by the user; see our official documentation for more details, or run dtoverlay -a in a terminal window for a list of available overlays.

Pink Pony/Unicorn

A feature request for a future Raspberry Pi model that is unlikely to happen.

PINN

A third-party development of the NOOBS system, often a better option than the official NOOBS.

PoE

Power over Ethernet, a mechanism to power a device through its Ethernet connection; we produce a PoE HAT for the Raspberry Pi 3 Model B+ and Raspberry Pi 4 Model B.

Polyfuse

A self-resetting electrical fuse used on some Pi models to protect against over-current; can take hours or even days to reset.

raspi-config

A command line tool for configuring Raspberry Pi OS's operating system features; see our official documentation.

Raspberry Pi Imager

The official graphical tool for downloading and installing operating system images to an SD card. Download it here.

Raspbian

An armhf build of the Debian source repositories.

Raspberry Pi OS (32bit)

A distribution of the Raspbian repositories targeted at the entire Raspberry Pi range.

Raspberry Pi OS (64bit)

A distribution of the Debian repositories targeted at the Pi 3 and Pi 4 models.

Raspberry Pi Configuration Tool (rcgui)

A graphical equivalent of raspi-config.

Raspberry Pi Desktop

A version of the LXDE desktop environment, specifically tailored to the Raspberry Pi (used to be called PIXEL).

raspivid, raspistill, raspiyuv, raspividyuv

A set of applications to run the Raspberry Pi Camera Module in various modes; see our official documentation.

RPF

Raspberry Pi Foundation, the original, UK-registered educational charity (1129409) that launched the Raspberry Pi.

RPT/RPF(T)

Raspberry Pi Trading, a wholely owned commercial subsidiary of the RPF which designs and develops all Raspberry Pi products, including magazines; all profits from the RPT go to the RPF for use in their educational programmes.

rpi-update

A program you can run on a Raspberry Pi to download the very latest test firmware and Linux kernel; there is no guarantee that the latest version will work correctly, so you should only run rpi-update if recommended by a Raspberry Pi engineer.

SoC

System on a Chip, an integrated circuit that comprises all components of a computer.

SPI

Serial Peripheral Interface bus, a synchronous serial communication interface specification used for short distance communication.

SSH

Secure Shell, a cryptographic network protocol for operating network services securely over an unsecured network; see our official documentation or the Wikipedia article on SSH.

TLA

Three-letter abbreviation, almost the entire reason for this glossary.

TLS

Transport Layer Security, a cryptographic protocol used to supply security over a computer network, often used to secure other protocols such as MQTT.

TP1/TP2

Test points.

UART

Universal Asynchronous Receiver-Transmitter, a protocol for asynchronous serial communication in which the data format and transmission speeds are configurable.

USB

Universal Serial Bus, the main Raspberry Pi models have four USB sockets for connecting USB devices, for example mice or keyboards.

VC4, VC6

The VideoCore4 or VideoCore6 GPU used on the Raspberry Pi; contains a large number of hardware blocks that handle graphics, cameras, display, CODECs, etc.

VNC

A graphical desktop sharing system that uses the Remote Frame Buffer protocol (RFB) to remotely control another computer; see our official documentation.

Volt (V)

SI-derived unit for electrical potential difference.

vcgencmd

A Raspberry Pi-specific tool for communicating with the VideoCore GPU.

Watt

A measure of power often used when specifying power supplies.