Raspberry Pi is a series of inexpensive single board computers.
Contents
Hardware
Raspberry Pi 1
The Raspberry Pi A, A+, B, and B+ boards, the Pi Zero, and the Compute Module feature a 700MHz ARM11 armv6hf processor, with the following distinctions between the models:
- A: 1 USB, no ethernet, 256MB RAM. Uses SD cards. $25.
- A+: Smaller than the A, 1 USB, no ethernet, 256MB RAM. Uses microSD cards. $25.
- B (Version 1): 2 USB, 10/100 ethernet, 256MB RAM. Uses SD cards. $35.
- B (Version 2): 2 USB, 10/100 ethernet, 512MB RAM. Uses SD cards. $35.
- B+: 4 USB, 10/100 ethernet, 512MB RAM. Uses microSD cards. $35.
- Compute Module: No onboard ports, in a SODIMM form factor. 256MB RAM. Also has 4GB of eMMC. $30 (in batches of 100).
Raspberry Pi 2
The Raspberry Pi 2 Model B is a new model, featuring a quad core ARM v7 processor running at 900MHz. It has 4 USB ports, 10/100 ethernet, 40 GPIO pins and 1GB of RAM. Uses microSD cards.
Raspberry Pi 3
The Pi 3 model B was introduced in early 2016, and features a 64-bit ARM processor running at 1.2 GHz, and featuring integrated Bluetooth and WiFi. Otherwise, it is identical to the Pi 2 model B.
Other Notes
Raspberry Pis do not have onboard storage (except for the Compute Module), and they do not have onboard WiFi or Bluetooth (excepting the B 3). All Pis (except for the Compute Module) support 3.5mm audio out (poor quality, but useable), HDMI out supporting 1080p30, and composite SD video out. Some also support I2S audio out. All Pis feature the VideoCore IV GPU, which is fairly powerful given the rest of the components. It's roughly as powerful as the GPU in the iPhone 4s.
Software
The Pi can run various distros of Linux, as well as BSDs and some other Unixes ported to ARM. The main distro is Raspbian, which is based off of Debian Jessie. The Pi also supports Arch Linux ARM, OpenELEC, and RISC OS.
The Pi 2 can also run Ubuntu Snappy Core, Ubuntu MATE, and windows 10 IoT Core.
The Pi 3 is limited at the moment, because it uses a 64bit version of the ARM instruction set.