History of Raspberry Pi

In 2006 several concept versions of the Raspberry Pi were developed and it took six years of hardware development to create the Raspberry Pi. In 2011 twenty-five beta versions of the Raspberry Pi were assembled and auctioned to raise money for the Raspberry Pi Foundation.  The first generation (Raspberry Pi 1 Model B) was released in February 2012, and it was followed by a simpler and inexpensive model Model A (Nov. 2012). The first production run consisted of 10,000 boards of Raspberry Pi manufactured overseas in China and Taiwan. During this year the foundation was able to upgrade the Model A Raspberry Pi to 256 MB of RAM instead of the 128 MB. This upgrade in memory size allowed the Raspberry Pi to perform even more amazing tasks, such as real-time image processing.

 In 2014, the foundation released a board with an improved design in Raspberry Pi 1 Model B+. Improved A+ and B+ models were released a year later. A cut down "compute module" was released in April 2014, and a Raspberry Pi Zero with smaller size and limited input/output (I/O) and general-purpose input/output (GPIO) abilities was released in November 2015 for $5. The Raspberry Pi 2 which added more RAM was released in February 2015. Raspberry Pi 3 Model B released in February 2016 is bundled with on-board WiFi and Bluetooth

The Raspberry Pi is now manufactured in the United Kingdom

The performance of the original release was roughly equivalent to a 300 MHz Pentium II computer that was available back in 1999. Graphics in the Raspberry Pi are provided by a Videocore 4 GPU. The graphic performance of the graphics processing unit (GPU) is roughly equivalent to the Xbox, launched in 2011, and can play full HD movies

The Raspberry Pi has several different variants: the Model A and the Model B. The Model A is a low-cost version and unfortunately omits the USB hub chip. This chip also functions as a USB to an Ethernet converter. The Raspberry Pi Foundation has also released the Raspberry Pi Model B+ that has extra USB ports and resolves many of the power issues surrounding the Model B and Model B USB ports.

Comparison table of the different versions:

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Checking the model/type

The model of the Raspberry Pi can be found out by command: cat /proc/cpuinfo 

By looking at the line "Revision", it will tell you the board, board revision, RAM:

Revision        : 000f

• Raspberry Pi Model A: 0007, 0008, 0009

• Raspberry Pi Model B (Rev 1.0, 256Mb): 0002, 0003

• Raspberry Pi Model B (Rev 2.0, 256Mb): 0004, 0005, 0006

• Raspberry Pi Model B (Rev 2.0, 512Mb): 000d, 000e, 000f

• Raspberry Pi Model A+: 0012

• Raspberry Pi Model B+: 0010, 0013

• Raspberry Pi 2 Model B: 1041

Or command "dmesg" can also help:
$ dmesg | grep model
[    0.000000] Machine model: Raspberry Pi Model B Rev 2