Guide to Raspberry Pi - Intro－小眼睛的健康世界

It’s the ultra-cheap computer that’s turning heads. Darren Yates introduces you to the Raspberry Pi, the single-board computer that’s cheaper than taking the kids to the movies.

Imagine a circuit board the size of a compact Android phone, surrounded by sockets with a tiny processor in the middle and you’ve pretty much got the Raspberry Pi single-board computer (SBC). Designed in the UK and available in Australia through Element14, the Raspberry Pi gives you a fully functioning computer for $38 plus shipping. That means that your overall outlay wouldn’t be much more than $50.

Connectivity

The board itself features a wide array of connection options including composite video out and HDMI output, along with 3.5mm stereo analogue audio, two USB Type-A/host ports plus a microUSB port for power and built-in 10/100 Ethernet socket.

There’s no storage on board, but you can supply up to 64GB through the SecureDigital card slot on the underside of the board, which also supplies the bootup mechanism and the operating system you run.

The processor

The brains behind the Pi is Broadcom’s BCM2835 SoC, a 700MHz single-core ARMv6 media applications processor with 256MB of onboard RAM and accelerated H.264 decoding up to 1080p (1,920 x 1,080-pixel) resolution at 30fps. Because it uses the superseded ARMv6 architecture, though, it doesn’t run Android, nor will it run any Ubuntu-based Linux distro. However, Ubuntu’s parent distribution, Debian, does support ARMv6 and you’ll find one or two options available (including our very own APC piLinux for Raspberry Pi).

Raspberry Pi SBC

The drawback at the moment is that single board computer although the BCM2835 has a hardware floating-point (HFP) processing engine, most available distros use software-based floating-point processing, which is considerably slower. Raspberry Pi made a decent move forward with the HFP release of a new official Debian Wheezy distro specifically built for the Pi. Reports are that HFP can increase performance by as much as 60% or more.

Importantly, though, you don’t need ARMv6/HFP to play back 1080p H.264 video — while you do need to keep the overall video bit rate down to around 3.5Mbps, the Pi will do the job on the standard ARMv6 Debian release.

Booting up the Pi

We’ll look more at this in a moment, but the Pi requires a special two-partition boot disk in order to launch: a small 64MB FAT32 boot partition and a secondary extended (Ext4) formatted partition with the operating system proper. Windows doesn’t support multi-partition creation on SD cards or flash drives, but Pi-compatible distros come as an .IMG file that’s basically a multi-partitioned ISO image, which you can write to an SD card using a free Windows utility.

You can use any SD card 2GB or larger, although we’d recommend an 8GB card (they’re cheap enough) and one that’s at least Class 6 in speed.

Starting the Pi is pretty simple — there’s no power button or reset button. You simply add power to the microUSB port to power up and remove it to power off or reset.

Imagination

If you’re looking for a complete computer system with nothing to do, it might disappoint you. However, there are some incredible projects being built around the Pi, from gaming consoles to voice recognition — the possibilities are only limited by your imagination.