Professional Code

Bifferboard – Linux in 3 Inches

Ben Lamb — Fri, 02 Apr 2010 14:54:10 +0000

The Diminutive Bifferboard

The Bifferboard is a 486 processor running at 150Mhz, one or two USB ports depending on model, 24Mb RAM and a paltry 8Mb of flash storage. This is easily fixed with a £2 USB hub and a £7 2Gb memory stick.

As shipped the Bifferboard comes with a very minimal Linux system but even this contains a webserver. In order to make things more comfortable you need to put a full Linux distribution onto a memory stick. Things get confusing as there are numerous choices including Debian and Slackware. Installing Debian was a breeze, there is a script to copy it onto a memory stick and a ready-made kernel for the Bifferboard hardware.

Once done you have an all singing dancing Linux box albeit based around 15 year-old technology.

What’s exciting is that these things only cost £35 and can run off a battery. So you have a very powerful computer you can deploy anywhere. I’m very tempted to stick one on the roof of my building plugged into a webcam. I’m already using USB wireless networking, 3G would be equally doable.

I bought one for an electronics project as the board has several GPIO (General Purpose Input Output) lines, and can support the I2C bus, a popular way of interfacing microcontrollers.

The complete setup

My Sheevaplug Plug Died

Ben Lamb — Fri, 02 Apr 2010 14:43:54 +0000

I’m a big fan of the Sheevaplug, an all in one Linux device about the size of a power adaptor. One of the nice things about it is that it plugs directly into the mains. Unfortunately one of mine died recently. I thought the flash had become corrupted since the LEDs on the device were flashing but I wasn’t able to communicate with it. I found several forum posts about power supplies failing so decided to open mine up.
The internal metal case of the power supply had rust marks on it. Curiously the output of the PSU was still 5V but I’m guessing it wasn’t providing enough current. Connecting the power supply from another Sheevaplug confirmed the board itself was working perfectly. So I decided to open the broken power supply and take a look:

Not a pretty sight

Several exploded capacitors, nasty. I’m surprised it was still letting current flow.

I’ve emailed Globalscale, who make the device, to see whether they sell replacements. The unit is not yet a year old but the warranty is only one month, besides shipping charges to the US would make repair uneconomic.

The power supply is a custom part, not listed in the bill of materials Globalscale supply. Obtaining a part that can provide 15W that will fit into the original space will cost nearly £40 so I’ll replace it with an external PSU.

Disappointing as the unit was not connected to any external USB devices and under normal operation. Otherwise I’ve been very impressed with the Sheevaplugs.

Moving Servers

Ben Lamb — Thu, 24 Sep 2009 22:02:42 +0000

After ten years of physical boxes in Telehouse I’m moving to a virtual Linux instance hosted on Debian. It’s an opportunity to review the software I’m running. Out goes Apache2 in favour of Lighttpd. SquirrelMail, you served me well but RoundCube is full of AJAX goodness and more importantly can display HTML emails.

Courier IMAP, I always hated you, and was very happy to discover Dovecot. Postfix and BIND, you remain. Behind the scenes I’m running Samba bound to an internal IP address that’s routed via a VPN to my home LAN. The VPN also lets me forget about securing individual services such as PostgreSQL and Subversion, they’re also VPN accessible only and at home or on the road I can access them conveniently without passwords.

For backups, I’m experimenting with AmazonS3 mounted via FuSE and rsync.

As should be fairly obvious I’m using WordPress to run my blog.