Group: Hardware/Computers/Single Board Computers/Plug Computers

Plug Computers are computers that fit in a small form-factor, are power-efficient and do not interact with the user directly through I/O devices such as monitor and keyboard, but are rather controlled remotely. Most of the time, Plug Computers use a System-on-a-Chip (SoC) with an ARM processor, run a GNU/Linux system and are used as domestic servers.

Software freedom comparison

While some Plug Computers can be used with fully free software running on the main processor, not all of them are perfect. Hence, here is a comparison of different models of Plug Computers and their flaws regarding software freedom.

Flawless targets

These plug computers can be operated with all the hardware features available, using only free software.

• The Globalscale SheevaPlug can be operated using only free software:
  • The bootloader is free software and can easily be replaced
  • The kernel and all the drivers needed are free software
  • There is no hardware component that requires a non-free loaded firmware

Seriously flawed targets

These plug computers are usable with free software, but important hardware features are not functional. There may be workarounds for these however.

• The Globalscale DreamPlug is flawed as the WiFi and bluetooth hardware require non-free firmwares
  • The bootloader is free software and can easily be replaced
  • The kernel and all the drivers needed are free software
  • WiFi and bluetooth both need a non-free loaded firmware, but the USB ports make it possible to use external WiFi and/or bluetooth dongles that can work with free software (both USB2 ports can provide up to 500mA). You can get a USB wifi device that Respects Your Freedom like ThinkPenguin TPEN150USB or Tehnoetic TETN150 and use that.

Free software-compatible hardware features comparison

This table compares plug computers hardware features that work with free software. Hence, it does not mention hardware that requires non-free software to function.

Name	Manufacturer	SoC	CPU frequency	RAM	Internal storage	External storage	USB	PCI	Ethernet	WiFi	Bluetooth
SheevaPlug	Globalscale	Kirkwood 88F6281	1.2 Ghz	512 Mb	512 Mb	SD card	1xUSB2	N/A	1x10/100/1000	N/A	N/A
DreamPlug	Globalscale	Kirkwood 88F6281	1.2 Ghz	512 Mb	4 Gb (µSD card)	e-SATA, SD card	2xUSB2	N/A	2x10/100/1000	No	No

Software features comparison

Currently, the best way to run fully free software on these plug computers is to use Debian with the matching ARM architecture. However, the situation with Debian is not good enough[1] for freedom, since Debian hosts a repository of non-free software and encourages their use through the packages web interface and the Debian wiki. Hence, it does not meet the requirements for Free System Distributions[2].

The FreedomBox software[3] is based upon Debian and comes with the same issues as Debian, mentioned above.

Name	Manufacturer	Architecture	Bootloader	Kernel	GNU/Linux
SheevaPlug	Globalscale	ARMv5/armel	Upstream U-Boot support	Upstream Linux support	Official Debian support
Dreamplug	Globalscale	ARMv5/armel	Upstream U-Boot support	Upstream Linux support	Official Debian support

See the FSDG distributions page in the Hardware section for more details (on the lack of) FSDG distributions support for ARMv5.

Single Board Computers

In a lot of cases, other ARM computers such as single board computers, with the appropriate case, can be used instead of plug computers.

See the FSF article about Single Board Computers for more details.