MiraBox Review – Super Raspberry Pi?
A fully functional low-cost single-board computer with dual Gigabit Ethernet and two USB 3.0 ports, is the MiraBox an ARM-based miracle?
Removed from its packaging, the MiraBox looks remarkably like a desktop Ethernet switch. Its shiny white plastic top and bottom is ringed by an impressively solid-feeling metal centre, and it’s only when you turn the device around to view the two Ethernet ports and two USB 3.0 ports on the rear that you realise there’s a little more to it than a simple switch.
The MiraBox is the latest development platform from Globalscale, the company that commercialised Marvell’s SheevaPlug plug-top computer concept. The plug-type design with its integrated power supply – a source of long-term reliability issues in the original SheevaPlug design – has been ditched in favour of a compact desktop chassis that would clearly be at home sitting near network switches and routers.
Inside, the MiraBox boasts a Marvell Armada 370 system- on-chip processor, featuring a single-core 1.2GHz ARMv7 application processor and plenty of additional input and output capability. Much of this is exploited on the outside of the device: two full-speed USB 3.0 ports, connected to the SoC via one of its PCI Express lanes, provide high-speed connectivity to external storage devices, while a pair of Gigabit Ethernet ports mean the MiraBox can easily do double-duty as a gateway, firewall or intrusion detection system.
Powering the device on, the boot sequence – which can be viewed and, through the ubiquitous U-Boot BIOS, modified via a micro-USB serial console – loads a version of Debian Squeeze based on the 2.6.35 kernel tree. That, unfortunately, is where the MiraBox begins to lose some of its lustre: compiled for soft-float, the bundled Debian OS – pre-installed on a 1GB NAND flash module – is a poor performer.
A SysBench CPU test results in a 95th percentile time of 65.57ms, compared to a much speedier 51.45ms on a Raspberry Pi running the hard-float version of Raspbian – despite the MiraBox boasting a more modern processor running at almost twice the clock speed.
Compatibility can also be an issue with the MiraBox: while most common Debian packages are available within its repositories, some software simply won’t install correctly. Connecting two USB 3.0 SuperSpeed hard drives to the MiraBox and attempting to set up a Btrfs RAID1 array brought the device to a shuddering halt, thanks to a lack of kernel modules – despite the btrfs-tools packages being available and installed.
The software is definitely the MiraBox’s weakest link, which is a shame as there is evidence that Globalscale has thought hard about making the device as accessible as possible: a selection of scripts provide easy ways to enable the off-by- default Bluetooth radio, for example, or to toggle the integral Wi-Fi radio between client and access point modes.
If a community rallies around the MiraBox, as it did with the original SheevaPlug, many of these concerns could go away: all it will take is for someone to prepare a system image with a hard-float version of Debian for the device and provide it as a download and then its true potential will be unlocked. For now, though, it’s certainly a drawback to bear in mind.
For those who don’t mind rolling their own operating system, the MiraBox’s hardware should definitely hold appeal – and if the included connectivity options aren’t enough, the case hides a mini-PCI Express slot for adding in extra hardware.
For developers, an optional breakout box provides access to the Armada 370’s general-purpose input-output (GPIO) capabilities along with JTAG debugging support, but comes at a cost: the breakout box alone costs £45, although when bought with a MiraBox this drops to £40.
Price: £124.17 (excluding VAT)
Processor: Marvell Armada 370 SoC (PJ4Bv7 ARMv7L) 1.2GHz single-core
Memory: 1GB DDR3
Storage: 1GB NAND flash, 2x microSD expansion slots (1x internal)
Expansion: Mini-PCI Express slot, 2x USB 3.0
Network: 2x Gigabit Ethernet, 802.11b/g/n Wi-Fi, Bluetooth 3.0
Dimensions: 133.2 x 93.9 x 20.4mm(excluding power supply)
Weight: 185g (excluding power supply)
Link: New IT
Excellent hardware let down only by somewhat troublesome software. If you’re willing to spend the time compiling your own operating system, or don’t need the very latest Linux kernel, it’s still well worth investigating – and you’re unlikely to find another single-board computer this compact that packs as much potential for high-performance