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InfoQ Homepage News Raspberry Pi Leaps into 64-bit Computing with Model 3

Raspberry Pi Leaps into 64-bit Computing with Model 3

A new Raspberry Pi, the Model 3, has been launched on the fourth anniversary of the eponymously named Raspberry Pi Foundation. The device is still pitched at the same price point – $35 or £30 – as the previous Raspberry Pi Model 2, but brings significantly more punch to the table.

Pi 3

Photo by Gareth Halfacree. Click to enlarge.

While all previous Raspberry Pi models have been based on a 32-bit Broadcom system on a chip, the Raspberry Pi Model 3 is the first to launch with a 64-bit Broadcom SoC. This brings an improved architecture with more registers and potentially faster computing to the embedded device market, and is likely to propel itself to the highest selling 64-bit embedded device this year. However although the chip supports 64-bit, it can continue to run 32-bit programs (in the same way that modern operating systems can do both). The clock speed is slightly faster, at 1.2GHz, although the fact that it is a quad-core means that multi-threaded (or simply multiple) programs will execute faster than before. Halfacree has run more detailed benchmarks which highlight the improvements.

The Pi website, hosted by Mythic Beasts, have also added some Pi 3s to the main hosting mix for the Raspberry Pi website, with around 1 in 12 requests being served by Pi 2 or a Pi 3 at the time of writing. Both also have their own Twitter handles (Pi 2, Pi 3). The blog post states that:

If you read the headers you’ll see on some requests
  HTTP/1.1 200 OK
  X-Served-By: Raspberry Pi 3

indicating your page request came off a Raspberry Pi 3.

For the time being, the Raspberry Pi Foundation's default operating system is Raspbian, a derivative of the Linux Debian platform, and exists at the moment in 32-bit form. It's unlikely that a Raspian system that supports 64-bit only will be released in the near future, although the long-term trajectory for embedded devices is surely aiming at 64-bit eventually. Part of this may be because the device's chip still contains 1Gb of memory, which is unchanged from previous models. Since 64-bit computing is only required if going above 4Gb of memory, the limitations to run a 32-bit operating system are not a show-stopper at this stage. What is more likely to be a driver to the 64-bit world is support for additional instructions and registers that may bring more economical performance for the same price point. as with prior versions of the Raspberry Pi, they can also run Windows, and Microsoft have made available an updated image of Windows Core IoT with support for the Raspberry Pi Model 3.

The other significant difference with the Raspberry Pi Model 3 is the availability of embedded WiFi and Bluetooth. Previously, the majority of use-cases running on a Raspberry Pi are likely to have used the USB ports for connecting a wireless keyboard (over Bluetooth) or to a network (over WiFi). With the Raspberry Pi Model 3, both of these additional requirements are gone – it can simply use the device itself. Cleverly, the antenna is embedded into the board itself, which means that no additional cabling or connectivity is required to use it.

The WiFi support on board supports 802.11n at 2.4GHz, but not 5GHz. Given that the majority of routers sold in the last few years have supported multiple bands, this shouldn't be too much of an issue, although the 2.4GHz bands are typically more congested than those in the 5GHz band.

The Bluetooth support is based on Bluetooth LE, the low-energy version of the protocol for connecting devices to a host. One of the key advantages of Bluetooth LE is that it can communicate with battery powered sensors in a wireless protocol that remains off most of the time, only activating when there is data to send. As a result, battery operated devices can last far longer than they would under traditional active wireless systems used in Bluetooth 3 and below. Recent smartphones and devices have used Bluetooth LE for communicating between low-power devices (such as the Apple TV and Watch) as well as smart tags that can be used to identify locations when triangulating devices. Given that a Raspberry Pi Model 3 now has the ability to do much the same thing, it's likely that such applications will come to maker projects in the future.

Ebon Upton, founder of the Raspberry Pi Foundation, spoke to Makerzine about what's new:

Although this is a 64-bit core, on day one, we’re only going to be running 32-bit code. We’re still running Raspbian, which is our ARMv6 operating system. There are some benefits from going 64-bit, primarily it brings a broader range of operating systems [on to the Raspberry Pi].

We’re expecting to see a lot more people using the Raspberry Pi as an IoT hub. It’s sat there, either connected to your network via wired Ethernet or via Wi-Fi and then it has a cloud of [generally] BLE sensors around it.

One of the real surprises for me — as a software engineer — is the extent of which the exciting things to do with [the Raspberry Pi] are physical computing (hacking) projects. We have this suspicion that kids are going to do existing IoT-type projects, we have a suspicion that the connectivity stuff adds more value than you’d expect.

Although the Model 3 is now available for order, the Raspberry Pi Foundation will continue to make Model 2 and other parts for those customers that continue to need it. It is expected that a future release of the Model A (which has fewer USB ports) and a Zero will be available supporting the new SoC in the future, although the timelines for those were not announced. Right now, the factory in Wales is creating as many Raspberry Pi Model 3 as it can – about 100,000 per week – to satisfy the demand for the new device.

The Raspberry Pi, only four years old, continues to drive education for youngsters and allows them to play with cheap devices where there is less concern about accidental damage. Having merged with CodeClub, the Raspberry Pi Foundation continues to invest in the education centre, and has even worked with NASA, ESA and Tim Peake to send two Raspberry Pi devices under the Astro Pi banner to the International Space Station (they have their own Twitter handles; Astro Pi Izzy is the female Pi and Astro Pi Ed is the male Pi). Last year a competition was launched which offered students a chance to code their own computer science experiments to be run in space, with seven winning programs sent to the ISS. Now a new competition has been annouced for UK school children to write programs that will fly with Tim Peake in space. The competition closes at the end of March.

The Raspberry Pi can also claim to be the best selling British computer ever. This was widely reported almost a year ago, after the foundation announced that they had surpassed 5m units. However it then emerged that the Amstrad PCW machine had sold in larger numbers, around 8 million in total. Sales of the Raspberry Pi have now surpassed that figure, the foundation confirmed via Twitter:

Speaking at the launch of the Pi 3 Eben Upton stated that his new goal was to overtake the Commodore 64, putting the Pi in third place behind Mac and PC.

Update: In an interview with Upton for the MagPi magazine, Gareth Halfacree uncovered that the Broadcom SoC also supports PXE and USB mass storage booting, which means that in future it is possible that a Raspberry Pi won't need a memory card installed in order to boot.

USB and PXE network boot

Even with the chip designed and taped out in March of last year, the Foundation had some final input for Broadcom in order to add twonew features: direct USB massstorage and PXE network boot capabilities. “Gordon rewrote the boot ROM for the chip and then provided an updated boot ROM to Broadcom, saying ‘shove this in the chip, it’ll work’,” Eben laughs. “And it does!

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