Raspberry Pi 4 AMA: Founder Eben Upton Answers Your Burning Questions

The Future of the Raspberry Pi Foundation

Q: This tech could be really helpful in schools to give kids practical knowledge of putting together computers. have you thought about working with schools to create affordable packs that can be sent to institutions where this kind of tech may not be readily available? Maybe partnering up with other organizations and nonprofits?

A: The Raspberry Pi Foundation has a number of partnerships with organizations that aim to put computers in the hands of schoolchildren, particularly from disadvantaged backgrounds. And some of our reseller partners (Canakit for example) have a lot of experience doing kitting for the education sector. In general, we try to make the bits of the package we control (the board itself, PSUs, cables) as cheap as possible to make these sorts of packages doable.

Q: In my experience the Code Club and CoderDojo 'mergers' have been successful for the foundation and should be commended, can you speak to the impact and success that has been made to the original mission statement and the number of children becoming involved with programming?

A: These mergers have both been great successes for the Foundation. We're looking at something like 15,000 clubs globally, reaching 250,000 students.

Q: Do you conduct any outreach to UK governmental departments to inform on the national curriculum?

A: Raspberry Pi is part of a consortium delivering the National Centre for Computing Education, a £84m UK government program to train teachers to support the new Computer Science curriculum in England.

Q: The Raspberry Pi has clearly been a success by almost any metric with millions of units being sold, but do you feel that it has fulfilled the original goals as originally envisioned?

A: Overall sales far exceeded our original estimates, that we're having more impact than we'd hoped for even with "only" 10-20% of sales going into education. With respect to our original parochial goal, we see ~1100 applicants per year to CS at Cambridge, up from a low of ~200 in 2008, and substantially above our previous dot-com era peak of 600 in 1999.

Q: Do you foresee a situation were the industry's price/performance ratio stagnates somewhat and you're forced to increase the price in order to release better hardware?

A: It will happen eventually, but I think Moore's Law has more to give. When it happens, stagnation will hit power/performance as much as it hits price/performance, so two things to worry about.

Q: What kinds of industrial applications does the Raspberry Pi excel at?

A: Signage, thin-client desktops, industrial control, automation and (particularly) monitoring. Particularly monitoring because the barriers to entry are lower: you can deploy a monitoring overlay over whatever systems you already have, and get added value without worrying about interop.

Q: Is the Compute Module still in demand for new industrial users or is the expectation that the Raspberry Pi 4 will become their primary platform?

A: I think it will be a mix, as it is today. Compute Module is attractive to people who want:

  • On-board eMMC storage.
  • Form factor flexibility.
  • The full range of interfaces (e.g. dual CSI, dual DSI).
  • A lot of people start off thinking they want to build a CM-based design, but end up concluding that adding a HAT to the standard product is a better approach.

Q: I would be very interested in a 'server' variant without the whole display, audio and wireless parts, leaving only the Ethernet and USB. Do you think such a product will be viable in the future?

A: Possibly. The savings aren't particularly compelling (with the possible exception of wireless), so the rationale would have to be about form factor rather than cost.

Q: Are there any future plans for different form factors? I understand you probably couldn't confirm here, but it is something to think about.

A: No plans at present, though of course we're interested in doing a CM4.

Q: Is there a timeframe for a proper HW documentation release?

A: We'll have an update to the venerable "BCM2835 Peripherals" document in the next week or so. Docs for the PCIe and GMAC (which you may want to play with) may take a little longer to get out, but we're working on it.

Q: Did you consider making some more radical changes to the board design of the Pi 4 that you always wanted to since designing the very first Pi, or at least the B+? If yes, why didn't you go farther than you have? 

A: I think we're happy with the basic form factor: big z-height ports on the right, GPIO at the top and everything else along the bottom. One amusing observation that has come up recently (while shooting the videos for the launch) is that the unit often ends up on the desk "upside down", so that the HDMI and power go towards the back of the desk. It did occur to us that we really should flip the board, or just the silk screen, to account for this.

Q: What regrets or what you would do differently if you were where you were back in 2011?

A: Interesting. I think, in no particular order:

  • If we'd been more organised, we might have been able to launch a year earlier, though probably with less RAM.
  • It would have been good to jump straight from ARM11 to Cortex-A53, though the team that implemented the A53 was stronger than the one that implemented the A7, and we wouldn't have had access to them at the time we did BCM2836.
  • It would have been good to get dual-rank (so 2GB) support into the 40nm chips, though that would have entailed a lot of tear-up of the design (BCM2836 and 2837 are very incremental).

Q: Since the Raspberry Pi debut 7 years ago, have you seen an increased need for single board computers? Is this still as relevant as envisioned in 2008? Do you have any evidence that children are using their tablet or mobile phones as computing devices for learning purposes?

A: If anything I think we're seeing an increased level of interest in the sorts of physical computing activities at which Raspberry Pi excels. There's definitely some interesting work going on with teaching on tablets and mobiles, but ultimately they're very limited platforms compared to a real PC.

Q: Looking forward to the next five years, do you expect that devices released by the Raspberry Pi Foundation to change significantly or incrementally? What do you see as being the largest challenge for the foundation?

A: I expect we'll continue to invest in software support for all Raspberry Pi platforms, back as far as Raspberry Pi 1B from 2012. There's a lot of work to be done to enable some of the more advanced features of the new platform. I guess the challenge will be to allocate resources to this work while also (in a year or so) starting to think about what a future hardware platform might look like.

Q: What are the biggest challenges facing miniaturization? Anything you can share on where you see the tech going?A: Simply getting the required amount of routing onto a Raspberry Pi-sized 6-layer PCB was a major challenge. Early prototypes were ~3mm longer, but James Adams was able to squeeze it back down (primarily through optimization of the LPDDR4 SDRAM interface - see how close the SoC and RAM are) for production. Lots of manufacturability work on those micro-HDMI connectors too. Making sure they don't rip out of the board if you put force on them, and that they are suitable for automatic optical inspection for quality on the line.

Q: What features would you like to have on the Raspberry Pi 5? Also are there any features in your mind that make you say, "It would be great if we had it, but alas, we cannot"?

A: The interesting thing is that really our feature set hasn't changed since Raspberry Pi 3B in 2016: newer models just have "more" of everything, even if all of that "more" sometimes stacks up to a more qualitative change (e.g. from "not a PC" to "a PC"). I suppose Raspberry Pi 5, whenever it arrives, is likely to just have more of everything. One hope is that over the next few years we see enough decline in RAM prices to allow us to fit more memory into the baseline $35 device.

  • TCA_ChinChin
    This type of content is refreshing and interesting. Thanks for the interview and also thanks to Upton for the nice answers. The Pi 4 is certainly a neat little piece of kit.