6

I have been told by some friends that Raspberry Pi computer is the "next best thing". I am trying to understand what it is and what it can do before I jump on the bandwagon.

After doing some research, I found that the Raspberry Pi is a computer that runs a Linux distro, but at a very cheap price. My question is this. If I already have a desktop running Linux, can't I already do all the Pi projects with my desktop? Obviously, I need to move the hardware around a smaller computer will be easier to carry, but functionality-wise, isn't my Linux desktop just as good as the Pi?

I'd be happy to be proven wrong!

13

I have been told by some friends that Raspberry Pi computer is the "next best thing".

This is an ambiguous, unqualified, and subjective statement -- if my favourite thing is racing cars it is very unlikely I would consider the Raspberry Pi "the next best thing", etc.

So to be meaningful and usefully evaluated, we need to consider some further context.

If I already have a desktop running Linux, can't I already do all the Pi projects with my desktop? [...] but functionality-wise, isn't my Linux desktop just as good as the Pi?

Yes and no. Or maybe no and yes would be the correct order, in the sense that:

  • No, you cannot do "all the Pi projects with your desktop". However, all or most of the things that you can't do with your desktop may in fact be things that you are not interested in doing. (There is a bit of a qualification to this which might make the answer "yes", which I'll get to).

  • Yes, your desktop is "just as good as the Pi" and in fact is certainly way, way, way better than any current model of Pi unless you have an antique desktop. However, here I'm considering the standards people evaluate normal computers by, such as processor speed, memory, bus types, etc.

The Pi is not a replacement for a desktop and anyone who tells you this is delusional and/or a particular sort of iconoclast. I'm not using the latter in a pejorative sense, BTW; if you are a similar sort of iconoclast you may just love it. But most consumers will be disappointed in this context.

So why would I want one?

There's any number of reasons for that, but most of the major ones have to do with the GPIO breakout. For example, this includes access to an I2C bus. Your desktop probably has one for purposes listed in that wikipedia article (e.g., working with the real-time clock on the motherboard) but it is not something you can find by looking inside and it certainly won't be anything you can make much use of.

This is not true on the pi, where the two serial lines which are the I/O for the bus are directly accessible and can be attached to a wide variety of sensors and devices in a form that is about as small and inexpensive as such devices can get. I mentioned earlier that "there is a bit of a qualification to this" regarding your desktop, because you can, in fact, buy a USB to I2C adapter and do the same kind of things -- except these adapters tend, as far as I'm aware, to cost at least as much if not substantially more than a Raspberry Pi.

There's also power consumption. A pi will use < 5 watts sans peripherals. So if you have a purpose for a computer you want to leave on somewhere 24/7, that is a major advantage over your desktop, which will use at least an order (or two) of magnitude more electricity, take up a lot of space, and probably be as silly (or eccentric) in comparison as using a pi for a desktop. Any model of pi will match the power and potential of most home routers, NAS systems, etc., with the important caveat that its network throughput is more limited. Put another way, they make great general purpose home servers.

They are also used as digital media/entertainment centers (which is sort of a combination of home server and lightweight GUI computer), primarily via Kodi. There are various arrangements along this line depending on how tech savvy you are; my personal use case here revolves around an FM transmitter attached to the aforementioned GPIO pins. Beware that the analog output sound system is not very high quality, but there are ways around that (such as streaming to another device and using an external adapter).

  • 1
    A Raspberry Pi 3 can make an okay desktop replacement, if you're good with understanding and living with its limitations. – scruss Apr 10 '16 at 14:37
  • @scruss So can a plain old B. But trying to claim either one of them is anywhere near as "good" in this sense as a modern desktop is totally ludicrous. A hatchback can be used to transport things, but it is not really a "replacement for" a pickup truck. – goldilocks Apr 10 '16 at 14:40
  • Actually my pi 2 is faster and more enjoyable to use as a Desktop than all my other computers...of course my computers are verrrry old. :-) Depends on what your used to. – NULL Apr 13 '16 at 11:46
  • @goldilocks thank you for entirely invalidating my experience with Raspberry Pis over the last four years. Clearly I have no idea what I am doing, and you know my use cases better. I said it can, with limitations, not that it should for everyone. – scruss May 28 '16 at 12:42
4

Like anything else both have their respective pros and cons. Your desktop does not have GPIO pins which can interface with sensors. LED's etc. Your desktop will also cost many times the approximate $1-2 a month it costs to run a PI 24/7.The Pi also has no fan or disk drive and so is silent. On the other hand your desktop is likely more powerful than even the Pi 3.

2

Size and cost. The pi is good for applications where you don't want a large desktop computer i.e. Embedded, sensors, home automation, etc. It also is $35.00 give or take. Most desktops are much more expensive.

2

Dedicated and practically disposable: Would you give up your computer to control a light bulb? Would you give it up to be a dedicated web cam? Would you hide your computer under a bridge somewhere set up to transmit some pirate radio for fun?

It's not that it does more powerful things--it's that it can be used for a single purpose without costing $50 or more.

Small & low power: You can't use your computer to power and control lights on your clothes or bicycle for hours at a time. You wouldn't mount it permanently in your car as a music & wifi source. You can't mount it inside a game pad to make it into a stand-alone game controller.

Most of all, you won't be able to imagine, design, manufacture and sell a dedicated smart device for under $80 that uses a laptop as a core--but people are doing it all the time with the PI.

1

Actual, factual random number generation - none of that pseudo-random mumbo jumbo we have to live with on our laptops* :) Plus all the stuff that's already been mentioned like GPIO, saving power/space, of course.

*As mentioned in the comments by @scruss (who happens to be the owner of the blog I'm linking to above), modern intel CPUs also have a hardware random number generator. That being said, the developers of the BSD distros have chosen to not rely on this feature due to concerns about its integrity and a potential compromise. Either way, as alluded to by @edo1 in the comments, distrusting one manufacturer (in this case intel) should not automatically increase one's trust in the competitor (Broadcom). Build your own RNG if you're into that sort of thing and don't forget to thoroughly test your output if you want to use it for cryptography.

  • 1
    Most Intel laptops now have DRNG, so they too have true RNGs on board. – scruss Apr 9 '16 at 1:24
  • @scruss Which I don't trust because people far smarter than I don't either. – jDo Apr 9 '16 at 1:30
  • @jDo Thank you for the your answer. Could you explain your last comment? I do not understand it. – Tosh Apr 9 '16 at 2:17
  • @jDo ok, you do not trust Intel, why do you trust Broadcom? – edo1 Apr 9 '16 at 2:23
  • 1
    The BSD suspicions are based on no evidence, as Linus pointed out: even if you fed a huge stream of zeroes into the kernel RNG, it wouldn't reduce the entropy. It's very hard to get a HWRNG correct, and homebrew ones are very slow and extremely easy to compromise. – scruss Apr 10 '16 at 3:40

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.