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Eben Upton Explains the Raspberry Pi Model A+'s Redesign
M-Saunders writes It's cheaper, it's smaller, and it's curvier: the new Raspberry Pi Model A+ is quite a change from its predecessor. But with Model Bs selling more in a month than Model As have done in the lifetime of the Pi, what's the point in releasing a new model? Eben Upton, a founder of the Raspberry Pi Foundation, explains all. "It gives people a really low-cost way to come and play with Linux and it gives people a low-cost way to get a Raspberry Pi. We still think most people are still going to buy B+s, but it gives people a way to come and join in for the cost of 4 Starbucks coffees."
Given the purpose of these devices, cheaper would be better than faster.
Four Starbucks coffees? I thought the Raspberry Pi was supposed to be cheap!
Nintendo Wii has a 729 MHz CPU and 88 MB of RAM https://en.wikipedia.org/wiki/... (not that you can directly compare CPUs by clock speed).
Here at work, people have built essentially the same project (USB control of relays) with three different platforms, an Arduino, an rPi, and an old Pentium with MBs of RAM. All three did the job.
The Pi processor runs 44 times as fast as the Arduino, meaning it was 44 times as fast as needed for the purpose it was used for. The Pi has 512 MB of RAM, the Arduino accomplished the same task and has 2 Kb of RAM. The Pi has up to 16 GB of flash storage, the Arduino 32 KB.
So they ALREADY did "up the specs" to about 50 times as powerful as needed for these types of tasks. The Arduino used for the project cost $5-$10, the Pi $35.
Suppose the Pi had 2 GB of RAM and cost $150, would you suggest that they "up the specs" to 4 GB and $250? If that's what you want, you can get it here:
http://www.walmart.com/ip/Dell...
The Pi isn't a desktop computer. It's designed for particular types of tasks, and those tasks don't need gigs of ram. In fact, looking at the Pi-related web sites and the Arduino related web sites, the applications are often very similar, which indicates that the Pi is way over-speced for the many of the applications it is used for.
When I started my web hosting business we offered servers that ran Linux, just like the Pi does. The standard dedicated server had 256 MB of RAM, the upgraded option had 512 MB - just like the Pi. Web sites served hundreds of GBs of traffic every month off those 512 MB servers. Why does the Pi need more?
The A+ and B+ boards still have composite video, they just output it on the smaller 3.5mm jack to save space, like many other mobile devices do. You can get adapter cables to split out the typical red,white,yellow RCA connectors for a couple bucks.
For most tasks, it has more than enough power. The pi isn't for people looking to use it as a PC replacement for productivity. It is a low cost board. The reason the RAM is always fixed at 512MB is because the cheap SoC (system on chip) is a PoP (package on package) design. Inside the chip you see on the Pi lives both the SoC and the RAM. There is no external memory bus so it is impossible to upgrade the RAM without redesigning the silicon and retooling an entire production line. That isn't going to happen because Broadcom isn't interested in upgrading an outdated (which is why it is cheap) chip.
It's best use is an embedded controller that runs Linux. I have used one for a little home brew project and it works perfect. You don't need 700MHz for a control loop to turn relays on and off. But it does come in handy when you want to make a web based controller. I installed node.js and the cloud 9 IDE like the Beaglebone and I had a web page controlling relays in a matter of a few hours. Sure you can make a web based controller in a much smaller device like the Mbed but having Linux makes it much easier as you have a familiar development environment and tools. And you can write the software right on the Pi itself, no need for cross compilers, tool chains or a separate PC. Just a keyboard, mouse and monitor.
Faster would be nice, of course, but there are just scads of applications that don't require it. I use my pi B+ machines via SSH shell, not a desktop. In that environment, typically I have midnight commander up for both its editing capabilities and the simplification it provides for common operations; I write Python, which as one of the fastest scripting languages and really doesn't seem to be noticeably slow within the context of the B+. I drive relay boards (Sainsmart... the PiFace is a joke, severely limiting both voltage and current due to insufficient trace widths / clearance on the PCB) and use those relay boards to perform a number of remote-able tasks for me. I just don't feel a lack of speed.
However, I *do* notice swapping from time to time when I'm editing and testing, and (of course) there is a speed drop then, but that's not something you can attribute to the CPU. It's happening because the machine simply doesn't have enough RAM; I have read (somewhere... can't be sure), there are SOC versions that do upgrade the RAM available that are essentially drop-ins. If that's the situation, then I would be *very* willing to swap out the B+ boards for C+ or whatever such a thing would be called. As we have all known for years, there are few things that contribute as much to a smoothly running modern OS as enough RAM so it can really breathe.
I can't say I have any interest at all in the A; I didn't even bother with the pi until the B+ became available. The B+, however, strikes me as a wonderful platform, and when you add the cheap sensors and other hardware, plus the drivers... whahoo. :)
We have three here already, and I'm probably about to add a fourth.
If you're a shell/raspian user, tip of the day is:
sudo apt-get update
sudo apt-get install mc
Then either:
mc
or
sudo mc
I've fallen off your lawn, and I can't get up.
Olympic size swimming pools filled with Starbucks coffee for large quantities.
I was promised a flying car. Where is my flying car?
A better comparison might be that the Nintendo DS has 4MB of RAM and two ARM CPUs (one ARM9 running at 67MHz, and one ARM7 running at 33.5MHz). The Raspberry Pi's got the 700MHz ARM11, 256MB of RAM, and a GPU that handles 1080p video decoding and 3D performance similar to the first XBox game system. Interface it with some buttons and a display (or two), and something like the model A+ could potentially make an excellent little game system, provided that someone decides to write the software for it.
It is pitch black. You are likely to be eaten by a grue.
While the Pi is good for most of its intended tasks, it is lacking in many areas. The Beaglebone is a good upgrade but it too has shortcomings. But if you need more power, the Beagle team has another board in the pipeline.
If you want some serious power for an embedded project look no further than the Beagleboard X15. This thing is going to be a beast:
Dual core A15 ARM @ 1.5GHz
2GB DDR3L RAM
Dual core GPU (unfortunately PowerVR SGX, not open source friendly)
2D accelerator and Video accelerator
Dual C66x DSP processors
Dual Cortex M4 Image processors (only one is user programmable)
Dual PRU-ICSS ( programmable cpu accelerator to offload ethernet packet processing for industrial protocols like Ethercat, Profinet, etc.)
eSATA
USB 2.0 and 3.0
Dual PCIe ports, Gen 2, one x1 and one x2 (Yes they will be routed to ports)
Appears to have some type of video in, probably a camera port.
And more...
Rumored to cost about $150. Yes it costs much more than the Pi but you get what you pay for; a boat load of processing power and memory.
There are _NO_ 1Gb DDR1 chips in that form factor.
If you can manage to persuade any memory factory to build a couple of million of them at a price simmilar to the existing 512Mb ones - the whole world will be thanful.
All the 1Gb chips on the market now are DDR2 or faster - incompatible with RPi.
Eben Upton & the Foundation has tried and failed - nobody wants to make so few 1Gb DDR1 chips for so cheap.
1% APY, No fees, Online Bank https://captl1.co/2uIErYq Don't let your $$$ sit in a no-interest acct.
You forgot to include "at a similar price point." Because, despite all the hoopla about its other features, that is the biggest selling point of the RPi: it's easy to replace a fried unit after a voltage calculation mis-places a decimal point.
> I drive relay boards
> We have three here already, and I'm probably about to add a fourth.
If you need to drive a lot of relays, you might consider a serial-to-parallel chip feeding a ULN2803 octal darlington array. That's about $2.50 of electronics per eight relays. With connectors and such, call it $0.50-$1 per relay. You can connect up to 256 addressable serial-to-parallel chips to a single IO on one Pi (or a PC, through a $2 level shifter). So for the price of another Pi, you can add 35-70 more relay outputs to your existing Pi.
The Model A boards have 256MB, the Model B have 512MB. They could have put 512MB in the Model A, but it would have cost them a bit more and they were trying to make it cheaper. (I still wish they'd done it.)
But one reason the board is so cheap is that it's using a System On A Chip that's designed for other applications, not custom for them, so making it faster, or using a newer ARM instruction set, or (apparently) putting more than 512MB on the board would be hard, requiring a major redesign and increasing costs. For instance, the BeagleBone Black costs about twice as much, and while it uses a faster CPU with a newer instruction set, the video processing part is slower, so it's not a total win.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks