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by ejolson
Sat Dec 16, 2017 5:32 pm
Forum: General discussion
Topic: Pi 3 hangs periodically
Replies: 6
Views: 239

Re: Pi 3 hangs periodically

I'm using the power supply that came with the Pi3 from AdaFruit. If that's not adequate, I'm open to suggestions. Currently, I have an Aeon z-stick (zwave controller) along with a 32GB USB thumb drive, which I use a boot drive. Those are the only devices connected to the Pi3. Can you provide instru...
by ejolson
Sat Dec 16, 2017 4:56 pm
Forum: Teaching and learning resources
Topic: Super-cheap Computing Cluster for Learning
Replies: 7
Views: 198

Re: Super-cheap Computing Cluster for Learning

Raspbian is getting bloated, PiCore trims back Linux but is still perfectly usable, Ultibo throws away the OS. I want to learn how to do CV/ML/AI etc without Linux. According to the link, it would appear the cluster hat people have a modified version of rpiboot. My version of rpiboot has been modif...
by ejolson
Sat Dec 16, 2017 3:24 am
Forum: General discussion
Topic: Pi 3 hangs periodically
Replies: 6
Views: 239

Re: Pi 3 hangs periodically

I'm actually using a USB thumb drive as my boot drive instead of the SD, but I had the same problem when using SD. I'm not impatient when this happens. I'm talking at least an hour with no response. I would suggest checking your power supply to make sure it can supply enough current for the 3B. You...
by ejolson
Fri Dec 15, 2017 5:24 am
Forum: Teaching and learning resources
Topic: Super-cheap Computing Cluster for Learning
Replies: 7
Views: 198

Re: Super-cheap Computing Cluster for Learning

I use Zero's with no SD cards all the time now with USBboot. The Cluster Hat is a bit $$ but no USB hubs needed etc and it is very small. The cluster hat does look suitable, though maybe it blocks the HDMI ports. You are right that the total cost after adding up the cables and USB hub is similar. I...
by ejolson
Fri Dec 15, 2017 3:18 am
Forum: Teaching and learning resources
Topic: Super-cheap Computing Cluster for Learning
Replies: 7
Views: 198

Re: Super-cheap Computing Cluster for Learning

Gavinmc42 wrote:
Fri Dec 15, 2017 3:02 am
Why not use a Cluster hat?
A cluster hat would work just as well except one fewer Zero. If you have one, you could follow along with the main part of this thread--software, configuration and programming--almost no changes.
by ejolson
Fri Dec 15, 2017 2:46 am
Forum: Teaching and learning resources
Topic: Super-cheap Computing Cluster for Learning
Replies: 7
Views: 198

Super-cheap Computing Cluster for Learning

The use of Linux in high performance computing dates back to 1993 when Donald Becker wrote the first network device drivers to create Beowulf clusters of desktop computers. Today almost all supercomputers run Linux in some sort of cluster arrangement. The aim of this thread is to document setting up...
by ejolson
Thu Dec 14, 2017 7:20 pm
Forum: General discussion
Topic: Pi Cluster and OpenCV?
Replies: 1
Views: 73

Re: Pi Cluster and OpenCV?

My question is whether a Pi cluster would increase video streaming performance using OpenCV. I've been experimenting with OpenCV on a Raspberry Pi3 and a Minoru "3D" Webcamera. With the Pi connected to a VGA monitor, I'm able to generate two "320" x "240" videos with minimal lag on either image. Ho...
by ejolson
Thu Dec 14, 2017 5:18 pm
Forum: General discussion
Topic: STICKY: USB boot now working on Pi3
Replies: 476
Views: 120686

Re: STICKY: USB boot now working on Pi3

"just don't do that" isn't an option for a security vulnerability. Yes, it is. That bit would have to explicitly be set. If someone is able to get into your system and do that then they already have full access to it. Good security is not just about having a hard eggshell which is difficult to brea...
by ejolson
Thu Dec 14, 2017 4:53 pm
Forum: General discussion
Topic: Need Help Improving Zero USB Ethernet Gadget setup / HOWTO
Replies: 20
Views: 3785

Re: Need Help Improving Zero USB Ethernet Gadget setup / HOWTO

So I have a zero connected to a B+ through a Sabrient 7 Port USB hub which powers both devices and am looking at the output from netperf . I now have an initramfs that I can place in a boot partition that switches the Zero to gadget mode and mounts the root filesystem over NFS. This required adding...
by ejolson
Thu Dec 14, 2017 6:14 am
Forum: General discussion
Topic: Kernel module for fleshing led on Pi
Replies: 8
Views: 303

Re: Kernel module for fleshing led on Pi

I have rasbain installed on Pi 3. How to create a kernel module that will flesh an LED connected to the Raspberry Pi. I know that I need a compiler tool and I have to write program in one language. Can you tell me, which compiler tool need to install on Pi (c or python). As flashing an LED does not...
by ejolson
Thu Dec 14, 2017 2:36 am
Forum: General discussion
Topic: Raspbian with Read-only Root
Replies: 144
Views: 32934

Re: Raspbian with Read-only Root

Then, result was indicated. :o 02E00578: 61 65 The results have the difference at address " 02E00578:" in the each "DiskImageFile"s. This is a very interesting result. Is that address part of the boot partition? As has been pointed out, the boot partition is mounted rw for convenience. It is possib...
by ejolson
Wed Dec 13, 2017 7:43 pm
Forum: General discussion
Topic: Once again: uSD vs. USB - FS options w. power fail
Replies: 2
Views: 127

Re: Once again: uSD vs. USB - FS options w. power fail

I'm planning to have a USB and a uSD. One for the regular operation and the other as fall back with recovery options to rebuild the other media in case of a corruption. First question is which media to use for which purpose .. any suggestions? In my opinion the uSD card should be mounted read-only ...
by ejolson
Mon Dec 11, 2017 9:08 pm
Forum: General discussion
Topic: Need Help Improving Zero USB Ethernet Gadget setup / HOWTO
Replies: 20
Views: 3785

Re: Need Help Improving Zero USB Ethernet Gadget setup / HOWTO

So I have a zero connected to a B+ through a Sabrient 7 Port USB hub which powers both devices and am looking at the output from netperf . My results are Source Destination Throughput Pi B+ Pi Zero 47.59 Mbps Pi Zero Pi B+ 84.90 Mbps Simultaneous Transfers Pi B+ to Zero Pi Zero to B+ 4.27 Mbps 93.95...
by ejolson
Sat Dec 09, 2017 8:59 pm
Forum: General discussion
Topic: Need Help Improving Zero USB Ethernet Gadget setup / HOWTO
Replies: 20
Views: 3785

Re: Need Help Improving Zero USB Ethernet Gadget setup / HOWTO

Also for what it's worth, I've got a part written python script to generate fixed MAC addresses for g_ether. Give me a few days and I'll put it up on github. I would like to see how you do fixed MAC addresses. It would appear that only locally administered MAC addresses , that is those with the sec...
by ejolson
Fri Dec 08, 2017 5:08 am
Forum: Teaching and learning resources
Topic: Hour of Code week experiences
Replies: 2
Views: 154

Re: Hour of Code week experiences

Three of my Pi3s overheated. This has never happened to me before. Our computer lab is the only air conditioned room in the building and each device has heatsinks installed. Each time when it happened, the mouse stopped responding, then the red led on the bottom of the mouse went out. Next, the tem...
by ejolson
Thu Dec 07, 2017 10:25 pm
Forum: General discussion
Topic: Maximum drives?
Replies: 4
Views: 222

Re: Maximum drives?

So now I'm really confused. Each flash drive is definitely functional. Both hubs are definitely functional. All ports on the pi are definitely functional. Each pi is definitely good, but the pi refuses to run 16 drives at any one time. The really confusing thing is the different number it will load...
by ejolson
Sat Dec 02, 2017 6:57 am
Forum: General programming discussion
Topic: Monitoring CPU/GPU Temp in real time
Replies: 16
Views: 14331

Re: Monitoring CPU/GPU Temp in real time

What's the point? What does collecting those data do for you? So, your RPi is busy, it's running hot, so what? Yes, I am replying to a dated post, but collecting temperature data is critical in my case. I have built a portable wooden box containing a small screen, Pi 3, 500Gb (2TB is possible) powe...
by ejolson
Fri Dec 01, 2017 5:35 am
Forum: General discussion
Topic: SD cards - the Pi's greatest weakness
Replies: 89
Views: 3269

Re: SD cards - the Pi's greatest weakness

Note, 17M sold so far, and the failure rate of SD cards, as seen on the forums, is not huge. So I suggest it is actually quite rare. Compare these 17M sold Pi-s with the number of users of this forum. It is extremely clear that many SD failures are not reported here. That doesn't follow. This is th...
by ejolson
Thu Nov 30, 2017 5:14 am
Forum: General discussion
Topic: Buying More Than One Pi Zero
Replies: 24
Views: 1143

Re: Buying More Than One Pi Zero

I think the message is clear enough. We are all only supposed to get one Pi Zero each. If you live near MicroCenter you can fetch another Zero on the way home from grocery shopping every week, but once in the store be careful to not buy too many other things. As a learning environment for teaching ...
by ejolson
Mon Nov 27, 2017 3:44 pm
Forum: Other languages
Topic: Rust seems to bring some love to Rpi
Replies: 41
Views: 5916

Re: Rust seems to bring some love to Rpi

That's not quite true now is it mifwoo. Yes Rust compiles itself but it generates an intermediate representation of the code, LLVM IR. One then needs LLVM to optimize and generate code from that intermediate representation. LLVM is written in C++. So, if you want to build a complete Rust tool chain...
by ejolson
Mon Nov 27, 2017 4:51 am
Forum: General discussion
Topic: What to do with 4 old sata drives?
Replies: 27
Views: 954

Re: What to do with 4 old sata drives?

I have 4 old internal 80Gb sata drives. If these are 3.5" drives taken from desktop machines, you will need to use powered USB enclosures, in which case there is no problem hooking four to the Pi. If they are 2.5" notebook drives, use adaptors to place them in powered enclosures for 3.5" drives. Pe...
by ejolson
Sun Nov 26, 2017 1:26 am
Forum: General discussion
Topic: Getting more processing power from Raspberry Pi 3
Replies: 13
Views: 799

Re: Getting more processing power from Raspberry Pi 3

A point of minor interest for the particularly suspicious...the OP hasn't posted again in this--or any other--thread. I suspect he or she is reading the responses and just lurking. OpenCV is one of those software libraries that has already been well optimized. However, the speed and non-parallel na...
by ejolson
Sat Nov 25, 2017 3:47 pm
Forum: General discussion
Topic: Getting more processing power from Raspberry Pi 3
Replies: 13
Views: 799

Re: Getting more processing power from Raspberry Pi 3

Heater wrote:
Fri Nov 24, 2017 8:44 pm
But getting cpu frequency from 1200 to 1300 is kind of lost in the noise and hardly noticeable.
Either 1200 or 1300 MHz is about twice better then the 600 MHz that a Pi runs without a heatsink.
by ejolson
Fri Nov 24, 2017 6:57 pm
Forum: General discussion
Topic: Getting more processing power from Raspberry Pi 3
Replies: 13
Views: 799

Re: Getting more processing power from Raspberry Pi 3

I was wondering if there was a way to get more processing power from the Raspberry Pi 3. I would like to use it to code in python and OpenCV, which I am aware requires a lot of power. Would a Pi cluster possibly increase the processing power, or is overclocking the only way? Thanks. The usual way t...
by ejolson
Wed Nov 22, 2017 11:12 pm
Forum: General discussion
Topic: Cannot install autotools on fresh latest Raspbian Strecth Lite, why?
Replies: 5
Views: 233

Re: Cannot install autotools on fresh latest Raspbian Strecth Lite, why?

HermannSW wrote:
Wed Nov 22, 2017 9:48 am
What am I missing?
Did you remember to type

apt-get update

before the install?

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