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by ejolson
Sun Sep 20, 2020 10:53 pm
Forum: Troubleshooting
Topic: I may have fried my Pi...
Replies: 8
Views: 127

Re: I may have fried my Pi...

MarkthePig wrote:
Sun Sep 20, 2020 10:16 pm
Alright, I would just like to clarify this again, the robot itself is perfectly functional and was working for quite a while.
Removing the yellow jumper is not about the robot being functional, but to prevent the relay board from burning out the Pi.
by ejolson
Sun Sep 20, 2020 7:04 am
Forum: Beginners
Topic: Remote logon to Raspberry Pi
Replies: 3
Views: 156

Re: Remote logon to Raspberry Pi

In the past to remotely logon to my Raspberry Pi from a Windows PC, I first downloaded XRDP on the Pi and then used the "Remote Desktop Connection" app on the PC to create the connection. While looking at the Raspberry Pi Manual, I found out that you can use VNC to achieve the same goal. Since VNC ...
by ejolson
Sat Sep 19, 2020 3:59 am
Forum: Networking and servers
Topic: wireguard on raspian buster
Replies: 36
Views: 2191

Re: wireguard on raspian buster

mox386 wrote:
Fri Sep 18, 2020 8:20 pm
I eventually figured out that under [Peer] i was putting the public key of the client when it should have been the public key of the server. This corrected the problem.
Woohoo! Glad you got it sorted!
by ejolson
Fri Sep 18, 2020 4:31 pm
Forum: General discussion
Topic: Loosing Ethernet and WiFi connection
Replies: 3
Views: 118

Re: Loosing Ethernet and WiFi connection

Thanks, I never thought of that! Another idea is to flash a new SD card with the latest Raspberry Pi OS image and check if that makes a difference. While I understand you have a custom SD card image which was working well, trying the latest official version should help diagnose the problem. Note si...
by ejolson
Fri Sep 18, 2020 12:38 pm
Forum: General discussion
Topic: Pi4 Sysbench results
Replies: 35
Views: 10086

Re: Pi4 Sysbench results

Welcome to the surprising world of the Raspberry Pi 4B desktop replacement! And its trivially easy to overclock the Pi4 to 2.1GHz or more ... All for $35 and we conclude that cause this number is higher than a number a number given from a entry level amd SoC (is it.. I honestly didn't check it) we'...
by ejolson
Fri Sep 18, 2020 2:11 am
Forum: General discussion
Topic: Pi4 Sysbench results
Replies: 35
Views: 10086

Re: Pi4 Sysbench results

After polishing the code I'll provide a link. The code is available at http://fractal.math.unr.edu/~ejolson/pi/pichart/gpubench-current.tgz Here is another run $ ./gpubench gpubench version 2 (compiled for CUDA ARCH=sm_60) CUDA Device Tesla P100-PCIE-12GB: Compute Capability Version 6.0 Multiproces...
by ejolson
Thu Sep 17, 2020 9:18 pm
Forum: General discussion
Topic: Pi4 Sysbench results
Replies: 35
Views: 10086

Re: Pi4 Sysbench results

By the way, how fast is sysbench on the Pi 4B with the overclock you mentioned earlier? Since the output of the different versions can be difficult to compare, it would help to post the full output, if you run the test. Here we are. That's a 3249.23/2329.02 = 1.4 times performance boost or 40 perce...
by ejolson
Thu Sep 17, 2020 4:38 pm
Forum: General discussion
Topic: Why is Raspberry Pi OS based on debian?
Replies: 52
Views: 2177

Re: Why is Raspberry Pi OS based on debian?

Luckily we have Debian. :) I think Debian even includes systemd for the last two releases. Does systemd work on the Redox kernel? Rather than chasing after the hardware with a set of rusty device drivers, it might be more helpful to rewrite the Linux init system in Rust. Such churn is especially im...
by ejolson
Thu Sep 17, 2020 3:24 pm
Forum: General discussion
Topic: Pi4 Sysbench results
Replies: 35
Views: 10086

Re: Pi4 Sysbench results

Hence, there must be a little detail that results in this performance difference. It seems the Cortex-A72 is very fast at performing 64-bit integer division. 64-bit integer division on ARM and aarch64 are simplistic compared to the Intel one. Intel's division takes a double width (128-bit) number a...
by ejolson
Thu Sep 17, 2020 2:50 pm
Forum: General discussion
Topic: Pi4 Sysbench results
Replies: 35
Views: 10086

Re: Pi4 Sysbench results

Hence, there must be a little detail that results in this performance difference. It seems the Cortex-A72 is very fast at performing 64-bit integer division. In the ARM versus Intel comparison, the tables would be turned for floating-point, unless you happen to be using the A64FX ARM processor join...
by ejolson
Thu Sep 17, 2020 2:22 pm
Forum: General discussion
Topic: Why is Raspberry Pi OS based on debian?
Replies: 52
Views: 2177

Re: Why is Raspberry Pi OS based on debian?

Mind you - things are slowing down. The differences in ubuntu versions a decade ago left us breathless in anticipation. I never noticed such excitement around Ubuntu. All I noticed years ago was that the Ubuntu machines in our office were constantly getting into a mess. Replaced them all with Debia...
by ejolson
Thu Sep 17, 2020 2:56 am
Forum: General discussion
Topic: Why is Raspberry Pi OS based on debian?
Replies: 52
Views: 2177

Re: Why is Raspberry Pi OS based on debian?

Usually when people say ARM is "limiting" they mean it won't run their Windows x86 binaries. Or even their Linux x86 binaries, Here is an LLVM based open source compiler that doesn't run on ARM but which I would definitely like to have working on my Raspberry Pi. http://cilk.mit.edu/ After Intel di...
by ejolson
Wed Sep 16, 2020 5:00 pm
Forum: General discussion
Topic: Pi4 Sysbench results
Replies: 35
Views: 10086

Re: Pi4 Sysbench results

Here are my results from a newish pre-Ryzen dual-core AMD A6-9225 based notebook: $ grep "model name" /proc/cpuinfo model name : AMD A6-9225 RADEON R4, 5 COMPUTE CORES 2C+3G model name : AMD A6-9225 RADEON R4, 5 COMPUTE CORES 2C+3G $ sysbench --threads=2 --cpu-max-prime=20000 --validate cpu run sysb...
by ejolson
Wed Sep 16, 2020 4:31 pm
Forum: General discussion
Topic: Pi4 Sysbench results
Replies: 35
Views: 10086

Re: Pi4 Sysbench results

Unfortunately, you made need to be more careful to use the exact same version of sysbench on each system in order to compare the systems. The example in the post https://www.raspberrypi.org/forums/viewtopic.php?p=1711176#p1711176 indicates the 64-bit Pi 4B achieves 5920.95 events per second with a p...
by ejolson
Wed Sep 16, 2020 3:09 pm
Forum: Other programming languages
Topic: Julia the Language
Replies: 3
Views: 246

Re: Julia the Language

I am puzzled of why multiplying a by its transpose is twice faster than multiplying A by itself. (your figures seem reliable). Due to different memory access patterns (rows with rows rather than rows with columns) multiplying A'*A results in about half the cache pressure as A*A. The data locality a...
by ejolson
Tue Sep 15, 2020 11:55 pm
Forum: Troubleshooting
Topic: Pi Zero OTG
Replies: 29
Views: 698

Re: Pi Zero OTG

thagrol wrote:
Tue Sep 15, 2020 11:22 pm
RichShumaker wrote:
Tue Sep 15, 2020 4:46 pm
Edit #2 - I will be hooking up a keyboard later to check more of the configurations on the PI.
Do you mean hooking a keyboard up to the zero?
Rather than GPIO would a Bluetooth keyboard work?
by ejolson
Tue Sep 15, 2020 4:03 pm
Forum: Troubleshooting
Topic: Pi Zero OTG
Replies: 29
Views: 698

Re: Pi Zero OTG

Okay I am deep in this rabbit hole. In an earlier post to this thread However, that can also be an advantage, because the thread describes how I solved problems that may not have happened if someone knowledgeable about Windows were to set things up. https://www.raspberrypi.org/forums/viewtopic.php?...
by ejolson
Tue Sep 15, 2020 3:38 pm
Forum: Off topic discussion
Topic: ARM sold to Nvidia
Replies: 85
Views: 3407

Re: ARM sold to Nvidia

"What do you mean the laptop uses a lot of power it only has a 180W power brick or battery." Seem you are messing processing power and electrical power. BTW: 180w (a laptop, with GPIO hidden inside tiny M2 slots) > 25W (a jetson nano, but Heater thinx it is overkill) The Pi 4B is shipped with a 15W...
by ejolson
Tue Sep 15, 2020 1:26 pm
Forum: Troubleshooting
Topic: Pi Zero OTG
Replies: 29
Views: 698

Re: Pi Zero OTG

The picture has the OTG adapter in the 2nd USB Connector and then a standard USB cable to get it to the PC As already mentioned, you do not want an OTG adapter, but the more common USB cable with a micro B at one end and an A connector at the other. From what I understand, OTG is a way to connect k...
by ejolson
Tue Sep 15, 2020 3:23 am
Forum: General discussion
Topic: A Pi Pie Chart
Replies: 173
Views: 23527

Re: A Pi Pie Chart

The good news is that it did not take that much longer for zeppo to finish the build of gcc with memory running at 333 MHz than for gummo to do the same at 786 MHz. Everything seemed quite clear last night. There was even a moment of magic as the full moon rose over the mountains in the distance. T...
by ejolson
Mon Sep 14, 2020 5:38 pm
Forum: Off topic discussion
Topic: Happy 1.6 Gigaseconds Day!
Replies: 36
Views: 1388

Re: Happy 1.6 Gigaseconds Day!

I'm all for a Programmer's Day but I would be happier if it fell on Alan Turing's birthday or perhaps Ada Lovelace's. Something of substance in the world of programming, not numerology trivia. What about October 4? https://en.m.wikipedia.org/wiki/John_Vincent_Atanasoff This has the advantage of arr...
by ejolson
Mon Sep 14, 2020 3:25 pm
Forum: Off topic discussion
Topic: Happy 1.6 Gigaseconds Day!
Replies: 36
Views: 1388

Re: Happy 1.6 Gigaseconds Day!

Today I find that despite all the publicity and hyping of 1.6 Gigaseconds Day and world wide celebration, nobody noticed it was also "Day Of The Programmer": https://en.m.wikipedia.org/wiki/Day_of_the_Programmer Possibly the most stupid national day I have ever heard of. It seems you are upset that...
by ejolson
Mon Sep 14, 2020 2:49 pm
Forum: General discussion
Topic: Why is Raspberry Pi OS based on debian?
Replies: 52
Views: 2177

Re: Why is Raspberry Pi OS based on debian?

Where do people find such slow x86 machines? If w$10 is a reference to the price, that could explain why it's slow. The price explanation seems a bit confusing as https://en.m.wikipedia.org/wiki/Dollar does not list any countries beginning with the letter w that use dollars. Maybe the w is for West...
by ejolson
Mon Sep 14, 2020 12:23 am
Forum: Troubleshooting
Topic: Pi Zero OTG
Replies: 29
Views: 698

Re: Pi Zero OTG

Hey everyone. I am looking for some guidance on getting the Pi Zero OTG working on Windows 10. A couple years ago I made a thread that described how to boot a Pi Zero without an SD card and mount the root filesystem from a Windows share. Aside from a few problems getting the built-in DHCP server in...
by ejolson
Sun Sep 13, 2020 10:54 pm
Forum: Other programming languages
Topic: Julia the Language
Replies: 3
Views: 246

Julia the Language

This semester I've been teaching two courses using Zoom. One class covers linear algebra and the other numerical methods. Since Julia is free, easy to use, performs well and runs on Windows, Macintosh and Raspberry Pi, I've been using it in both courses. For linear algebra the book http://vmls-book....

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