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by jahboater
Fri Mar 04, 2016 5:06 pm
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 17431

Re: Pi3 speed compared to Pi2

Well I made it 3.6 seconds for 664579 primes.
My pi3 is not over clocked.
Its running Jessie Lite.
by jahboater
Fri Mar 04, 2016 3:43 pm
Forum: Beginners
Topic: Just cannt seem to get an OS to run
Replies: 18
Views: 1706

Re: Just cannt seem to get an OS to run

Jahboater, I am not sure where you think I was going wrong as the instructions state that you need to format the SD card and I see that the image has the partitions all set up which can then be seen after the dd has finished. The RPi just did not want to boot r talk to the SD card. Regards Matt Its...
by jahboater
Fri Mar 04, 2016 2:03 pm
Forum: Beginners
Topic: Just cannt seem to get an OS to run
Replies: 18
Views: 1706

Re: Just cannt seem to get an OS to run

To save time in the future, you NEVER need to format the card first before installing Rasbian from a ".img" file. The image file has the partition table and the two partitions already set up. This is not a typical Linux "install" as such. It is a simple copy of a complete working system (I have neve...
by jahboater
Fri Mar 04, 2016 1:42 pm
Forum: General discussion
Topic: Pi 3 power supply & USB cable
Replies: 71
Views: 331068

Re: Pi 3 power supply & USB cable

http://thepihut.com/collections/raspber ... wer-supply
Its a great power supply 5.1v 2.5A and only £6.
It comes with a decent cable attached and the correct micro-usb plug of course.
by jahboater
Fri Mar 04, 2016 1:34 pm
Forum: General discussion
Topic: The Raspberry Pi 3 Model B Q&A thread
Replies: 457
Views: 215414

Re: The Raspberry Pi 3 Model B Q&A thread

The LEDs (and others) seem now to hang off a GPIO expander - the WiFi/BT combo chip gobbled up so many there weren't enough left. No idea about the details yet. From what I have seen, I am led to believe that the LED's are now controlled through a Mailbox, the additional class for the virtual GPIO ...
by jahboater
Fri Mar 04, 2016 1:19 pm
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 17431

Re: Pi3 speed compared to Pi2

On the Pi3 I found no measurable difference in performance between "-mcpu=cortex-a7" and "-mcpu=cortex-a53" options. The executable was a few bytes smaller for the a53 version.
by jahboater
Thu Mar 03, 2016 8:29 pm
Forum: General discussion
Topic: The Raspberry Pi 3 Model B Q&A thread
Replies: 457
Views: 215414

Re: The Raspberry Pi 3 Model B Q&A thread

asandford wrote:Not a showstopper, but poweroff command leaves the green LED on.
I think there is something wrong with the on-board leds.
In "/sys/class/leds", there is only led0, there should be led1 as well which was the red power led.
How do you turn off the red led?
by jahboater
Thu Mar 03, 2016 2:18 pm
Forum: Raspbian
Topic: Raspbian Jessie (64bit) for RPi3?
Replies: 145
Views: 135221

Re: Raspbian Jessie (64bit) for RPi3?

The quoted article mentioned 15-30%, I have seen somewhere 25-30% improvement (ignoring the extra address space that usually will not be used). Maybe that's just the 31 64-bit registers compared to 15 32-bit registers. According to ARM a 64-bit kernel can run 32-bit programs, but not vice versa. So ...
by jahboater
Thu Mar 03, 2016 10:49 am
Forum: General discussion
Topic: RPi 3 SoC at nearly 100 °C, reporting 80 °C
Replies: 238
Views: 99931

Re: RPi 3 SoC at nearly 100 °C, reporting 80 °C

I like this one for £1, easy to peel off the thermal backing tape, sticks firmly, and appears very effective. http://thepihut.com/collections/raspberry-pi-accessories/products/raspberry-pi-heatsink Nice. That's very similar to the one on my Pi2B that drops load temps by around 10°C in a ventilated ...
by jahboater
Thu Mar 03, 2016 10:33 am
Forum: General discussion
Topic: RPi 3 SoC at nearly 100 °C, reporting 80 °C
Replies: 238
Views: 99931

Re: RPi 3 SoC at nearly 100 °C, reporting 80 °C

I like this one for £1, easy to peel off the thermal backing tape, sticks firmly, and appears very effective. http://thepihut.com/collections/raspberry-pi-accessories/products/raspberry-pi-heatsink The best position, if you have a choice, is vertical/vertical, that is, the board held upright and the...
by jahboater
Thu Mar 03, 2016 9:04 am
Forum: Troubleshooting
Topic: RPi 3 - Very poor wifi performance
Replies: 77
Views: 121257

Re: RPi 3 - Very poor wifi performance

rurwin wrote:The Pi3 does not do 5GHz, although the power levels for it are listed in syslog/dmesg. That's not a bug; that's a limitation of the hardware.
Just for interest, the on-board antenna does support 5GHz
by jahboater
Thu Mar 03, 2016 9:02 am
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 17431

Re: Pi3 speed compared to Pi2

Pithagoros wrote: I'm also a bit disappointed that I can't lower the clock speed down to 1GHz.
Why can't you? Are you saying this doesn't work in config.txt?

Code: Select all

arm_freq=1000
by jahboater
Mon Feb 29, 2016 8:53 pm
Forum: Off topic discussion
Topic: Pine64+ a good deal?
Replies: 191
Views: 53821

Re: Pine64+ a good deal?

Do you mean something like this? int count = 0; *count = 42; Which produces the error "error: invalid type argument of unary '*' (have 'int')". So we try *(int*)count = 42; which produces "warning: cast to pointer from integer of different size" (its 64-bits). So we then try int64_t count = 0; *(int...
by jahboater
Mon Feb 29, 2016 7:20 pm
Forum: Off topic discussion
Topic: Pine64+ a good deal?
Replies: 191
Views: 53821

Re: Pine64+ a good deal?

C makes life very unpleasant but at least tries to do something close to reasonable for integer/float issues. Of course it completely screws us for signed unsigned stuff, though given that they forgot to make pointers something separate to numbers I guess it had to be that way. I'm not sure I follo...
by jahboater
Mon Feb 29, 2016 3:25 pm
Forum: General discussion
Topic: The Raspberry Pi 3 Model B Q&A thread
Replies: 457
Views: 215414

Re: The Raspberry Pi 3 Model B Q&A thread

dom wrote:
jamesh wrote:Do you need any specific compile flags to get that extra NEON performance? I'll try a build of x264 to see what sort of encode speed I can get.
No, NEON instructions are just quicker. No compiler flags need changing.
The non-neon stuff may benefit from -mcpu=cortex-a53 instead of cortex-a7
by jahboater
Sun Feb 28, 2016 7:03 pm
Forum: C/C++
Topic: Learning C / C++
Replies: 38
Views: 5589

Re: Learning C / C++

I would like to learn to program my Pi with C / C++. Is there a list of the included Libraries and what they do / contain? A pdf would be very nice. How can I program if i don't know what commands are available? Thanks Good for you, the Pi is a great platform for learning. Because there is a vast n...
by jahboater
Sun Feb 28, 2016 6:43 pm
Forum: Beginners
Topic: ./ProgramName results in "Permission denied"
Replies: 14
Views: 1968

Re: ./ProgramName results in "Permission denied"

Most compilers will compile to object then you have to use the linker. Which modern compiler does that??? Had you just done: gcc -o hello hello.c then ./hello it would have worked fine. By default GCC does the link for you. As previously mentioned use gcc -c (-c means compile only) if for some obsc...
by jahboater
Sun Feb 28, 2016 9:53 am
Forum: Camera board
Topic: Issues with Pi Cam and Pi Display? (solved)
Replies: 38
Views: 40760

Re: Issues with Pi Cam and Pi Display? (solved)

Add it to a file called "/boot/config.txt".
You need privilege to alter this file, so you will need to use "sudo".

Code: Select all

sudo nano /boot/config.txt
by jahboater
Sat Feb 27, 2016 5:30 pm
Forum: Advanced users
Topic: Overclocking
Replies: 1125
Views: 605400

Re: Overclocking

Read the past couple of pages of this thread, Jimmy. Almost any Pi2B RAM will be completely stable at 500MHz with some achieving complete stability at 600MHz with the appropriate updates and config.txt settings. Definitely. See the changes to the firmware by dom, some time ago in this thread which ...
by jahboater
Sat Feb 27, 2016 4:34 pm
Forum: General discussion
Topic: Achievable kernel boot time with pi zero?
Replies: 9
Views: 2106

Re: Achievable kernel boot time with pi zero?

My Pi Zero (stock speed):-
pi@raspberrypi:~ $ systemd-analyze
Startup finished in 2.377s (kernel) + 17.066s (userspace) = 19.443s
Not far off two seconds.
by jahboater
Sat Feb 27, 2016 3:15 pm
Forum: Beginners
Topic: Need help on learning how to program.
Replies: 8
Views: 1130

Re: Need help on learning how to program.

Fortunately on the Pi you have a number of languages already installed or quickly available (and free!). Python, C, and C++ will work straight away. My choice would be C and Python but not both at the same time! More than half the worlds software is written in C, including the Rasbian OS and much of...
by jahboater
Fri Feb 26, 2016 9:09 am
Forum: Beginners
Topic: Some noob questions.
Replies: 8
Views: 1209

Re: Some noob questions.

Also what is the functional difference between ARM and x86 architecture? i am If you write code in a high level language such as C, C++ or Python, you will not normally see much functional difference at all (ignoring GPIO stuff). Python being interpreted will simply run directly on either architect...
by jahboater
Fri Feb 26, 2016 8:36 am
Forum: General discussion
Topic: How to connect a 10v dc fan to the raspberry pi 2
Replies: 11
Views: 1953

Re: How to connect a 10v dc fan to the raspberry pi 2

I think far too many people vastly underestimate the amount of heat the GPU kicks out when it's overclocked and being pushed hard. The heat generated by all 4 CPU cores of a Pi2B being pushed hard is very small by comparison. Yes, most of the area of the chip is taken up by the GPU. You are lucky y...
by jahboater
Thu Feb 25, 2016 8:31 am
Forum: General discussion
Topic: Sleeping RPI to reduce power?
Replies: 8
Views: 4913

Re: Sleeping RPI to reduce power?

It is not like x86 which has a variety of sleep states that can be returned from very rapidly. Most Pi users run some form of Linux which has a frequency scaling governor. The minimum and maximum frequencies are set in the config file in /boot. You could set the minimum (or both) to 100Mhz, or less,...
by jahboater
Wed Feb 24, 2016 12:29 pm
Forum: General programming discussion
Topic: Programming Pi on a laptop
Replies: 2
Views: 865

Re: Programming Pi on a laptop

You may not have spotted it, but both versions of Python are included as standard on the Pi. You can ssh in from the laptop.

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