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by jahboater
Sun Sep 22, 2019 8:41 am
Forum: Advanced users
Topic: RaspberryPi 4: heatsink or fan
Replies: 83
Views: 27965

Re: RaspberryPi 4: heatsink or fan

From my experience of using my Raspberry Pi 3 B+ as a Desktop PC, the only thing that would completely eliminate throttling I suggest you try a Pi4 (which is also the topic of this thread). The Pi3B+ was pushing the limits of the old 40nm node size. The new Pi4 has had a die shrink to 28nm and so r...
by jahboater
Sun Sep 22, 2019 7:24 am
Forum: General discussion
Topic: Ideal SD Card Size for Raspberry PI 4
Replies: 3
Views: 249

Re: Ideal SD Card Size for Raspberry PI 4

32GB cards are now cheaper than 16GB cards .... https://www.amazon.co.uk/SanDisk-microSDHC-Memory-Adapter-Performance/dp/B073S8LQSL/ref=sr_1_3?crid=2BO877DW9VQRM&keywords=sandisk+ultra+32+gb+microsdhc+memory+card+%2B+sd+adapter+with+a1+app&qid=1568927532&sprefix=sandisk+a1+app%2Caps%2C162&sr=8-3 If ...
by jahboater
Sat Sep 21, 2019 6:00 pm
Forum: C/C++
Topic: Raspberry Pi project in c++ build on Windows
Replies: 4
Views: 283

Re: Raspberry Pi project in c++ build on Windows

I am building an C++ application for RPi but the problem is tha compiling takes too long and it is slowing me down. I am using a RPi 1. My RPi 2 is reserved for another project. The simplest answer perhaps is just to look at getting the new Pi4 model. Compiling is fast on the Pi4 for any sized prog...
by jahboater
Sat Sep 21, 2019 7:31 am
Forum: Advanced users
Topic: RaspberryPi 4: heatsink or fan
Replies: 83
Views: 27965

Re: RaspberryPi 4: heatsink or fan

To my way of thinking, why run it any hotter than you have too? I'm a lot happier knowing my temps stay at 40c instead of climbing to 80c. Cooler is better Yes definitely, cooler is better - it might last for 35 years instead of 30 years :) Mine idles in the upper 40C's. I just did a largish compil...
by jahboater
Fri Sep 20, 2019 8:26 pm
Forum: Advanced users
Topic: RaspberryPi 4: heatsink or fan
Replies: 83
Views: 27965

Re: RaspberryPi 4: heatsink or fan

If you can live with it naked, and ambient temps are not too high, mounting it vertically may work. @Jamesh reports good results running that way and I suspect he logs lots of hours with a Pi. It does work. My Pi4 will not throttle under any load, even stress tests like cpuburn. No fan is required ...
by jahboater
Thu Sep 19, 2019 9:16 pm
Forum: General discussion
Topic: ARMv8 32-bit mode and 64-bit division
Replies: 11
Views: 685

Re: ARMv8 32-bit mode and 64-bit division

Are 32GB cards now recommended or have I done something strange to make Raspbian take more storage than in should? I don't know, cards are so cheap now that I only use 64GB or 128GB. and 32GB cards are now cheaper than 16GB cards !!!!!! https://www.amazon.co.uk/SanDisk-microSDHC-Memory-Adapter-Perf...
by jahboater
Thu Sep 19, 2019 10:45 am
Forum: General discussion
Topic: ARMv8 32-bit mode and 64-bit division
Replies: 11
Views: 685

Re: ARMv8 32-bit mode and 64-bit division

Are you sure your original reported Pi 3B+ run times were accurate? Since Raspbian Buster includes gcc-4.9, gcc-5.5, gcc-6.5 and gcc-7.3 I installed and tried them all. Using variations of -mcpu=cortex-a53 -mfpu=neon-fp-armv8 -mfloat-abi=hard -mneon-for-64bits all run times are greater than 30 seco...
by jahboater
Thu Sep 19, 2019 9:57 am
Forum: Other programming languages
Topic: ScriptBasic
Replies: 1398
Views: 60673

Re: ScriptBasic

If I can't find a stable 64 bit OS, will the standard Raspian 32 OS for the RPi 4B access all 4 GB of system memory? Yes, 32-bit Raspbian can use all of the 4GB memory. It uses a special LPAE kernel. pi@pi4:~ $ free total used free shared buff/cache available Mem: 3.8Gi 334Mi 2.4Gi 97Mi 1.0Gi 3.2Gi...
by jahboater
Wed Sep 18, 2019 12:40 pm
Forum: Beginners
Topic: Can you turn off the pi 4 pwr and Ethernet lights?
Replies: 2
Views: 123

Re: Can you turn off the pi 4 pwr and Ethernet lights?

I turn the power led off by adding this to /etc/crontab

Code: Select all

@reboot root echo 0 > /sys/class/leds/led1/brightness
works on the Pi3 and the Pi4.
There must be a better way .....
by jahboater
Wed Sep 18, 2019 12:32 pm
Forum: Networking and servers
Topic: creat UDP connection
Replies: 6
Views: 210

Re: creat UDP connection

Heater wrote:
Wed Sep 18, 2019 12:31 pm
There are a million ways to do what you want.
Indeed!
Heater wrote:
Wed Sep 18, 2019 12:31 pm
Firstly, what programming language would you like to use?
The OP said Python on both sides.
by jahboater
Wed Sep 18, 2019 12:19 pm
Forum: Networking and servers
Topic: creat UDP connection
Replies: 6
Views: 210

Re: creat UDP connection

i want to create a UDP connection between two Raspberry pi, using python in both sides what i want to do. You cannot create a UDP "connection", that's not how it works. You probably want TCP (a Connection Oriented Transport Service). UDP is individual, unrelated, datagrams. Furthermore, there is no...
by jahboater
Mon Sep 16, 2019 6:07 pm
Forum: General discussion
Topic: ARMv8 32-bit mode and 64-bit division
Replies: 11
Views: 685

Re: ARMv8 32-bit mode and 64-bit division

From this post I was expecting 64-bit divisions done in 32-bit mode on the Pi 4B to be on par with 64-bit mode. What am I doing wrong? 32 bit mode has udiv and sdiv instructions from ARMv7 onwards, but they only work with 32 bit operands. In 32-bit mode, 64 bit division is done by a call to a libra...
by jahboater
Mon Sep 16, 2019 9:32 am
Forum: General discussion
Topic: free some RAM
Replies: 14
Views: 439

Re: free some RAM

david_1234 wrote:
Mon Sep 16, 2019 9:14 am
I'm waitng for PI4 to arrive - it will be next week ~

just to be sure
this is how I increase the SWAP ?

Code: Select all

sudo nano /etc/dphys-swapfile
change it to 1024?
Yes

Code: Select all

sudo sed -i 's/^CONF_SWAPSIZE=[0-9]*$/CONF_SWAPSIZE=1024/' /etc/dphys-swapfile
sudo /etc/init.d/dphys-swapfile restart
by jahboater
Wed Sep 11, 2019 10:35 am
Forum: C/C++
Topic: GCC frustrations
Replies: 4
Views: 572

Re: GCC frustrations

One program doesn't work because the log ( ) function generates errors about libraries that don't exist, For that, you need the math library which is included by adding -lm to the gcc command line. gcc hello.c -o hello -lm If you type: man log it gives you all the details. You will need to include ...
by jahboater
Mon Aug 19, 2019 12:30 pm
Forum: C/C++
Topic: Looking for advice with C++ learning
Replies: 29
Views: 5947

Re: Looking for advice with C++ learning

needs to become something like [64 bit signed integer] a [64 bit signed operator] = [64 bit signed integer] b [ignoring overflow 64 bit signed integer operator] + [64 bit signed integer] b; I can't see that catching on ! PeterO Did you mean "checking overflow"? I think Heater wants all integer arit...
by jahboater
Sun Aug 18, 2019 10:33 pm
Forum: C/C++
Topic: Looking for advice with C++ learning
Replies: 29
Views: 5947

Re: Looking for advice with C++ learning

It's not clear to me that parsing the comments and matching it up to the code is any more simple than putting something into the syntax itself. Yes true, for a static checking program like lint. For the compiler however, a comment is just a comment, much easier. Though yes, its a different matter r...
by jahboater
Sun Aug 18, 2019 10:15 pm
Forum: C/C++
Topic: Looking for advice with C++ learning
Replies: 29
Views: 5947

Re: Looking for advice with C++ learning

The code I presented above has no complaints at all when compiled on my Pi: No, as I said case 1: case 2: case 4: case 4: will not elicit a complaint because there is no code. Stuff like this will: { case '0'...'7': --p; base = 8; case 'x': start = p; and this does read quite nicely IMHO { case '0'...
by jahboater
Sun Aug 18, 2019 9:56 pm
Forum: C/C++
Topic: Looking for advice with C++ learning
Replies: 29
Views: 5947

Re: Looking for advice with C++ learning

// OOPS! Missing case falls through Works on my Pi! try.c: In function ‘parse_escape’: try.c:2313:9: error: this statement may fall through [-Werror=implicit-fallthrough=] 2313 | base = 8; | ~~~~~^~~ compilation terminated due to -Wfatal-errors. I use /*fallthrough*/ when a break is deliberately mi...
by jahboater
Sun Aug 18, 2019 6:54 pm
Forum: C/C++
Topic: Looking for advice with C++ learning
Replies: 29
Views: 5947

Re: Looking for advice with C++ learning

Some of the issues above are caught by the compiler already. -Wall and -Wextra are really helpful. I suggest at least:- -Wall -Wextra -Wconversion -Wuninitialized -Wcast-qual -Wcast-align -Wundef -Werror -Wfatal-errors The last two options mean that you cannot finish the compilation until the code ...
by jahboater
Sun Aug 18, 2019 12:18 pm
Forum: General discussion
Topic: pi 4 sd card
Replies: 2
Views: 260

Re: pi 4 sd card

Yes.
And using a new card means that all your stuff remains on the old card which you may access from your Pi running the new buster.
by jahboater
Sun Aug 18, 2019 12:13 pm
Forum: Advanced users
Topic: Avoiding circular symlinks in an install script
Replies: 18
Views: 1281

Re: Avoiding circular symlinks in an install script

This is actually a command called "test"

To see the details of the options, including -L, try

man test
by jahboater
Sun Aug 18, 2019 12:05 pm
Forum: Troubleshooting
Topic: Raspberry Pi 4 temperature
Replies: 558
Views: 161506

Re: Raspberry Pi 4 temperature

The heatsinks wont help (much) inside that poorly ventilated case.

Try moving the Pi outside of the case temporarily and monitor the temps.
I find the temp is a little lower if the Pi board is on edge and the heat sink fins are aligned vertically.
by jahboater
Sun Aug 18, 2019 10:37 am
Forum: Beginners
Topic: microSD card size?
Replies: 17
Views: 830

Re: microSD card size?

card to boot the Raspbian Operating System. The reply from @DrGeoff looks succinct and accurate to me: Only a small partition (about 250 Mbyte) on the card will be FAT and Linux will not normally store your user files there. The remainder of the card will be a Linux file system which can store file...
by jahboater
Sun Aug 18, 2019 8:36 am
Forum: C/C++
Topic: Looking for advice with C++ learning
Replies: 29
Views: 5947

Re: Looking for advice with C++ learning

If you want to get into C/C++ be ready to spend a lot of time checking every line of your code carefully for these and and a host of other possible slip ups. And finding the cause of obscure bugs that you create as a result. Get familiar with tools like valgrind and the "sanitizer" tools that come ...
by jahboater
Tue Aug 13, 2019 2:19 pm
Forum: General discussion
Topic: Why moving to 64bit?
Replies: 259
Views: 20523

Re: Why moving to 64bit?

You may want to add:

-mfpu=neon-fp-armv8

or it will use the old VFP instead (even with -march=native)

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