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by jahboater
Fri Apr 20, 2018 8:43 am
Forum: General discussion
Topic: Heatsink required for Raspberry Pi 3 B+?
Replies: 43
Views: 1738

Re: Heatsink required for Raspberry Pi 3 B+?

If you have not done so already, plugging things into the sockets should draw heat away from the ground plane while the board is in a case. An HDMI lead with a heavy metal plug for a start.
by jahboater
Fri Apr 20, 2018 8:38 am
Forum: Troubleshooting
Topic: Raspberry Pi 3 B+ lockups
Replies: 202
Views: 6976

Re: Raspberry Pi 3 B+ lockups

A bit of a "hit" for those of use with machines that are stable at 500Mhz :( You can always add to /boot/config.txt sdram_freq=500 The schmoo setting is then automatically added. Mine seems to be completely stable at 500Mhz after various stress tests. But I do have a 15mm cube heatsink on the memor...
by jahboater
Fri Apr 20, 2018 7:27 am
Forum: Other languages
Topic: A Extended Pascal Implementation : CONCEPT.
Replies: 22
Views: 741

Re: A Extended Pascal Implementation : CONCEPT.

DavidS wrote:
Thu Apr 19, 2018 2:11 am
As far as C is concerned, I am a strong believer that compilers should be written in the language they host,
Yes, its a good test for the new language. If its not capable of implementing an efficient compiler I probably would not want to use it for real world large scale coding.
by jahboater
Thu Apr 19, 2018 9:01 pm
Forum: General discussion
Topic: display current cpu frequency
Replies: 3
Views: 114

Re: display current cpu frequency

so I tried "vcgencmd measure_clock arm" the result is: "frequency(45)=1200126000" what does this mean ?? No its correct, its the frequency in Hz. Divide by 1 million to get the cpu clock speed in MHz There is also:- cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq and for other info:- vcge...
by jahboater
Wed Apr 18, 2018 5:34 pm
Forum: Troubleshooting
Topic: RPi 3B+ Ethernet not working
Replies: 5
Views: 165

Re: RPi 3B+ Ethernet not working

jimb137 wrote:
Wed Apr 18, 2018 5:15 pm
A few things missing (can't find lshw or nmap).
These are both available with:-
sudo apt update
sudo apt install nmap lshw
by jahboater
Wed Apr 18, 2018 6:29 am
Forum: Beginners
Topic: dd of SD Card where Rasbpian is up and running...
Replies: 8
Views: 179

Re: dd of SD Card where Rasbpian is up and running...

Does that program copy entire card like DD? Not exactly like dd but the result is very similar. I used it to copy SD card to SSD to boot over USB and it worked fine. It re-created partitions on SSD so it would fill whole space and asked me if partitions/filesystems should have same UUID as on SD ca...
by jahboater
Tue Apr 17, 2018 5:56 pm
Forum: Networking and servers
Topic: RPI3 and virus spreading.
Replies: 2
Views: 151

Re: RPI3 and virus spreading.

+1 When I had various Windows machines I was constantly paying for/managing/updating etc the anti-malware / anti-virus software that really was needed. Over time I migrated all my computers to Linux - and I have not given a minutes thought to anti-virus / anti malware software since! And since the P...
by jahboater
Tue Apr 17, 2018 5:10 pm
Forum: Raspbian
Topic: SWI Kernel Calls broke?
Replies: 8
Views: 800

Re: SWI Kernel Calls broke?

I don't understand what system calls (as in "svc 0") have to do with dynamic linking (which is linking libraries at runtime rather than at build time, or using dlopen/dlsym etc). The mechanism of making calls to OS hosted functionality from the application varies a lot between OS's Thats true, and i...
by jahboater
Tue Apr 17, 2018 8:47 am
Forum: Raspbian
Topic: mjpg-streamer fails to compile
Replies: 17
Views: 313

Re: Failed to compile

I suspect I would see the same problem trying to compile any code. No, the compiler on the Pi works fine, and millions (perhaps) of people use it. Try a little hello world program and see. cc hello.c -o hello ./hello I see you start it with "make", perhaps it should be "cmake" ? Anyway it looks lik...
by jahboater
Tue Apr 17, 2018 8:43 am
Forum: Networking and servers
Topic: 2048 bit RSA too quick to generate?
Replies: 5
Views: 244

Re: 2048 bit RSA too quick to generate?

ARMv8 has some special hardware instructions for doing this, which if used, make the process a couple of orders of magnitude faster. But I don't know if they are available in 32-bit mode.
by jahboater
Mon Apr 16, 2018 3:49 am
Forum: Troubleshooting
Topic: RPi 3B+ Ethernet not working
Replies: 5
Views: 165

Re: RPi 3B+ Ethernet not working

You can turn off the Wifi with:

Code: Select all

rfkill block all
put it in /etc/rc.local

The wired ethernet usually should "just work"

There is also:

Code: Select all

dtoverlay=pi3-disable-bt
dtoverlay=pi3-disable-wifi
In /boot/config.txt, but I am not sure if thats actually needed.
by jahboater
Sun Apr 15, 2018 5:10 pm
Forum: Gentoo
Topic: Updated 64-bit Gentoo Image for RPi3 Released (now also for RPI3B+)
Replies: 15
Views: 4650

Re: Updated 64-bit Gentoo Image for RPi3 Released

sakaki wrote:
Wed Apr 04, 2018 1:59 pm
Version 1.2.1 of this bootable 64-bit Gentoo image is now available on GitHub (here).
Wow! Thank you so much for this!
Works perfectly.
by jahboater
Sun Apr 15, 2018 2:43 pm
Forum: Beginners
Topic: Beginner with Raspbian
Replies: 3
Views: 104

Re: Beginner with Raspbian

Where can I find a guide to all the Raspbian/Linux abbreviations? Every time I use the terminal, I come across abbreviations such as, -h or -sS . Is there a handy list of what these mean anywhere? These are option flags and mean different things for different commands, though there are some common ...
by jahboater
Sun Apr 15, 2018 6:25 am
Forum: C/C++
Topic: 64-bit math
Replies: 2
Views: 157

Re: 64-bit math

I've got a project I've been mulling about for awhile and it's going to involve quite a bit of 64-bit floating point operations. Enough of them that it'd be worth it to do quite a bit of legwork in optimizing the code and OS around those operations. With all the discussion of a 64-bit OS I haven't ...
by jahboater
Sat Apr 14, 2018 7:35 am
Forum: General discussion
Topic: Heatsink required for Raspberry Pi 3 B+?
Replies: 43
Views: 1738

Re: Heatsink required for Raspberry Pi 3 B+?

There are two stages to the throttling. First, at 70C it drops from 1.4GHz to 1.2GHz (the speed of the old Pi3) and reduces the voltage: Time Temp CPU Health Vcore 08:10:22; 64.5'C 1400MHz 0000000000000000000 1.3625V 08:10:32; 66.6'C 1400MHz 0000000000000000000 1.3688V 08:10:42; 69.8'C 1400MHz 00000...
by jahboater
Fri Apr 13, 2018 6:53 am
Forum: C/C++
Topic: C coding with system calls
Replies: 7
Views: 258

Re: C coding with system calls

The reboot works fine for my Pi.
Perhaps you could post the complete program as tested, (there is a typo in the above code)?

https://stackoverflow.com/help/mcve
by jahboater
Thu Apr 12, 2018 4:59 pm
Forum: Other languages
Topic: A Extended Pascal Implementation : CONCEPT.
Replies: 22
Views: 741

Re: A Extended Pascal Implementation : CONCEPT.

I prefer to hand code the lexer in the target language to create a self hosting compiler. Yes, I too would write the lex part by hand, but not the main grammar. Lex seems to produce huge code. Here is a yacc grammar for the C language: https://www.lysator.liu.se/c/ANSI-C-grammar-y.html I couldn't w...
by jahboater
Thu Apr 12, 2018 4:52 pm
Forum: General programming discussion
Topic: Raspberry Pi Benchmarks
Replies: 103
Views: 44462

Re: Raspberry Pi Benchmarks

For me "benchmarking" and "overclocking" are two entirely different things. Benchmarking is pure "measurement", "overclocking" is performance tuning (likely beyond manufacturers spec). The two are only related because benchmarking is required to assess the effectiveness of an overclock.
by jahboater
Thu Apr 12, 2018 3:59 pm
Forum: Beginners
Topic: Fortran Compiler on Raspbian?
Replies: 3
Views: 118

Re: Fortran Compiler on Raspbian?

Edit - see B.Goodes reply!
by jahboater
Thu Apr 12, 2018 8:11 am
Forum: Other languages
Topic: A Extended Pascal Implementation : CONCEPT.
Replies: 22
Views: 741

Re: A Extended Pascal Implementation : CONCEPT.

My experience from many many years ago was that it quite easy to write a lexical analyzer that is smaller and faster than lex can produce (but the lex source is easier to change and more readable). Yacc on the other hand does a brilliant job - the parser it produces is small and very fast. Most impo...
by jahboater
Thu Apr 12, 2018 7:01 am
Forum: C/C++
Topic: Building code to support wheezy
Replies: 19
Views: 347

Re: Building code to support wheezy

If it were me, I would go to great lengths to first remove any dependency on a specific version of the library from the code.

Even better stick rigidly to section 7 in the C11 standard.
by jahboater
Thu Apr 12, 2018 6:52 am
Forum: Other languages
Topic: A Extended Pascal Implementation : CONCEPT.
Replies: 22
Views: 741

Re: A Extended Pascal Implementation : CONCEPT.

The goal is a simple Pascal compiler that is easy to use, with an integrated IDE, specifically targeting ARMv5/ARMv6/ARMv7/ARMv8 CPU's, and with extras specific to the Raspberry Pi. If you want to write compilers, have you looked at bison (and I suppose flex) ?? They are the replacements for yacc (...
by jahboater
Thu Apr 12, 2018 6:27 am
Forum: General programming discussion
Topic: Raspberry Pi Benchmarks
Replies: 103
Views: 44462

Re: Raspberry Pi Benchmarks

One trick to get closer to hardware speed in the presence of a full-blown multitasking time-sharing operating system is to run the benchmark multiple times and then take the minimum timing from among the trials. This mitigates the effects of Linux temporarily suspending your job while it goes out t...
by jahboater
Wed Apr 11, 2018 6:19 pm
Forum: Bare metal
Topic: low cost or free assembler books / tutorials?
Replies: 10
Views: 549

Re: low cost or free assembler books / tutorials?

How do you get as (Gnu as aka gas) to assemble the common syntax of !objasm, and the many other common RISC OS assemblers (where the arm began)? You cannot of course, there is no reason for as to support even more versions of ARM assembler syntax, especially something decades out of date. But here ...
by jahboater
Wed Apr 11, 2018 1:01 pm
Forum: General programming discussion
Topic: Python, Java or both?
Replies: 5
Views: 450

Re: Python, Java or both?

What about: Java -> JNI -> C

Though I would code it all in plain C personally, easier (better support) and faster.

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