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by jahboater
Thu Feb 11, 2016 12:08 pm
Forum: Beginners
Topic: Pi as a desktop replacement
Replies: 28
Views: 4340

Re: Pi as a desktop replacement

Would a kernel compile time be a useful metric for comparison? Obviously stop after "make zImage modules dtbs" unless you want to test your newly built kernel... Just for interest I did this:- real 87m31.611s user 319m2.530s sys 17m21.430s Make -j5, standard Pi2 overclock (1000/500/500). I didn't s...
by jahboater
Thu Feb 11, 2016 8:33 am
Forum: Beginners
Topic: Pi as a desktop replacement
Replies: 28
Views: 4340

Re: Pi as a desktop replacement

I'd wonder the following two things: 1. How into the swap file was the job? 2. How full was the sdcard? Some people can take the risk of messing up their card more than others. I would suspect that wear leveling works better if a card isn't nearly full. I would also suspect that if the job didn't g...
by jahboater
Thu Feb 11, 2016 8:17 am
Forum: Beginners
Topic: Pi as a desktop replacement
Replies: 28
Views: 4340

Re: Pi as a desktop replacement

I discovered that it only over-commits memory for a short time near the start of the build and 99.9% of the time its fine. I read somewhere that -j should be Ncpus + 1 - and it worked for me. It takes about two days with -j1. When I compile kodi I cannot use more than -j3 and only If I reduce the G...
by jahboater
Wed Feb 10, 2016 7:15 pm
Forum: Beginners
Topic: Pi as a desktop replacement
Replies: 28
Views: 4340

Re: Pi as a desktop replacement

@GTR2Fan Did you ever compile a large package (like kodi or VLC) on SD card? I compile gcc now and again, always directly on the SD card. The last time I tried it took 6 hours 45 mins (overclocked Pi2, make -j5, 1GB swapfile). I never have problems with SD cards. I assume you meant -j3 or -j4 (I ne...
by jahboater
Wed Feb 10, 2016 3:52 pm
Forum: Beginners
Topic: Pi as a desktop replacement
Replies: 28
Views: 4340

Re: Pi as a desktop replacement

gkreidl wrote:@GTR2Fan
Did you ever compile a large package (like kodi or VLC) on SD card?
I compile gcc now and again, always directly on the SD card.
The last time I tried it took 6 hours 45 mins (overclocked Pi2, make -j5, 1GB swapfile).
I never have problems with SD cards.
by jahboater
Mon Feb 08, 2016 10:33 am
Forum: General discussion
Topic: Usbourne - 80s learn programming books now free
Replies: 23
Views: 4201

Re: Usbourne - 80s learn programming books now free

jahboater, Perhaps an aversion to 'P' is why the successor to C was named C++, not P (next letter after B and C in BCPL). Interesting concept, that P should come after C because of BCPL. I have a vague memory that after B and C, they couldn't decide between D as in abcD, or P as in bcPL and so avoi...
by jahboater
Mon Feb 08, 2016 10:21 am
Forum: General discussion
Topic: Usbourne - 80s learn programming books now free
Replies: 23
Views: 4201

Re: Usbourne - 80s learn programming books now free

I have never used PL/1, it was an IBM main frame thing if I recall correctly. I have read many complaints about it though. I mentioned it merely as a possible exception to your list of languages starting with P. I didn't know it well, but it was very powerful. It made the mistake of having everythi...
by jahboater
Mon Feb 08, 2016 9:03 am
Forum: General discussion
Topic: Usbourne - 80s learn programming books now free
Replies: 23
Views: 4201

Re: Usbourne - 80s learn programming books now free

Yes, Python is horrid. As is Perl, Pascal, PHP, PL/M, Postscript and Prolog. See pattern here? Stay away from any language that starts with a "P". There are many more. PL/1 is a fine language! As for BASIC (Baby's All-purpose Simple Instruction Code), like assembler on old 8-bit micros, proper basi...
by jahboater
Sun Feb 07, 2016 9:48 pm
Forum: Beginners
Topic: Find IP when headless.
Replies: 6
Views: 1729

Re: Find IP when headless.

or try something like:- sudo nmap -sn 192.168.0.*/24 The traditional Pi's with ethernet show the Foundation name, the Zero has a separate USB ethernet adaptor. Nmap scan report for pi2 (192.168.0.80) Host is up (-0.096s latency). MAC Address: B8:27:EB:D1:4D:D8 (Raspberry Pi Foundation) Nmap scan rep...
by jahboater
Sun Feb 07, 2016 8:56 am
Forum: Troubleshooting
Topic: OOM compiling on pi2b
Replies: 4
Views: 848

Re: OOM compiling on pi2b

Make sure you are using "make" or "make -j1" rather than "make -j4" in the build. It will take longer but use a lot less memory.

I just use an old or cheap SD card and don't worry swap hammering it.
by jahboater
Sat Feb 06, 2016 9:26 am
Forum: Troubleshooting
Topic: SD Card Resizes after installing Raspian OS
Replies: 6
Views: 780

Re: SD Card Resizes after installing Raspian OS

SSH is enabled by default on Raspbian so you can always use something like "scp" to copy files across.
by jahboater
Sat Feb 06, 2016 8:50 am
Forum: General discussion
Topic: Best High Capacity Battery?
Replies: 8
Views: 1334

Re: Best High Capacity Battery?

When you turn off the pi with a system shutdown, can you just press the button to start it up again? Or do you need to unplug it and plug it back in? You need to unplug and plug it back in. I tried "sudo poweroff" as well as "sudo halt" and both sockets on the battery. Running Jessie, so its system...
by jahboater
Sat Feb 06, 2016 1:56 am
Forum: General discussion
Topic: Best High Capacity Battery?
Replies: 8
Views: 1334

Re: Best High Capacity Battery?

This might sound like a weird question, but does it have a power button that signals for it to start dishing out juice, or does it start whenever any USB device is plugged in?
The answer is both! Just plug the Pi in and it powers up. But there is a button on top as well.
by jahboater
Fri Feb 05, 2016 5:50 pm
Forum: General discussion
Topic: Best High Capacity Battery?
Replies: 8
Views: 1334

Re: Best High Capacity Battery?

I have a ravpower 16,000mah that works fine with a Pi2. Edit: that was a modestly overclocked 1GHz pi2, I just tried the ravpower with a standard Pi Zero (with a USB ethernet adapter)and its booted fine. Edit2: that was the 2,4A socket, I have now tried the 2.1A "smart" usb socket and that works OK ...
by jahboater
Fri Feb 05, 2016 5:06 pm
Forum: General discussion
Topic: Just got my first RPi2.
Replies: 13
Views: 1802

Re: Just got my first RPi2.

Could you give me an example of where the ARMv7 instruction set would benefit the core of RISC OS? All of the core stuff is pretty much integer only, and very little that does a repeated operation on multiple data elements. So for the OS itself I do not see the advantage, with very few exceptions. ...
by jahboater
Thu Feb 04, 2016 5:01 pm
Forum: Advanced users
Topic: GPIO level twilight zone
Replies: 5
Views: 844

Re: GPIO level twilight zone

I saw "you can configure the input gate to act as a Schmitt trigger". Maybe its not the default.
Looks like you can switch hysteresis on and off as well.
I've no idea how any of this is done.
by jahboater
Thu Feb 04, 2016 4:29 pm
Forum: Advanced users
Topic: GPIO level twilight zone
Replies: 5
Views: 844

Re: GPIO level twilight zone

Could a schmitt trigger help?
by jahboater
Thu Feb 04, 2016 4:20 pm
Forum: Beginners
Topic: How to detect corrupted file system
Replies: 5
Views: 1338

Re: How to detect corrupted file system

You probably want fsck (man fsck for details).
For boot messages try dmesg
by jahboater
Thu Feb 04, 2016 12:46 pm
Forum: Advanced users
Topic: Overclocking
Replies: 1125
Views: 615330

Re: Overclocking

Yes. If sdram_freq>450 on Pi2 we disable the part of PVT that caused overclock issues, and we also bump over_voltage_sdram_p to 2 which helps a little. You may want to bump that voltage a little more if you are going above 500. It does work perfectly, rock solid. Thanks again! Perhaps the raspi-con...
by jahboater
Thu Feb 04, 2016 12:16 pm
Forum: General discussion
Topic: Just got my first RPi2.
Replies: 13
Views: 1802

Re: Just got my first RPi2.

Of course you are correct that Thumb is a subset of ARM, and Thumb2 a slight extension of Thumb. Though Thumb uses a 16 bit instruction word, and eliminates many of the advantages of the ARM ISA, such as almost all ARM instructions are conditional, not so with Thumb, as wall as a few other things T...
by jahboater
Wed Feb 03, 2016 11:09 pm
Forum: Advanced users
Topic: Overclocking
Replies: 1125
Views: 615330

Re: Overclocking

Hi Dom, Thanks for doing all this, its really appreciated. Interesting. I've done some digging and found the part of disable_pvt that seems to help. Can you test this firmware: https://dl.dropboxusercontent.com/u/366 ... e_pvt2.zip Does this firmware version from rpi-update also include the above di...
by jahboater
Wed Feb 03, 2016 10:05 am
Forum: General discussion
Topic: Compiling on the Pi
Replies: 6
Views: 998

Re: Compiling on the Pi

Also another little question. Does the Raspbian allow compiling out of the box or should I install additional packages?
Yes, it comes with support included for the common languages and others are easily installed.
The Pi is 32-bit by the way.
by jahboater
Wed Feb 03, 2016 9:49 am
Forum: Beginners
Topic: Everything is a file?
Replies: 15
Views: 1937

Re: Everything is a file?

And get disk information from /proc/diskstats
by jahboater
Wed Feb 03, 2016 8:52 am
Forum: General discussion
Topic: Just got my first RPi2.
Replies: 13
Views: 1802

Re: Just got my first RPi2.

And some of those are extensions, not ARM (NEON, thumb/thumb2). I don't think thumb2 is an extension, some v7 processors (the Cortex-M series) support thumb2 only. If you are using UAL which people should be now, it doesn't matter anyway. RISC OS does not use them either. That's sad, there is a rea...
by jahboater
Tue Feb 02, 2016 11:28 am
Forum: General discussion
Topic: Just bought my second Pi 2
Replies: 13
Views: 2583

Re: Just bought my second Pi 2

Adrianfu wrote:Ok its the start of an adiction
Interference in only on AM radio and my HF radio gear
Four Pi2's, two Pi Zero's, two B+, one B - older ones given away to schools.
Perhaps the interference is down to the switching regulators?

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