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by jahboater
Wed May 03, 2017 7:03 am
Forum: C/C++
Topic: GCC 7.1 released
Replies: 0
Views: 466

GCC 7.1 released

by jahboater
Tue May 02, 2017 7:52 am
Forum: Troubleshooting
Topic: execute script by pi after startup
Replies: 9
Views: 1143

Re: execute script by pi after startup

Try this then:

Code: Select all

python /home/pi/ledmatrix/ledmatrix.py /home/pi/ledmatrix/image.png & 
As noted above the environment is different, and its already root.

In you case it doesn't run in your home directory and so has no idea where the "ledmatrix" folder is - so you must give it the full path.
by jahboater
Tue May 02, 2017 6:33 am
Forum: Beginners
Topic: How fast can the GPIO be?
Replies: 4
Views: 808

Re: How fast can the GPIO be?

For C, use the pigpio library (already included with Raspbian)
http://abyz.co.uk/rpi/pigpio/
by jahboater
Tue May 02, 2017 6:27 am
Forum: Troubleshooting
Topic: execute script by pi after startup
Replies: 9
Views: 1143

Re: execute script by pi after startup

JustM3 wrote:

Code: Select all

sudo python /home/pi/ledmatrix/ledmatrix.py image.png & 

The .png file is a image that displays on the matrix board.
Where is the .png file? perhaps put the full path in, something like this:-

Code: Select all

sudo python /home/pi/ledmatrix/ledmatrix.py /home/pi/image.png & 
by jahboater
Sun Apr 30, 2017 12:31 pm
Forum: Troubleshooting
Topic: Why yours and not mine
Replies: 38
Views: 3512

Re: Why yours and not mine

mikerr wrote:

Code: Select all

 sudo sh -c 'unzip -qc 2017-04-10-raspbian-jessie-lite.zip >/dev/sde '
Probably the best yet, and "sh" is a link to "dash" which is around 1/10 of the size of bash.
by jahboater
Sun Apr 30, 2017 12:16 pm
Forum: Troubleshooting
Topic: Why yours and not mine
Replies: 38
Views: 3512

Re: Why yours and not mine

cp /bin/bash asroot
sudo chown root asroot
sudo chmod +s asroot
:|
by jahboater
Sun Apr 30, 2017 11:47 am
Forum: Beginners
Topic: GPU/CPU temperature limit for RPI3
Replies: 27
Views: 7283

Re: GPU/CPU temperature limit for RPI3

I know that these times are dependent on several factors, but the objective of my question is to know if it is worthy to put the fan on my RPI case or not. For example, if it varies from 5 to 3 years, maybe it is worthy for me not to use the fan. Its not worth using a fan unless you are into extrem...
by jahboater
Sun Apr 30, 2017 10:50 am
Forum: Troubleshooting
Topic: Why yours and not mine
Replies: 38
Views: 3512

Re: Why yours and not mine

Even though swapping dd for tee is still a bit messy to type, using unzip -c does save up to 4GB of wear and tear on your PC's SSD (if you care about that) and it does seem fast even though tee only uses an 8KB block size.
by jahboater
Sun Apr 30, 2017 10:42 am
Forum: Troubleshooting
Topic: Why yours and not mine
Replies: 38
Views: 3512

Re: Why yours and not mine

Martin Frezman wrote: $ sudo bash
# and then do your stuff here
and ^D to finish with.

or "sudo su" (two less characters to type :))

I chose tee because I don't like working in a root shell if I can avoid it.
Its a bit messy either way.
by jahboater
Sun Apr 30, 2017 10:29 am
Forum: Troubleshooting
Topic: Why yours and not mine
Replies: 38
Views: 3512

Re: Why yours and not mine

Sorry, yes ...

Code: Select all

unzip -qc 2017-04-10-raspbian-jessie-lite.zip | sudo tee /dev/sde >/dev/null
by jahboater
Sun Apr 30, 2017 7:41 am
Forum: Troubleshooting
Topic: Why yours and not mine
Replies: 38
Views: 3512

Re: Why yours and not mine

strace on unzip shows it calls write() with a block size of 64KB which is the same as the cp command does. It should be pretty efficient.

So thanks Martin for that tip.

sudo unzip -qc 2017-04-10-raspbian-jessie-lite.zip >/dev/sde

"7z e -so" does exactly the same by the way (writes 64KB blocks).
by jahboater
Sat Apr 29, 2017 9:31 am
Forum: Troubleshooting
Topic: Why yours and not mine
Replies: 38
Views: 3512

Re: Why yours and not mine

Interesting, I just looked up DD and its short for the Data Definition JCL statement.
For decades I thought it was a contraction of DasD or Disk Dump.
by jahboater
Sat Apr 29, 2017 8:56 am
Forum: Troubleshooting
Topic: Why yours and not mine
Replies: 38
Views: 3512

Re: Why yours and not mine

Don't you like the IBM JCL syntax of the dd command? ;)
by jahboater
Fri Apr 28, 2017 5:42 pm
Forum: Troubleshooting
Topic: Why yours and not mine
Replies: 38
Views: 3512

Re: Why yours and not mine

I use dd because I can set the block size, usually bs=1M for one megabyte. I'm not sure what the optimal block size is. I'm pretty sure that when you write directly to the device, it uses whatever is the optimal block size. In any case, I've never noticed it to be any slower than any other method. ...
by jahboater
Fri Apr 28, 2017 5:26 pm
Forum: Troubleshooting
Topic: Why yours and not mine
Replies: 38
Views: 3512

Re: Why yours and not mine

Be careful!!! /dev/sda is often the drive with the Linux OS installed on it. Point taken, but if you follow the narrative in my previous post, you'll see that I'm largely recommending this be done on a Pi (i.e., not on a Linux desktop PC). In any case, that's where I've most commonly used this meth...
by jahboater
Fri Apr 28, 2017 4:52 pm
Forum: Troubleshooting
Topic: Why yours and not mine
Replies: 38
Views: 3512

Re: Why yours and not mine

Now, suppose you want to setup a machine using the "raw image" form of Raspbian. You can do it with 'unzip' alone - you don't need 'dd' or any other "write to disk" program. Here's how (and trust me, I've done this many times; I know it works): (Do this as root [of course] and make sure that /dev/s...
by jahboater
Fri Apr 28, 2017 4:25 pm
Forum: General discussion
Topic: Why don't we announce products in advance?
Replies: 14
Views: 2661

Re: Why don't we announce products in advance?

W. H. Heydt wrote: Actually...it wouldn't surprise me if the next version has the same power requirements, or even a bit less than the Pi3B.
Agreed. My guess is we will have to wait a bit and then a 20nm (or less) SoC Pi4 will appear (trouncing the competition probably).
by jahboater
Fri Apr 28, 2017 12:37 pm
Forum: Troubleshooting
Topic: Why yours and not mine
Replies: 38
Views: 3512

Re: Why yours and not mine

I've tried so many times to download and then copy the disc image to an micro sd card after I've formatted it. First I thought it was the card, but now, 20 cards later There is absolutely no need to format the sd card first. You have formatted 20 cards for nothing! I use unzip and dd, 100% reliable...
by jahboater
Fri Apr 28, 2017 12:25 pm
Forum: Advanced users
Topic: Moving Linux kernel to 4.9
Replies: 289
Views: 120466

Re: Moving Linux kernel to 4.9

PhilE wrote:Yes, we updated the stable branch and rebuilt the raspberrypi-kernel package yesterday.
Running fine on Pi0, Pi0W, Pi2, Pi3, all good as far as I can see.

Thanks to the RPF engineers for this!
by jahboater
Thu Apr 27, 2017 6:31 pm
Forum: Off topic discussion
Topic: Etcher..
Replies: 6
Views: 1767

Re: Etcher..

supra wrote:Both of them are 4 yrs old
Could it just be worn out?
by jahboater
Thu Apr 27, 2017 2:33 pm
Forum: Off topic discussion
Topic: Etcher..
Replies: 6
Views: 1767

Re: Etcher..

The Etcher site doesn't say anything about a max capacity - so I guess just try it. It doesn't work. The maximum sd card up to 32gb. I tried 64gb but failed many times. Thanks. Are you sure your SD card is genuine? I don't use Etcher (I use dd) but 32GB seems a surprising and pointless limitation. ...
by jahboater
Tue Apr 25, 2017 6:10 pm
Forum: C/C++
Topic: New Gcc 7.1, his build sources result success with B model A
Replies: 52
Views: 7761

Re: New Gcc 7.1, his build sources result success with B mod

There are other versions of the compiler available.

apt-cache search gcc-4

shows 4.4 to 4.9 downloadable.

Perhaps some later versions could be made available in the same way.

This of course has nothing to do with the stability of the thousands of other packages in the repo.
by jahboater
Tue Apr 25, 2017 6:00 pm
Forum: C/C++
Topic: New Gcc 7.1, his build sources result success with B model A
Replies: 52
Views: 7761

Re: New Gcc 7.1, his build sources result success with B mod

There's no way a normal person is going to know all that stuff you wrote. No of course not, but its easy enough to follow a script (like the one above) that someone else has done (which is what I did a long time ago). You said it was just "make", but clearly it is much more than that. Obviously, bu...
by jahboater
Tue Apr 25, 2017 5:29 pm
Forum: C/C++
Topic: New Gcc 7.1, his build sources result success with B model A
Replies: 52
Views: 7761

Re: New Gcc 7.1, his build sources result success with B mod

You have to download a *lot* of other packages and you have to build each of those other packages. Umm no you dont. The "download_prerequisites" script does it all for you. The (three) packages get built along with GCC, you never have to deal with them at all. And it always works. Typically it goes...
by jahboater
Tue Apr 25, 2017 4:56 pm
Forum: C/C++
Topic: New Gcc 7.1, his build sources result success with B model A
Replies: 52
Views: 7761

Re: New Gcc 7.1, his build sources result success with B mod

Note: I have never compiled up a GCC myself - it is kind of on my bucket list to do it at some point. So, no, telling a forum poster help-seeker (and the default assumption is that forum help-seekers are generally 'beginners') to compile it up himself is just rhetoric. That's why I suggested instal...

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