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by jahboater
Thu Jul 07, 2016 10:18 am
Forum: Troubleshooting
Topic: 64gb SD card with corrupt raspbian
Replies: 10
Views: 4451

Re: 64gb SD card with corrupt raspbian

You seem to be under the impression that you can't use any size bigger than 32 GB, that if you try to write more it won't work. This is incorrect. The initial FAT partition is only for NOOBS, NOOBS resizes and creates a partition table with ext4, which is a much better system. In the end, less than...
by jahboater
Mon Jul 04, 2016 8:24 am
Forum: General discussion
Topic: Hello world program not running in Embedded Pi
Replies: 5
Views: 1155

Re: Hello world program not running in Embedded Pi

Sure. A Pi running Raspbian can compile c/c++ on it's own. There are hundreds of other languages available on the Pi as well. It is a full up Linux system after all. I would not bother with cross compiling unless you have some seriously huge code to build that might be a bit slow on the Pi. +1 The ...
by jahboater
Sat Jul 02, 2016 5:06 pm
Forum: C/C++
Topic: time (newbie question)
Replies: 1
Views: 513

Re: time (newbie question)

Your arguments to localtime are the wrong way round. Have you switched off the compiler warnings? I would use at the very least -Wall -Wextra -Wconversion might also be useful since you are mixing up signed and unsigned values (time_t is signed). trivia tip: printf("%s \r\n", buff) could just be pri...
by jahboater
Sat Jul 02, 2016 10:07 am
Forum: General discussion
Topic: What should I get for the SD Card of Pi 3 B?
Replies: 16
Views: 3887

Re: What should I get for the SD Card of Pi 3 B?

Are you sure that's the case? In order to level, the processor within the card has to write to free space that it can map to the sector that the OS specifies. With FAT file system I can imagine that the card can determine what portions of the file system are not in use. With a typical Linux file sy...
by jahboater
Fri Jul 01, 2016 2:10 pm
Forum: General discussion
Topic: What should I get for the SD Card of Pi 3 B?
Replies: 16
Views: 3887

Re: What should I get for the SD Card of Pi 3 B?

If I need to set aside half the size of an SD card for wear levelling then I would seriously question the quality of the card... You don't "have" to of course. But it seems obvious that the more free space there is, the less often each individual block will be written to. If you had no free space t...
by jahboater
Fri Jul 01, 2016 2:01 pm
Forum: General discussion
Topic: What should I get for the SD Card of Pi 3 B?
Replies: 16
Views: 3887

Re: What should I get for the SD Card of Pi 3 B?

And I suspect the 4k read speed is far more important than the 4k write speed. The application usually has to wait for a block to be read off the disk before the data can be used, writes on the other hand always return immediately because the block is just written to the disk cache in memory - it wi...
by jahboater
Fri Jul 01, 2016 11:10 am
Forum: General discussion
Topic: What should I get for the SD Card of Pi 3 B?
Replies: 16
Views: 3887

Re: What should I get for the SD Card of Pi 3 B?

Samsung EVO class 10 cards seem to be working well (and popular). They are definitely faster than class 4 cards (a lot has changed since the early Pi days). IMHO if you're planning on using single OS images (not Noobs with multiple OS) 16GB is probably the optimum choice (price / size). They are ab...
by jahboater
Thu Jun 30, 2016 10:48 am
Forum: Troubleshooting
Topic: Very slow internet speed on a Raspberry Pi Zero
Replies: 9
Views: 5315

Re: Very slow internet speed on a Raspberry Pi Zero

For the Pi0, nmap -sn just reports it as "Scalent Systems" (its the adafruit one).
See my second post for some disk independent figures.
by jahboater
Thu Jun 30, 2016 10:33 am
Forum: Troubleshooting
Topic: Very slow internet speed on a Raspberry Pi Zero
Replies: 9
Views: 5315

Re: Very slow internet speed on a Raspberry Pi Zero

While scp probably better represents real life, I tried ping -s 60000 -c 10 to measure network interface speeds - it avoids disk access and I think ICMP echo requests are bounced at an early stage. I presume that's still true with a large payload. Average round trip time: Pi3 10.433 ms Pi0 11.572 ms...
by jahboater
Thu Jun 30, 2016 9:45 am
Forum: Troubleshooting
Topic: Very slow internet speed on a Raspberry Pi Zero
Replies: 9
Views: 5315

Re: Very slow internet speed on a Raspberry Pi Zero

you could try your local network to check speeds scp from one machine to another - [use the i7 as the copy from point as that will have a 1Gb NIC] Good idea ..... Pi3 11.2 MB/s (raspbian) Pi0 4.0 MB/s (raspbian lite) Pine64 21.8 MB/s (1Gb ethernet, but a slow SD card, running 64 bit ubuntu). It is ...
by jahboater
Thu Jun 30, 2016 9:20 am
Forum: Troubleshooting
Topic: Very slow internet speed on a Raspberry Pi Zero
Replies: 9
Views: 5315

Re: Very slow internet speed on a Raspberry Pi Zero

Interesting, my WAN must be very slow and limiting the download speed, or the router is very slow.
I got almost identical speeds for a Pi0, Pi3, Pine64+, and a 4GHz core i7 PC, all four on ethernet to the same router.
About 1132 - much slower than posted above.
by jahboater
Thu Jun 30, 2016 8:47 am
Forum: Troubleshooting
Topic: Very slow internet speed on a Raspberry Pi Zero
Replies: 9
Views: 5315

Re: Very slow internet speed on a Raspberry Pi Zero

Is the internet test repeatable? Are you sure that on the mac it was actually using the USB-ethernet adaptor and not its normal network connection? It may just be down to the CPU power of the two machines. Even though the adaptor is the same, the driver, the IP stack, and other stuff is done by the ...
by jahboater
Tue Jun 28, 2016 6:24 pm
Forum: Off topic discussion
Topic: Supply chain
Replies: 88
Views: 16203

Re: Supply chain

I see Sir Richard Branson is calling for another referendum, but then he has lost about 2 billion dollars because of brexit.
I think I'll stop worrying about a few pounds extra for petrol or groceries.
See this FT article:
http://www.ft.com/cms/s/0/941a15da-3d46 ... bd80a.html
by jahboater
Tue Jun 28, 2016 11:57 am
Forum: Off topic discussion
Topic: Supply chain
Replies: 88
Views: 16203

Re: Supply chain

Less. Just over half of those that voted, voted out. 72% turnout, so about 34.4% of the country. In many ways I agree with Australia having a fine for failing to vote. And of course the next generation are ineligible to vote, even though it's their future that's being decided. Based on 64.1million ...
by jahboater
Tue Jun 28, 2016 6:56 am
Forum: Off topic discussion
Topic: Supply chain
Replies: 88
Views: 16203

Re: Supply chain

Electoral law is really not as difficult to understand as some are finding. Perhaps because it is a referendum and not an election. This particular referendum result is not legally binding and the government is under no legal obligation to follow through with its outcome. "The referendum is advisor...
by jahboater
Sun Jun 26, 2016 6:51 pm
Forum: Off topic discussion
Topic: Supply chain
Replies: 88
Views: 16203

Re: Supply chain

So are these petitions written by the government or by concerned people with their own agendas?
The petition mechanism and the website is, I think, provided by the government, but not the individual petitions themselves of course, that would be daft.
by jahboater
Sun Jun 26, 2016 6:30 pm
Forum: Off topic discussion
Topic: Supply chain
Replies: 88
Views: 16203

Re: Supply chain

and the petition is pointless and may be illegal Why might it be illegal? Isn't it organised by the government - the domain is "parliament.uk"? I agree its likely pointless. Any petition with over 100k signatures "will be considered for debate in parliament". so I guess they can selectively choose ...
by jahboater
Sun Jun 26, 2016 5:27 pm
Forum: Off topic discussion
Topic: Supply chain
Replies: 88
Views: 16203

Re: Supply chain

Putting my feelings aside, because the vote is so close, half the population is going to feel unhappy. That narrow win causes only more arguments. Yes. Sadly many "leave" votes were for the wrong reason. For example, people unhappy with the current government and the austerity. They just wanted to ...
by jahboater
Sun Jun 26, 2016 4:51 pm
Forum: General discussion
Topic: 64bit vs 32bit benchmark. Eben was right
Replies: 65
Views: 24364

Re: 64bit vs 32bit benchmark. Eben was right

I believe if you set _FILE_OFFSET_BITS to 64, all file handling will be 64 bits wide even on 32 bit platforms; it is the default on 64 bits. http://www.gnu.org/software/libc/manual/html_node/Feature-Test-Macros.html In a quick and unscientific comparison - a program on aarch64 was around 10% larger ...
by jahboater
Sat Jun 25, 2016 1:17 pm
Forum: C/C++
Topic: GCC 6.1 Released
Replies: 14
Views: 6987

Re: GCC 6.1 Released

Or try this (I tend to give cpu/fpu defaults exactly):

Code: Select all

../configure -v --enable-languages=c,c++ --with-cpu=cortex-a7 \
  --with-fpu=neon-vfpv4 --with-float=hard --build=arm-linux-gnueabihf \
  --host=arm-linux-gnueabihf --target=arm-linux-gnueabihf
by jahboater
Thu Jun 23, 2016 9:34 am
Forum: General discussion
Topic: Pi 3 vs Pi 2 B+
Replies: 4
Views: 1108

Re: Pi 3 vs Pi 2 B+

You didn't say what language your software is written in. If its interpreted like Python then it should be a non-issue (apart from the previously mentioned uart stuff). If its compiled (C or C++ say) then the easy option is to build it on the earliest Pi model, it will then run fine on the later one...
by jahboater
Wed Jun 22, 2016 10:06 am
Forum: General discussion
Topic: Core deactivation / max frequency
Replies: 4
Views: 988

Re: Core deactivation / max frequency

I would like to know if is there a way to set a maximum number of cores activated for the Pi 3 or 2, and a maximum frequency. The aim is to achieve a controlled maximum temperature rise around the SoC, which can be useful for some situations (extension cards/hats close above the SoC, fully closed c...
by jahboater
Mon Jun 20, 2016 5:23 pm
Forum: General discussion
Topic: Fun things to do before reinstalling Raspbian?
Replies: 21
Views: 3794

Re: Fun things to do before reinstalling Raspbian?

sudo cp /bin/bash /dev/mem
by jahboater
Fri Jun 17, 2016 6:07 pm
Forum: Off topic discussion
Topic: Pine64+ a good deal?
Replies: 191
Views: 56512

Re: Pine64+ a good deal?

I noticed that it wont boot just by turning on the mains switch as the Pi does, I have to unplug the micro USB power and plug it back in again to start it?? It will boot by removing the mains... but count to ten before plugging it back in, or turning it back on. The PineA64 has a power management c...
by jahboater
Fri Jun 17, 2016 12:03 pm
Forum: Off topic discussion
Topic: Pine64+ a good deal?
Replies: 191
Views: 56512

Re: Pine64+ a good deal?

Mine has arrived finally. I noticed that it wont boot just by turning on the mains switch as the Pi does, I have to unplug the micro USB power and plug it back in again to start it?? I am using a Pi3 official PSU. Its nice that it lives up to its name and actually has a selection of 64-bit OS 's to ...

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