Go to advanced search

by jahboater
Sun Feb 19, 2017 8:44 am
Forum: C/C++
Topic: Maximizing SIMD performance
Replies: 8
Views: 5132

Re: Maximizing SIMD performance

My point in posting the article is to share the idea that SIMD is not 'scary' and for those who use the crutch of the C compiler "-O3" option and assume they're code is being vectorized, they might be surprised when it isn't able to do it. Well you need more than -O3. -ftree-vectorize at the very l...
by jahboater
Sat Feb 18, 2017 9:39 pm
Forum: C/C++
Topic: gpp 5.2 or better, providing C++14 for Jessie ?
Replies: 26
Views: 4560

Re: gpp 5.2 or better, providing C++14 for Jessie ?

hello, what must I do to install gpp 5.2 or better feat. C++14 for Jessie ? I just purchased a C++ guide book which introduces especially to C++14 features and so requires 5.2 or better as stated in the preamble. Will this 5.x version then also work trouble-free and out of the box with the current ...
by jahboater
Fri Feb 17, 2017 10:07 pm
Forum: Raspberry Pi OS
Topic: Help for raspian booting problem
Replies: 14
Views: 2474

Re: Help for raspian booting problem

DougieLawson wrote:You made a wrong choice. You should always take a backup just before you make a non-reversible change.
You mean apart from trying to install upstart :)
by jahboater
Fri Feb 17, 2017 5:19 pm
Forum: Troubleshooting
Topic: grep [a-zA-Z] only finds "r"
Replies: 5
Views: 886

Re: grep [a-zA-Z] only finds "r"

You might need some extra brackets for that?
by jahboater
Fri Feb 17, 2017 5:10 pm
Forum: Raspberry Pi OS
Topic: Help for raspian booting problem
Replies: 14
Views: 2474

Re: Help for raspian booting problem

1) It's not what I'm used to. (I've been using Linux & BSD since 1999, & haven't needed it.) 2) It has worked it's way into many programs, making some of them incompatible with other init systems. 3) It's not the unix way. 4) It stores it's data as binary, (so I'm told, which makes problem solving ...
by jahboater
Fri Feb 17, 2017 4:54 pm
Forum: Beginners
Topic: About External USB Drives
Replies: 7
Views: 1475

Re: About External USB Drives

BrianOBrien wrote: Now that it's mounted can't i repartition it and format it?
If so, how?
You should unmount it first with umount (see man umount for details).
by jahboater
Fri Feb 17, 2017 4:46 pm
Forum: Troubleshooting
Topic: grep [a-zA-Z] only finds "r"
Replies: 5
Views: 886

Re: grep [a-zA-Z] only finds "r"

Wondering if anyone else has encountered this issue: grep [a-zA-Z] filename This sequence was working, but suddenly stopped (pi 3B). Now it only finds the "r" if the file contains the entire alphabet. All other grep usage seems to work fine and this usage still workes just fine on another ripi. Tri...
by jahboater
Fri Feb 17, 2017 3:34 pm
Forum: Advanced users
Topic: How far have you overclocked?
Replies: 4
Views: 7250

Re: How far have you overclocked?

Trouble is most people have moved on to the Pi2 or probably the Pi3. The Pi3 is quad core armv8 (compared to single core armv6 on the B+) at 1.2GHz with 1GB of ram.

If speed is what you are after, the Pi3 is many many times faster than the B+ (ten times or more) and its the same purchase price!
by jahboater
Fri Feb 17, 2017 3:18 pm
Forum: General discussion
Topic: Read USB MBR Data and modify
Replies: 6
Views: 1293

Re: Read USB MBR Data and modify

Thats cool! But why the seek(512)? surely it starts at offset zero. After changing the MBR a seek(0) would be needed in order to rewind the file and write out the new MBR starting at zero. Or have I missed something?
by jahboater
Fri Feb 17, 2017 3:09 pm
Forum: General discussion
Topic: Read USB MBR Data and modify
Replies: 6
Views: 1293

Re: Read USB MBR Data and modify

However, I face problems doing the same on raspberry Pi. I do CreateFile based on drive letter. (\\.\<DriveLetter> ). But CreateFile with drive letter on Raspberry Pi fails. CreateFile is a Windows API function, and "drive letters" are a Windows thing. The Raspberry Pi runs a different operating sy...
by jahboater
Fri Feb 17, 2017 2:57 pm
Forum: Beginners
Topic: customise PI image
Replies: 13
Views: 2009

Re: customise PI image

How can i customise linux kernel as per I can start my GUI on start up. I can not use raspbian. I want to customise linux as. if I will give power to raspberry pi 3, it will directly start my GUI application. I don't understand why you need to "customize" the linux kernel for this, and I don't unde...
by jahboater
Fri Feb 17, 2017 11:55 am
Forum: General discussion
Topic: Multiple concurrent uses
Replies: 3
Views: 795

Re: Multiple concurrent uses

The OS (Raspbian Linux) for the Pi is fully multi-user multi-tasking, so it can and normally does run many things concurrently. The Pi2 and Pi3 are quad-core too, so its reasonably fast. I don't know what these apps you mention are. If they are for the PC they will be for Intel x86 processors. The P...
by jahboater
Fri Feb 17, 2017 11:41 am
Forum: Beginners
Topic: Lightweight Antivirus for Pi? To catch Windows viruses.
Replies: 25
Views: 13218

Re: Lightweight Antivirus for Pi?

Could you perhaps do the AV scan on the Windows PC before copying the files to the Pi?
I speculate (I have never used ClamAV) that a good Windows AV, regularly updated, would do a better job.
Especially as you are actually looking for Windows x86 viruses.
by jahboater
Fri Feb 17, 2017 11:33 am
Forum: Beginners
Topic: customise PI image
Replies: 13
Views: 2009

Re: customise PI image

jignesh.patel47 wrote:I want to start automatic python base GUI Application after booting on Linux kernel that i have builded for raspberry pi.
Thats OK, but why do you need to build a special kernel?
There are plenty of posts about starting GUI apps automatically.
by jahboater
Fri Feb 17, 2017 11:07 am
Forum: Wanted
Topic: Write some RPi software for me?
Replies: 18
Views: 4312

Re: Write some RPi software for me?

But that would still involve me having to build a RPi - and I don't want to do that... They come ready built and tested ;) If you mean the software, it takes me a few minutes to install Raspbian and configure it (but I have done it countless times to be fair), the longest part is downloading the 4G...
by jahboater
Fri Feb 17, 2017 11:00 am
Forum: Wanted
Topic: Write some RPi software for me?
Replies: 18
Views: 4312

Re: Write some RPi software for me?

Its a fairly unusual request. Most people enjoy the learning process and the satisfaction of building their own project. You will learn nothing if you pay someone else to have all the fun. Anyway, Dougie is right, there may well be some software to do what you want readily available. So if you could...
by jahboater
Fri Feb 17, 2017 10:48 am
Forum: Beginners
Topic: customise PI image
Replies: 13
Views: 2009

Re: customise PI image

jignesh.patel47 wrote:How can i customise linux kernel as per I can start my GUI on start up.
Raspbian (full) starts the GUI anyway at boot and has done for some time. The Lite version has no GUI at all.

What do you mean by "my GUI" ?
by jahboater
Fri Feb 17, 2017 10:15 am
Forum: Raspberry Pi OS
Topic: Raspberry Pi runtime
Replies: 4
Views: 1286

Re: Raspberry Pi runtime

I may have deleted the default runtime files in an attempt to format the sd card all of the data is on. :? I tried to download and burn raspbian pixel and lite onto the sd card, but every time I try to launch the raspberry pi it will not turn on. How can I fix that? You do not need to remove any fi...
by jahboater
Thu Feb 16, 2017 3:42 pm
Forum: General discussion
Topic: Testing for Invalid Date in bash
Replies: 18
Views: 3574

Re: Testing for Invalid Date in bash

Its got a basic debugger but I cant see the raw hex in the memory registers which is what I'm used to as some of the bugs I've found in the past have been bugs in the language runtime itself and without a decent debugger you cant find all the bugs as easily or quickly. I doubt you will get that wit...
by jahboater
Thu Feb 16, 2017 11:45 am
Forum: General discussion
Topic: Testing for Invalid Date in bash
Replies: 18
Views: 3574

Re: Testing for Invalid Date in bash

I think of bash as a JCL (job control language) not a general purpose programming language like Python. Yes for a large script, Python with the occasional os.system() will be much better. As a JCL though, bash is more powerful and cleaner than most I have seen, especially mainframe ones.
by jahboater
Thu Feb 16, 2017 10:57 am
Forum: C/C++
Topic: Read analog inputs at 4kHz
Replies: 14
Views: 2404

Re: Read analog inputs at 4kHz

juranga wrote:Would be easier to achieve the same thing using another embedded linux platform (i.e. industrial embedded board)?
The Odroid-C2 has two 10-bit ADC's in the GPIO. I have no idea how fast they are though.
by jahboater
Thu Feb 16, 2017 9:17 am
Forum: Troubleshooting
Topic: sudo: Command not found
Replies: 34
Views: 8058

Re: sudo: Command not found

Ok, I'm sorry for that, I simply can't see the benefit, Just talking about basic permissions, nothing platform specific ;) Some benefits of file access control, put simply:- 1) You don't want to be able to alter or delete someone else's private data, nor even read it or execute it without their exp...
by jahboater
Wed Feb 15, 2017 6:13 pm
Forum: Other programming languages
Topic: Regina-REXX and the COMPUTE.REX module for Dougie Lawson
Replies: 42
Views: 10815

Re: Regina-REXX and the COMPUTE.REX module for Dougie Lawson

Michael1950 wrote:Well, that is a surprise, I would've thought that folks using REXX would be using the THE (mark hessling's) editor.
I used XEDIT which I thought was rather good (on a 3270).
After using EXEC2 for some time, REXX was a breath of fresh air in comparison!
by jahboater
Wed Feb 15, 2017 3:42 pm
Forum: Troubleshooting
Topic: sudo: Command not found
Replies: 34
Views: 8058

Re: sudo: Command not found

I'm as much of a Unix afficionado as anyone, but I do realize that there are one or two things that Windows got right. I never said there wasn't. The discussion however was about file system permissions for executable files, not a general UNIX vs Windows debate. Your blanket statement that "They ar...
by jahboater
Wed Feb 15, 2017 3:02 pm
Forum: Troubleshooting
Topic: sudo: Command not found
Replies: 34
Views: 8058

Re: sudo: Command not found

These are not "errors", ... They are errors, likely a result of Unix's long history. No, learn that long history! Unix was always multi-user (well apart from a very short period early on) and Linux has always been multi user. Unix and Linux filesystems have always had permissions and metadata. DOS ...

Go to advanced search