[arm-allstar] RPi2 image file shasums-- Was: Arch vulnerabilities

[David McGough]

Hi Fred,

Earlier, I confirmed that your shasum of the 4GB image file was accurate. 

So, you've got to have some sort of local system problem, including
possibility a bad SD card or card reader/writer.

Our image file is almost 4GB in size. Are you sure you're not hitting some
32-bit OS limit which might present itself on -any- file bigger than 2GB?

Also, if you're seeing many re-reads of the source datafile, that may 
be indicating hard drive failure on your computer?

Remember: From your host computer's perspective this is just binary data! 
The dd command is simply copying that data. All other distros are also 
binary data. From your host computers viewpoint, the only difference is 
the size of the file--is doesn't matter what the file contents are!


73, David KB4FXC



On Fri, 1 May 2015, Fred Moore wrote:

> Doug, (and list)  I really am not trying to be controversial, nor am I
> complaining, I actually very much appreciate the work you guys are
> doing.. However as you most likely know the card class has nothing to do
> with reading speed, it is 100%  only about the write speed.. I actually
> when running don't plan on writing a lot of files..
> 
> The problem I was having was simple, The first time I attempted to dd
> your image it was taking a huge amount of time after more than 1.5 hours
> I aborted the dd, and fired up the tools to investigate what was going
> on.  My investigation showed I could write the rasberrian iso at around
> 3.1 m/s to a  4 m/s device with no problems at all (just as I would
> expect),    When I was writing to the same card with your image I was
> only getting .9 m/s average and what looked like a huge number of
> re-read's from the input file.. ,  I will track down why this is only
> occurring on your image, and not others.. I have used 3 different
> copies, of your image, they all show the same problem. Before anyone
> asks they were not file links.. they were different files with different
> inode numbers. 
> 
> I have dd 2 other distributions today and they don't show any problem..
> all write to this card at around 3-3.3 m/s, exactly what I would expect.
>   I will investigate it further as soon as I have some time..   I won't
> bother the list further on this subject..
> 
> I only asked if anyone else was having any issues they were seeing as I
> didn't want to reinvent the wheel..
> 
> I do wonder why you recommend a class 10 card when the PI2 sd card you
> can order directly from them is a class 6 ?   Anyway back to other
> stuff.. I need to hook up a radio,  and get it working between stuff
> that I have to do to keep my family eating..    BTW the card I am using
> is branded Sandisk..  Fred
> 
> 
> On 5/1/15 9:20 AM, Doug Crompton wrote:
> > You mentioned a 16G class 4 card. We recommend nothing less than a
> > class 10 and in most cases we are using class 10 plus cards at this
> > time. Also Sandisk brand is recommended.  Using cheap unbranded cards
> > and cards of less than class 10  can lead to the problems that people
> > often complain about in other distributions.
> >
> > So far we have had very little SD card problems. I have programmed and
> > run dozens of systems and never had a problem with Sandisk class 10 8G
> > or 16G cards. I never expand the file system nor do I recommend doing
> > it unless you have a specific application.
> >
> > Write times vary mostly depending on the writer and USB speeds when
> > you are using a class 10 but are usually in the 10 minute range.
> >
> > It is always a good idea to have a backup card but as long as you
> > don't change anything much from the setup in many cases it would be
> > just as easy to setup a new card if you lost the old one for some reason.
> >
> > *73 Doug
> > WA3DSP
> > http://www.crompton.com/hamradio*
> >
> >
> >
> >
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