Thank you everyone for your attention to this.

I was able to get a free (as in free beer) memtest86 installed on a USB drive.  Memtest86 did lead me to a bad memory module.  I am operating on 1/2 ram until I get a replacement ram module.  Memtest86+ does not seem ready for a "secure boot" environment.

When I did the copy I was talking about, I was in the folder that the file exists:  I did a simple "cp file file2 "with no options.  There was no error messages of any kind, the ram issue was silent, if I recall correctly the bad copied file was always the same size as the original.  The issue lead to this was that I could not install a very large software package.  I would have random issues that were related to a corrupted file.

I wanted to use the minimum resources possible withe C code to eliminate confounding factors.

I am currently downloading the file and I will try to install the application today.

On 4/28/2022 4:44 PM, Doug Mildram wrote:

doug> I manually added Kevin back

       ....full blown (Kevin Stratton <kstratton@fastmail.us>      style)

on my reply header above.

I just like seeing it.  Or causing trouble.  

Ignore and/or X-out ifyou hit reply here..pardon the noise.

THE BIG FILE debug. In general, first I think it's very cool

appropriate to post an (easy-ish) C-code read/write task!

I stripped comments, repasted below, pardon again:

#define NUMBER 0x1FFFFFFFF  // copies without md5 detected error,file len 8589934591

int main()
{
    FILE * fp;
    uint32_t rand;
    uint64_t count;

    fp= fopen ("bigfile","w+");

    for (count=0;count<NUMBER;count++)
    {
        rand = random();
        fwrite(&rand,sizeof(random),1,fp);    }
    fclose (fp);
return 0;
}

dmildram/doug> First, try the memtest86+ , reply-to-list,

and i hope we swap stories on memtest later

after we figure out your fun puzzle,

I definitely want to hear where you ran into (+found) trouble!

BUT you didn't show the shell command (syntax)

that YOU RAN...was it quiet output? (what was the output?)

OR... did you get  error messages

or stop midway on you? I await your chapter 2....

as you said it could be HW, is semi-random

AND i don't get your whole story yet (close...) --doug

On Thu, Apr 28, 2022 at 11:55 AM Kevin Stratton via WLUG <wlug@lists.wlug.org> wrote:

I have been chasing my tail trying to download a very large to my desktop.  The bug is strange enough that it might be specific to hardware.

The issue is that I can not copy very large files accurately.  The threshold value size of the file seems to be about 8589934592.  Any file this size or larger seems to be uncopyable on my desktop.

I had downloaded a corrupted file of 71.9GB with Ubuntu 20.04, Ubuntu 22.04, Windows 10 virtua machine running under Ubuntu 20.04,  Manjaro.  All of theses OS;s were running on the same hardware.

I had no issues downloading the file from a raspberry pi with and external hard drive.

I have included the C file I used to create the files which also has some notes opn the results of the tests.



Any advice or help would be appreciated.





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