Issues with downloading files

[newuser1234]

hi all, i'm a new ubuntu user and am hoping someone can help me with my issue. i have ubuntu v.12.04, 64 bit running on an asus u41sv laptop. it's installed as a dual boot with windows 7 64 bit. as far as i can tell, i have the latest ubuntu updates installed.

basically, i get errors in large files (academic files ~5-6 Gb) that i download from a server, or copy from a hard drive. once the files are downloaded, i find that text from other files on my hard drive are introduced into the downloaded/copied files. at first i thought it was a RAM issue, but i don't seem to have this issue when i download the same files using windows 7. the RAM and hard drive have also been tested by the retailers who said everything seems fine.

anyway, i'm hoping someone might be able to help on this issue. thanks in advance.

[apollothethird]

hi all, i'm a new ubuntu user and am hoping someone can help me with my issue. i have ubuntu v.12.04, 64 bit running on an asus u41sv laptop. it's installed as a dual boot with windows 7 64 bit. as far as i can tell, i have the latest ubuntu updates installed.

basically, i get errors in large files (academic files ~5-6 Gb) that i download from a server, or copy from a hard drive. once the files are downloaded, i find that text from other files on my hard drive are introduced into the downloaded/copied files. at first i thought it was a RAM issue, but i don't seem to have this issue when i download the same files using windows 7. the RAM and hard drive have also been tested by the retailers who said everything seems fine.

anyway, i'm hoping someone might be able to help on this issue. thanks in advance.

Your issue is a bit confusing. First I'll try to isolate the unrelated things of your post. It doesn't matter whether you have dual boot or not. When booting under Ubuntu, that's the operating system that you're running.

Also, I don't understand what you mean when you say download. Are you using a browser to download files? Which browser are you using?

If you mean you're copying files from one drive (or device) to another, how are you copying the files? Are you using the commandline (cp [/path-to-file/filename] [newfilename]"? Are you using Nautilus?

Finally, you suggest this only happens with large files. It may make a difference whether you have a 32bit or 64 bit installation. Since I you mention "64 bit" in your title, I'm assuming it's a 64 bit installation. Will you verify this with:

Click - Power Icon > System Settings > Details (And tell us what you have for OS Type?

Your answer to those questions might identify the problem or bring up more questions. Since both downloading and copying files should be non-issues, the resolution should be simple.

-- L. James

--
L. D. James
ljames@apollo3.com
www.apollo3.com/~ljames

[The Cog]

Also, what filesystem (ext4, NTFS etc) are you saving the files on?

[newuser1234]

thanks apollo/cog, and apologies for the lack of detail/confusion.

i'm using a 64 bit ubuntu OS. the issue arises when i use either the scp command to copy the files off a server (using ethernet connection), and when i copy the files off a portable hard drive through a usb connection (either command prompt or dragging files from one directory to another in the ubuntu "windows"). actually, i'm not sure if the issue only arises with big files, but i've noticed it for the big files as i've been working on them quite intensely lately.

the hard drive is partitioned and formatted to ext4 for ubuntu. i have these issues when i copy these files directly into the ext4 formatted partition when using the ubuntu scp command . however, the files copy perfectly from the server when i'm using windows 7 and the winscp program. in windows 7, i copy the files to a ntfs partition on my hard drive that's accessible to ubuntu. i've been working on these files in ubuntu using this shared ntfs partition.

anyway, please let me know if you need any more detail/clarification. cheers!

[apollothethird]

thanks apollo/cog, and apologies for the lack of detail/confusion.

i'm using a 64 bit ubuntu OS. the issue arises when i use either the scp command to copy the files off a server (using ethernet connection), and when i copy the files off a portable hard drive through a usb connection (either command prompt or dragging files from one directory to another in the ubuntu "windows"). actually, i'm not sure if the issue only arises with big files, but i've noticed it for the big files as i've been working on them quite intensely lately.

the hard drive is partitioned and formatted to ext4 for ubuntu. i have these issues when i copy these files directly into the ext4 formatted partition when using the ubuntu scp command . however, the files copy perfectly from the server when i'm using windows 7 and the winscp program. in windows 7, i copy the files to a ntfs partition on my hard drive that's accessible to ubuntu. i've been working on these files in ubuntu using this shared ntfs partition.

anyway, please let me know if you need any more detail/clarification. cheers!

I would like to try to duplicate the problem. To make it easier, try starting out with a couple of small files. Give us the exact command you're using. Use the code tags to make it easy to follow. Also try the "cp" command if you're copying from a USB drive. Immediately after copying the file run the cmp command to identify what has happened (if you're copying from a usb drive).

For example:

$ cp /mnt/usbdrive/filea ~/filea
$ cmp /mnt/usbdrive/filea ~/filea

After you post your "scp" examples I'll test what you're using on my computer also.

-- L. James

--
L. D. James
ljames@apollo3.com
www.apollo3.com/~ljames

[newuser1234]

thanks. i'm kinda new to the linux environment so i won't be too specific re. my scp command in case it's not a god thing (even though my account is password protected), but it is essentially:

scp my_user_account@server.university.edu.au:/home/my_user_account/file .

with re. to copying from my hard drive, i used the following command:

cp /media/linux/Seq/Raw_data/22Rv1_DHT_L1_1.fq .

as suggested, i then compared the two files using cmp:

laij@laij:~/temp$ cmp -b /media/linux/Seq/Raw_data/22Rv1_DHT_L1_1.fq22Rv1_DHT_L1_1.fq
/media/linux/Seq/Raw_data/22Rv1_DHT_L1_1.fq 22Rv1_DHT_L1_1.fq differ: byte 526385153, line 8524481 is 61 1 124 T

i copied the file 5 times, and four times it was corrupted (on one copy it was good). also, it's not always at the same place where the errors start (or what's introduced into the file) in the copied file.

as suggested, i then made two smaller files of the original that's on my external hard drive using the following command:

laij@laij:/media/linux/Seq/Raw_data$ head -100000 22Rv1_DHT_L1_1.fq >shorter
laij@laij:/media/linux/Seq/Raw_data$ head -10000000 22Rv1_DHT_L1_1.fq >short

-rw-rw-r-- 1 laij laij 6139190 Nov 4 16:33 short
-rw-rw-r-- 1 laij laij 61316 Nov 4 16:30 shorter
-rw------- 1 laij laij 5476503134 Jun 12 12:24 22Rv1_DHT_L1_1.fq ===> original file

i copied and then compared both files (with their respective original on the external hard drive) 10 times and they were fine for all copies.

laij@laij:~/temp$ cp /media/linux/Seq/Raw_data/short .
laij@laij:~/temp$ cmp -b /media/linux/Seq/Raw_data/short short
laij@laij:~/temp$ cp /media/linux/Seq/Raw_data/shorter .
laij@laij:~/temp$ cmp -b /media/linux/Seq/Raw_data/shorter shorter