dd "Input/output error"

yys2000 · 08-16-2007, 09:24 AM

Hi:

I am using dd command to copy a compactflash card (64M):
Put the CF card to card reader then insert it to the laptop USB port.
Then use the command to copy whole CF card to local hard drive:
dd if=/dev/sdb of=/tmp/CFtmp bs=64M count=100

I got the error msg:
dd: reading '/dev/sdb/:Input/output error
0+1 records in
0+1 records out
64192512 bytes (64 MB) copies, 83.3284 seconds, 780 kb/s

thx

pwc101 · 08-16-2007, 09:30 AM

Setting the bs value to 64M means that you only need a count of 1, not 100. At the moment, dd's trying to read 64MB of data from the compact flash card 100 times. That's why it complains about there being no more data to copy (Input/output error).

I'd recommend not setting bs to 64M in case there's a problem, in which case it's generally considered better to have smaller blocks.

yys2000 · 08-16-2007, 10:58 AM

Quote:

Originally Posted by pwc101

Setting the bs value to 64M means that you only need a count of 1, not 100. At the moment, dd's trying to read 64MB of data from the compact flash card 100 times. That's why it complains about there being no more data to copy (Input/output error).

I'd recommend not setting bs to 64M in case there's a problem, in which case it's generally considered better to have smaller blocks.

Thx!
You are right.
So I think I can use the default values:
dd if=/dev/sdb of=/tmp/CFtmp

The error msg just gone.

yys2000 · 08-16-2007, 11:02 AM

BTW, how can I get rid of DD output msg?
125440+0 records in
125440+0 records out
64255280 bytes (64M) copies, 12.2689 seconds, 5.2 MB/s

I just want to run dd quitely.

pwc101 · 08-16-2007, 11:07 AM

In bash:

Code:

dd if=/dev/sdb of=/tmp/CFtmp &> /dev/null

yys2000 · 08-16-2007, 12:33 PM

Quote:

Originally Posted by pwc101

In bash:

Code:

dd if=/dev/sdb of=/tmp/CFtmp &> /dev/null

Thx!
It works.