[comp.unix.admin] dd problems

frazier@oahu.cs.ucla.edu (Greg Frazier) (06/22/91)

Hello!
	Yes, it is me again, the guy who is having troubles
with his dumps.  I am using dd to verify that the writes to
the tape happened correctly.  Well, it seems that my troubles
are with dd, not with dump, and I'm confused.  From the
keyboard, I type

	prompt) dd if=/dev/rst1 of=/dev/null bs=1024

and this error msg appears on the console:

st1:     Error for command 'read', Error Level: 'Fatal'
        Block: 0        File Number: 0
        Sense Key: No Additional Sense
        Incorrect Length Indicator Set

What is a length indicator?  Is this something on the tape,
or is this an undocumented parameter of dd?  Any help would
be appreciated.  Oh, the details: this is an exebyte drive
on a sparcstation running SunOS 4.1.1.  There are multiple
files on the tape, I get this error msg no matter which
file I attempt to dd.  I have also tried *not* setting
a block size on the dd (i.e. letting it be the default).

Thanks for any help.
-- 


Greg Frazier	frazier@CS.UCLA.EDU	!{ucbvax,rutgers}!ucla-cs!frazier

cpcahil@virtech.uucp (Conor P. Cahill) (06/23/91)

frazier@oahu.cs.ucla.edu (Greg Frazier) writes:

>	prompt) dd if=/dev/rst1 of=/dev/null bs=1024
>and this error msg appears on the console:
>st1:     Error for command 'read', Error Level: 'Fatal'
>        Block: 0        File Number: 0
>        Sense Key: No Additional Sense
>        Incorrect Length Indicator Set

>What is a length indicator?  Is this something on the tape,
>or is this an undocumented parameter of dd?  Any help would

This is not an error message from dd.  It is probably an error
message from the device driver for the tape drive (or scsi drive
if the tape drive is hung off the scsi bus).  I would guest that
the data was written to tape with a larger block size than you 
are reading it with.  Try to increase bs (set it equal to the
blocking factor used in makeing the tape).

>file I attempt to dd.  I have also tried *not* setting
>a block size on the dd (i.e. letting it be the default).

This would be worse because dd usually defaults to 512.
-- 
I guess these are the views of VTI - since it is my consulting company.

Conor P. Cahill              (703)430-9247              uunet!virtech!cpcahil 
Virtual Technologies, Inc.  46030 Manekin Plaza            Sterling, VA 22170