[ python-Bugs-1362587 ] Problem with tapedevices and the tarfile module

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Bugs item #1362587, was opened at 2005-11-21 08:44
Message generated for change (Settings changed) made by gustaebel
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Category: Python Library
Group: Python 2.4
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Henrik (esshenrik)
>Assigned to: Lars Gustäbel (gustaebel)
Summary: Problem with tapedevices and the tarfile module

Initial Comment:
Problem to read a archive from tape that was created 
with the tarfile module in python.

Error:
>>> tar = tarfile.open("/dev/st0", "r")
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/usr/local/lib/python2.4/tarfile.py", line 
916, in open
    return func(name, "r", fileobj)
  File "/usr/local/lib/python2.4/tarfile.py", line 
933, in taropen
    return cls(name, mode, fileobj)
  File "/usr/local/lib/python2.4/tarfile.py", line 
811, in __init__
    fileobj = file(self.name, self.mode)
IOError: [Errno 16] Device or resource 
busy: '/dev/st0'


I was creating the archive with succes:
>>> tar.close()
>>> tar = tarfile.open("/dev/st0", "w")
>>> tar.add("/tmp/bin1.tar")
>>> tar.add("/tmp/bin2.tar")
>>> tar.close()
>>>

When I try to read the tape without pyton the 
folowing error:
[root at localhost tmp]# tar tvbf 20 /dev/st0
tar: Record size = 8 blocks
-rw-r--r-- root/root 128614400 2005-11-20 19:53:11 
tmp/bin1.tar
tar: /dev/st0: Cannot read: Cannot allocate memory
tar: /dev/st0: Cannot read: Cannot allocate memory
tar: /dev/st0: Cannot read: Cannot allocate memory
tar: /dev/st0: Cannot read: Cannot allocate memory
tar: /dev/st0: Cannot read: Cannot allocate memory
tar: /dev/st0: Cannot read: Cannot allocate memory
tar: /dev/st0: Cannot read: Cannot allocate memory
......

Can anyone help me with this problem or have another 
module for tarfile that works with tapedevices?

/Henrik 


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Comment By: Martin v. Löwis (loewis)
Date: 2006-07-03 14:31

Message:
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user_id=21627

Lowering priority, as the issue doesn't appear that urgent.

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Comment By: Lars Gustäbel (gustaebel)
Date: 2005-11-21 09:40

Message:
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user_id=642936

Could try and use tarfile's stream interface for writing and
reading and see if that works? Just append a pipe symbol to
the mode, e.g.:

tar = tarfile.open("/dev/st0", "w|")

----------------------------------------------------------------------

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