Message-ID: <4ADF2690.9080407@RevolutionONE.com>
Date: Wed, 21 Oct 2009 10:19:44 -0500
From: "Jeffrey C. Smith" <Jeff AT RevolutionONE DOT com>
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Subject: Re: Quantum LTO 4 tape drive and Cygwin 1.7?
References: <4ADE1C79 DOT 1090701 AT RevolutionONE DOT com> <20091021105914 DOT GG16678 AT calimero DOT vinschen DOT de>
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Corinna,

Thanks for your reply. My responses below...

Corinna Vinschen wrote:
> On Oct 20 15:24, Jeffrey C. Smith wrote:
>> I'm trying to use tar from Cygwin 1.7 Beta on a Win 2008 R2 machine to 
>> backup some files to a Quantum LTO 4 SAS tape drive. I've tried all the 
>> usual POSIX paths (/dev/nst0, /dev/st0, /dev/st1, etc.) as well as some 
>> other variants (\\.\tape0) with no joy. tar fails with a "No such file or 
>> directory" error.
> 
> The right way to access tapes is to use the /dev/stX or /dev/nstX
> variation.  Using the Windows path \\.\tapeX will not work as expected.

OK...

> Typically the first tape drive attached to a Windows machine is
> called "tape0", which is what Cygwin tries to access when specifying
> /dev/st0 and /dev/nst0.
> 
> If you want to see the name of the tape drive on your system, just open
> the Device Manager and then open the device tree element "Tape drives".
> You should find an entry named like your tape device, for instance
> "QUANTUM ULTRIUM 4" or something along these lines.  Double click opens
> the Properties dialog.  There's a tab called "Tape Symbolic Name".  Open
> it.  It will show you the string "tapeX" with X some number >= 0.  THis
> is the same number to use in Cygwin.

OK. I'm looking at the window titled "Quantum LTO 4 Tape Drive 
Properties" under the tab titled "Tape Symbolic Name" and the tape name 
appears to be "Tape2147483646" (that's a long way from tape0!).

I started Cygwin as administrator and tried this:

$ mt -f /dev/nst2147483646
mt: /dev/nst2147483646: No such file or directory

$ mt -f /dev/st2147483646
mt: /dev/st2147483646: No such file or directory

> I just mounted a tape drive to my Windows 7 machine and it showed up as
> \\.\tape0 in the device manager.  I could use mt(1) on it:
> 
>   $ mt -f /dev/nst0 status
>   drive type = STK 9840
>   drive status = 1107361792
>   sense key error = 0
>   residue count = 0
>   file number = 0
>   block number = 0
>   Tape block size 65536 bytes. Density code 42 (unknown).
>   General status bits on (410b0000):
>    BOT ONLINE IM_REP_EN
> 
> Using the correct /dev/[n]stX, I never saw a "No such file" error yet.
> What I can easily reproduce is a "Permission denied", though.  Under
> UAC, if you're using the standard command line you don't have admin
> privileges.  More exact, you don't have backup/restore privileges.
> Accessing a tape drive without these privileges fails.  If you want
> to access the tape drive, you have to start cygwin elevated.

Do you think the tape name "Tape2147483646" is a problem? At the bottom 
of the "Tape Symbolic Name" tab there is a comment that says "Symbolic 
name such as Tape0. It would seem that the name "Tape2147483646" is 
somewhat out of the ordinary. BTW, 2147483646 is -2 in a two's 
complement 32 bit number. Could this be some type of overflow/underflow 
error?

Also, this is Windows 2008 R2. I'm told that 2008 R2 and Win 7 share the 
same code base. Is 2008 R2 an officially supported platform for 1.7?

I really appreciate your help. If there is anything I need to do on my 
end to help resolve the issue please let me know.

Thanks,
Jeff
--
Jeffrey C. Smith                                   Phone: 512.692.7607
RevolutionONE                                      Cell : 512.965.3898
Jeff_at_RevolutionONE.com


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