Connect to Tape Drive, Nonexistent GPIB interface

[conn.lee]

HI,

I tried to connect to tape drive (USB DAT 40 tape drive , win 7, driver working)

Following the example:   CreateFile(TEXT("\\\\.\\TAPE0"),         in :

https://docs.microsoft.com/en-gb/windows/win32/backup/creating-a-backup-application

when I wire the path \\.\TAPE0 to CreateFileA call library, I got Error 7, Nonexistent GPIB interface , any idea how to create the handle for tape drive? 

[RTSLVU]

 I don't see how this is LabVIEW related, specially when the example you gave/tried was in C++

But I am going to go out on a limb here and guess that the "path" is different for the USB tape drive.

As "\\\\.\\TAPE0" may only work on old school tape drives with a dedicated internal interface.

I believe the old ones that weren't proprietary were some sort of SCSI device.

[conn.lee]

Thanks for your reply. This is labview related as I am doing this in Labview and got Error7. 

The C++ is Microsoft's example, I tried to replicate that in Labview, Call library Kernel32.dll using function CreateFileA(Path...)

It's an old style DAT 40 tape drive, I have the windows driver working, I am trying to connect via Labview, to revive an old XP backup app; it is an external USB tape drive, (SCSI driver is no longer available for Win 7)

It seems Tape drive doesn't mount to a logical drive letter like C:\\ and needs to be referred to as \\.\Tape0, but Labview doesn't seem to recognise it.

Any comment much appreciated.

[RavensFan]

Did you read the entire error description for Error 7?

Only the second part says non-existent GPIB interface.

The first part says, "File not Found".  That is more likely the error you are seeing.

(Some errors happened to have the same error codes, so LabVIEW shows all possibilities.  You need to read them all and see which makes the most sense for your situation!)

"\\.\"  seems like an odd start to a file path.  Generally \\xxxxx is the start to describing a server name.  So having just a dot there seems wrong.

[conn.lee]

Yes thanks you are right, it does say ‘File not found'. 

and that's where I'm lost, what is the file handle for Tape drive..?

on Miscrosoft Dev's page, the example given for Tape drive path \\.\Tape0  https://docs.microsoft.com/en-gb/windows/win32/backup/creating-a-backup-application I also tried wiring string 'Device Instance Path' as listed in Windows' Driver Properties '\USBSTOR\SEQUENTIAL&...' long string, no avail.

[conn.lee]

The error says Nonexistent GPIB IEEE488 interface, the USB Tape drive uses a type A USB to connect to my PC, not GPIB IEEE488 converter, could this be the problem..?

[GerdW]

Hi Lee,

no, it's the missing/wrong filepath.

Can you use any other tool to write to that tape drive? Can you create and save a textfile from Notepad to this drive? Once you figure out how to create a proper filepath with any other tool you can use the same filepath in LabVIEW…

[conn.lee]

Thanks,  I've done some digging:

https://stackoverflow.com/questions/23778814/tape-drive-directory-path-on-windows-8-1

"Most likely you'll want to enumerate the attached devices using SetupDiGetClassDevs() passing GUID_DEVINTERFACE_TAPE as the class GUID, followed by SetupDiEnumDeviceInterfaces(), then you can get the device path using SetupDiGetDeviceInterfaceDetail(). You can then open it using CreateFile(). "

Looks like I need to use  Setupapi.h  to setup the API first, would it be just like a call class function? looks like I need to include the .lib import library, any pointers much appreciated.

[RavensFan]

---

@conn.lee wrote:

The error says Nonexistent GPIB IEEE488 interface, the USB Tape drive uses a type A USB to connect to my PC, not GPIB IEEE488 converter, could this be the problem..?

---

AGAIN, that is the 2nd half of the message.  It probably does not apply.

Reread the 1st half of the message.

2 errors share the same error number.  One of those two error messages apply.  You need to figure out which error message applies when error code 7 was thrown.  The vast majority of the time it is NOT the GPIB message.

[rolfk]

---

@RavensFan wrote:

"\\.\"  seems like an odd start to a file path.  Generally \\xxxxx is the start to describing a server name.  So having just a dot there seems wrong.

---

The error is definitely meaning that the file somehow could not be created. It has nothing to do with GPIB.

\\.\ is a valid Windows kernel path prefix indicating that it is actually a device specification rather than a filesystem specification but if the Tape0 device name is valid or not depends if the actual drivers are installed and mapped to that device name. Most likely it's not and just because a Microsoft example uses that name does not mean that your tape drive is actually installed under that device name. That depends on the installed driver and how it registers its device in the Windows device namespace.

But even if you find the correct device name to use with CreateFile() you are still nowhere! Accessing the device will CERTAINLY involve calling the DeviceIOCtrl() function since you can't just go and try to call ReadFile() on a device handle and hope to get anything intelligent with that. DeviceIOCtrl() is however a rather diffcult API to use and even more difficult to use through a LabVIEW Call Library Node. I really doubt that you want to go down this path!