Problem with USB external hard drive

[Bret Busby <bret.busby@gmail.com>]

Hello.

I have a 1TB USB external hard drive, to which, I had been making
backups from different computers,  and, to which HDD, I had also moved
some data, to  free up system storage.

I unplugged the HDD from one computer, after having shut the computer
down, to get some  hardware work done on the computer.

When I reconnected the HDD to the computer, the HDD could not be read
- I got an error message
"Error mounting: mount: /dev/sdb1: can't read superblock"

I get that error when I try to read the HDD, using the file managers,
and, when I try to mount the HDD,  using the file managers.

I have tried to access the HDD from different computers (plugging it
in before booting, then, booting the computer, and trying to access
the HDD via the file managers, which each return the same error), with
both Debian 6.x, from which it was last successfully accessed, and,
this installation of Debian 7.5 xfce; each is Debian amd64.

The device still shows in lshw; giving, on Debian 7.5,

"
*-scsi
          physical id: 1
          bus info: usb@3:3
          logical name: scsi6
          capabilities: emulated
        *-disk
             description: SCSI Disk
             product: External USB 3.0
             vendor: TOSHIBA
             physical id: 0.0.0
             bus info: scsi@6:0.0.0
             logical name: /dev/sdb
             version: 0101
             serial: 367045A3
             size: 931GiB (1TB)
             capabilities: partitioned partitioned:dos
             configuration: ansiversion=6 sectorsize=512 signature=ff317295
           *-volume
                description: Windows FAT volume
                vendor: MSDOS5.0
                physical id: 1
                bus info: scsi@6:0.0.0,1
                logical name: /dev/sdb1
                version: FAT32
                serial: 10c0-c930
                size: 931GiB
                capacity: 931GiB
                capabilities: primary fat initialized
                configuration: FATs=2 filesystem=fat
"

Is a utility available in Debian Linux, to overcome the superblock
problem, so as to allow me to resume accessing the data on the USB
external HDD?

Thank you in anticipation.

-- 
Bret Busby
Armadale
West Australia
..............

"So once you do know what the question actually is,
 you'll know what the answer means."
- Deep Thought,
 Chapter 28 of Book 1 of
 "The Hitchhiker's Guide to the Galaxy:
 A Trilogy In Four Parts",
 written by Douglas Adams,
 published by Pan Books, 1992

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