Flash drive--invalid partition table

[dougmack]

Tried to repartition and reformat a 64 GB flash drive--PC went into screensave shutdown while formatting. Now GParted says
"Invalid partition table on /dev/sdb-wrong signature ffff"
Can this drive be saved?  How?
Thanx--doug

[agmg]

Can you see any partition using the fdisk -l command?

[dougmack]

No.  GParted shows a completely unallocated partition area.  Windows 7 thinks there is a 29GB partition.

[agmg]

How much GB does this unallocated area show in Gparted? Smaller than 64GB?

As su give the command fdisk -l /dev/sdb
This will show the size of your partition.

[dougmack]

I just ran GParted again.  Now it shows the ntfs partition (that Windows knew about) and it allowed me to make to make 2 logical partitions in the extended partition area. But it still says the partition table is invalid with signature ffff.  Now I found a window that says libparted bug found--invalid partition table fetc.
I'm not sure what's going on now.  How long should a 32-bit relatively slow machine take to format a couple of 30GB partitions?

[agmg]

So, you have the whole disk available now? And created two partitions of about 30GB each?

I can't know what's going on on your device until you give me the result of the fdisk command.

Just by guessing, I would go to the Device menu of the GParted window and give a try to the option "Create Partition Table"
You can also use "fdisk /dev/sda" and then press "w" to make an attempt to write the partition table to the disk.

Give me some more info about the state of your drive and I will be able to help you further.

[dougmack]

OK, things were getting past me.  I aborted the so-called format--it didn't seem to be getting anywhere.
But I did the fdisk /dev/sdb   w trick and it said it fixed the partition table. GParted now shows the whole drive unallocated,
as I would expect, and does not come up with the partition table error anymore.  Now I think I have a chance to
get it right, but I'm going to wait until tomorrow--it's 4:03 AM here!

Thanx for the answer on the partition table, and your patience with a tired old man here!

--doug

--

[agmg]

Glad you sorted it out!

You don't need to format the drive.
Just use the unallocated space to create the partition(s) you need with the filesystem you prefer and you're done!

Have a nice rest!

[dougmack]

That's (welcome) news to me--that I don't have to format the partitions. How come?

I started this whole thing because I decided to backup my whole system, not just pieces, and was encouraged by the PCLINUX Help Knowledge Base,
which is something else I didn't know about until a couple days ago. It's quite useful, and should somehow become more readily obviously
available--I've been using PCLOS for 2-1/2 years and just discovered it.  It may not be on a par with the information the Ubuntu people put out,
but it's certainly a step in the right direction, and I commend the devs who contribute to it!

--doug

[agmg]

When creating a new partition with Gparted it will be formatted with the filesystem you selected.
You don't have to format it unless you want to clean it or change the filesystem.

That is what I meant, sorry if I didn't express myself well

[dougmack]

Let me be clear on this--before I messed with the flash drive, it was formatted in a DOS filesystem, like all flash drives. I'd like to make some partitions with
ext3 filesystem, to copy some Linux partitions onto. You say I don't have to format them, is this correct?

--doug

[agmg]

Before you went to bed we were at the point where you recovered the partition table of the drive and had the whole of it as unallocated space.
From that point, use Gparted to create your partition(s) with the ext3 filesystem.

Right click on the drive and select "New" and select ext3 as the filesystem.
If you just need one partition, use all the available space.
If you need more than one, adjust them according to your needs.
The first partition will be a primary one.
Next one will be an extended one containing one or more logical partitions.

When you're done, click "Apply" and Gparted will create them and format them with the selected filesystem.
No need for an extra format as I wrote in my previous post.

[Just17]

The first partition will be a primary one.
Next one will be an extended one containing one or more logical partitions.

The second, third and fourth partitions (if required) can be primary.

You only need logical partitions if you intend to have more than four partitions on the device ....  in which case the fourth one can be an Extended Partition to hold the Logical Partitions you wish to create.

[agmg]

The first partition will be a primary one.
Next one will be an extended one containing one or more logical partitions.

The second, third and fourth partitions (if required) can be primary.

You only need logical partitions if you intend to have more than four partitions on the device ....  in which case the fourth one can be an Extended Partition to hold the Logical Partitions you wish to create.

Thanks Just17. By habit, I create all my partitions this way

[Just17]

The first partition will be a primary one.
Next one will be an extended one containing one or more logical partitions.

The second, third and fourth partitions (if required) can be primary.

You only need logical partitions if you intend to have more than four partitions on the device ....  in which case the fourth one can be an Extended Partition to hold the Logical Partitions you wish to create.

Thanks Just17. By habit, I create all my partitions this way

It *can* be important to have primary partitions ......  for instance if writing a suitable hybrid ISO to a partition, it requires a primary partition to boot (apparently). At least I found it would not boot from a logical partition. 
So for multiple hybrid ISOs on partitions the full compliment of primary partitions can be advantageous.