USB connected HDD's recognized some times, not some times in 12.04

[Odyssey1942]

I have been testing several older HDD's that been collecting here to determine which work, and which do not. I am using a USB kit consisting of an external power supply with a molex and a cable with a USB male on one end and an EIDE adapter on the other. I am plugging the USB into the back of the computer.

The first thing I notice is that 10 of 12 HDD's are not recognized at all by a Ubuntu 12.04 computer. However all but two of the 10 show data transfer when plugged in (the cable glows red at the adapter when data is being transferred.) AFAIK all the drives but two were working when put into the drawer.

So the first question is, are the 10 drives, which I thought were good, bad or is there an issue, such as formatting, which keeps them from being recognized, and if so what might that/those issue/s be? BTW, I have tried a combination of Master, Slave, and Cable Select and AFAICT, it doesn't matter how the jumper is set.

Secondly, for the two drives that do work, they are not consistently recognized. For example, if I reboot the machine, and plug in one of the "non-working" drives, then try one of the working drives, they are usually not recognized. But if I reboot with them plugged in, they are recognized. Or if I reboot, then plug in the working drive before trying another drive, it is recognized.

Anyone shed any light on this?

[bc.haynes]

Are you using the same USB port for all drives? I read a post (don't remember where) that someone han an external HDD that worked in the USB 2.0 port, but not in a USB 3.0 port. That's about all I have to offer. I'm a noob.

[Odyssey1942]

same port

[J_Me]

Are your drives being 'ground' properly by isolating any bare metal parts. Also it maybe that your drives do work but are not automatically mounted 'cat /proc/partitions' will list anything plugged in, mounted or not. You can use that in conjunction with 'mount' to get more info.

[squakie]

Try the following each time you put a different drive in the external setup:

-open a terminal (ctrl/alt/F1)
- type:

sudo blkid <press enter>

Is the disk listed?

sudo df -g <press enter>

Is the disk listed?

if not, install gparted:

sudo apt-get install gparted <pess enter>

usse your normal userid and password (the password is not echoed to the screen)

you only need to do this once.

then for each disk:

sudo gparted <pess enter>

On the top bar, on the left, click the first option, then go down to devices - is the disk listed? If you click on the disk you can see if it is partitioned or not. If there is a red circle with a white exclamation point in it then it probably means you need to create a partition table. This can happen, for example, on drives that have been "wiped". DO NOT MAKE ANY CHANGES UNLESS YOU KNOW WHAT YOU ARE DOING AND BE *SURE* YOU ARE ON THE CORRECT DRIVE - OTHERWISE YOU CAN RENDER YOUR INSTALL USELESS AND HAVE TO REINSTALL.

[squakie]

I should also mention the following:

If you have created a mount statement for this external drive, be careful of using /dev/sd"x". This can change with USB devices. Also, you don't want to mount by UUID in this case as each drive will have it's own UUID (mounting a known USB drive by UUID is the recommended way).

[Odyssey1942]

J_Me and Squakie

Thanks for all the tips and clear step by step explanations

None of the "dead" drives responded to any of those commands.

Also " sudo df -g " returned an error message (no such parameter "g", I think it was. )

Is there any point in trying to boot with them connected to an internal EIDE cable, or would that create boot issues?

Or would you conclude that they are all dead?

[Odyssey1942]

It occurred to me that I should try the known "good" drives.

Without rebooting the computer, the only command that showed me that something was there was

cat /proc/partitions

which listed the good drives as sdb.

But neither blkid nor gparted could detect them.

[varunendra]

I have been testing several older HDD's that been collecting here to determine which work, and which do not. I am using a USB kit consisting of an external power supply with a molex and a cable with a USB male on one end and an EIDE adapter on the other. I am plugging the USB into the back of the computer.

Is the USB cable short enough? Extra length of the USB cable is the most common cause for all the symptoms you mentioned.

Is the external Power Supply powerful enough to supply sufficient power to the drives? Low power, especially the 5 volts supply, is the next most common cause for all the symptoms you mentioned.

The best and safest way to check if the drives themselves are functional or not is to directly connect them to the internal IDE ports (if you have them). There is no harm or added complexity in doing so.

I have tried a combination of Master, Slave, and Cable Select and AFAICT, it doesn't matter how the jumper is set.

It won't matter as long as you are using it via the USB kit. It WILL matter when connecting internally. It seems you already know how and when to set it to what, usually CS is okay, or for some not-so-smart BIOS, manually setting it to Slave when there is another one connected to the same cable as Master (or vice-versa).

[Odyssey1942]

I have two of these kits and have used both. No way to know if the power is sufficient because, as I understand it voltage needs to be tested under load to get a true reading. My multimeter will only give an unloaded voltage.

The USB cable is about 26" long. In your opinion is that too long?

I will try a flat cable and try to mount them internally. This will reqiure a shutdown and power off since I will be hooking up an IDE cable. Will work on this tomorrow and let everyone know how I get on.