removable HD stops

[Lenny]

Hi,
I have a new 250GB external USB HD. When I plug it into one of my older
machines and try to copy a large file(s) it starts and then the light on the
front goes out and the copying stops. I am still able to view the file
structure but not transfer anything else. This happens everytime. If I take
the HD to one of my new computers I don't seem to have any problems with the
transfers at all.. I have changed the file system to ntfs. Does this happen
or have I got a faulty HD?

 

[philo]

Hi,
I have a new 250GB external USB HD. When I plug it into one of my older
machines and try to copy a large file(s) it starts and then the light on the
front goes out and the copying stops. I am still able to view the file
structure but not transfer anything else. This happens everytime. If I take
the HD to one of my new computers I don't seem to have any problems with the
transfers at all.. I have changed the file system to ntfs. Does this happen
or have I got a faulty HD?

If the older machine is fat32...there is a 4 gig files size limit

NTFS drives have no such limitations.
except for the space used by the MFT...a file on an NTFS drive could take up
the entire volume if so desired

 

[Bob Willard]

If the older machine is fat32...there is a 4 gig files size limit

NTFS drives have no such limitations.
except for the space used by the MFT...a file on an NTFS drive could take up
the entire volume if so desired

Uh, NTFS/FAT32/FAT16 is not an attribute of the PC; it is an attribute of
*each* partition of each HD. On this (XP) PC, for example, I have one HD
with at FAT16 part, one with a FAT32 part, and other NTFS parts; XP reads
and writes correctly to all parts.

It may be that the older PC cannot handle large HDs; perhaps the 127GB limit.
If so, a BIOS update may cure the problem.

 

[Paul]

Hi,
I have a new 250GB external USB HD. When I plug it into one of my older
machines and try to copy a large file(s) it starts and then the light on the
front goes out and the copying stops. I am still able to view the file
structure but not transfer anything else. This happens everytime. If I take
the HD to one of my new computers I don't seem to have any problems with the
transfers at all.. I have changed the file system to ntfs. Does this happen
or have I got a faulty HD?

Is the external drive a 2.5" or a 3.5" drive ?
If it is 3.5", in probably has its own power supply.
If it is 2.5", it may be bus powered from the USB bus.

Some USB external enclosures come with a "2-to-1" USB cable.
This cable can carry extra power, if the drive needs more
than +5V @ 500mA to operate. This kind of cable is only
necessary for external 2.5" drives, where the drive draws
too much current. Some new drives don't need it.

http://images10.newegg.com/NeweggImage/productimage/17-163-056-04.jpg

It is possible the new computers are providing more current on
the single USB connector.

If the drive works on some of the computers, then the
drive is functional. But something must be different, about
the cases where the light goes off.

If you want a test to try, try the following. You will need a
USB optical mouse (one with the red LED light output), as well
as the external drive. Go to the computer that gives you problems.
Plug in the mouse and the external drive, into the same "USB stack".
Desktop computers usually arrange USB connectors in pairs, in a stack.
The two USB connectors in a stack, share the same power source.

Now, with both the USB mouse plugged in and the USB drive
plugged in, you should see the red LED on the optical mouse
light up. When the USB hard drives stops functioning, does
the LED on the mouse go out too ? If so, that means the
automatic fuse, or current protection feature, is cutting
off the power to that USB stack. My motherboards here,
have an automatic fuse per USB stack (two connectors), so
if the fuse disconnects the power, both USB connectors
in the same stack lose power at the same time. The fuse
recovers when it cools off, so may take a few seconds to
cool, once the overload has been removed. The fuse does
not need to be replaced, if it is a Polyfuse.

http://en.wikipedia.org/wiki/Polyfuse

If you are still having problems, post back what make and
model of external drive this is. Some external drive products
seem to have poor reliability, and you should read the product
reviews before you buy them. Nothing worse, than using an
external drive for backups, and the external fails within
the first few weeks of usage.

Paul

 

[philo]

Uh, NTFS/FAT32/FAT16 is not an attribute of the PC; it is an attribute of
*each* partition of each HD. On this (XP) PC, for example, I have one HD
with at FAT16 part, one with a FAT32 part, and other NTFS parts; XP reads
and writes correctly to all parts.

It may be that the older PC cannot handle large HDs; perhaps the 127GB limit.
If so, a BIOS update may cure the problem.

 

[Lenny]

thanks for that reply paul,
I will check that idea about the usb stack.

Just for the record it is a 3.5" powered 250GB Freecom Classic USB External
HD 8MB Cache. I did check the reviews on this product and they were OK if
not very good.

 

[Paul]

thanks for that reply paul,
I will check that idea about the usb stack.

Just for the record it is a 3.5" powered 250GB Freecom Classic USB External
HD 8MB Cache. I did check the reviews on this product and they were OK if
not very good.

Since it is self powered from the wall, that removed a lot of the easy answers.

You could try UVCView, and see if anything changes before and after a write
failure. What you'd be looking for, is a change in the place the drive shows
up, or a change in the connect speed.

http://www.microsoft.com/whdc/device/stream/vidcap/UVCViewdwn.mspx

Perhaps the Event Viewer would report a delayed write failure or something
similar, on the affect drive. But none of the tools that I know of, will
be able to say exactly what went wrong.

For USB ports, electrically I'd prefer to use the USB ports on the back
of the computer. They should have better quality signals, compared to the
ones on the front. Some computer cases have dodgy USB wiring to the front
panel.

But since you can still see the drive after the failure, it is a pretty
strange failure. Can you actually visit folders you haven't accessed in
the current session (i.e. so Windows cannot just rely on cached info,
but has to do actual read operations on the disk) ? It would be pretty
strange, if reading worked, but writing didn't.

Paul

 

[Lenny]

I have come to the conclusion that it is the USB ports on this one computer
that are causing the error and not the removable HD. I have run it on a
newer machine for a few days now without any problems and since having this
problem the USB's are now not recognising any USB devices (although when I
first wrote the post all other USB devices were working just fine). Now both
stacks and the front ones are all causing errors even after uninstalling
them all from Device manager. I will have to find a way around this some how
but will probably back up via the network in this case.
Thanks for everyone's efforts. We got there in the end and at least it isn't
another item to send back.

 

[Paul]

I have come to the conclusion that it is the USB ports on this one computer
that are causing the error and not the removable HD. I have run it on a
newer machine for a few days now without any problems and since having this
problem the USB's are now not recognising any USB devices (although when I
first wrote the post all other USB devices were working just fine). Now both
stacks and the front ones are all causing errors even after uninstalling
them all from Device manager. I will have to find a way around this some how
but will probably back up via the network in this case.
Thanks for everyone's efforts. We got there in the end and at least it isn't
another item to send back.

You could try placing a PCI USB2 card in the defective machine.
That'll allow you to compare some new ports, with the old ones.

Paul