Re: USB port issue by Jo-Anne
Jo-Anne
Fri Jun 27 20:07:37 PDT 2008
Thank you, Bill and Paul! I just checked my hub, and I think it's OK. It's a
Kensington with its own power supply, which claims to be .6 amp. A good
thing, given that I'm backing up to portable drives, which don't have their
own power supply.
What I read at the user forum for the backup software is that sometimes a
backup will "error out" during a restore from a drive connected to a USB hub
(even if the drive has worked before while connected to that hub) but will
restore well if connected directly to a USB port on the computer.
I'll keep that in mind in case I run into trouble.
Thank you again!
Jo-Anne
"Paul" <nospam@needed.com> wrote in message news:g442jn$9md$1@aioe.org...
> Jo-Anne wrote:
>> The beginner's guide to a backup program for my Windows XP SP3 desktop
>> computer says to always connect the backup USB device directly to a port
>> on the back of the computer. It emphasizes "Do not use 2-4 port
>> connectors." I have a 7-port hub connected to one of the USB ports on the
>> back of the computer. It seems to work OK, in that when I connect the USB
>> drives to the hub, they show up in Windows Explorer and in the taskbar.
>> Is there any reason not to use the hub for backing up to the USB drives?
>>
>> Thank you!
>>
>> Jo-Anne
>
> One potential issue with a hub, is power.
>
> First of all, there are a couple kinds of external enclosures.
> A 3.5" has its own power supply. It doesn't need to draw power from
> the USB port to work. If you wanted to use a USB hub, between the
> computer and that kind of enclosure, it should work.
>
> A 2.5" external USB drive, may try to extract the power it needs
> to run the hard drive, from the USB bus. A port on the back of the
> computer, is good for 500mA. If you use a bus powered hub (i.e.
> a hub without its own power supply), then each port on those hubs
> is limited to 100mA. If you use a self-powered hub (hub has a
> good sized wall wart to power it), then each port should be
> capable of 500mA again. I think one self-powered hub I saw, had
> something like a 3 amp supply for a wall wart.
>
> If you have any doubts about your USB hardware, then plugging into
> the back of the computer is good advice. If you know your external
> hub is USB2 capable, and has its own power source, then chances are it
> won't have any limitations to speak of. But when hubs cost so little,
> there is also the possibility of some junky hubs as well.
>
> Paul