2nd External Drive doesn't work

I have been using a USB external disk drive for a long time and it works fine. Recently I bought a second USB external disk drive. It works OK by itself. when I plug in the second drive, then the first drive quits working. I can't copy to the first drive anymore although the second one works OK. If I unplug the second drive and reboot, then the first drive works again. So clearly it's an operating system problem, or maybe a USB driver problem. Does anybody know what the problem is and how to fix it? Thanks in advance.

I'm using Windows XP Pro fully updated.

 

I recommend you investigate if the power being drawn may be too much for your USB system. If you don't have a self-powered USB hub, I suggest you get one and run the drives through that.

Matt
Me, I would not run two external HDDs without one.

 

Thanks, Matt, for your response.
But the external hard disk drives both have their own power supplies and are plugged in to my UPS (uninterruptible power supply). Why would they be draining power from the USB system, or from anything else?

Thanks for any other comments.

 

I will let you do some research. There is a place in Windows where you can see the power being drawn by a particular USB device. I can't find it offhand. I went to the very helpful site USBman (maybe a relative of mine ), when I tried to do a search I found this

Wow, great, I hope they are pleased with how clever they are. I hope they get the same some day when they are looking for information.

I think you will find HDD drives still draw a fair amount of power even if they have their own power supply.

Matt

 

The other area I would consider is the allocation of resources. I often connect USB drives to PC's at work. Sometimes they don't appear because resources cannot be allocated (sometimes it shows an error that a drive letter cannot be allocated, often nothing happens when the drive is connected).

Matt

 

Roger at CCCC

Check power and bandwidth usage by going to Start > Run, type devmgmt.msc and press Enter, then click View > Show hidden devices. Expand Universal Serial Bus controllers, then:

- Right-click each USB Root Hub > Properties > Power Tab to see the current draw in mA (milliamps). A mouse typically draws 100mA and a keyboard about 70mA.
- Right-click each Host Controller > Properties > Advanced Tab to display the percentage Bandwidth used. Typical settings are 10%, 11% and 23%.

 

Thank you for all the comments so far. I will be working more on this problem tomorrow (Mon, Oct 20) and will report any progress, but I don't have time today. Thanks again for your comments.

 

2nd External drive unexpectedly starts working correctly

Thanks again for your previous comments. My previous problem disappeared when I plugged both USB External Disk drives into the REAR of my PC. If I plugged one into the rear and one into the front, then the system did not work, as described below. Actually, I would still prefer to be able to run one of the USB disk drives from the front USB port. So if anybody has any additional suggestions about that, or about why the error occurs in the first place, I would be glad to know it. Note, as described below, that the Device Manager information was exactly the same both when the system worked and when it didn’t.

Here are additional details about the problem:

Computer: Dell Dimension 2400; Pentium 4, 1 GB RAM; The PC has four USB 2.0 ports on the back and two USB 2.0 ports on the front.
New USB External Disk Drive: Western Digital MyBook Model WD6400H1U-00 (640 GB) USB 2.0
Old USB External Disk Drive: Maxtor Personal Storage 3100 USB 2.0, 200 GB
Both of these USB drives have their own power supply and are plugged into my UPS.

Control Panel/System/Hardware/Device Manager Information for Universal Serial Bus Controllers:
Intel 82801DB/DBM USB 2.0 Enhanced Host Controller - 24CD
(PCI bus 0, Device 29, function 7; Bandwidth Used: 10%;
Driver Date: 6/1/2002, Driver Version 5.1.2600.0; Driver files: drivers\usbehci.sys, drivers\usbhub.sys, usbport.sys, hccoin.dll, usbui.dll, File Version 5.1.2600.5512 (xpsp.080413-2108 )
Intel 82801DB/DBM USB Universal Host Controller - 24C2
(PCI bus 0, device 29, function 0; Bandwidth Used: 10%;
Driver Date: 7/1/2001, Driver Version: 5.1.2600.1106; other Driver details same as above )
Intel 82801DB/DBM USB Universal Host Controller - 24C4
(PCI bus 0, device 29, function 1; Band width Used 23%; other Driver details same as above)
Intel 82801DB/DBM USB Universal Host Controller - 24C7
(PCI bus 0, device 29, function 2; Bandwidth Used 10%; other Driver details same as above)

With the new Hard disk and wireless mouse plugged into the back of the PC and nothing in the front, the new hard disk works correctly and the Device Manager reports the following:
USB Mass Storage Device (Location 0)
USB Root Hub (Location 0; 2 ports available, Power =0 ma, Driver file details: drivers\usbd.sys, drivers\usbhub.sys, File version: 5.1.2600.0 (XPClient.010817-1148)
USB Root Hub (Location 0; Logitech USB Cordless Mouse Power= 50 ma; 1 port available, other Driver file details same as above )
USB Root Hub (all details same as first Root Hub above, including Power = 0 )
USB Root Hub (Location 0; USB Mass Storage Device Power = 2 ma; 5 ports available, other details same as above)

First experiment:
With the new Hard disk and wireless mouse plugged into the back of the PC and old Hard disk plugged in the BOTTOM USB port on the front of the computer, the new Hard disk no longer works. When I try to create a file on the new hard disk, I get the error message "Unable to create....the system cannot find the file specified."
After a few seconds, an additional error message occurs: "Windows-Delayed Write Failed"
Device Manager reports 2 USB Mass Storage Devices at Location 0 and 2 USB Mass Storage Devices on the fourth USB Root Hub as follows:

USB Mass Storage Device (Location 0 - Personal Storage 3100)
USB Mass Storage Device (Location 0 - MyBook)
USB Root Hub (Location 0; 2 ports available, Power =0 ma, Same driver file details as above)
USB Root Hub (Location 0; Logitech USB Cordless Mouse Power= 50 ma; 1 port available, other Driver file details same as above )
USB Root Hub (all details same as first Root Hub above, including Power = 0 )
USB Root Hub (Location 0; USB Mass Storage Device Power = 2 ma; USB Mass Storage Device = 100 ma, 4 ports available, other details same as above)

Second Experiment:
With the new Hard disk and wireless mouse plugged into the back of the PC and old Hard disk plugged in the TOP USB port on the front of the computer, the new Hard disk no longer works and all Device Manager information is exactly the same as the first experiment. In particular, both USB Mass Storage Devices still appear on the same USB Root Hub.

Third Experiment:
With the new Hard disk, the old Hard disk, and the wireless mouse plugged into the back of the PC, the system (unexpectedly) continues to work correctly and I was able to copy a folder directly from the old hard disk to the new one. However, all Device Manager information is exactly the same as in the first experiment which failed. In particular, both USB Mass Storage Devices still appear on the same USB Root Hub (the fourth one).

There are a variety of other questions about the USB device manager information: Why are there four USB Root Hubs? Why are they all at "Location 0� Why do the first three Root Hubs have 2 ports available but the last one has 6 available? How do these Root Hub ports relate to the six available physical USB connections? What does "Bandwidth Used" mean and why does one Universal Host Controller use 23% while the others only use 10%? Does it matter that the driver dates seem very old (2001 and 2002)?

My only goal is to get both USB drives working at the same time which has now occured. But the error seems to me like a relatively straightforward Windows or USB driver error that should have been detected and fixed long ago. Is it possible/necessary to update the drivers? As mentioned above, I would still like to be able to run one of the USB drives from a front USB port, so if anybody has any additional suggestions about that, I would appreciate it. Thanks again.

 

Thanks Pete, a USB extension cable looks like the best alternative. Your response raised two questions for me:
1. What does it mean that the front USB ports are "soft wired "?
2. You said that the difference between front and rear ports is "well known ". Is this written up anywhere in a Dell or Windows service document?

Thanks again for your help.

 

Thanks again, Pete. I looked again at the instructions for my new USB drive. There were no words at all, only pictures, but the picture, sure enough, was of a USB cable plugged into the rear of a PC. So I guess the instruction is there, but there was no warning that a front port might not work. Not very obvious, in my opinion.