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Audience: Users / Technical Support
- How can I solve problems in a typical Userful Desktop system?
- What are some common troubleshooting issues?
- 1 Devices
- 1.1 General Stuff
- 1.2 USB Devices
- 1.2.1 Q: How should USB devices be connected to Userful Desktop?
- 1.2.2 Q: Why should I use a powered USB hub?
- 1.2.3 Q: What kind of powered USB hub should I use?
- 1.2.4 Q: What if I don't have a powered USB hub?
- 1.2.5 Q: Which flash drives work best with Userful Desktop?
- 1.2.6 Q: Why do some USB devices not work when plugged into the keyboard?
- 1.2.7 Q: Can I chain my USB hubs together?
- 1.2.8 Q: Can I use USB extension cables?
- 1.2.9 Q: How do I access my USB storage device?
- 1.3 Floppy Drives
Q: How should I set up my hardware?
A: Properly. For a stable, reliable system (especially a multistation system) you need to set up your hardware properly. Please see the Hardware Setup Guide for instructions.
Q: What does it mean to "mount" a storage device?
A: Think of a horse.
Since Userful Desktop is based on Linux, the concept of "mounting" and "unmounting" a storage device is used. It's kind of like riding a horse: You mount the horse, and stay on until you arrive at your destination, then you unmount the horse. You can't put the horse out to pasture or leave it in its stall unless you unmount it first. Trying to do so without nicely unmounting will result in either you or the horse being injured or, at least, unhappy.
Your storage device is the horse. And you can't use it without mounting and unmounting. Below we will show you the steps involved in mounting and unmounting.
Q: How should USB devices be connected to Userful Desktop?
A: Best to connect them in relation to the station. We recommend using powered USB hubs, one for each station. All USB devices (including USB floppy drives and CD/DVD drives) for a station should be connected to the station's USB hub.
Q: Why should I use a powered USB hub?
A: To prevent problems with insufficient power going to your USB devices.
Because each USB port only provides a power supply of up to 500mA for all devices connected to it, connecting multiple bus-powered devices to an unpowered hub or a keyboard can easily exceed this maximum power supply. For example, if you have three devices, a keyboard, a mouse, and a camera, with the mouse and camera attached to the keyboard, and the keyboard attached to the computer, and they each draw 200mA, then they are trying to draw a total of 600mA from one USB port on the computer. Obviously this exceeds the 500mA limit, and one of the devices will not work properly.
This limitation can be circumvented with the installation of a powered USB hub. The keyboard and mouse, and various other USB devices can then all be plugged into the powered USB hub, and all the devices will be given sufficient power to operate properly.
Q: What kind of powered USB hub should I use?
A: A good quality one.
We strongly recomend using a powered USB hub (meaning it has its own power adapter) for each station where users will be attaching USB devices. The USB hub should be USB 2.0 Certified. Userful has tested a number of these devices and currently recommends the D-Link DUB-H4 or the Dell 1707FP/FPV monitor with built-in powered USB hub. (Userful has special rates on the D-Link hub for our customers. Contact your Userful Sales Account Manager for details.)
For technical details on the USB standard, please see http://www.linux-usb.org/USB-guide/x33.html
NOTE: Poor quality USB hubs can cause damage to your hardware. There are many cheap powered USB hubs out there that do not fully meet the USB standard. These low-quality hubs often feed power back to the computer, which can cause damage or may result in failure to boot properly.
Q: What if I don't have a powered USB hub?
USB ports built in to the system unit and are often found on the back of the computer (some computers also have one or two ports in the front for easy access). These ports are all fully powered by the computer and can be used if your USB device does not work in the keyboard's USB ports and there is no available powered USB hub for the station.
When you use one of these USB ports in the system unit, it will be considered a "shared" device. This means that attaching a device to one of these ports will not assign it to any station. It will appear in all stations' lists of storage devices. For example, if it is a USB floppy drive, plugging it into the back of the system unit will result in all stations seeing "External Floppy Drive" in their file browser.
All shared devices are available on a first-come-first-served basis. This means that whoever opens the device in their session first, will gain exclusive access to it until they unmount it.
For detailed instructions in setting up your USB devices without hubs, please see the Hardware Setup page.
For detailed steps in accessing your USB devices please refer to these pages:
Q: Which flash drives work best with Userful Desktop?
A: In general, you should have no problems using USB flash drives (aka USB keys or thumb drives) with Userful Desktop. Flash drives which do not have hardware defects (or are fake) should work fine. However, here are some comments and suggestions that should help you make the best choice:
- Look for flash drives with well-known brands, such as SanDisk, Lexar, Kingston, Memorex, etc. These are most likely to adhere to USB standards.
- Avoid flash drives which require a special driver to work on your computer. If you must install something to use the drive, this would be a poor choice to use with a Linux-based system like Userful Desktop. Some drives have optional software; this is not a problem.
- Avoid flash drives using bleeding edge technology, squeezing massive amounts of storage into a standard-sized flash drive package. These drives might be using non-standard protocols and may require new drivers to work.
- Some flash drives will draw more power than others. These power-greedy drives will often not work when plugged in to a keyboard's USB port (because the keyboard needs some of the power for itself). In some cases, the drive's icon will show up, but opening it and looking at the files will not work because of these power issues. The workaround in this case is to use powered USB hubs or to plug the flash drive into one of the system unit's (aka the box or the tower) free USB ports.
Q: Why do some USB devices not work when plugged into the keyboard?
A: Every USB device has different power requirements. USB devices can either be self powered (e.g. USB CD-Drives, powered USB hubs, etc.) or bus powered (e.g. audio headsets, keyboards, mice). Self powered devices come with a power adaptor that plugs into a wall socket. Due to the power demands of some devices, they may be getting insufficient power from the keyboard. It is best to connect such USB devices to a powered USB hub.
Keyboards should never be plugged into spare ports on other keyboards, and floppy drives should never be plugged into keyboards.
Q: Can I chain my USB hubs together?
A: That depends on the kind of hub. If the hub is a powered USB hub (having its own power adapter that plugs into an outlet), then any USB device can be attached to it, including other USB hubs. However if the hub is bus powered (gets its power from the computer's USB port), then only low power (100mA max) devices can be attached to it. A bus powered hub should not be connected to another bus powered hub -- you should alternate between bus powered and self powered hubs. Better yet, just use powered USB hubs, and forget about the bus powered hubs.
Q: Can I use USB extension cables?
A: Yes, but not too long. If necessary, short USB extension cables can be used. However, our testing shows that extension cables longer than 2 m (6 ft.) tend to have problems maintaining a consistent signal. Here are some factors to weigh:
- Cheap, lower quality cables will be more prone to signal errors.
- A well insulated cable will perform better.
- A cable's proximity to power cables (such as for monitors and computer system units) will affect its performance. Power cables generate stronger electromagnetic fields than other kinds of cables, which can interfere with USB cables.
Q: How do I access my USB storage device?
A: Access is quite simple. You just need to remember a few steps:
Files from any USB-compatible storage device, such as a digital camera with a USB cable or a flash drive can be opened (mounted) as follows:
- Plug a USB storage device (such as a flash drive) into an open USB port on the keyboard or the same USB hub the keyboard is attached to.
- Double-click on the
Computericon on the desktop.
- Find the icon for your USB device, and double-click on it.
- Find the file you wish to open and double-click on it.
- right-click on the device's icon in the file browser window, and select
Unmountfrom the menu. (This last step is critical in preventing data loss or damage to your storage device.)
Q: Why can't I mount my floppy disk?
A: It might be a bad disk. If you see a "Cannot mount volume" message when you try to open a floppy disk icon, it probably means that the disk is bad. If the disk seems to work on the computer you first used it on, that might mean that a floppy drive's read/write head is slightly off, causing it to write to the disk in a non-standard fashion.
There are three main options:
- Reformat the disk. This will result in complete loss of all data on the disk.
- Get another disk.
- Use a USB flash drive instead. This is a much better option for many reasons, including reliability, portability, and storage space. Floppy drives will very soon go the way of the Do-Do, so moving to a flash drive is a wise option.
Q: Why can't I save to my floppy disk?
A: It might be write-protected. Some applications might give you a message like this OpenOffice.org error. This indicates that your floppy disk cannot be saved or written to. You may have a similar error if you try to format a write-protected disk.
Floppy disks have a little black tab that slides to block the "write-protect" hole in one of the corners of the disk. If you can see through the hole, that means that write-protect is on and you cannot save (or "write") to it.
Note that many floppy disks have a second hole on the other corner of the disk. This other hole does not have a black plastic sliding tab and has nothing to do with write protection.
Steps for troubleshooting:
- Unmount the disk.
- Remove it from the drive.
- Check the write-protect tab. If write-protect is on, slide the black plastic tab so that it covers the hole.
- Reinsert it into the drive.
- Try saving the file to it again.