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| Thread ID: 79837 | 2007-06-02 23:05:00 | USB Problem | B.M. (505) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 555434 | 2007-06-02 23:05:00 | Can anyone explain just what happens when one plugs in and unplugs a USB device? I know when you plug them in they are automatically detected, but when you close them down you should do so from the Icon on the taskbar. The reason I ask, is my daughter has just been plugging her camera into their computers and pulling the cord out when she’s finished. :blush: Now neither computers recognise the camera. So I’m curious as to what happens in the conventional closing down procedure and whether she has damaged the camera or computers. For instance, does the correct close down procedure remove the 5 volt power supply line before you remove the cord? :confused: |
B.M. (505) | ||
| 555435 | 2007-06-02 23:51:00 | This should not be a problem.Are you sure that the camera is not shown as portable media device or another disk in "My computer" I think you will find it there somewhere when the camera is plugged in. | kjaada (253) | ||
| 555436 | 2007-06-02 23:59:00 | Even though USB devices are Plug & Play—that is, they're ready to go upon being plugged in—you shouldn't just unplug them. A USB port has current running through it, so the power jolt caused by unplugging a "hot" connection can corrupt data on a storage device, camera, or mp3 player. | pctek (84) | ||
| 555437 | 2007-06-03 01:19:00 | This should not be a problem.Are you sure that the camera is not shown as portable media device or another disk in "My computer" I think you will find it there somewhere when the camera is plugged in. Unfortunately, the camera can not be found anywhere, cleverly disguised, in My Computer. :( Device Manager also shows a clean bill of health. I even ran SFC /scannow thinking I might find a corrupt file but no such luck. It’s interesting you say that her unceremonious exits shouldn’t matter despite teachings to the contrary. She has been simply pulling the plug as it were on all her USB Devices for years now. This is her first problem and may still have nothing to do with her actions. All of which seems to support your view. ;) I’m still interested to know if the “ceremonious” version of the disconnection, disconnects the 5 volts. :) |
B.M. (505) | ||
| 555438 | 2007-06-03 01:40:00 | There have been plenty of posts about this including camera's and external HDD's that have been corrupted or fried because the owners simply "pulled the plug" It might be safe but why not take the extra 1.5 seconds to disconnect it properly and save yourself a lot of grief down the line. Like this for example. |
beeswax34 (63) | ||
| 555439 | 2007-06-03 02:28:00 | USB is a hot-plugging interface. It's not the sudden remoival of power which can lead to file loss. It's "surprising" the OS that does the damage. Any USB device which has a file system is treated like a disk by the OS. For speeed, the directories are kept (and updated) in system memory while the device is active. Buffering might mean that a file is not be written immediately. The reason for the "removal" icon is that the OS must be told that you are removing the device. That allows it to flush any file buffers, and, most important, write out the updated directories to the device, and ensure that there's no activity when you do remove it. Rushed removal can mean that the directory does not agree with what's on the device. That is a corrupted directory. Any writing to the file system using an out of date directory will cause file corruption. Pulling the plug while a disk is still writing (even after the transfer is thought to be completed) is a good recipe for disaster. |
Graham L (2) | ||
| 555440 | 2007-06-03 02:50:00 | Righty ho Graham I’m getting the picture. (well I wish I was) :D I can understand how one can loose data and corrupt files, but shouldn’t the Computer and associated devices be able to recover from such an event?. Imagine a power cut in Auckland. Every computer, (without a no-break supply) and USB device attached, is in jeopardy. Now, although anything held in RAM is lost, the Computers reset themselves when the power comes back and I guess so do all the USB devices, off which I suggest there are ten’s of thousands. Surprisingly, the daughter has disconnected her USB devices, in this uncivilised manner, thousands of times over a period of years and everything except one camera is still working fine. :confused: |
B.M. (505) | ||
| 555441 | 2007-06-03 03:09:00 | Potential problems don't always bite you. Buffers and directories are written out periodically. But some of those thousands of computers do get problems. We are often told about it here. :D Usually, if you have just read from a USB device there's no problem. The directory hasn't changed. So, usually, a camera will not be affected. It is still nice to let the OS know. ;) |
Graham L (2) | ||
| 555442 | 2007-06-03 03:12:00 | We have 2 Win98se pcs' with USB connections. No icon appears on the Taskbar, so we go to My Computer Removable Disk and Right Click and use the Eject function. We usually put any other appliances into a cold machine and switch on. Is it any different when the need arises in connecting a usb printer connection, we suppose that will stuff up the buffer memory?. Not that we have moved printers between 4 pcs'. Lurking |
Lurking (218) | ||
| 555443 | 2007-06-03 03:16:00 | What is the camera BTW Is it a Canon because canons do not appear as a drive. They have their own software to transfer the data. |
Tony.br (4018) | ||
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