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| Thread ID: 41878 | 2004-01-25 12:13:00 | dpc-ud1 usb drive | stevej (1205) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 209873 | 2004-01-25 12:13:00 | hi i have a dpc-ud1 xd picture card usb drive and in the instructions it says that on a system with win me you have to tell it to eject the drive before i can un plug the drive what would happen if i just unplugged it from the usb without ejecting it first ? on my other comp with win 98se it doesn't need to be ejected |
stevej (1205) | ||
| 209874 | 2004-01-25 23:49:00 | bump | stevej (1205) | ||
| 209875 | 2004-01-26 04:42:00 | It is a"disk" with a directory. Most "modern" OSs buffer the directories of disks. The buffers are written out periodically. But if a disk is removed before the buffered directory is written out, the contents and directory might not match. :_| This is a good way to lose files. ;-) I would tend to "eject" such devices (whatever the OS). It doesn't take long to make sure that the directory has been written out. |
Graham L (2) | ||
| 209876 | 2004-01-26 05:29:00 | ok so this is were i show how little i know :-) what do you mean by The buffers are written out periodically.? |
stevej (1205) | ||
| 209877 | 2004-01-26 05:41:00 | The directory is an area of the "disk" . It is a list of the files,and where they are stored . For speed, the OS might keep a copy in memory, rather than read and write the actual disk each time it is used . The disk copy is called a "buffer" . If you tell the OS to eject the disk, it will write the directory to the disk . That is "writing (or "flushing") out the buffer" . (Sometimes files are not written immediately they are produced by the computer --- they also need to be written before the disk is removed) . Usually, the OS will check every so often -- 5 secs or so-- whether there are any buffers which have not been written out, and do so . |
Graham L (2) | ||
| 209878 | 2004-01-26 06:00:00 | Plugging another memory card in without "stopping" or "ejecting" the old one does get some card readers upset I have found . Corrupt files on the second card one result . Probably as a result of the buffer getting re-written to the wrong card? This is where significant time has elapsed since last accessing the first card as well, so its not a 5 second issue . I now use an embedded card reader, which does not suffer from the problem . It does not require stopping and I cannot make it fault by changing cards . |
godfather (25) | ||
| 209879 | 2004-01-26 06:13:00 | That was a problem with CP/M floppies, too . :D That's what Ctrl/C was for . . . and it happened in some MSDOS versions too . Then floppy drives were given a "media change" line in the interface . Then a few generation of hardware and software later the problems recur . A "single-drive" USB device such as this one will probably risk having its directory corrupted . The OS would recognise the device being unplugged (and unregistered by the USB controller) as a medium change . "There is nothing new under the sun . " The worst "bugs"are those which are continually reinvented . |
Graham L (2) | ||
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