On Wednesday 25 October 2006 02:02, Tim wrote: >On Tue, 2006-10-24 at 11:36 -0400, Gene Heskett wrote: >> That depends. In my case, swapping memory cards can be dangerous >> because the credit card thick memory used has open contacts, subject to >> static damage, I blew the original card that way I believe. > >I would have thought they'd design these things to handle users taking >no anti-static precautions, because that's what most people are going to >do (rip it out and treat it like just a piece of plastic). > >What's clearly obvious to me is that the compact flash cards have >fragile pins that can bend or break off, and the socket they plug into >can wear out too. So I was never keen on taking the card in and out of >my older digital camera. > >My newer one uses MMC/SD cards. The cards look more robust, but I still >wonder about how well designed the socket is, with those tongues >sticking out. > >> One thing I did find is an old vfat bug thats never been fixed. If >> there are 40 or so pix in the camera, you cannot move them to the >> computer without losing the last ones as vfat thinks, when the >> directory sector contains no files, that it has reached the end of the >> file list. Not so. So when moving files to the computer, always start >> at the bottom of the list and work backwards else that bug will grow >> some awesome teeth and draw blood, requiring the card be formatted to >> recover. > >Why would *reading* some files from the card cause a corruption? > Not reading, but moving, which implies deletion of the moved file. And when you have a whole 512 byte sector with no valid files in a vfat directory, thats considered to be the end of the directory, so if you start such an operation at the begining of the directory, those files beyond that empty sector can become inaccessable. I *think* one coud take another pix, which would result in the first available slot in the directory being re-used, and that might restore the ability to access the other 75 pix on the card, but I haven't tried that due to not having thought out the reasoning the first and only time it ever happened to me. Fortunately, the lost pix weren't all that precious although I certainly was pi$$ed at the time. So the lesson is to scroll to the bottom of the cameras directory (I use mc for this) and start moving the pix to the computer from the bottom of the list, which works perfectly now for about 4 years even if there's 80 pix on the card. That way you never self-generate a huge gap in the listing that triggers this bug. It seems to me that this could be fixed if M$ wanted to. I, OTOH, have NDI if the msdos and vfat file systems even have a data field to indicate the true length of the directory on the disk. If they don't have this data field, I'd be tempted to pay a visit, with a fresh hickory pick handle in hand, to the coders responsible for that particular piece of the spec. Dumb... -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Yahoo.com and AOL/TW attorneys please note, additions to the above message by Gene Heskett are: Copyright 2006 by Maurice Eugene Heskett, all rights reserved.
