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Re: [OM] Digital dweeb needs help

Subject: Re: [OM] Digital dweeb needs help
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Thu, 09 Aug 2012 07:50:58 -0400
Actually, I think I would do a "full format" on the PC first followed by 
a format in-camera followed by shooting a bunch of test images followed 
by a read test in the PC.  If it fails after that throw it out.

I've been trying to think of what sort of malady might cause the problem 
described and not coming up with anything to my own satisfaction.  The 
PC thinks the directory is empty so there are bits somewhere the PC 
isn't reading correctly and/or the camera doesn't care about.

When a camera formats a flash card it only does a "quick format" which 
just zeros out the directory without erasing any of the image data. 
When a PC does a format it also normally does a quick format but can 
optionally do a full format.  A full format does a write to and read 
back from every sector on the media.  If a read fails the sector will be 
marked as bad and not used again.  That's at least what happens with a 
hard or floppy disk.  Exactly what happens with a flash card which 
employs "wear leveling" I don't know.  Although not mechanical, flash 
cards do have a maximum number of write cycles.  Sectors near the front 
of the media would normally get more usage than those at the back since 
the media is rarely completely filled.  To keep the front sectors from 
wearing faster the actual physical locations of sectors 0, 1, 2, 3, etc 
don't correspond to their addresses.  The physical locations are 
continually remapped to assure even usage across the media.  I assume 
that the remapping algorithm knows how to take care of marking bad 
physical sectors but don't know that for sure.  Regardless, I would 
still recommend following my advice in the first paragraph.

Chuck Norcutt


On 8/8/2012 12:45 PM, piers@xxxxxxxx wrote:
> Never mind trying to diagnose the problem, Rich, find a way round it -
> connect the camera to the PC via USB (you may need to bring the car
> into the house for this, unless you can extract the G5 from the car!).
> Having done that, you should be able to copy the image files to the
> PC. Then reformat the CF in the camera. Good lick!
>
> Piers
>
> On 08/08/2012, Rick Beckrich <ribec@xxxxxxxxx> wrote:
>> I cranked off some shots at last night's National Night Out celebration at
>> the nearby town of North Beach on the lovely Chesapeake Bay.
>>
>>   Played back on the Canaon G5, some of the images looked worth exploring
>> further.
>>
>>   However, when I booted the CF card to my laptop, the Zoom Bowser told me
>> "No Pictures!"
>>
>>   Actually, it said "no images to download."
>>
>>   This morning I took the card back out to the G5 (It's my
>> keep-in-the-car-camera) and hit play - Voila!
>>   30+ frames, some good.
>>
>>   Back to the computer - SAME ZIP AS EARLIER.
>>
>>   Tried downloading with an HP program... same answer.
>>
>>   Help... PLEASE!
>>
>>   Analog Rick
>> --
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