loosing CF free space with delete, answer?

I think i might know why, (my 990s off at nikon getting repaired so i can't verify it.

Since i noticed the available memory after deleting an image isn't the same as it is before you take the pic, I've been wondering why. This is what I think is going on. Its the info.txt, the camera records the image info in there, and maybe it doesn't remove the info when you delete an image?

so it continues to grow until a format gets done or other method. Since theres probably a fixed cluster size it should only lose it every so many deletes, unless each info record is greater than the cluster size.

charlie

charlie wallace said:

This is what I think is going on. Its the info.txt, the camera
records the image info in there, and maybe it doesn't remove the
info when you delete an image?

Click to expand...

Hi Charlie,

This is only true if you delete the images from the card while
the card is plugged into a computer. The in-camera "delete"
function will remove the entry for that image from the INFO.txt
file. However if you are moving all the images off the card onto
your computer you can also move or delete the INFO.txt
file (or you can delete it anyhow because the information is
stored inside the image files anyway; the file is created or
added to (on the end) any time a new picture is taken.)

As mentioned a few threads back, the file system on the cards
is just an ordinary Microsoft FAT file system. This has the
usual issues with clusters and defrag'ing etc. but there is no
magic to any of this.

By the way, any thoughts about a Linux version of cPix?
--david

dh said:

charlie wallace said:

This is what I think is going on. Its the info.txt, the camera
records the image info in there, and maybe it doesn't remove the
info when you delete an image?

Click to expand...

Hi Charlie,

This is only true if you delete the images from the card while
the card is plugged into a computer. The in-camera "delete"
function will remove the entry for that image from the INFO.txt
file. However if you are moving all the images off the card onto
your computer you can also move or delete the INFO.txt
file (or you can delete it anyhow because the information is
stored inside the image files anyway; the file is created or
added to (on the end) any time a new picture is taken.)

As mentioned a few threads back, the file system on the cards
is just an ordinary Microsoft FAT file system. This has the
usual issues with clusters and defrag'ing etc. but there is no
magic to any of this.

By the way, any thoughts about a Linux version of cPix?
--david

Click to expand...

no i dont think so if you use cPix to measure it , do a delete last pic and you'll see the memory disappear, which does happen with the camera too. If you have a 16mb card after a few deletes you'll lose 1 hires picture in capacity.

memory is defintely getting lost somewhere. I realize its a FAT style system
but theres something iffy going on.

hopefully i'll get my camera back soon so i can figure it out.

i'm doing a mac version so a linux version shouldnt be out of the question but gphoto/photopc already has xphoto going on there, and it does most of the simpler stuff cPix does

charlie wallace said:

no i dont think so if you use cPix to measure it , do a delete last
pic and you'll see the memory disappear, which does happen with the
camera too. If you have a 16mb card after a few deletes you'll lose
1 hires picture in capacity.

memory is defintely getting lost somewhere. I realize its a FAT
style system
but theres something iffy going on.

hopefully i'll get my camera back soon so i can figure it out.

Click to expand...

I cannot recreate any loss either with the interspersed shots
and in-camera deletes or cPix delete last picture tests. Perhaps
the loss you are seeing is the fact that the used bytes for the
INFO.txt will only change as it's size crosses a FAT boundary?
This won't happen (adding or deleting a picture) with even
a few records; The average record size is maybe 325 bytes or
so while the minimum allocation size is I believe 4096? Even at
1k alloc units this would be true for 3 INFO entries or so.
Anyhow, taking FAT math into account I can't find any
loss after a few trials. Will be interested to hear what you
find when your camera is back.

dh said:

I cannot recreate any loss either with the interspersed shots
and in-camera deletes or cPix delete last picture tests. Perhaps
the loss you are seeing is the fact that the used bytes for the
INFO.txt will only change as it's size crosses a FAT boundary?
This won't happen (adding or deleting a picture) with even
a few records; The average record size is maybe 325 bytes or
so while the minimum allocation size is I believe 4096? Even at
1k alloc units this would be true for 3 INFO entries or so.
Anyhow, taking FAT math into account I can't find any
loss after a few trials. Will be interested to hear what you
find when your camera is back.

Click to expand...

Are you using a 990 with 1.1 firmware? What size/make CF?

Be aware that the camera is rather conservative in it's calculations for available space. The last thing you want is to be told there is room for 1 picture and try to take it, only to be told it does not fit!

It could only take 1 info.txt entry OR one additional Directory entry to 'tip the scales' from having 10 to 9 images on a 16mb card (hypothetical numbers here - substitute the correct ones)

By Directory entry, I mean the 100NIKON directory immediately after a format will only contain enough space for, what?, 20 pictures? After that, the internal structures for the directory must be extended to make room for more files. Once this happens, possibly 1k (the amount depends on the allocation size and how many allocation units are required to extend the directory) is 'lost' to the directory structure. The new images are then added to this directory, but if they are deleted, the Directory itself is not reduced in size. It remains allocated. New images will simply use the already allocated directory space.
This is quite possibly the effect that is being seen.
...Lyall

charlie wallace said:

dh said:

I cannot recreate any loss either with the interspersed shots
and in-camera deletes or cPix delete last picture tests. Perhaps
the loss you are seeing is the fact that the used bytes for the
INFO.txt will only change as it's size crosses a FAT boundary?
This won't happen (adding or deleting a picture) with even
a few records; The average record size is maybe 325 bytes or
so while the minimum allocation size is I believe 4096? Even at
1k alloc units this would be true for 3 INFO entries or so.
Anyhow, taking FAT math into account I can't find any
loss after a few trials. Will be interested to hear what you
find when your camera is back.

Click to expand...

Are you using a 990 with 1.1 firmware? What size/make CF?

Click to expand...

naw thats not it, i measured the actual bytes free on the CF before and after..

Lyall Pearce said:

It could only take 1 info.txt entry OR one additional Directory
entry to 'tip the scales' from having 10 to 9 images on a 16mb card
(hypothetical numbers here - substitute the correct ones)

By Directory entry, I mean the 100NIKON directory immediately after
a format will only contain enough space for, what?, 20 pictures?
After that, the internal structures for the directory must be
extended to make room for more files. Once this happens, possibly
1k (the amount depends on the allocation size and how many
allocation units are required to extend the directory) is 'lost' to
the directory structure. The new images are then added to this
directory, but if they are deleted, the Directory itself is not
reduced in size. It remains allocated. New images will simply use
the already allocated directory space.
This is quite possibly the effect that is being seen.
...Lyall

charlie wallace said:

dh said:

I cannot recreate any loss either with the interspersed shots
and in-camera deletes or cPix delete last picture tests. Perhaps
the loss you are seeing is the fact that the used bytes for the
INFO.txt will only change as it's size crosses a FAT boundary?
This won't happen (adding or deleting a picture) with even
a few records; The average record size is maybe 325 bytes or
so while the minimum allocation size is I believe 4096? Even at
1k alloc units this would be true for 3 INFO entries or so.
Anyhow, taking FAT math into account I can't find any
loss after a few trials. Will be interested to hear what you
find when your camera is back.

Click to expand...

Are you using a 990 with 1.1 firmware? What size/make CF?

Click to expand...

Click to expand...

Hi Guys:

Just my 2 cents for what it's worth--I have 2 lexar cards, 1 san disk card & a new simple tech. card--the 2 lexars & sandisk reflect no change whether deleting images (all at one time) in camera or formatting (in camera)--the resulting space for new images is the same # of images available for new shooting--however, the simple card does lose image space if only deleting (in camera) as opposed to formating the card in camera--the simple card directions that came with the card clearly state to format the card after downloading the images--the lexars & sandisk never made mention of any one technique for dealing with clearing of images off the cards--

I did talk with a sandisk tech rep after purchasing my 990 some months ago & he said to delete images (in camera) rather than continually formatting as formatting will shorten the life of the card--go figure--

So what i now do is delete the images (in camera) for the lexars & sandisk with an occasional format just to clean things up & format the simple card as it directly makes a difference in storage space and it was recommended by simple--I can only surmise that cards from different manufacturers are somewhow configured differently internally and respond differently to procedures--I hope this makes some sense to somebody--cheers, Pat

charlie wallace said:

Lyall Pearce said:

It could only take 1 info.txt entry OR one additional Directory
entry to 'tip the scales' from having 10 to 9 images on a 16mb card
(hypothetical numbers here - substitute the correct ones)

By Directory entry, I mean the 100NIKON directory immediately after
a format will only contain enough space for, what?, 20 pictures?
After that, the internal structures for the directory must be
extended to make room for more files. Once this happens, possibly
1k (the amount depends on the allocation size and how many
allocation units are required to extend the directory) is 'lost' to
the directory structure. The new images are then added to this
directory, but if they are deleted, the Directory itself is not
reduced in size. It remains allocated. New images will simply use
the already allocated directory space.
This is quite possibly the effect that is being seen.
...Lyall

charlie wallace said:

dh said:

I cannot recreate any loss either with the interspersed shots
and in-camera deletes or cPix delete last picture tests. Perhaps
the loss you are seeing is the fact that the used bytes for the
INFO.txt will only change as it's size crosses a FAT boundary?
This won't happen (adding or deleting a picture) with even
a few records; The average record size is maybe 325 bytes or
so while the minimum allocation size is I believe 4096? Even at
1k alloc units this would be true for 3 INFO entries or so.
Anyhow, taking FAT math into account I can't find any
loss after a few trials. Will be interested to hear what you
find when your camera is back.

Click to expand...

Are you using a 990 with 1.1 firmware? What size/make CF?

Click to expand...

Click to expand...

Click to expand...

And... Line drop out or something?

Facts, Figures...

Everything is speculation so far...

charlie wallace said:

naw thats not it, i measured the actual bytes free on the CF before
and after..

Click to expand...

I'm not following your first line ?

Its not speculation, its fact, it does happen, its the why i'm trying to figure out. If it were speculation i'd have no proof of it, i can reproduce it easily.

I have seen it happen on 900 v1.1 with kingston cards i have, it does seem that certain combinations of cards dont suffer from it, so it may be that some people don't see it because there card does not suffer from it.

I don't think its fragmentation since that should only affect a card with files on it, not an empty one.

charlie

Lyall Pearce said:

Facts, Figures...

Everything is speculation so far...

charlie wallace said:

naw thats not it, i measured the actual bytes free on the CF before
and after..

Click to expand...

Click to expand...

What I was saying was that the post looked incomplete.
I was waiting for some figures.

Simply making a statement with no facts to back up the statement makes the statement speculation until proven otherwise.

Supply card make/model, camera make/model/version (which has already been done - Nikon CP990 V1.1)
Supply procedure performed to arrive at conclusions.
Eg.

Formatted card 16mb in camera. 15.43mb available (Camera says space for 8 pictures or however many fit at the current settings, Windows says so many kb available)
Took x pictures.
Deleted y pictures consisting of x space
Remaining space was z
Took more pictures of size x
Deleted more pictures of size y
Remaining space is z, where is the difference?

You could be right about the different model of cards - I have no idea about how they work internally although, I am currently skeptical.
...Lyall

i wrote software to talk to the camera, and it tells me the exact number of bytes free on the card, if a picture is taken, then deleted with the delete last command, the amount of free memory does not equal the amount before the picture was taken.

I first noticed it when my 16MB card had one less HI than when i started using it, formatting it restored it back to normal. I concurred with other posters that they had a similar problem.

even after deleting all the images the memory would not be returned,
only formatting it could do that. which means its not fragmentation

I have tested this extensively with my software(cpix), gphoto and the camera itself.

Unless i can somehow get the camera CF card and software into this forum, i'm afraid i'll be doing is making statements, you can try it yourself but you may be unable to reproduce it if it is CF specific.

I have facts to back it up, as well as other people with the same problem.

fact: my 990 v1.1 with original 16mb and kingston 128mb lose some memory after a delete last after taking a picture, formatting it returns the memory.

proof: the cameras register that says how much memory is left, is not the same as before the image was taken.

Lyall Pearce said:

What I was saying was that the post looked incomplete.
I was waiting for some figures.
Simply making a statement with no facts to back up the statement
makes the statement speculation until proven otherwise.

Supply card make/model, camera make/model/version (which has
already been done - Nikon CP990 V1.1)
Supply procedure performed to arrive at conclusions.
Eg.
Formatted card 16mb in camera. 15.43mb available (Camera says space
for 8 pictures or however many fit at the current settings, Windows
says so many kb available)
Took x pictures.
Deleted y pictures consisting of x space
Remaining space was z
Took more pictures of size x
Deleted more pictures of size y
Remaining space is z, where is the difference?

You could be right about the different model of cards - I have no
idea about how they work internally although, I am currently
skeptical.
...Lyall

Click to expand...