I've gone blue

[jno]

When I call up a list - eg click on My Documents to get a list of folders, or Photoshop to look at a list of photos in a folder - the names in the list appear in blue. It was black yesterday, and I haven't done anything to change it that I know of. How do I change the default back? Is there a display option somewhere?

[rojash]

Windows shows compressed files in blue. You may think you did nothing, but maybe you did a disk clean-up (or have your machine set up to do it automatically)?

To decompress them, right-click the folder in Explorer
Choose Properties
Click the Advanced button
Uncheck the option "compress contents to save disk space"

Alternatively, if you want them to be compressed, but don't want them shown in blue:

Open Windows Explorer
Click Tools/Folder Options
Click the "View" tab
Uncheck the option "Show encrypted or compressed NTFS files in color"

[jno]

aha, yes, that will be it, some compressing has been carried out, I have now been informed. What does compression involve, anyway? Does it mean anything was actually lost?

Thanks, three stars!

[dave m]

nothing was lost,yor pc compressed the file 2 save disc space,(file now uses less MB than before)no need tp worry

[jno]

Thanks, dave m. So how does that work exactly? Why do files occupy more space than they need to in the first place?

[rojash]

It's not so much that they occupy more space than they need to, it's that they are literal copies of your work. There are many different forms of compression that may be used, but a VERY simple example is as follows:
Let's say you have a database file that has 5, 30 character fields for the address, and 100 records. When you save the file (ignoring overheads) the file will take 5x30x100 bytes of storage regardless of whether the fields are blank or not - i.e 15,000 bytes. Now assume that 50% of the content is just blank. If we replace all the groups of contiguous spaces with a number to indicate how many there are, followed by a symbol to indicate space, we can reduce the size of the file. So 20 spaces which would take 20 bytes becomes (say) 20{ = 2 bytes.

The disadvantages are potentially threefold. First, if we copy the file to another system which doesn't know the compression method used, then the copy is useless; second, it takes time to perform the compression and decompression; third, the database program probably can't work with the compressed file, so the file will need to be completely decompressed before use, then re-compressed again when it has been closed.

[rojash]

By the way, this type of compression is called lossless, because all the original information can be recovered by reversing the process. There are other forms of compression (mp3, mpg, jpg, etc) which are lossy, in that information which is considered non-essential is discarded in the compression process, so that the exact original can never be recovered. This why it's a good idea to always edit a copy of a picture rather than the original picture in jpg format, and why a DV camcorder is a better option than a DVD camcorder if you are intending to edit your movies.

[jno]

thanks, rojash... Yes, I'd been thinking of the loss of info in jpgs and wondering if the compression used by the computer in this case also discarded anything permanently. (My knowledge of computers doesn't run deep.)