Why isn't Windows random desktop picture not really random?

Factual Questions
1

I am a photographer, and have about 10,400 photos (j pegs) spread out among 230 different folders and sub folders. Windows XP allows the desktop image to change randomly (mine is set to change every 15 minutes). You would think that with over 10k images, repeats would be rare, wouldn’t you?

I see the same photos so often it makes me wonder exactly what “random” really is. I usually shut down at night, but the box is on around 16 hours per day, so one should see around 64 different images in that time frame.

I understand that turning it off will “reset” the chances of seeing an image again the next day. But it happens so often as to be ridiculous. Some days I will see two or three images that popped up yesterday. And yet entire folders remain unseen for months and months.

Does anyone know how these random schemes work? Am I truly seeing true coincidences, or is something else going on? :confused:

2

I never had any expectation that the desktop changer would venture into sub-folders.

That said, the thread Is it true that computers can’t generate true random? has a nice discussion of this particular phenomenon.

3

Yes, it does venture into subfolders, which is what I want.

Thanks for the link, that was interesting and informative.

I’m still annoyed at it however. :mad:

4

This isn’t really a limitation of pseudorandom generators, just poor program design. (It’s possible to have to program know which pictures have already been shown, and to skip them until everything else has been displayed once first – regardless of how bad your random number generator is.) Have you tried other wallpaper changes to see if they’re any better? There are a lot of them out there.

This one, for example, keeps a playlist of your pictures and says that “The playlist has a smart feature that allows you to cycle through the wallpapers in the playlist more evenly. This means that no image will be used more often than other.”.

5

Besides problems with pseudorandomness, there’s also the issue that (as I’ve heard it reported), the grand majority of code written and Microsoft is written by interns. So it’s likely that this was coded by someone who simply wasn’t very good at his job.

6

Which is reasonable, in a way. There’s got to be someone who’s the worst programmer at Microsoft, and you’ve got to give that guy some job or another. I’d much rather have that guy writing the code that randomly shuffles through wallpapers than the password authentication code.

7

Little did you know the password authentication code IS the wallpaper shuffler. They had to sacrifice SOMETHING to pay for the Zune losses.

8

Thank you Reply! That is exactly what I need to do, methinks. Great link.