Inspired by Tivo I'm here asking the question: why do we delete files?

I think the answer, for most people, comes down to ensuring that there is enough space left on their hard drive for files they may create in the future. But, on your 120 GB hard drive, are you really worried about the 100 KB document or the 2 KB e-mail? I think a secondary reason is organization. "In this folder I have only the things I'm interested in." So we delete the other things, kinda like throwing the junk mail off of your desk.

But, what if you decide later that you really want to order pizza? How can you find that coupon you threw away? Well, that's where the Trash Can comes in. You can still organize by throwing your files into purgatory, eventually saving them or emptying the trash periodically. Emptying the trash can be hard though. You're making the final decision on those files, they make a final appeal for their lives; trying to appear interesting in your trash folder. But alas, you empty the trash to satisfy condition one: to make sure you have surplus disk space.

Tivo doesn't work this way. You set up your programs, how many of the program you'd like to keep, and how long you'd like to keep it for. The goal of Tivo is to always keep your hard drive full. If you're not using the space, it will download things for you. There is always some space saved for live feeds, and things that are planning on being recorded, but for the most part, the hard drive stays full. This is great! I don't have to worry about having space on my hard drive, it is made when I need it.

I need a filesystem that works this same way. It needs to have its own trash, but then delete the files when I need the space, not before then. That way I can always have as much data as possible, but never run out of space. Seems simple enough, and makes someone else do the dirty work of killing my files.


posted May 7, 2005 | permanent link