About

My "Academic Pensieve" (named after Prof. Albus Dumbledore's pensieve) contains almost every handwritten mathematical note that I wrote for my internal use since February 2008, almost every tiny silly internal-use computer program that I wrote in that period, many images, TeX documents, PDF files, and some further raw stuff. Currently there are approximately 16,401 documents in my pensieve, excluding index files and blackboard shots.

Why?

• Why not? Most of my notes are in digital form anyway (I mostly write on the screen of my tablet computer and not on paper). Backups must be made, and backing up on a web server takes the same amount of disk space as backing up anywhere else. I must organize my notes if I ever want to look back at them, and organizing them for myself is more or less all that I do.
• I often wish to show something to my students or my colleagues, and giving them a URL is often the easiest way to do it.
• When I work with others I want them to have access to our joint work.
• The easiest way to give access to a changing group of people is to have no access control at all.
• Most of what's here is low quality and should not be read by others. So what? I'm not asking anyone to read anything, only enabling the possibility. As I wrote above, there are times when this possibility is useful. And it is much easier for me to post everything rather than think and make choices.
• I have nothing to hide. I'm not worried about people "stealing my work" - most people are kind and will credit me fairly. But even if not - if you took something raw and made it pure, it's probably more yours than mine anyway. Quite to the contrary - if you take anything from here and make it useful, that's great!!! (If you want to steal the latest, go to Monoblog.pdf, or to This Month, or to Recent Changes, or to the top of blackboard shots).
• I'm all for openness elsewhere and almost anywhere. That's my tiny statement on the subject.
• I just enjoy playing with technology.

About a year after starting, I learned that there is a buzzphrase for what I do - it is "Open Notebook Science".

How?

On my file system, I work just like I'd work on any other directory tree, except I avoid touching a few "system" files and subdirectories, unless I really mean to (these are, all "index.html" and "index.m" files, and all "nb/", "one/", and "thumbs/" subdirectories). Occcasionally I click on one "Quick Launch" icon that I've arranged for myself, and it runs the program that updates the PDF files, thumbnails, and all the index files that need updating. That program I wrote myself; it is completely undocumented yet fully available as a part of this pensieve, under Projects: AcademicPensieve.