KVS
This page is about KVS, a simple, single-user version control library.

One day, I decided I should keep a revision history of my web-site. The main criteria I was looking for in the version-control system were simplicity, and the ability to view files without having to check them out from the archive. I also use Darcs (and, to a much lesser degree these days, TLA), which I very much enjoy, but I have no need for all the complicated and strange filenames, and—more importantly—don't want to have to navigate through long directory structures to find my files in the archive. So, I decided, like any good geek, why not write my own version control system?! ‘KVS’ is the name I used for the joke versioning system that I used as an undergrad (it basically involved manually using ‘mkdir’ and ‘cp’), so I decided to call my new system this. It is implemented as a domain-specific embedded language in O'Caml. Running KVS usually involves using a custom top-level interpreter.

I've been using KVS for my web-site and numerous work and personal projects. I can honestly recommend it over other version control systems: It's faster, easier, and more flexible. KVS is not a system for collaboration, though—it's a single-user-only tool. I have, however, used successfully it in collaboration with other tools (SVN, CVS, PerForce): I used KVS to maintain small, local edits, then pushed these changes through the other concurrent versioning software.

Because KVS is implemented as a library, it is easy to interact with archives, etc. from OCaml code. I've used this to implement a simple library for visualising changes to the archive over time (e.g., graphing file sizes in bytes / LOC over time, for filtering out the files that have been most actively edited).

If you use KVS, if you try KVS (whether you love or despise it), please send me an e-mail! I'd love to hear thoughts about what's useful or lacking.

• 2009-07-03–I've uploaded a minor (functionality-wise) change to KVS, that I have been working on for some time; it is the fourth iteration of KVS, and, thus, it is named KVS2d. Despite only small additions (mostly ‘derived’ functionality), there has been a complete rewrite—KVS is now implemented in CamlTrax. Additionally, the names of the KVS functions have been changed to ‘Camel case’, and the documentation has been updated accordingly. I am planning to begin work on a self-contained interface for KVS; if I write this, it will probably be a Curses-based ‘GUI’.
• 2008-09-01–I've uploaded a new version of KVS that incorporates a number of changes / additional functions that I added during the past several months. The largest change is the ‘quick_restore’ family of functions: They allow to restore a version, copying only the files that have changed, which tends to be quite a bit quicker on decently-large projects. N.b., I had some trouble with the gzipping under Cygwin, so you may need to disable compression (by commenting that out) if you're using Windows.
• 2008-01-15–I've uploaded a bug-fix version of KVS; the big problem with the last upload was that I forgot to include the line-wrapping code used by several functions. The new version requires CamlTrax to compile, which can be found on the academe page.
• 2007-10-26–I've finally made the new version available. Besides using gzip to keep archives smaller, it has some new regexp filtering facilities (e.g., for filenames) and a super-fantastic utility to test whether a version compiles given a particular command (e.g., ‘make all’). The latter is vaguely like ‘trackdown’ in Darcs, and I'm finding it very useful.
• 2007-06-05–I've implemented an extension to KVS2 that keeps the pool / archived files gzipped (unless doing so results in a larger file size). It's still experimental, but it looks like it saves about 25% of disc space for my case study (i.e., for my web site, which is approximately 180Mb, counting the active version, archive, and bookkeeping files). Archive validation is vastly faster, but actual imports suffer a bit (because of the compression time). The extension is backward-compatible with KVS2 archives, but only newly-added files will be compressed; I'm sure I've written a converter, but I've no earthly idea where it is.
• 2006-08-07–I've made some minor changes to KVS2 and uploaded it. Original KVS is no longer available, and I've removed all information pertaining to it from this site.
• 2006-07-18–I've been using KVS2 with quite a bit of success; I'm not finding bugs like crazy anymore, and the ‘unexpected behaviours’ I am finding are simply unforseen—but acceptable—consequences of my design decisions. KVS2 has dreadful performance, largely (I think) because I'm using ‘Unix.system’ for moving, renaming, etc. files; I did this because I ran into problems otherwise (i.e., that ‘Sys.rename’ doesn't do the same thing as ‘mv’).
• 2006-06-28–KVS2 is almost ready for a release. It's fairly nice to work with, and the tutorial is done. Using the KVS and KVS2 codes, I've cobbled together a converter taking a KVS archive and creating an equivalent KVS2 archive. I'm still finding bugs too frequently to release the code yet, though—mostly corner cases I didn't consider.

KVS is intended to be used for small projects that take place over a short period of time—projects for which the effort involved in setting up a ‘proper’ archive would be more costly than the benefit of maintaining the version history. It is also usable for projects that are essentially a collection of files—where one wishes to view changes at the file level rather than from a finer-grained view (e.g., line- or character-based changes). One case where someone might wish to do something like this would be when the archive consists largely of binary files.

• KVS2d source code (CamlTrax)(tgz) (20090703)
• KVS source code (OCaml)(tgz) (20080901)
• tutorial explaining some basic functionality and usage scenarios (pdf)
• converter from old-format archives (tgz) (20060807)

Well, there's really no more information available for the time being, sorry! Please check back soon, though, or e-mail me if you have specific questions.