lab 85 - stowage
NAME lab 85 - stowage NOTES In an earlier post I defined a venti-lite based on two shell scripts, getclump and putclump, that stored files in a content addressed repository, which in that instance was just an append-only gzip tar archive with an index. After learning a little about the git SCM , this lab re-writes those scripts to use a repository layout more like git's. The key thing to know about the git repository is that it uses sha1sum(1) content addressing and that it stores the objects as regular files in a filesystem using the hash as the directory and filename, objects/hh/hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh In the objects directory is 256 directories named for every 2 character prefix of the sha1hash of the object. The filename is the remaining 38 characters of the hash. Putclump calculates the hash, slices it to make the prefix and filename, tests if the file already exists, and if not writes the compressed data to the new file. Here is the important part...