In response to last week’s inSync tips on archiving data, one reader brings to light a useful technique for avoiding troubles with corrupt documents.
When computers write out most files (i.e. save your work) the operating system first truncates the file to zero length and then writes the data in order, from start to end. If for any reason (power failure, program crash or hang-up) this write is interrupted, or if the program’s internal data has otherwise become corrupted and it thereby writes garbage, your work since the last backup is gone.
To prevent such loss I append a “rolling” letter or number to the filename, incremented with each save (e.g. MyProj_000619a, MyProj_000619b, etc.; alternatively MyProj_000619_01, MyProj_000619_02). The first part is the project name and date-code in year, month, day form. Especially useful on file systems supporting long filenames, though a short form of this can be used even on 8.3 names. This technique automatically preserves a revision history if you need to revert to a long-past version.
I periodically groom the directory, typically removing all but the last-saved file for a given date. This preserves the ability to revert to a given point and — if you save at reasonably consistent intervals — the magnitude of the rolling letter provides a histogram of each day’s workload, if you care.
If you use letters rather than numbers, here’s one solution to handle the “z” problem: keep the z and append yet another rolling letter. That is, after MyProj_000619z, do MyProj_000619za, MyProj_000619zb, etc.
By the way, for the software authors in the audience: this could trivially be handled automatically in programs, at the user’s option.
Editor’s Note: While not a major problem these days, Pro Tools users of years past are well acquainted with the problem of documents becoming corrupt. Often you don’t know you’ve got a bad data file until the next time you turn your system on and try to load it. Depending upon your data archiving strategy you may have even written over a good archive file with a bad one. It’s a good practice when a lot of work is at stake to save copies and use rotating names as suggested above. Back in those days we suggested making a copy of the data file BEFORE beginning work each day. Just copy it to another location. The next day make another, and simply date the names. It only takes a few seconds, but can be a life saver.