Some time back, I mentioned getting data off CD-ROM and putting it on hard disk with a second hard disk for back-up. As time passes, this gets more critical. I think archivists start getting antsy about CD-ROM after a decade or so, and I have media that go back to 1996.
And I have run into CD-ROM data disks with various reading errors.
So I thought that I would mention a freeware tool for Windows that addresses getting what can be gotten from a CD-ROM with problems. This is Roadkil’s Unstoppable Copier (RUC). Fortunately, you can stop it in bad circumstances by killing the process in Task Manager. I’ve done this after setting it to work on a CD-ROM with an obvious, visible blemish. In its default setup, RUC will attempt multiple reads of bad sectors in order to recover as much of a file as possible. This leads to it taking a long, lllllooooonnnnngggg, time to get through a patch of damage. Longer than I was willing to wait, anyway. So in the “Settings” tab, I set it to “Auto Skip Damaged Files”. This copies off all the undamaged files from the CD-ROM, and it does so fairly expeditiously. For some CDs, I may decide to let it trundle for a few days to analyze things, but first I want to get as much of the good stuff secured as I can. This tool looks to be a help in that regard.
The lengthy recovery process is probably most useful for large text files, where recovering a majority of a file is preferable to losing all of it due to a possibly small section that is damaged. For binary files, this may not be universally useful. The data files I have are raw integer data, so as long as the reconstituted file preserves the same length, I can recognize the bad patches and leave them out of analysis. That may not hold true for ZIP files and other compressed archives, JPG images, and the like.