revc@gwsd.UUCP (Bob Van Cleef) (07/29/85)
If there is anything wrong on the input, you get a "phase error" and the thing dies. If, for any reason, you have to skip one of a multi-media set, you get a "phase error" and the thing dies. What we need is a utility (or a cpio option) that will continue after a phase error, and will attempt to identify the next good file. The bad file could be saved as a /tmp file to allow human determination as to its value. Most of the time, a partial recover (noted as such) is preferred to NO recovery. 'cpio' has apparently become AT&T's choice for all archiving to floppy on the PC7300 and the 3b2's. This has caused some major problems. For example; one of our clients did a full backup of /usr prior to getting his system upgraded to Rel. 2.0. It amounted to seventeen floppy diskettes. Upon the return of his system, he found that diskette two had a bad spot... "phase error". All the other diskettes were OK. To recover, he used 'dd' to copy each floppy to the hard disk, 'split' to break the resulting file into small pieces (to isolate the binary files), and 'vi' to manually search for the file names and put everything back together. Bob -- Bob Van Cleef ...sdcsvax!gwsd!revc Gateway Computer Systems (619) 457-2701 4980 Carroll Canyon Road San Diego, CA 92121
mats@dual.UUCP (Mats Wichmann) (08/02/85)
>> >> If there is anything wrong on the input, you get a >> "phase error" and the thing dies. If, for any >> reason, you have to skip one of a multi-media set, >> you get a "phase error" and the thing dies. > > What we need is a utility (or a cpio option) that will continue > after a phase error, and will attempt to identify the next good > file. The bad file could be saved as a /tmp file to allow > human determination as to its value. Most of the time, a partial > recover (noted as such) is preferred to NO recovery. > Yes, CPIO sucketh on all the counts charged. It seems to work better, on the whole, that most of the other backup stuff (how many time have you fought errors in dump???), but it suffers from all of the previously mentioned problems, plus another one: it cant' tell too much about links, so it archives one copy of the file for each link when it comes up...(for something like vi, which is liked to some subset of view, vedit, e, ex, edit; this is a real serious problem - not everyone has a nine-track tape that will hold a ton of data). The fixes to CPIO to get around `out of pahse' errors are quite simple, but not that many people have source any more (would vendors please provide atg least this option, if nothing else?????). The business about links is basically impossible, due to the way CPIO is set up.... The IEEE P1003 (UNIX-like OS's) committee is trying to deal with this by specifying a more complete but backwards compatible version of TAR, but besides my not being to pleased with the specs, AT&T has burned a lot of bridges in this regard by supporting CPIO in releases since Sys III came out.... Mats Wichmann Dual Systems ...{ucbvax,ihnp4,cbosgd,decwrl,fortune}!dual!mats