On Mon, 04 Mar 2013 04:15:48 -0600, Joshua Isom wrote: > I'd call bs= essential for speed. Any copying will be faster with > something higher.
I thought about that. Narrowing down _if_ something has found is easy, e. g. when the positive 1 MB unit is dd'ed to a file, further work can easily be applied. > Also, there's the possibility, very annoying, that > your search string overlaps a place where you read. I'd probably check > 1M blocks, but advance maybe 950k each time. I also thought about that, that's why the distinctive phrase I'm searching for is less than 10 characters long. Still it's possible that it appears "across" a boundary of units, no matter how big or small I select bs=. But I don't know how to do this. From reading "man dd" my impression (consistent with my experience) is that the option skip= operates in units of bs= size, so I'm not sure how to compose a command that reads units of 1 MB, but skips in units of 950 kB. Maybe some parts of my memory have also been marked "unused" by fsck. :-) > Make sure you're reading > from block offsets for maximum speed. How do I do that? The disk is a normal HDD which has been initialized with "newfs -U" and no further options. ad6: 953869MB <Hitachi HDS721010DLE630 MS2OA5R0> at ata3-master UDMA100 SATA 1.5Gb/s The file system spans the whole disk. > I know disk editors exist, I > remember using one on Mac OS 8.6 for find a lost file. That was back on > a 6 gig hard drive. Ha, I've done stuff like that on DOS with "important business data" many years ago, using the "Norton Disk Doctor" (NDD.EXE) when Norton (today: Symantec) wasn't yet synonymous for "The Yellow Plague". This program actually was quite cool, and you could search for things, manipulate disks on several levels (files, file system and below). I had even rewritten an entire partition table from scratch, memory and handheld calculator after an OS/2 installation went crazy. :-) > Depending on the file size, you could open the disk in vi and just > search from there, or just run strings on the disk and pipe it to vi. You mean like "strings /dev/ad6 | something", without dd? That would give me _no_ progress indicator (with my initial approach I have increasing numbers at least), but I doubt I can load a 1 TB partition in a vi session with only 2 GB RAM in the machine. If I try "strings /dev/ad6" I get a warning: "strings: Warning: '/dev/ad6' is not an ordinary file". True. But this opens a useful use of cat: "cat /dev/ad6 | strings". (Interesting idea, I will investigate this further.) The file size of the file I'm searching for is less than 10 kB. It's a relatively small text file which got some subsequent additions in the last days, but hasn't been part of the backup job yet. I can only remember parts of those additions, because as I said my brain is not good with computer. :-) Or do you think of something different? If yes, please explain. The urge to learn is strong when something went wrong. :-) -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"