Hi, On 17 May 2013, at 01:30, Greg 'groggy' Lehey wrote: > On Thursday, 16 May 2013 at 19:56:14 -0400, Zaphod Beeblebrox wrote: >> On Thu, May 16, 2013 at 5:08 PM, Bob Bishop <r...@gid.co.uk> wrote: >>> On 16 May 2013, at 21:51, Zaphod Beeblebrox wrote: >>> >>>> I have to retrieve some very old backups. They were made on FreeBSD and >>>> are on tape... specifically DDS4. [etc] >>>> However, attached to either controller (after a reboot of the machine >>> and a >>>> powercycle of the drive), I get: >>>> >>>> [1:25:325]root@run:/home/foo> dd if=/dev/sa0 of=tape5 >>>> dd: /dev/sa0: Input/output error >>>> 0+0 records in >>>> 0+0 records out >>>> 0 bytes transferred in 0.002930 secs (0 bytes/sec) >>>> >>>> ... which is a return code of '1' and no messages on the console... >>>> >>>> I have, before you ask, tried "bs=10k" and 20k ... but I believe this >>>> command should run by itself fetching the first 512 bytes of each block >>> --- >>>> narrowing down the block size logically comes after making the tape go. >>> >>> >>> Try bs=64k >> >> Same result. Besides, as far as I understand, the proper operation >> (if the blocksize is too small) is to read the first $n bytes and >> then write them to the output..
My (dim) memory says the drive won't read at all if you get the blocksize wrong, so may be worth trying other sizes... > The obvious question: can you write tapes and read them back? ...but certainly try that. > My > experience with DDS tapes was of extreme unreliability. The age > doesn't make things any easier. There's a lot to go wrong with settings etc. See for instance: http://fixunix.com/setup/398541-dds-4-tape-drive-compatiblity.html > Greg > -- > Sent from my desktop computer. > Finger g...@freebsd.org for PGP public key. > See complete headers for address and phone numbers. > This message is digitally signed. If your Microsoft MUA reports > problems, please read http://tinyurl.com/broken-mua -- Bob Bishop r...@gid.co.uk _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
