Trouble with 'tar', tape archiver.

[Bill Vermillion]

In article <1991Jan19.212640.18364 at portia.Stanford.EDU-> fangchin at elaine43.stanford.edu (Chin Fang) writes:
->In article <1991Jan19.040951.2883 at NCoast.ORG> ramsey at NCoast.ORG (Cedric Ramsey) writes:
->>Hello. I am running ESIX a unix sys V compatible os. I've been
->>trying to backup a directory, /mnt/code, using tar. I want to
->>do the backups to floppy disk. I used the following command:
->>$tar cevfk /dev/rdsk/f0q15d 1200 /mnt/code
->>This will backup all files an subdirectories but when I get close
->>to the last file I get 'tar read tape error'. Also, the tar does 
->>prompt me to put in the floppies when needed. and the directory
->>/mnt/code has sub directories too. Can anybody help me?
->>
->I think for backing up to and from floppies, you are better off with the cpio
->utility because it senses backup media boundary (ie. when the reading or
->writing is reaching the end of the media, it will info you so and prompt you
->for new floppy).  As far as I know, not every tar does this. ESIX's? I think
->the answer is no too.  Xenix' tar will do but that's an exception?

But the answer is yes.  I just tried it now, since you said you didn't
think it did it.

Syntax is a snap.  If you are using 1.2 meg 5.25" in drive 0 cd to the
directory hierachy you wish to save and type

tar cv2 .

The 2 is the number of the proper drive type in the /etc/default/tar file.
It knows how long the disk is, and it's blocking factor.   That's one of
the nice features from the Xenix side, a default tar file so you never get
the k and b swapped, you always specify the proper device, it flags between
non-seeking and seeking.

If I didn't do tar cv2 .   it would be
tar cvfkbn /dev/<device.name> 1200 20 .

I think tar cv2 .   is better

bill
->
->The syntax:
->
->from hard disk to floppy:
->
->cd to the directory you want to backup;
->
->find . -depth -print |cpio -ocavmB > /dev/rdsk/f0t (1.2 Meg) or f1t (1.4 Meg)
->
->or if no subdirectory;
->
->ls * (assuming you want everything) |cpio -ocavmB > ... (same as above)
->
->from floppies to a directory on hard disk:
->
->assuming you use 1.2 Meg drive and 5.25" floppies,
->
->cd to the appropriate directory (I can't tell you where, you set up your
->file tree)
->
->cpio -icvmB < /dev/rdsk/f0t
->
->You don't need f0q15dt or others, ESIX's floppy devices files are generally
->slightly faster (not necessary more solid, so always DOUBLE CHECK your 
->backup-ed floppies to make sure there are no errors before you erase your
->originals on the hard disk!!!!!)
-- 
Bill Vermillion - UUCP: uunet!tarpit!bilver!bill
                      : bill at bilver.UUCP