[comp.unix.xenix.sco] how do you determine end of tape?

jay@gdx.UUCP (Jay A. Snyder) (12/08/90)

the tar that comes with SCO xenix knows when I gets to the end of a
floppy, and then prompts for another.  Does anyone out there know how
this is done?  I want to write a program that I can pipe the output of
a program through so that I can write multiple floppies worth of data
to foppies.

The reason I want to do this is:

tar zcvf - | floppyswapprogram > /dev/fd0

J

davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (12/10/90)

In article <79@gdx.UUCP> jay@gdx.UUCP (Jay A. Snyder) writes:
| 
| the tar that comes with SCO xenix knows when I gets to the end of a
| floppy, and then prompts for another.  Does anyone out there know how
| this is done?  I want to write a program that I can pipe the output of
| a program through so that I can write multiple floppies worth of data
| to foppies.

  I hate to say this, but this was done some time ago. I posted 'bundle'
to the net several years ago, it knows about multi-volume, prompts you
for new ones and has the corresponding utility to read the volumes back
in. The latest version also will use shared memory instead of pipes for
double buffering, and so is much faster, but the one in the archives is
still about 3x faster than writing to floppy, even if you only have one.

  The new version is in the comp.source.unix queue, and should be posted
in 2002 at the rate stuff is coming out (I have things in there well
over a year now).
-- 
bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen)
    sysop *IX BBS and Public Access UNIX
    moderator of comp.binaries.ibm.pc and 80386 mailing list
"Stupidity, like virtue, is its own reward" -me

jak@sactoh0.SAC.CA.US (Jay A. Konigsberg) (12/12/90)

In article <79@gdx.UUCP> jay@gdx.UUCP (Jay A. Snyder) writes:
> 
> the tar that comes with SCO xenix knows when I gets to the end of a
> floppy, and then prompts for another.  Does anyone out there know how
> this is done?  I want to write a program that I can pipe the output of
> a program through so that I can write multiple floppies worth of data
> to foppies.
>

The file /etc/default/tar tells tar how big the media is. You can
specify it yourself. This will work for a 20MB tape:

tar cvfbk /dev/rct0 20 61440 /usr /u

c - collect data
v - verbose (display file names)
f - specify archive file (tape drive here)
b - blocking factor (typically 10, 18, or 20)
k - kbytes (1024 * 60)


-- 
-------------------------------------------------------------
Jay @ SAC-UNIX, Sacramento, Ca.   UUCP=...pacbell!sactoh0!jak
If something is worth doing, it's worth doing correctly.