Standart input in "uncompress" command

[Alter]

Hello!

When I make backup I execute the following command

$tar cvf - tmp/label $FILES | compress -c > /dev/rmt/0n

So to restore files I make temporary file db.Z:

$cat /dev/rmt/0n > /arch/db.Z
$zcat /arch/db.Z | tar xhvf -

When I try to restore whithout making temporary file, I get an error.

$cat /dev/rmt/0n | uncompress | tar xhvf -
cat: input error on /dev/rmt/0n: Not enough space

Can you explain me what's wrong?
Thank you.

 

[KenCunningham]

Try using /dev/rmt/0cn , the compressed version of the device. Cheers.