Is there a way to make rdump to Exabyte faster?

[Andreas Karrer]

caroline at pangea.Stanford.EDU (Caroline Lambert) writes:

[...]
>Doing a remote dump from a DEC5000 (Ultrix 4.1) I am using the 
>parameters recommended by the manufacturer of the tape drive, 
>for lack of anything better (there's no 'b' parameter for the ultrix rdump).
>This is for a 2GB tape:
>rdump 0unsdBf 346 4137733 2097152 tapemachine:/dev/nrmt0h /filesystem

we don't use rdump anymore. we use basically 
dump 0uf - /dev/r<pastition> | rsh tapehost "buffer -s 126b > /dev/<exabyte>"
and get transfer rates (DECsystem 5500 -> Sun 4/490) of 220KB/s, close
to the streaming speed of the exabyte (246 KB/s ?).

buffer is a highly useful program written by Lee McLoughlin, Imperial College
(lmjm at doc.ic.ac.uk or lmjm%uk.ac.ic.doc at nsfnet-relay.ac.uk). It is
basically a "dd" that splits itself into two processes that communicate
thru shared memory and does re-blocking. we run it under SunOS 4.1.1
and Ultrix 4.[0|1].

buffer was posted to alt.sources some time back, but i can't readily find it
on any ftp site. so i put it on 
ural.ethz.ch[129.132.1.45]:software/source/buffer.tar.Z

+-----------
  Andi Karrer, Communication Systems, ETH Zuerich, Switzerland
  karrer at bernina.ethz.ch                 - terible simplifieur
  /s=karrer/ou=bernina/o=ethz/prmd=switch/admd=arcom/c=ch/