SUMMARY: Dump parameters for Exabyte 7/14 GB tapes (160m XL)

From: Cheng-Yue Zhang (
Date: Tue Sep 19 1995 - 04:40:21 CDT

My original question is about the parameters (density and size) needed by
dump command on SunOS 4.1.x systems for Exabyte 7/14 GB 8 mm tape drive.
Similar questions have also been asked by John Rosenberg
(, who has an excellent summary posted
on Sept. 14.

Since the question is answered in John's summary, I am not going to
summarize all the responses I got. The point I want to make is that
from the responses I got I found that many people used their own
wisdom to cope with insufficient information provided by
the manuals or like. The most notable one is that very often people tend to
increase the size of 13000 for 112m tapes (5GB), e.g., multiplying 13000 by 7
and dividing it by 5, to get a size for the 160 m tape (XL, 7GB).
As pointed out by the tech support person from Exabyte, this increase
in size is not going to have any effect for the SunOS 4.1.x dump command at
all, because there is an internal limitation on data set size of about
4.3GB in SunOS 4.1.3, larger parameters won't help. The correct parameters
are as SUN recommended for SunOS 4.1.x: b - 126, s - 13000, and d - 54000.
Note: one does not need these parameters when using Solaris 2.x ufsdump
command. Having adopted the above suggestions I have been able to
dump all our disks of different systems (7 Sparcs) on to one single XL tape.
(roughly about 10 GB data)

David Tsai has kindly provided the phone number to call Exabyte at
1-800-EXA-BYTE and their email address:

Credits should go to the following people: (David Tsai) (Thuan X. Nguyen) Thu Sep 7 16:36 MDT 1995 Thu Sep 7 18:40 MDT 1995
Ian_MacPhedran@engr.USask.Ca Thu Sep 7 22:56 MDT 1995 Fri Sep 8 07:05 MDT 1995 Fri Sep 8 07:51 MDT 1995 Fri Sep 8 08:30 MDT 1995 Fri Sep 8 09:54 MDT 1995 Fri Sep 8 16:12 MDT 1995 Mon Sep 11 14:42 MDT 1995

Cheng-Yue Zhang
Department of Physics and Astronomy
University of Calgary

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