SUMMARY: WANTED: dd command to duplicate 8mm dump tape(s)

From: Rex Espiritu (
Date: Thu Apr 15 1993 - 15:37:04 CDT


1) Use tprobe; Find via Archie; can ftp from internet host archives including: /usenet/comp.sources.3b1/volume02 /pub/comp.sources.3b1/volume02

2) Use copytape; Find via Archie; can ftp from internet host archives including: /usenet/comp.sources.unix/volume10 /Comp.sources.unix/Volume10 /pub/comp.sys.sun/volume10

3) Use tcopy; % man tcopy (1)

4) Use "our tape duplication process shell script" or "my C program".

5) Use dd with the following options, et. al.; Or don't/why make copies at all.

> dd if=/dev/nrst0 of=/dev/nrst1 bs=126b
> Of course, this would need to be in a loop to process all the dump file
> son the tape. The block size should be the same as used for the dump
> command, 126 blocks (63k) is typical and the recommended value.
> You definitely _do_not_want_ conv=sync as this will pad blocks, ie add
> extra bytes into the file(s). You shouldn't need any conv options. Also

> Don't do conv=noerr, because that will ignore read errors in the copy.
> Also, you should add obs=blocksize.
> Why would you make copies in the first place? The mechanism I use is
> much easier:
> - Once a week, I made a complete backup set that would allow me to rebuild
> from scratch if it ever becomes neccessary
> (colleagues needed those some weeks ago because a strike would not allow
> anyone on the place their computers were and they had to move to another
> spot. So, backups are a good idea)
> - The fresh newest backup set remains on-site that week for uncareful users;
> - The next older one goes to the off-site spot.
> - NEXT DAY, the older-older set comes back from that spot (so there is
> *always* at least one copy off-site)
> - Then copies wait a few weeks until they are re-cycled. After a few cycles,
> they are archived. I have one archive copy per month.
> That is a much better approach, IMHO. Much less work.

Nico Garcia <> tprobe
Phil Blanchfield <> copytape
Koper Zangocyan <> copytape
Mike Raffety <> tcopy (1)
Henry Katz <> tcopy (1)
Andy Toy <> tcopy (1)
Steve Vu <> tcopy (1)
John P. Linderman <> tcopy (1),
Javier Santos <> own sh script
Piete Brooks <> own C program
Glenn Satchell <glenn%ups.uucp@fourx.Aus.Sun.COM> dd (1), et. al.
Geert Jan de Groot <> dd (1),mechanism


--- Forwarded mail from (Rex Espiritu)

>From espiritu Mon Mar 29 14:46:37 1993
>From Tue Mar 30 03:56:15 1993
>From: (Rex Espiritu)
Reply-To: (Rex Espiritu)
Followup-To: junk
To: Sun Managers Mailing List <>
Subject: WANTED: dd command to duplicate 8mm dump tape(s)
Cc: Rex Espiritu <>
Status: ORS

I'd like to make duplicate copies of 8mm dump tapes to keep the month end
backups on-site as well as archived off-site. If anyone else does this on
a regular basis, I'd appreciate your sending me the exact dd command(s)
you use for comparison. I'm particularly interested if any "conv" option
is desirable to use, e.g.:

        # dd if=/dev/nrst0 of=/dev/nrst1 conv=noerror,sync

Thanks in advance,

M. Rex Espiritu, Jr.                      Carnegie Group, Inc.                          5 PPG Place
Voice: 412 642-6900 x233  FAX: -6906	  Pittsburgh, PA  15222

--- End of forwarded message from (Rex Espiritu)

This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:07:44 CDT