Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mtndew!ctisbv!pim
From: pim@cti-software.nl (Pim Zandbergen)
Newsgroups: comp.unix.i386
Subject: Re: Multiple tape backups with cpio
Message-ID: <1990Aug22.161617.10183@cti-software.nl>
Date: 22 Aug 90 16:16:17 GMT
References: <1990Jul17.221141.5971@esegue.segue.boston.ma.us> <1437@mic.UUCP> <75@towers.UUCP> <1990Aug1.214903.699@cichlid.com> <3465@rsiatl.UUCP> <11134@alice.UUCP>
Distribution: na
Organization: CTI Software BV, The Hague, The Netherlands
Lines: 25

>>Yeah, it's way too complicated.  KISS. :-)  Cpio is SUPPOSED to detect end
>>of file and prompt you for a new tape.  Says so right in TFM.  At least
>>under ISC 2.0.2 and 2.2, it does not work. (experience with 4 systems so 
>>far in that regard.)  

>It does work with stock AT&T sVr3.2 and the stock cpio, and the prompt for
>a new tape is really based on the system detecting the end of the tape.
>You do have to use the -O option for write and -I for read though.

This really depends on the device driver. cpio expects the device
driver to fail the write() with errno == ENXIO (no such device or address)
on end of medium.

With ISC, the Wangtek driver will give this error, but the SCSI tape
driver will not send any write failure, it will just hang when it reaches
the end of the tape. So even pax, which will query you for a new medium
for *every* write failure, will not properly work.

I  use a modified afio, which will recognize ENXIO for
"normal" devices and uses the byte count method for the SCSI tape.
-- 
Pim Zandbergen                            domain : pim@cti-software.nl
CTI Software BV                           uucp   : uunet!mcsun!hp4nl!ctisbv!pim
Laan Copes van Cattenburch 70             phone  : +31 70 3542302
2585 GD The Hague, The Netherlands        fax    : +31 70 3512837