Re: Installation from a tape

[Nobuyoshi SATO <nobu-s%iwate-pu.ac.jp@localhost>]

Happy new year all,

On Wed, 31 Dec 2025 10:54:16 -0500,
Brandon Applegate <vom513%gmail.com@localhost> wrote:

> Not intending to hijack this thread - but I see talk of the st driver and
> block devices etc.  I submitted a PR a while ago about problems using
> physical tape drives (not for booting but just general use):
> 
> https://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=59570
> 
> Could there be some relation or intersection between that and this thread ?
> 
> tl;dr - Physical tape drives give errors on reads in NetBSD.  Going back to
> NetBSD 7.2 seems to have things work without errors.  Same hardware when
> connected to Solaris or Linux works error-free / as expected.

I think this may be essentially the same st(4) problem. Perhaps
st(4) has been changed after NetBSD 7.2 so that st(4) has
somehow strange behavior.

I tried reading/writing real tape device with tar and dd in
some ways:

# tar cvf /dev/st0 /usr/pkg
    --> write success
        reading with
	# tar tvf /dev/st0 causes "damaged archive" errors.
	# dd if=/dev/st0 bs=512 | tar tvf -  causes "damaged archive" errors.
	# dd if=/dev/nrst0 bs=512 | tar tvf - caused "dd: /dev/nrst0: Input/output error"
In this case, data on the tape itself damaged.

# tar cvf /dev/nrst0 /usr/pkg
    --> write success
        reading with
	# tar tvf /dev/st0 causes tar: Error opening archive: Error reading '/dev/st0'
	# dd if=/dev/st0 bs=512 | tar tvf - causes dd: /dev/st0: Input/output error 
	# dd if=/dev/nrst0 bs=512 | tar tvf - causes dd: /dev/st0: Input/output error
In this case, data on the tape itself damaged too or could not be
written into the tape.

# tar cvf - /usr/pkg | dd of=/dev/st0 bs=512
    --> causes write error

# tar cvf - /usr/pkg | dd of=/dev/nrst0 bs=512
    --> write success. reading tape with
        # tar tvf /dev/st0 causes "damaged archive" errors.
        # dd if=/dev/st0 bs=512 | tar tvf -  causes "damaged archive" errors.
	# dd if=/dev/nrst0 bs=512 | tar tvf - read success without error.
In this case, data on the tape is OK, but reading through
/dev/nrst0 and using dd always required.

Handling of /dev/st0 may be corrupted after NetBSD 7.2. Also,
I noticed reading/writing real tape device when dd is not
used is two or three times faster than dd is used.


So back to tape boot installation, I think modifying a tar reading 
sh script on src/distrib/sparc/ramdisk/dot.profile
from:
    echo "Extracting installation utilities... "
    (cd $INSTFS_MP && tar $bsa -z -x -p -f $dev) || return 1
to (I hope this works fine, according to gzip's source):
    echo "Extracting installation utilities... "
    (cd $INSTFS_MP && gzip -dc $dev | tar -x -p -f -) || return 1
or (add dd in ramdiskbin needed but reliable):
    echo "Extracting installation utilities... "
    (cd $INSTFS_MP && dd if=$dev bs=$bsa | tar -z -x -p -f -) || return 1
is realistic way to keep port sparc tape installation working.


I'm creating installation tape images in both way above now.
And I will test tape images in a real tape after I will return
to physical console of MY SS20 in my university. It will be
Jan 5 or 6.





> On Wed, Dec 31, 2025 at 9:32 AM Nobuyoshi SATO <nobu-s%iwate-pu.ac.jp@localhost>
> wrote:
> 
>> If tape device had raw device such like disks (ex. /dev/rsd0 for
>> /dev/sd0), solution would be very easy.
>>
>> According to manpage st(4), /dev/rst0 is "Mode 0, Rewind on close",
>> however, in manpage mtio(4) describes:
>>      The raw device name is the block device name with an "r" prepended,
>> e.g.
>>      /dev/rst0.
>>
>> Hmm... This inconsistency that all device files of st(4) work
>> as only block device seems to be introduced some tens years
>> ago. Fixing st(4) so that it work with raw devices is correct way,
>> but quick and dirty fix above might be realistic solution
>> because capacities of tape cartridges might not be a problem
>> since they are at least 150MB for old Sun QIC tape drives.
>> (More older QIC-11 or QIC-24? size of base.tgz goes over the
>> capacity!)






Lecturer / Faculty of Software & Info. Sci., Iwate Prefectural Univ.
Nobuyoshi Sato, Ph.D / nobu-s%iwate-pu.ac.jp@localhost / +81-19-694-2612