RE: port-amd64/53890: st(4) driver for tapes not working o variable block size

["G J van der Grinten" <pa0gri%amsat.org@localhost>]

The following reply was made to PR port-amd64/53890; it has been noted by GNATS.

From: "G J van der Grinten" <pa0gri%amsat.org@localhost>
To: <gnats-bugs%NetBSD.org@localhost>,
	<port-amd64-maintainer%netbsd.org@localhost>,
	<gnats-admin%netbsd.org@localhost>,
	<netbsd-bugs%netbsd.org@localhost>
Cc: 
Subject: RE: port-amd64/53890: st(4) driver for tapes not working o variable block size
Date: Sat, 19 Jan 2019 15:57:49 +0100

 Hello Michael,
 
 That is a very logical explanation.
 
 For TAPE files -as long a I worked with them (52 years) they Always are odd
 sized.
 (besides the inter-system tapes - they had precise formats)
 
 Now a patch and I will be happy.
 I am and long time standing - 386BSD user.
 
 Regards, Gerard.
 
 PS, being careful is fine but not always...
 
 
 -----Original Message-----
 From: Michael van Elst [mailto:mlelstv%serpens.de@localhost] 
 Sent: Saturday, January 19, 2019 3:45 PM
 To: port-amd64-maintainer%netbsd.org@localhost; gnats-admin%netbsd.org@localhost;
 netbsd-bugs%netbsd.org@localhost; pa0gri%amsat.org@localhost
 Subject: Re: port-amd64/53890: st(4) driver for tapes not working o variable
 block size
 
 The following reply was made to PR port-amd64/53890; it has been noted by GNATS.
 
 From: mlelstv%serpens.de@localhost (Michael van Elst)
 To: gnats-bugs%netbsd.org@localhost
 Cc: 
 Subject: Re: port-amd64/53890: st(4) driver for tapes not working o variable
 block size
 Date: Sat, 19 Jan 2019 14:42:42 -0000 (UTC)
 
  pa0gri%amsat.org@localhost ("G J van der Grinten") writes:
  
  >But on the recond read for a block I get an " Invalid argument" and that is
  >invalid by itself.
  
  Looks like this is not the tape driver itself. The kernel physio() routine
  does a sanity check on the I/O byte offset to be a multiple of DEV_BSIZE
  (== 512 bytes) and returns EINVAL if that's false. That's why the
  second read or write fails (the first starts at offset 0).
  
  That sanity check doesn't make sense for a tape and might not even be needed
  for e.g. a disk, the disk drivers do their own checks.
  
  -- 
  -- 
                                  Michael van Elst
  Internet: mlelstv%serpens.de@localhost
                                  "A potential Snark may lurk in every tree."