Re: what binds to port

From	Brian <ad44@cityscape.co.uk>
Newsgroups	linux.debian.user
Subject	Re: what binds to port
Date	2021-08-02 14:10 +0200
Message-ID	<CHEVA-3q2-7@gated-at.bofh.it> (permalink)
References	<CHDmN-2km-3@gated-at.bofh.it> <CHEiS-2WN-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Mon 02 Aug 2021 at 13:21:22 +0200, Thomas Schmitt wrote:

> Hi,
> 
> Brian wrote:
> > Isn't /dev/sg0 the block device?
> 
> /dev/sgX are character devices.
> 
>   https://tldp.org/HOWTO/SCSI-Generic-HOWTO/intro.html
> says
>   "The driver's purpose is to allow SCSI commands to be sent directly to
>    SCSI devices. [...] Various specialized applications for writing
>    CD-Rs and document scanning use the sg driver."
> 
> This is still the case for optical drives (sr) and hard discs (sd) which get
> an sg device file additionaly to their block device file. But it seems that
> the statement about "document scanning" could need an update.
> 
> 
> The main call for sg devices is ioclt(SG_IO) which performs a single SCSI
> command transaction.
> Since about 15 years it is possible to use it directly with a /dev/srX
> device file. But a bug introduced in a late version of kernel 2.6 prevented
> concurrent use of SG_IO on multiple sr devices. This ended with
>   https://github.com/torvalds/linux/commit/51a8588
> which i assume went into kernel version 5.6.
> So with the currently released Debian versions, /dev/sgX is still of use
> if there is more than one sr device.

I misread sr0 as sg0; sorry to have put you to the trouble of posting.
On the bright side, you have helped clear up a misconception of mine.

-- 
Brian.

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Re: what binds to port "Thomas Schmitt" <scdbackup@gmx.net> - 2021-08-02 10:00 +0200
  Re: what binds to port mick crane <mick.crane@gmail.com> - 2021-08-02 10:20 +0200
  Re: what binds to port Nicolas George <george@nsup.org> - 2021-08-02 10:40 +0200
    Re: what binds to port Brian <ad44@cityscape.co.uk> - 2021-08-02 16:10 +0200
      Re: what binds to port Nicolas George <george@nsup.org> - 2021-08-02 17:40 +0200
        Re: what binds to port Brian <ad44@cityscape.co.uk> - 2021-08-02 18:00 +0200
          Re: what binds to port Nicolas George <george@nsup.org> - 2021-08-16 20:00 +0200
            Re: what binds to port Brian <ad44@cityscape.co.uk> - 2021-08-16 21:00 +0200
              Re: what binds to port Brian <ad44@cityscape.co.uk> - 2021-08-17 12:30 +0200
  Re: what binds to port Brian <ad44@cityscape.co.uk> - 2021-08-02 12:30 +0200
    Re: what binds to port "Thomas Schmitt" <scdbackup@gmx.net> - 2021-08-02 13:30 +0200
      Re: what binds to port Brian <ad44@cityscape.co.uk> - 2021-08-02 14:10 +0200

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