[8912] in linux-scsi channel archive
Re: LINUX Jobs for 2.4 update [scsi]
daemon@ATHENA.MIT.EDU (Douglas Gilbert)
Sat May 27 16:59:50 2000
Message-ID: <393035DB.C9C9B99@interlog.com>
Date: Sat, 27 May 2000 16:53:48 -0400
From: Douglas Gilbert <dgilbert@interlog.com>
MIME-Version: 1.0
To: Paul Gortmaker <p_gortmaker@yahoo.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel@vger.rutgers.edu, linux-scsi@vger.rutgers.edu
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Paul Gortmaker wrote:
>
> > To Do
> > -----
> > Linux sends a 1K buffer with SCSI inquiries. The ANSI-SCSI limit is 255.
>
> [snip]
>
> > Linux uses TEST_UNIT_READY to chck for device presence on a PUN/LUN. The
> > INQUIRY is the only valid test allowed by the spec.
>
> The draft of SCSI-2 spec I have here hints that INQUIRY should be used
> to probe system configuration and that TEST_UNIT_READY is more for
> polling on devices with removable media. I tossed the TEST_UNIT_READY
> part out and INQUIRY alone works fine (one disk, 2 CDs and a tape on
> a BusLogic clone - all found as per usual).
I seem to remember the Bob Frey [formerly of Advansys and author of
that company's HBA drivers for several OSes] commenting that Linux
did something slightly different during initialization. Namely it
issued a TEST_UNIT_READY before an INQUIRY. I haven't checked if that
is still the case. Bob suggested that the Linux ordering was probably
incorrect (but seemingly harmless).
Doug Gilbert
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