Re: Simultaneous Net Calls

From: Oliver Rauch (oliver.rauch@Wolfsburg.DE)
Date: Sun Sep 24 2000 - 02:20:08 PDT

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    Grega Bremec wrote:
    >
    > Hi all,
    >
    > I must apologize in advance if this is a redundant question, but I was
    > wondering to what extent is the net backend's behaviour defined for
    > multiple "simultaneous" incoming requests to a single device?
    >
    > Does saned do any kind of resource locking, or is this entirely up to
    > individual backends?
    >
    > I did take a look at the network spec, but it doesn't seem to be
    > covered in there, however I did not look at the source.
    >

    Hi Grega,

    I did not test this but as far as I see there is started a separate
    saned (strange, on my system it looks like two saned's are started)
    for each net connection.

    This means that there sould be no difference between a
    net connection and a local connection to the backend.

    The backends have to make sure that the device is reserved
    when a scan is started. For scsi scanners this is normally
    done by a "RESERVE_UNIT" call that makes sure that only
    the process that called "RESERVE_UNIT" can talk to the scanner,
    other processes get a DEVICE-BUSY or RESERVATION-CONFLICT-error.

    bye
    Oliver

    -- 
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