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Re: [nslu2-general] Re: I need a hint (or several)...

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  • Michael Wagner
    ... Sorry, that was opportunistic locking. You re right, optimistic locking is a database term. ... That s what you can expect from MS :-) Try 296264. I
    Message 1 of 7 , Jan 3, 2005
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      At 03/01/2005 07:47 PM, you wrote:
      >I have searched for "optimistic locking" with Google but did only find
      >that term in connection with Access (or other SQL-type) databases.

      Sorry, that was opportunistic locking. You're right, optimistic locking is
      a database term.

      >I have implemented a couple of MS "knowledge base" tips with *no result*.

      That's what you can expect from MS :-)

      Try 296264. I haven't tried it yet, so no guarantees.

      Michael

      http://home.cogeco.ca/~michaelwagner/personal-page.htm
      "All I wanna do is have a little fun before I die" Sheryl Crow
    • Rob Lockhart
      ... Actually, a good switch would be better than a crossover cable. I believe that full duplex communications require either forcing on both ends, or
      Message 2 of 7 , Jan 8, 2005
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        On 1/3/2005 1:36 AM EST, unix fan wrote:

        >
        > You forgot about the box in the middle, your router or switch. What
        > is it?
        >
        > It's quite possible the connection to the NSLU2 has been incorrectly
        > autonegotiated with a mismatched duplex setting. Even high end Cisco
        > routers and Sun Workstations have this problem. That trashes the
        > network connection (lots of errors). I don't know how you can tell
        > what the router/switch port duplex setting is. But if you want to
        > probe at the problem, go buy a crossover cable and connect the NSLU2
        > directly to your computer's NIC )i.e., the RJ45 port. That would at
        > least get the router and the cabling to it out of the equation.
        >

        Actually, a good switch would be better than a crossover cable. I
        believe that full duplex communications require either forcing on both
        ends, or auto-negotiating with a NWAY hardware switch. One PC to
        another PC will likely not autonegotiate to 100Mbps full-duplex (may
        only be half duplex). If autonegotiations does not occur, the default
        behavior is to use forced half-duplex.

        You are right, though, that the wrong negotiations will cause all sorts
        of errors (and obviously collisions), which would cause excessive
        retransmissions and thus lower throughput.

        Most people don't have routers; they are called broadband routers but
        they are nothing more than a network switch connected to some ARM or
        equivalent processor for filtering and NAT to the WAN port.

        In regards to cabling, to ensure you're using the right kind of cable,
        you can do the following:

        Holding the cable in your hand with the tab sticking down and the the
        RJ45 connector pointing away from you as if you were going to plug it
        into a jack, pin 1 is the leftmost wire on the RJ45 connector. Check
        that the wires for pins 1 and 2 are opposite colors. I.e., if pin 1 is
        white with orange stripe, pin 2 should be orange with white stripe. Do
        the same for pins 3 and 6. If this is fine on both ends, then your
        cable is fine. I have seen some RJ45 connected cables made for digital
        phones that don't require the CAT5 / T568B (I think) wiring
        specification. It will work for 10Mbps but at 100Mbps it causes an
        excessive amount of crosstalk that can mess up a lot of ethernet
        switches and hubs. I have seen it for myself.

        Hope that helps.

        Regards,
        -Rob
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