Cisco F-UP



  • Because the Cisco Catalyst series are 'upmarket' switches the flickering lights you always have on each port can do several different things. One of these is to tell you whether the port is operating in full-duplex(only connected to 1 host) or half-duplex(connected to a hub and several hosts) mode.

    Anyway this port light mode has to have a name. What would you call it - Duplex mode? DUPL?

    No. The Cisco official documentation calls it the FDUP mode. The natural way to prounouce this is - of course 'effed-up'

    As a result it is now known universally at my workplace as the 'effed-up' mode :)

    In case you don't believe me



  • Every once in a while, engineers get to exercise their sense of humor.

    The
    6809 CPU's assembly instruction set has an instruction for converting a
    one-byte signed integer into a two-byte signed integer by replicating
    the sign bit of the original byte across the entire high byte. 
    This is the Sign Extend instruction.  Its mnemonic is SEX.



  • [quote user="j_pilborough"]

    full-duplex(only connected to 1 host) or half-duplex(connected to a hub and several hosts)[/quote]WTF?

    And how do you call the operating mode of a port that has no hosts connected to it? FileHost-not-found-duplex?

    Full-duplex == Can both send and receive at the same time

    Hal-duplex == Can only send or receive at a time, not simultaniously.

     How many MAC-adresses are associated with a givven port has nothing to do with duplexity.



  • The PowerPC CPUs used in Macintosh computers a few generations back had an instruction called "Enforce Inline Execution of Input/Output" -- or EIEIO for short.



  • [quote user="pnieuwkamp"]

    [quote user="j_pilborough"]

    full-duplex(only connected to 1 host) or half-duplex(connected to a hub and several hosts)[/quote]WTF?

    And how do you call the operating mode of a port that has no hosts connected to it? FileHost-not-found-duplex?

    Full-duplex == Can both send and receive at the same time

    Hal-duplex == Can only send or receive at a time, not simultaniously.

     How many MAC-adresses are associated with a givven port has nothing to do with duplexity.

    [/quote]

    I was only trying to give a simple explanation to the best of my knowledge. Full duplex is impossible when hubs get involved. Usually if a single host is connected in a point-to-point link that link will operate in full duplex.
     



  • This one's a register value, not an instruction, so there's no mnemonic, but the video chip for the Commodore 64 had a setting that would blank the video output and cause the chip to rapidly overheat.



  • [quote user="Carnildo"]This one's a register value, not an instruction, so there's no mnemonic, but the video chip for the Commodore 64 had a setting that would blank the video output and cause the chip to rapidly overheat.[/quote]

    Yes, the infamous "killer poke". There was also the HCF instruction: Halt and Catch Fire.



  • [quote user="j_pilborough"]I was only trying to give a simple explanation to the best of my knowledge. Full duplex is impossible when hubs get involved. Usually if a single host is connected in a point-to-point link that link will operate in full duplex. [/quote]

    FD with hubs is impossible, yes since they repeat on all ports as things come in.

    Everything else it's based on the connected devices limits. Most modern gear does FD now and settings are auto configured on connection, but older stuff and a fair few embedded systems only do HD due to hardware limits.



  • @CDarklock said:

    [quote user="Carnildo"]This one's a register value, not an instruction, so there's no mnemonic, but the video chip for the Commodore 64 had a setting that would blank the video output and cause the chip to rapidly overheat.

    Yes, the infamous "killer poke".

    [/quote]
    That was, unless I am mistaken, a property of the PET line. The C64 had no such thing.


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