A quick 'U' question...

Posted:
in Current Mac Hardware edited January 2014
What does 1U, 2U and 3U stand for when we're talking big servers?



I cant figure it out...

Comments

  • Reply 1 of 15
    i, fredi, fred Posts: 125member
    Quote:

    Originally posted by T'hain Esh Kelch

    What does 1U, 2U and 3U stand for when we're talking big servers?



    I cant figure it out...




    Unit - it's how many standard rack spaces a thing will take up.
  • Reply 2 of 15
    cellscells Posts: 20member
    1U == 1.75 inches
  • Reply 3 of 15
    Quote:

    Originally posted by cells

    1U == 1.75 inches



    A cookie if you can tell us why 1U == 1.75 inches.
  • Reply 4 of 15
    cliveclive Posts: 720member
    Quote:

    Originally posted by johnsonwax

    A cookie if you can tell us why 1U == 1.75 inches.



    Because it's more than 1.5 and less than 2.0?
  • Reply 5 of 15
    cellscells Posts: 20member
    Is it because 1.75 inches is about the size of an old tray loading optical drive? Enough for two PCI slots? 40 of them are exactly 70 inches? Size of an ATX power supply? I give up.
  • Reply 6 of 15
    rageousrageous Posts: 2,170member
    it's because 1u = 4.45cm.



    and 4.45cm = 1.75in.



    where's my cookie?
  • Reply 7 of 15
    dfilerdfiler Posts: 3,420member
  • Reply 8 of 15
    scottscott Posts: 7,431member
    That's not a reason. Why 4.45 then?
  • Reply 9 of 15
    saabmp3saabmp3 Posts: 52member
    I'm nearly posative it's just a standard that was developed a long time ago in 10 based hubs (rack mount of course). It's just seemed to carry on the current servers of today.



    BEN



    PS, somebody correct me if I'm wrong.
  • Reply 10 of 15
    shetlineshetline Posts: 4,695member
    Quote:

    Originally posted by johnsonwax

    A cookie if you can tell us why 1U == 1.75 inches.



    Because if you want to pull a 1U server out of its rack using your teeth, 1.75" is, on average, the optimum thickness for getting a good, solid bite-grip on the chassis?
  • Reply 11 of 15
    jlljll Posts: 2,713member
    Quote:

    Originally posted by saabmp3

    I'm nearly posative it's just a standard that was developed a long time ago in 10 based hubs (rack mount of course). It's just seemed to carry on the current servers of today.



    I don't know why it's 1.75" but I do know that the rack standard comes from the music industry.
  • Reply 12 of 15
    dominodomino Posts: 8member
    Quote:

    Originally posted by johnsonwax

    A cookie if you can tell us why 1U == 1.75 inches.



    Because there are 42 U's in a standard full size rack.... which as anyone who's read Douglas Adams knows, 42 is the answer to Life, the Universe, and Everything (pity nobody knows the question).



    In addition, 42U = 73.5 inches = 6ft 1.5inch, which is exactly how tall I am.



    Further proof of the intelligent design of the universe.
  • Reply 13 of 15
    danruiiddanruiid Posts: 7member
    Quote:

    Originally posted by saabmp3

    I'm nearly posative it's just a standard that was developed a long time ago in 10 based hubs (rack mount of course). It's just seemed to carry on the current servers of today.



    BEN



    PS, somebody correct me if I'm wrong.




    Because equipment racks, 19" wide, 46" deep, and 42U tall, were designed to accomodate telephone equipment over 50 years ago. 1.75 inches was the smallest one could engineer a network terminal and accomodate the power supplies available at the time. 19 inches wide was based on the size of the development lab (not kidding) so they could fit 8 racks side-by-side. The height was also based on the dev lab's dimensions. The depth was the shortest they could make a single 1U terminator to accomodate 8 phone lines.



    God I need a life....
  • Reply 14 of 15
    danruiiddanruiid Posts: 7member
    Quote:

    Originally posted by JLL

    I don't know why it's 1.75" but I do know that the rack standard comes from the music industry.



    Nope! The rack standard was originally defined by the now International Telecommunications Union. Currently such things are defined jointly by the EIA/TIA.



    Yay!
  • Reply 15 of 15
    danruiiddanruiid Posts: 7member
    Quote:

    Originally posted by Domino

    Because there are 42 U's in a standard full size rack.... which as anyone who's read Douglas Adams knows, 42 is the answer to Life, the Universe, and Everything (pity nobody knows the question).



    In addition, 42U = 73.5 inches = 6ft 1.5inch, which is exactly how tall I am.



    Further proof of the intelligent design of the universe.




    Well, *other* then the obvious...



    Love,

    Slarghty Bartfast
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