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This is a real noob question. I have never taken a proper look at a server. Can someone kindly explain what is inside a server (the hardware)? And how the user interacts with it?

All the images online show some "rack", "tower", "blade" etc... (what else?) without any screen/output or any input devices. It makes me wonder how to even start installing the OS or anything in it.

I make no sense of "rack" and "blade" expect that they can be stacked like document trays, but I imagine the "tower" server the similar to our home PC CPU except that the motherboard inside only has many HDD, RAM and NIC slots -- nothing else. Is that what it is?

Appreciate any inputs to help me understand how it works. Thanks.

2 Answers 2

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There is nothing in a server that couldn't be in desktop hardware (assuming Intel servers.) Some things that are in a server that make it better to provide services 24x7 than desktop hardware:

  1. RAID and multiple disks, so that a single disk failure won't take down the server or lose data.
  2. Better disks, that can handle more and longer duty
  3. Better disks, that can serve data faster
  4. Better RAM, that can handle data corruption and fix it with error checking
  5. Remote management tools, so you can reboot the machine and get to the BIOS even if you're not in front of it and the OS isn't responding. This also lets you do remote installs of the OS, as you asked.
  6. Better (more reliable) hardware in general

Edit- I missed this question : "And how the user interacts with it?" If the "user" is the IT staff that maintains it, they would use remote tools in the OS, or remote management hardware like #5, or KVM units that allow you to hook up a single Keyboard, Video, Mouse combo to many servers and pick which one should be controlled.

If the "user" is not the admin staff, then they interact with whatever the server is serving. If it's an email server, their mail client sends and receives via that server. If it's a web server, the user visits the web page. If it's a database server, the user typically is using an application that is designed to query and/or manipulate that database.

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  • Thanks mfinni. I read the specs of some DELL servers and it specifcally says it does not come with any OS. It makes sense. But What are the steps to get it installed in the first place?
    – Jake
    Dec 7, 2010 at 7:52
  • Told you - you can do it from the console same as a desktop, if you have a keyboard/monitor/mouse lying around. You can do it from the console with a KVM setup if you have one in your rack. If it's a blade, it has remote management and/or KVM built-into the bladecenter chassis. A decent server, non-blade, will also typically have remote management that will give you virtual KVM and often even let you mount remote media, like floppies and CD (or images of the same, like ISO files.)
    – mfinni
    Dec 7, 2010 at 13:52
  • Also, some OSes or deployment technologies are meant to be used without local console at all. NetBOOT, PXE, JumpStart, floppy with an answer file and a network connection - all of those work for for desktops, workstations, and servers, you just have to find out what the options are for the OS you care about.
    – mfinni
    Dec 7, 2010 at 13:56
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A server is nothing more than a typical computer built to perform better under specific conditions (utilization, environment, performance, reliability, etc) than a typical computer. Typically they have specialized hardware to help accomplish this.

A server rack is a container; it has rails on the four vertical corners to which equipment can be attached. They have common mounting patterns, vertically delineated as Rack Units (1U each). A rackmount server can be installed in one or more of these spaces (some servers take up more than 1U, some less, it depends on the server). Shelves can also be installed to support non-rackmount server.

A blade chassis can be installed in a rack as well. Blade servers are then installed into the blade chassis. Blade servers typically hold more specialized servers. The blade enclosure abstracts certain common hardware from the server and certain external features. Usually this includes power conversion, data buses, internetworking buses, and some management functions.

For more detailed information, please search/ask questions about specific pieces.

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  • Thanks Chris, i think i can get those specifics about form factor from wikipedia. What I wanted to know mainly was how the system admin set up software without IO hardware.
    – Jake
    Dec 7, 2010 at 7:47
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    @Jake - servers most definitely do have IO hardware. Just because you typically buy a server without a monitor doesn't mean you can't plug one in. (And they do still typically come with keyboards, at least on the Intel side.) In fact, as I've stated, they often come with more IO options than a desktop.
    – mfinni
    Dec 7, 2010 at 13:56
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    @Jake, in addition to mfinni's comment, most servers have serial ports, which can be used to boot a console OS (Linux, Unix, BSds, DOS, etc).
    – Chris S
    Dec 7, 2010 at 14:32

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