One of the systems you're likely to run into is the IBM z14. Now, you may not be working on a z14, you may have something older, you may have something newer. But chances are, it will look something like this. The parts might look a little different, they might be rotated, they might be in a slightly different place, but for as long as I can remember, the core components of the mainframe have always looked more or less like this. Starting from the right, and I'll explain why in a minute, you've got the CPC drawers. They call them drawers because they pull open like a drawer in a nightstand. In here, you've got all the processors and all the memory. They've also got the PCIe fanouts, which is a fancy way of saying all the cables that hook up to all the PCIe I/O cards. It's also got the flexible support processor which gives you redundant interfaces to all the internal management network, so you're never locked out, you can always log into one of these things. There's also two DCA invertors. These provide the specific power that everything in here needs, and there's two of them, just in case one goes down. Down here we've got the radiator pumps. These circulate refrigerant throughout the system keeping it down. It takes the cold air being blown up from the floor, and blows the hot air out the back. So cold air in the bottom, hot air on the back, chilled refrigerant all throughout the system. There are also water-cooled systems which tap into a site's chilled water lines. Looks slightly different but everything else is pretty much the same. This right here is the PCIe I/O drawer. This is where all the input-output devices live. That's your crypto cards, network cards, compression cards, and Phi card. Up top over here, there's batteries, there's two of them, and they're bigger than any batteries I own. They're there to provide a safe shutdown. So if the power does go out, none of the transactions in flight get lost. You've got four power supplies. Now, depending on how your mainframe is configured, you may have less than four, but part of the reason for so many is, you guessed it, redundancy. So ideally, if you've got four power supplies, you've got two of them hooked up to a power panel over here, and two others hooked up to a power panel over there for redundancy sake. Lastly, there's this display keyboard and these two servers up here. Those are called the support elements. We're going to come back to that so much more on that in a minute. I do want to mention that your mainframe might look like this. It might also be a single frame design. Now, a single frame design, usually called a business-class machine, is still a mainframe. It's for environments that don't require quite as much hardware so they can fit it all into a single frame. You might also find your mainframe the newer ones especially in an industry standard 19 inch rack. That's the size cabinet that most IT equipment lives in, stuff like servers, storage devices, and networking equipment. That means the mainframe doesn't have to live off in its own special area, it can be right in the middle of it all. So while the older mainframes get their own unique area, the rough metal ones get to hang out with all their other IT equipment buddies.
