When I tell you that I once spent a day trying to figure out how to change the NETBIOS hostname on a Macintosh, you know what I mean when I say understanding dots per inch (DPI) is best if you don't think about it. By the way, the hostname is in the network configuration for Macintosh... which makes perfect sense if you discount the possibility of a non-networked computer. And that little bit of knowledge may be the last time in this post that I state anything useful, the rest may be wandering thoughts about pixels... you are warned.
I have had the discussion about DPI many times with different professionals in different professions. None of them appear have the slightest clue about any resolution other than what they are used to. Print folks always want to see 300 DPI. Don't ask me why. The personal laser printer I bought in 1992 had the capability to output files 600 DPI, why would I want to produce files at half that resolution? Modern ink jet printers are capable of physical resolutions of 1200 DPI and they claim that through software to achieve resolutions twice that high. Yet in speaking to the fine art printer who is putting some images on canvas for me, their practice is to use their software (standard commercial stuff) to adjust the resolution and image to print always at 300 DPI.
And for the screen, we really don't care. Anything over 72~90 DPI is lost anyway. Thats how many dots per inch are on a computer screen. (For reference your large screen HD television is even lower resolution than this, but since the pixels are "moving" you tend not to notice.)