I do pretty close to the same thing only on my laptop. I have folders for each machine with photos before after and documenting repairs. I keep a text document with the Model#, Serial#, where purchased, for how much etc.
Those folders are separated into larger groups the "Herd" (mine), the "Hoard" (waiting for repair), Rehomed, etc..
I just recently started making up 3 x 5 cards for the machines as well to keep with them telling which way the needle goes, which way to thread, what shank feet, needle type and thread type. That comes in handy if I want a quick reminder and is also helpful for people who might adopt a machine. I see far too many machines abandoned at the thrifts and the dump that have the wrong bobbins and wonder if the owner couldn't get it to stitch right because tehy weren't aware the bobbin type makes a difference.