Ok, something occurs to me.
These days, the CPUs we have are a gazillion times faster than the mechanical parts (hard drives) we have in our computers. Anything having to do with loading data from the hard drive, the actual hard drive mechanics are the bottleneck in 99.9% of situations.
Coming up with numbers out of my ass, let’s suppose it takes 1 second to read a 1 megabyte file from the disk. Let’s say that we can compress that same file by half, and it takes .2 seconds to decompress (or shorter, relatively, with a fast CPU). These numbers seem reasonably proportional to me, but correct me if I’m wrong.
Now, the slowest part of the system, the mechanics of the hard drive, only have to read 500k of data - in half a second. Add decompression overhead on top of that, .2 seconds, and you have .7 seconds total, rather than the 1 second of the original file.
So it strikes me that now that our processors are way, way, way faster than our hard drives, the decompression process can work faster than the reading process - meaning compression would result in both a space and time efficiency saving.
But I’ve never read about compression ever being used as a performance thing, so I assume it’s not practical. Why not?