Glued carpet, my experience.
If it has a foam back, you are in for a mess. Work up a corner, grab it with a pair of pliers and start pulling. The back will separate, part staying with the carpet and part with the floor.
Then get yourself an industrial 90 degree electric hand held grinder, a big one, then take off the grinding wheel and put on a cup type wire brush.
Put on a face mask and respirator, cover everything you don't want foam dust getting into and start wire brushing it.
That's about all I know to do.
There is no foam backing here - just the very thin carpet glued down. Sounds like I should just rip it out and forget it and replace it after the job is done.