Poor young David's treated abominably at Salem House. But then, that was always the idea. His wicked stepfather Mr. Murdstone sent him there precisely because he knew it would be a living hell for the young lad.
The school's headmaster, the sadistic Mr. Creakle, is even more revolting than his good friend Murdstone, and is a firm believer in thrashing boys at every opportunity. Thanks to Murdstone he's got it into his head that David's a bit of a biter. So when David first arrives at Salem House he's forced to wear a humiliating placard round his neck that says "Take care of him. He bites." Mr. Creakle takes care of David, alright. He singles him out for extra beatings for no good reason, just as his chum Mr. Murdstone hoped he would.
All in all, David spends two pretty miserable terms at Salem House. But despite his ill-treatment, he does manage to make friends in the shape of Tommy Traddles and Steerforth. (Though in the case of the latter that's not necessarily a good thing) In any case, however bad things get at Salem House the school's an absolute picnic by comparison to his evil stepfather's blacking factory, where David will soon be forced to work.