Davidson, 21, is a promising prop forward who has joined the Roughyeds on a season-long loan.
Files, also 21, has signed a permanent deal, and head coach Scott Naylor is pleased with his two signings.
“Alex had a big game for us at Barrow yesterday and I’m absolutely delighted to get him on loan for the full season,” said Naylor.
“I’ve had my eye on him for a bit. He’s done all his pre-season training with Salford and he didn’t come to us until Saturday morning, so to play like he did at Barrow when he was thrown in like that says a lot about the lad.”
Files, a hooker by trade, spent last season on loan at Whitebank.
“Adam has chosen Oldham as the club with which he wishes to pursue and develop his career, and I think that says a lot about Roughyeds and what we are trying to build here.
“He was unfortunate not to get our 2013 Player of the Year trophy and we wanted him back from day one.
“After the end of last season I kept in touch with Brian Noble (Salford head coach) about him, but initially we were planning to get him on loan again or on dual registration.
“As things have turned out, he’s our player now and I couldn’t be more pleased.
“He’s going to be a great player for us.”
Of the performance in the 16-6 defeat to Barrow, Naylor added, “We were understandably rusty in the first-half.
“We were better in the second-half; more patient in possession, and that earned us repeat sets on two or three occasions.
“There was very little difference, if any, between the sides in the second-half.
“The new signings all did well, in what was a highly encouraging first hit-out against a team from a higher division.”