boskeun,
yes, the 4400 came with an IDE drive built in, so for an *exchange* an IDE/ATA hard disk would be fine.
However, I am afraid that the 4400 lacks the dual master-slave capability that is so common for IDE among PCs which means that in a modern PC, you can always add one IDE drive (most PCs today have two IDE channels, so one can use two master drives and two slave drives in total).
In a 4400, the two connections of the single IDE channel are already occupied by the existing HD and the CD ROM drive.
Correct me anybody if I am wrong ;-)
Regards,
Walter.