7200rpm Hard Drive running without the cover

Edit - No idea why this is getting so many views after 4 years, but let me provide more info. When the cover is on the drive, 1 screw goes into the middle of the disks. 1 screw goes into the middle of the pivot point, of the read-write arms. 2 screws go into the top of the magnets, that are over the coil that is sandwiched between the 2 magnets. Then 6 screws go into the frame of the drive. The cover, with all these screws, are going to hold it together. Clearly it won’t work without the cover. The drive worked fine before I removed the cover. It had data on it. I took a hash of all the files before I removed the cover. After running it with the cover removed, I put the cover back on, and checked all the file hashes. They came back the same. Wondering if that was a valid test, I took the drive out of this USB enclosure, popped it in a proper server hooked via SATA, and did a long format. Zero bad sectors. I then did the unspeakable, and put a fingerprint on the top of the top plater. Put the cover back on, and did another long format. It still came back with Zero bad sectors. Removed the cover, and the fingerprint was totally gone. The next step was more impactful, I took a black sharpie and drew a single line along the top platter, from the inside of the platter towards the outside. Put it back together. The drive was very unhappy. Some of it smeared around the platter, a single section in the middle was completely gone. I took some close-up pictures of the read-write head that was in contact with the sharpie mark, and there might have been some darkness around the edges. Too hard for me to tell. Alas the drive was dead.