I just opened my Late 2015 5k retina iMac to remove the hard drive and it's not where I expected it to be at all. It has a '1TB Serial ATA Drive +
iMac 27 2012-2015 Hard Drive Replacement with SSD
iMac G5 20” Hard Drive Replacement – TechBlog
Replacing a hard drive in an iMac | Orbits IT
iMac A1331 “Core 2 Duo” 3.06 21.5-Inch Late 2009 Hard Drive Replacement Service Dallas – Apple Mac Computer Repair Dallas , Laptop ,Desktop ,iMac ,MacBook iPhone iPad Data Recovery ,Virus
How to replace the Hard Drive in an iMac G3 333Mhz (Tray Loading) computer - HubPages