What brands do the big companies use?

Google, Yahoo, Apple, Microsoft, Sun... they all need very reliable backup systems. What hard disk brands do they use?

Instead of having one cheap disk crashing after another, I might as well go with the "recommendations" of these companies

Google uses thousands of PCs with weak hard disks on a giant cluster, and those hard disks are no more reliable than anyone elses. However IBM /etc. Use industrial strength SCSI disks that cost a few grand a piece. They also use them in high end servers where huge amounts of data are read back and forth all day, everyday. So, what are you using this backup system for? Another thing: open reel metal oxide tape, which uses around 300 bits per inch is said to be very reliable, because the large area of tape it uses to store each bit is resistant to small changes in polarity, but it is ungodly slow.