Could 6.4TB become the largest hard drive in the near future? A few months ago we reported that Western Digital was working on a large format hard drive that would be filled with helium to reduce drag and friction.  We speculated the size would be in the 5.6TB range.  There are 2 other key technologies on the horizon for increasing Areal density.  The first is called Shingled magnetic recording (SMR), which is the overlapping of data tracks to cram more tracks and hence more data onto a drive’s recording surfaces.  The second is Heat-Assisted Magnetic Recording (HAMR).  These techniques are being used by Seagate to push hard drives past the 4TB size they’ve been stuck at for the last several years.  The current perpendicular magnetic recording (PMR) technique is reaching it’s density limit.  Any attempt to reduce the size of the magnetic bits results in instability. SMR drives could begin shipping in late 2013 and enable a 20 – 25 per cent areal density increase. Taking a 4TB 3.5-inch drive and giving it an SMR upgrade would bump capacity up to 4.8TB to 5TB.  However SMR drives take longer to rewrite data because tracks overlapped by the new data track have to be reconstructed before the new data can be written. Sometime in 2014 Seagate hopes to introduce the even more sophisticated HAMR technology.  A tiny laser is added to the read/write head to quickly heat up spots on the disk.  Creating a trillion bits/in2 areal density a 4-platter 3.5″ HAMR drive could store up to 6.4T.  Seagate speculates that using HAMR with continuous improvements over the next 10 years could eventually produce a 60TB drive.