Seagate has breached a barrier and introduced a massive 3TB external drive in the form of an updated FreeAgent GoFlex.

The GoFlex line comes with a USB 2.0 adapter which can be changed to either a USB 3.0 or FireWire 800 one.

The good news is that can hold masses of videos, movies, music files, or whatever. The drive will continuously back up your desktop PC or Mac and has built-in encryption to keep the contents safe. There is an illuminated capacity gauge — not that you will need it for a good while — and it can be mounted vertically or horizontally.

Apparently you'll need 64-bit Windows or Mac OS support to get access to its full capacity.

Inside the black case is a single 3.5-inch drive about which Seagate is saying exactly nothing. We think it is an unannounced Barracuda or Constellation 7200rpm unit with four platters.

This would mean that each platter holds 750GB — a record in 3.5-inch drive land — and would use a fifth-generation perpendicular magnetic recording (PMR) technology and have an areal density above 500Gbit/in². Existing Barracudas and Constellations use fourth-generation PMR with a 330-350Gbit/in² areal density.

Seagate already uses this technology in its Momentus 5400.7 2.5-inch notebook drive, which has a capacity of 640GB and an areal density of 507Gbit/in². Toshiba has a two-platter notebook drive, the MK6465GSX, with a capacity of 640GB and an areal density of 528.5Gbit/in².

Neither Western Digital nor Hitachi GST has publicly reached such areal density levels, although a 3TB Western Digital drive has been rumoured.

We can expect Seagate to roll this new fifth-gen PMR technology out on its internal drives in the coming weeks or months, with 3TB Barracuda and Constellation models appearing. Western Digital will surely not be far behind.

The 3TB GoFlex costs about $250 (£161) and is available now. ®