The PlayStation 3 and PlayStation 4 beta of Destiny is coming in just three days, followed by the Xbox 360 and Xbox One on July 23, but some of the last-gen hardware won't be compatible with Bungie's game right from the get-go.
The beta has been revealed to be quite meaty, clocking in at around 12.5 GB on the Xbox One system, almost twice the size of the alpha build released for the PS4, which weighed around 7 GB. This is a pretty clear indication of the fact that the PlayStation 4 version of the beta client will also require a similar chunk of hard drive, so make sure you have enough HDD space left for it in order for everything to go well.
Developer Bungie has revealed that Destiny's hard drive requirement means that the beta will be incompatible with a number of Xbox 360 and PS3 models, namely the Xbox 360 Arcade Console, the Xbox 360 4GB Console, the Xbox 360 Core System, and the PlayStation 3 12 GB System, so if you own any of them and still want to try out the beta, your best bet is to consult the manufacturer in order to obtain some relevant hard drive upgrade information.
Destiny is currently scheduled for launch on September 9, for the Xbox 360, Xbox One, PlayStation 3 and PlayStation 4 platforms, with some timed exclusive content on Sony's platforms, counterbalanced by a Gift Card on Microsoft's.