I know Giga Vault Storage works across Windows, Linux, Mac, FreeBSD operating Systems. Does that mean the backups and restore can also be done across different operating systems?

Yes, Giga Vault Storage not only works across different operating systems, it is also interoperable across the supported operating systems. That is, you can backup your Mac OS X to a Windows or Linux OR backup your Windows to a Linux or Mac OS X and so on. The only limitation is that when you restore your data to any client machine (other than the originator machine), the new client machine has to support the same matching endian byte order. For example, a Mac OS X can backup to a Windows. But the backed up data has to be restored by only another Mac OS X system. This is because the blowfish encryption algorithm Giga Vault Storage uses is based on the endianess of the machine. If all the different machines are based on Intel processor, then there should not be any problems with the restore across operating systems.