PlayStation Broadband Navigator

PlayStation Broadband Navigator (also referred to as BB Navigator and PSBBN) is software for Japanese PlayStation 2 consoles that formats a hard disk drive for use with those consoles and provides an interface for manipulating data on that hard disk drive. It only works with official PlayStation 2 HDD units.

Apparently the PlayStation Broadband Navigator has a more strict region lock on it than normal PlayStation 2 software, as the software will only boot on NTSC-J systems with a model number ending in 0, meaning they are sold in Japan, making the software unusable on Korean and Asian NTSC-J PlayStation 2 consoles.

PlayStation Broadband Navigator offers many features that are not available with the original HDD Utility Disc software. Some Japanese releases take advantage of the features, and may even require a specific version (or higher) of the software.

Sony Computer Entertainment America released the HDD on March 23, 2004 with HDD Utility Disc 1.01 and bundled with Final Fantasy XI. Consumers that knew about PlayStation Broadband Navigator were confused as to why it wasn't included with the HDD Utility Disc. SCEA's response was always that PlayStation Broadband Navigator would be released in North America "at a later date." This date now appears to be never in light that SCEA has switched to only manufacturing the slim, HDD-incompatible PlayStation 2 models and stopping manufacture of HDD units for their region.

Sony Computer Entertainment Europe and Sony Computer Entertainment Australia never released the HDD outside of the Linux Kit before switching to only manufacturing the slim PlayStation 2 model, so it appears that neither HDD Utility Disc or PlayStation Broadband Navigator will be released in those regions.

Broadband Navigator can now be used on any PS2 by using a modified var.

A few games require PlayStation Broadband Navigator either for certain features to work, or for the game to work at all.

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Wikipedia