Tupac's Bodyguard's Hard Drive Expected to Fetch At Least 6 Figures at Auction

Tupac Shakur's right-hand man/bodyguard has a treasure trove of Pac-related gems that are seeing the light of day for the first time ... and are expected to fetch a pretty penny.

The late rapper's ex-bodyguard, Frank Alexander -- who has also since died -- once had a computer hard drive in his possession that's said to contain an unspoken amount of content covering all things Tupac ... including unseen photos, unheard music and legal docs giving new insight into his life.

The 83 GB drive -- which is being auctioned off by GottaHaveRockandRoll.com starting Wednesday -- will have an opening bid of $10,000 ... but we're told by people in the know that auction heads think someone will throw down way more for it -- about $600k or beyond.

Why's this thing so dang valuable, you may ask??? It's pretty simple actually ... especially when you get a gander at what's inside.

Among the digital files ... a sea of pics showing Pac and his pals behind the scenes, either hanging out and/or working on music and other projects.

Not just that, but we're told there's also a plethora of legal docs that pertained to Tupac that Frank owned ... such as depositions he gave, lawsuits he was named in, among other paperwork. Bottom line ... it's a very valuable collector's item for any hardcore fan.