19GB, take away from that all the duplicate data across all 3 discs and the game is much much smaller, especially when you consider that there is still allot of videos, may be low rez but they still consume space, to be honest it would not surprise me if the game byt it's self is just 7-10GB....if would be easier to tell if there was a PC version XD

I just hope this game let's you save before disc swaps

Install Disc 1
Play and Beat Disc 1
Save, Uninstall Disc 1, Install Disc 2

and repeat

Star Ocean annoyed me because it forced me to listen to my Jet-box for half an hour trying to get to the next save point

Pretty sure the game is quoted at being 6.8GN altogether on PS3, so maybe 2.5-3GB per disc on xbox and 3GB of movies on each disc

On the topic of installs, here is a neat article:

http://www.xbox.com/en-US/live/engineeringblog/default.htm

Would You Like a Side of MB with that Game Install?

Posted February 3, 2010 by Thomas Soemo (PM) - HSDPhantom

Today I am going to discuss the details of the packaging format for “Xbox 360 Games on Demand” and “Play from hard drive” features.  The “Play from hard drive” feature allows you to install Xbox 360 games to your hard drive, increasing the game performance. “Xbox 360 Games on Demand”, launched in 2009, allows you to download full Xbox 360 games directly to your console without needing a disc.  It also gives you the same benefits in regard to game performance.  Our 2009 update has generated some buzz regarding the size reduction in our play from hard drive packages that I wanted to explain.

All storage media (flash, hard drives, discs, etc) have a layout that dictates where and how the files will be stored.  Optical disc drives spin the disc at a constant velocity which means that as the head reads the data from the disc and moves towards the center, the data will be read faster.  Xbox 360 game disc layouts are optimized for the reading speeds of optical discs drives and attempt to concentrate the game disc data at the fastest read locations on the disc.  This typically ends up creating gaps at the beginning, end, and in the middle of the disc layout where layer 1 transfers to layer 2.  When we first released the “Play from hard drive” feature in 2008, we did not do any detection of gaps that can exist in between game code in disc layouts.  We started our game copy at the first sector where the game started (skipping the gap at the beginning of the disc) and copied the disc until we hit the last readable sector of the disc where the game code ended (skipping the gap at the end of the disc).   During the 2008 release, we decided to not optimize out the gaps that can occur in the middle of the game code in the disc layout.

Fast forward to the 2009 release: we went back and examined how much potential space savings we could deliver to customers by removing these gaps that can occur in the middle of the game code in the disc layout.  Around the same time, we got the official green light for Xbox 360 Games on Demand project which meant customers were going to be downloading these packages, thus it was even a higher priority to squeeze the image size down as small as possible.  We did a bunch of analysis to determine the sizes of these gaps in the middle of the disc layout as well as how we could remove it during the disc image creation process.  Since everyone loves data, here is a snap shot of the data that we collected to make the decision whether the code investment to remove the gaps in the middle would pay off:

After collecting this data we knew that this would be highly valuable since we would obtain a median savings of 453MB per game for both hard drive space and download time.  Since both “Play from hard drive” and “Xbox 360 Games on Demand” use the same underlying technology we were able to make the code change to remove these gaps for both.

Games that were installed from a game disc before this release will continue to function.  If the user deletes the game disc image and reinstalls the game it is possible that the resulting installed image will be smaller.   As is shown above, some games' installed image size will not be affected at all while some games will have a varying range of size savings.

I'm so used to this that it's a non-issue. I installed Lost Odyssey (4 DVDs. About 23+ GB), Blue Dragon (3 DVDs, about the same size of FF13. If not more), Star Ocean 4 (ditto) and Infinite Undiscovery (2 DVDs) all to my hard drive. Naturally I didn't have all those games installed at once as I only have a 60 GB drive. I just played on my DS while I waited for everything to install. I don't know why hard drive installs are made into such a big issue. They are totally worth it in the long run if you want to minimize wear on your discs and your console's optical drive.

Well to me optional downloadable content,filling entirely the hard disk of a console and lower quality visuals and sound shows that SE prefers profit from quality. One more disk on the xbox version should be fine. DVDs are not that expensive ...

you would only have 2 install 1 dvd at a time.

unless there is back tracking in game?

Here's the solution to this "problem." You simply delete, and then reinstall the new disc, thus eliminating the 18 gig spot. Don't tell me that a person can honestly sit and play the whole FFXIII straight through. If so, I hope they develop more social skills....

If you don't have the space, either install one disc at a time or just play from the disc with no install at all. It's not that big of a deal. Installs are not mandatory on the 360. It just improves loading speed (in some games), reduces system noise, and reduces wear and tear on the DVD drive. There is NO downside to 360 installs in any game (except Halo 3). It's a nice OPTIONAL bonus feature for those with a little extra HDD space.

@JaggedSac

So that's why my Borderlands game is only 3.3GB now when I install it. It had some crazy amount of copy data that could be removed when installed/downloaded.