When you are first installing 7 on a new drive or one previously wiped no longer seeing a primary you would be using the MS drive tools options found on the dvd there. You will also note the 1-8mb of unallocated drive space for changing between the Basic type of volume used mainly on desktops or the Dynamic for server geared.
The MS drive tools also prepare the 100mb reserved as part of the installation for 7 to include the repair tools. When the drive is already seeing an active primary as you are pointing to the installer still places the repair tools tucked away at the beginning of the existing primary eliminating the need for the separate 100mb section.
I had initially been wondering if the repair tools wouldn't be available until seeing the startup repair come up while trying to debug a sudden hardware or lack of hardware detection problem. Suddenly no internet, no tuner card available, and the sound went out?
When interrupting a restore point the startup repair tool suddenly stepped in showing that the Windows installer still sucessfully placed them on the drive without the need for the 100mb taken away. The concern when removing the 100mb section when not having a 7 dvd would be the need to burn a repair cd with 7 fortunately now seeing that option included!
The 3 cards were simply removed and reseated to suddenly hear ping, ping, ping "you must restart to see the changes put into effect"! when the system was started afterwards. Windows 7 again solved it's own dilemna with the fresh detection as well as seeing the repair tools onhand having used a 3rd party drive tool.
For those who want to reclaim the 100mb of drive space be sure to burn a repair cd to have onhand since that can also save on handling the 7 dvd itself as well as for those not having one in the case of 7 being preinstalled. For those about to install 7 on a bare drive and want to avoid the 100mb being taken then the use of a 3rd party drive tool is something to consider as well.