I have a laptop that has Win7, RHEL-6 and some other distros and used it to do a test install of EL7beta.
anaconda identified the installed Linux OSes and created proper entries for grub2. However, it did not find Win7. The Release Notes for RHEL 7beta says,
"In addition to the Linux file systems, GRUB 2 also supports non-Linux file systems such as Apple Hierarchical File System Plus (
HFS+) and Microsoft's
NTFS file system."
Maybe so in the GA release ...
Another thing to note is that I was not given a chance to avoid installation of grub in the MBR. So, I had to reinstall grub from RHEL-6 and then create a chainloader for EL7beta. Not nice. 🙁