Advantage: Native performance within either system.
Disadvantages: Not suitable for 24x365 servers. Have to reboot to switch programs.
Advantages: Various including security, stability, 24x365 servers, avoiding Windows tax.
Disadvantages: Doesn't support all Windows programs well or at all. Buying suitable hardware slightly more demanding.
Mitigation: Can run Windows programs in Windows or ReactOS guest VM under VMWare, VirtualBox or try WINE or Crossover Office.
This is a Linux Kernel running natively in privileged mode (Ring 0) under Windows, obtaining Windows mediated hardware services by interfacing with special device drivers. Probably the most practical way to install and use this is Portable Ubuntu.. This can display Linux applications on the Windows desktop as if these were native Windows applications, using a Windows Xserver (XMing).The disk strategy is similar to WUBI. As of mid 2009 this was found to be easily installable but not highly stable through forced Windows security patches.
You may need to change the device boot order. To do this you may need the BIOS password.
Swap partitions are faster than swap files. Allow 2.5 x RAM as swap as a guideline. Then decide which directories need seperate mounts and how much space to give these. Simplest is just to have everything as /. You may also want separate partitions for /usr (diskless clients), /home ( allows sharing of user files between Linux installs), /usr/local (where software not part of the distribution packaging system gets installed), /boot (boot system including kernel ?), /media ( all your music CDs and TV recordings). MS-Windows is probably better put onto low partition numbers. Having a second hard disk gives extra flexibility.
Check suitable tools that go with your chosen distribution. Consider also putting a disk image on a spare hard disk and using a boot USB stick or CD and a dd (data dump) command. This method can also obtain and restore a raw disk backup with any OS on it, either as an entire disk device, or on a partition basis.