question

> The free space information is densely > packed, so relatively few pages > contain this information. > > This increases speed by reducing the > amount of disk reads that are required > to retrieve allocation information. > This also increases the chance that > the allocation pages will remain in > memory and not require more reads. Please help me in understanding how extents are allocated and also help me understanding the above lines taken from MSDN. http://msdn.microsoft.com/en-us/library/ms175195(v=sql.105).aspx