About Partitions
You can think of a Hard Drive as a walk-in-closet with one large
space to store your "stuff". (Like an unformatted Hard Drive).
Before you can use a new closet, you must first choose the type of
storage system (hangers and shelves, etc.) that you will need to
organize your "stuff". (This is like formatting the Hard Drive and
choosing a Filing System - FAT32, NTFS, etc.)
Just as you can sub-divide a large walk-in-closet into separate
sections for "His & Her's", or, "His, Her's & Child", you can also
sub-divide (Partition) a Hard Drive into separate sections.
1. Each Partition has its own label (Drive Letter - C, D, etc.)
2. Each Partition has its own storage system (Filing
System - FAT32, NTFS, etc.)
Here are some additional "rules" when dealing with Partitions
and WINDOWS Operating Systems:
1. Ordinarily, Windows Operating Systems must be installed on
Primary partitions. Data may be stored on either Primary
partitions or Logical partitions. (Logical partitions are created
by sub-dividing a Primary partition.) Special software is used
to create and manage Partitions.
2. Unless special Boot Manager software is used an OS will not
be able to Boot properly unless it is installed at the beginning
of a Hard Drive (before what is called the 1024 cylinder
boundary - or, approximately within the first 8 GB of the Hard
Drive.)
In a single Hard Drive, Dual Boot scenario, the first Primary
partition on the Hard Drive must not be much larger than
6 GB. This size limitation is necessary in order to leave
approximately 2 GB of space still within the 1024 cylinder
boundary for the second Operating System to be installed
(in the second Primary partition).
The second Primary partition, in such a Dual Boot scenario,
would ideally begin at approximately 6 GB but can be
extended well past the 1024 cylinder boundary to be as
large as need be.
3. Primary partitions can be further designated as either
ACTIVE or HIDDEN, but, only one Primary partition may be
ACTIVE at one time. This is how the computer knows which
OS to boot. It can only "see" the OS on the Primary partition
which is designated as ACTIVE. If it "sees" more than one
ACTIVE Primary partition, and, more than one of these
ACTIVE partitions contain an OS, it may try to boot both
Operating Systems and permanent data loss may result.
In such a case, special partitioning software is needed to
"hide" one partition and make another ACTIVE.
Also, in a Dual Boot scenario, if there is no Boot Manager
installed or enabled, the last OS used before turning off the
computer will by default be the OS which the computer
"sees" at the next Bootup - because, the Primary partition in
which it is installed remains ACTIVE.