On MBR partitioned hard-drives only 4 primary partition can be created. (Use extended and logical partitions to create more partitions).
Diskpart.exe
Create one primary partition and an extended partition with four logical drives within it.
You have to create the primary partition, which will create a drive with assigned letter for you. Or you can create the extended partition where you can create logical drives it can be more than 1.
DiskPart command - line utility
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Typically you can only have 4 primary partitions per hard drive if you are using the MBR partition layout scheme. If you need more partitions than the maximum allowed (4), then there is a way to get many more partitions with only one hard drive.By creating an extended partition you can have as many logical partitions as you need within that extended partition, thus you can have more than only four partitions. You can have 3 primary partitions and one extended partition (for a total of 4), and inside the extended partition you can have as many logical partitions as you need.The one thing to keep in mind is that any type of Windows Operating System needs to be installed in a primary partition, otherwise you cannot boot into it. Windows XP in particular, needs to be installed in the first primary partition. For everything else, you can create as many logical partitions as you want inside the extended partition.
primary, extended, logical - 3 types
As many as it can handle (how big it is). And adding partitions does not make more space. It's like putting a brick wall in the middle of a football field. :-P This is depend on your disk style, if your disk is MBR, you could only create four primary partitions or three primary partitions with one Extended partition (you could create many logical partition under extended partition) at most If your disk style is GPT, you could create as many as you can. here is an article about how to make partition from http://www.partition-magic-windows7.com/res/create-partition-windows7.html
Yes. You need to create a Primary partition and then a secondary partition. You'll want to install your main OS on the Primary partition (Windows, Mac, Linux, Novell, ect.) and then put the other OS on the secondary partition (I typically see Linux.) Then you can choose to boot from the primary partition or the secondary partition in the BIOS. The bigger the hard-drive you have the better, and I wouldn't try it with anything less than 100 gigs.
DiskPart command - line utility