Same as it is for any other operating system: A primary partition is a "physical" partition that the Legacy BIOS's MBR partition table can recognize. Contrast this with a logical partition, which is a partition stored in an extended partition to work around Legacy BIOS' inability to handle 4 real, physical, primary partitions at a time.
Today, on UEFI systems which use GPT, the "primary partition" vs "logical partition" concept is pretty pointless, as you can have as many true-to-life partitions you want on your hard disk due to the face UEFI does things a load better than Legacy BIOS.
in Linux this is the second logical drive inthe extended partition on the primary slave hard drive
/dev/sdb3
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.
the sign for root partition in linux is : /
82 => Linux swap / Solaris 83 => Linux ext2 & ext3 85 => Linux Extended partition
83
Linux will not delete a partition unless you tell it to. If you have accidentally deleted a partition, but have not written to the disk, you may be able to restore most or all of the data that was on it. The program "testdisk", found on many Linux LiveCDs and partition editors, can restore the deleted partition flags.
That depends on what primary partition the fourth extended partition has been placed on. If it was on the first primary partition, it would be /dev/sdb5 (or /dev/hdb5). If it was on the second primary partition, it would be /dev/sdb6 (or /dev/hdb6). If the third, /dev/sdb7, etc... Of course that's assuming you have placed all your logical partitions in a single primary partition. There are several other arrangements you could theoretically have made.
82
simple volumnes
Yes. To achieve this, you need to shrink the window partition so there is space for the Linux partition on the disk.
Click the install as partition when installing Ubuntu.