Question about HD Partitions

I have three hard disks with two partitions in one of them.
I use WinXP Pro only.
I want to know what are advantages or disadvantages in terms of performance of Windows if I format a particular partition as "primary" as opposed to "logical"

Let me explain my question through two screenshots with two different cases (which are marked with red boundaries). This is about the particular partition H:. In Case 1 H: is formatted as Primary and in Case 2 H: is formatted as Logical.

Case 1 (H: is Primary)



Case 2 (H: is Logical)



Now what I want to know is in what way is Case 1 advantageous over Case 2
and vice versa?? Again by "advantage" I mean performance of Windows.

Also you can see from the screenshot that Disk 2 and Disk 3 are set as active. How do I make them non-active without having to format them??

 

I have 2 disks also both with 2 primary partitions and one with a great deal of unallocated space. I think the only difference between having a primary partition versus a logical one is that the primary partition can be used to support an operating system while a logical one can not(I'm not positive about this). If this is correct, probably a primary partition has some of its disk space set aside for a boot sector while a logical partition would not. Thus, probably more of the logical drive would be available for storage. The difference is probably minuscule and I would probably just make them all primary partitions. I doubt if there is any difference in access time to either write or retrieve information from the disk.
I think if you go to either Western Digital or Seagate's website and download a users guide for any one of their drives, you will probably be able to answer your question for sure. Good luck and keep using Partition Magic. It is a great program but you should always run it from a boot disk to be safest.

 

There are no performance advantages in either case.

The following is slightly loose in the details of the PBR, MBR and other minor issues, but I did not want to bore you with a treatise.

Prior to the use of hard disks, the original IBM PC came with one or two floppy drives. To boot to DOS a floppy was required, albeit if you had one of the really first ones you could ROM "boot" into a limited version of BASIC and use an attached tape recorder to load programs. (I am not making this up).

To this day removable devices have a PBR -- Partition Boot Record -- that can allow the system BIOS to boot the computer. This is simply the very first sector on the removable disk, and its first 512 bytes. This contains enough code to tell the computer where to go next to find additional instructions. Think floppy disks. Floppy disks do not have partitions; and it was not until later that they even had folders.

When hard drives were added, it was decided that the "massive" space available to the user with 10 megabytes of storage should be allowed to be divided into chunks. So the MBR -- Master Boot Record -- was added. This is nothing more than a table of four entries, (called the Partition Boot Table) for which each entry could point to essentially a Primary Boot Record for each partition. All partitions were primary in the beginning. One could be called 'Active' and all could declare themselves bootable by a special signiture in the table entry for the partition. For DOS and Windows, the partition used to boot was the one found to be the primary partition that was marked as Active, and bootable.

Drive capacities quickly zoomed past 10 megabytes, and as did the OS authors by adding a new partition type to Primary: Extended. What the extended type allowed was a new concept: Logical Volumes. It allowed for dividing the increased disk space into more than four partitions, at least in a virtual sense. You still cannot have more than four partitions on any drive; but an extended partition that can be divided into further chunks as Logical Volumes makes it appear as so to you and the OS.

Can you boot from a Logical Volume? Yes, you can. No problem.
Are there performance gains from using a Primary, rather than a Logical Volume defined under an Extended partition? No.

While doing the bootstrap at startup for a Logical Volume does require a little more calculation at start by the boot loader, we are talking at best a millisecond or two. And this insignificant penalty is extracted at the very start of things, not subsequently. How the NT family of Windows OS products has over time tweaked the entire bootstrap process would require a lengthy discussion. But for the purposes of answering the question asked here: there are no additional disk reads required to bootstrap from a primary or Logical Volume created on an Extended partition. And for NTLDR, the bootstrap agent under the NT OS family to decode the additional PBT table of the extended partition is insignificant as a time expense, and the expense is only incurred once.

 

Thanks ackerberg for your reply.
Yes today I made all my partitions as primary. Looks clean

About my second question. How do I make the partitions in Disk 1 and Disk 2 non-active without having to format them??

 

Wow Bill Castner!!
That was an excellent story. Loved reading it all. Got to know a lot of things.
And thanks for taking the pain to write such a long story and for your precise answer to my first question. I feel so much relieved now.

Let me pose my second question to you too. How do I make the partitions in Disk 1 and Disk 2 non-active without having to format them??

 

There is not a native XP utility to remove the Active state of a primary partition, although Dispart.exe can be used to set a primary partition as active. (Volume in Extended partitions cannot be made Active).

The active status for any partition is a single byte, 0x80, in the MBR of the drive.

It is not uncommon to see multiple primary partitions set as Active. I see no particular harm in this. I would just leave it alone. Anymore the value is there for compatability reasons and not because it is particularly important to XP.

There are partition editors that can be used; e.g. Partition Magic, but I cannot see any point in removing the setting. I would be a hard one to convince that it causes you any issues.

Some boot loaders, (Boot Magic, for instance) will on the fly change the active state attribute byte as part of their loading of multiple OS versions or instances. This makes some sense for non-XP OS versions in a multi-boot (Linux versions do not care at all about the Active state).

But as you can use Logical Volumes to boot the OS from, and Logical Volumes cannot be "Active" you can see that essentially it is little importance to XP or its loader, NTLDR.