What is the meaning of the various Boot.ini parameters?

Posted on 2001-08-04
Last Modified: 2010-04-13
I have a dual boot system with Windows 98 and Windows 2000 Pro.
Win 2000 was on drive "D" which was a slave on the secondary channel.
I want to add a third drive which requires me to move my existing D drive and make it a slave on the primary channel.
When I make it a primary slave I get a blue screen error that it cannot find certain files.
This is the present boot.ini entry:
  multi(0)disk(0)rdisk(1)partition(1)\WINNT="Microsoft Windows 2000 Professional" /fastdetect

1 What is the meaning of each of the parameters and what are the acceptable values. eg can partition be (0)?

2 Is there anything else that controls the boot process?

3 Can you suggest how the entry should be modified?

Question by:topman
LVL 25

Accepted Solution

dew_associates earned 200 total points
ID: 6352782
The BOOT.INI file's path options use the ARC naming convention. An ARC name has five parts.

Let's use this entry as an example:


Which controller?

The first part will contain the word multi or scsi and a number in parentheses. This part of the name identifies the controller that hosts this disk drive. If the controller is a Small Computer System Interface (SCSI) controller, you'll see scsi here. If you're using a multifunction adapter disk controller, such as IDE, EIDE, or ESDI, you'll see multi in this place. Well, that's almost true. In order to make their SCSI controllers easier to use with Intel systems, many manufacturers of SCSI controller cards create them to talk directly with the Intel BIOS. Of course, these cards may not be installed in an Intel machine; therefore, the makers allow you to enable or disable this feature. A SCSI controller that has this feature enabled is said to have its ROM BIOS enabled. A SCSI controller with its ROM BIOS enabled will be listed as multi in this first part of the ARC name. The number in parentheses (zero based) indicates which controller this is. A second IDE controller would be multi(1).

Which disk?

The next part of the name will always be rdisk; it tells the node address of this disk on its controller. Since only SCSI controllers have multiple nodes, the number here will always be zero (0) for a true multi (IDE or similar) controller. For a SCSI controller, this number will be the SCSI ID number of this disk on its controller, i.e., a number from 0 to 7 identifying this disk's address on the SCSI controller. Remember that a ROM BIOS-enabled SCSI controller will show up in BOOT.INI as multi. In this case, you could see a name beginning with multi(0)rdisk(3) in your file. You now know that this can't be an IDE drive; therefore, it must be a disk at ID 3 of a SCSI controller with its ROM BIOS enabled. This is a point that escaped even the early Microsoft certification tests for Windows NT and still isn't well documented in the NT texts. The third part of the name identifies which disk, at the node address specified under rdisk. Here, the SCSI controller must be zero (0), since only IDE and related controllers support master/slave disk configurations. The master disk on an IDE controller will be disk(0) and the slave will be disk(1). On a dual-channel EIDE controller, this number could be anything from 0 to 3.

Which partition?
To understand the fourth part of the ARC name, you must understand the Intel partitioning scheme. In current versions of DOS, Windows 95, and Windows NT, a disk may have up to four separate partitions. One of  these partition may be an extended partition. Any others must be primary partitions. A primary partition equates to a single drive letter; for example, C: is located on a primary partition. The extended partition dates back to the time, under earlier versions of DOS, when a disk could have only one primary partition. To allow better division of the available disk space, the extended partition was invented.

An extended partition took up the remaining space on the disk, but allowed the user to create multiple logical drives within the extended partition. The extended partition still exists, but is mostly useful only when you need more than four divisions of the available space on a disk.

You can have a disk with one primary partition or four primary partitions, or three primary partitions and one extended partition. Any combination of partitions is allowed as long as the total number of partitions doesn't exceed four, and there's no more than one extended partition. The numbering of these partitions is controlled by Intel BIOS and isn't intuitively obvious. Partition zero (0) refers to the entire disk, but it isn't used by any Microsoft operating system. Therefore, partition numbering in BOOT.INI starts with 1. The active partition, or the first partition if no partition is marked active, will be partition zero. If there are no extended partitions on the disk, then the remaining partitions will be numbered in the order in which they occur in the partition table. This is usually the order in which the partitions were created.

However, if you have an extended partition, the numbering scheme changes. The first logical drive in an extended partition will always be partition 2. Numbering will continue through the remaining logical drives of the extended partition until all logical drives are numbered.

Then the remaining primary partitions will be numbered starting with the next number after the last logical drive in the extended partition.

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Expert Comment

ID: 6353123
Can't add anything here
LVL 63

Expert Comment

ID: 6353457
To change the boot, remove the system, hidden, readonly attributes on the
 boot.ini file
edit it, and duplicate the entries as shown below.

multi(0)disk(0)rdisk(1)partition(1)\WINNT="Microsoft Windows 2000 Pro 1" /fastdetect
multi(0)disk(0)rdisk(0)partition(1)\WINNT="Microsoft Windows 2000 Prof 0" /fastdetect
multi(0)disk(0)rdisk(2)partition(1)\WINNT="Microsoft Windows 2000 Prof 2" /fastdetect
multi(0)disk(0)rdisk(3)partition(1)\WINNT="Microsoft Windows 2000 Prof 3" /fastdetect
multi(0)disk(0)rdisk(1)partition(1)\WINNT="Microsoft Windows 2000 Professional" /fastdetect

also try the same using disk (1) rather than 0.

This will give you all the options, and you will have them available for whatever changes you make.

You can use the comments to describe each boot option.

Then see which one works for you.

I hope this helps !

Author Comment

ID: 6354396

  Much Thamks
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Expert Comment

ID: 6354418
Glad I could help!

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