Converting a drive letter to a Partition ID / Disk ID

Question

Given a drive letter, how do I get the OSImage InstallTo Partition ID and Disk ID without using the registry?

Shaker

Hi; with that Partition ID you mean 1 based index of the partition ? – Alainealair

See here technet.microsoft.com/en-us/library/ff716430.aspx. This is what I need to determine. – Shaker

Answer 1

The WMI class Win32_DiskPartition is what I need. Now to figure out how to use WMI to get this information from a drive letter.

Win32_LogicalDisk is also useful, MSDN Example, and this stackoverflow answer.

Update: Hmm, this doesn't work! Not in the Windows Installer anyway (WMI is missing from Windows PE!!) so I am using the other answer QueryDosDevice (e.g. \\.\PhysicalDisk1\Partition0) and hacking it together. This sucks Microsoft, accept a damn path in your installer.

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Answer: IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS works to get the Disk ID. And DeviceIoControl IOCTL_DISK_GET_PARTITION_INFO_EX (thanks TLama) gets me the Partition ID.

Shaker

Answer 2

Have you tried simply calling QueryDosDevice?

Eyra

This doesn't look like it gives me the Disk ID # nor the partition ID. I am working with the program that installs Windows itself. The setup wants a disk id and a partition id. Not a virtual mapping. – Shaker

@unixman83: So the returned "target path" isn't something along the lines of "\\.\PhysicalDisk1\Partition0"? – Eyra

Hmm, the docs said differently: \Device\HarddiskVolume1. I didn't try it. I guess that would work. I'll have to try it tomorrow. – Shaker

@unixman83: I didn't try it either. Now I see the sentence in the documentation you're talking about. I think both forms are valid, one must be a link to the other. Then we just need to figure out how to follow symbolic links in the device namespace. – Eyra