These are direct mappings to the file system drives.
Registry Drives (HKCU, HKLM)
These correspond to the keys in the Windows registry.
Cert
Stores all installed certificates.
Env
Contains all environment variables.
Variables
Stores all defined variables.
Functions
Contains all defined functions.
To navigate to a path within a PowerShell drive, you need to add a colon (:) to its name - for example C:\, Env:\, etc.
Managing PSDrives
How-To: View PSDrives
To view all available PowerShell drives:
Get-PSDrive
How-To: Create PSDrives
To create a PSDrive you need to specify a name, a provider (FileSystem for a drive stored on the file system and Registry for a drive stored in the Windows Registry) and a root location for the drive.