This is a reverse engeneered Microsoft Vhdparser driver, which is originally used as a shim between storvsp (Storage Virtualization Service Provider) and vhdmp (VHD miniport driver). This shim enables us to write own filter drivers for virtual storages in Hyper-V (e.g. encrypting drivers, replication filters, changed blocked loggers etc.).
Storage service consumers (VMs) communicate with storvsp using SCSI protocol, this driver is used to filter I/O requests and pass it to the backing store. The whole architecture is briefly explained in presentation: http://download.microsoft.com/download/5/b/9/5b97017b-e28a-4bae-ba48-174cf47d23cd/vir049_wh06.ppt
It seems that Microsoft had planned to implement an expandability of virtual storage services (as VMware does with VAIO SDK) and to enable third-party virtualization storage developers to write their own enlightened I/O parser for their solutions. But unfortunatelly StorVSP API has not become public.
The purpose of this project is purely investigative (i.e. not meant to be used in production).
- Install this driver as a kernel mode service:
sc create evhdparser binPath=[path to evhdparser.sys] type=kernel
- Register this service as a default parser by replacing registry value
HKLM\CurrentControlSet\Control\StorVSP\Parsers{f916c826-f0f5-4cd9-be68-4fd638cf9a53}\ServiceName
from vhdparser to evhdparser (may require to take registry key ownership)