Windows Driver Overview

I have spent a lot of time working on a solution to update drivers on existing machines lately. Once I started working on this, I realised that I knew less about drivers than i thought i did. I thought i would write this article with a summary of technical details about windows drivers.

Who Produces Drivers, Microsoft?
Drivers are produced by Independent Hardware Vendors (IHV) and then submitted to Microsoft to gain Windows Hardware Certification (to be signed). System manufacturers such as Dell and HP (OEMs) do not produce drivers, but publish the ones for their systems produced by IHV’s. Sometimes OEM’s will work with IHV’s to improve drivers or customize them to interact with other components.

Types of Driver

  • InBoxDrivers which come with the Operating System are called “InBox Drivers” – with each version of Windows, Microsoft adds more and more of these drivers.
  • Windows UpdateWhen a driver is going through the Windows Hardware Certification process, the IHV has the option to add the driver to Windows Update. This means that you can search for a PNP ID (more about these later) here and find a nice signed driver to install on your system.
  • Exe PackageThese are drivers which have been re-packaged by an IHV or OEM into a convenient format to download and double click to install. These are great for normal users, but for system manager hoping for automation they are a nightmare. On occasion the original clean driver files can be extracted from the exe, but they may require user input to install correctly. Which is a problem when you want a silent installation for deployment.
  • FakeThere are numerous websites pretending to offer a magic tool to scan and update all drivers on your system – unless this tool is made by your system builder (Dell, HP, Lenovo, MSI, ASUS etc…) DO NOT USE! Read this article on How-To Geek for more information.

WTF is PNP?
PnP stands for Plug and Play and is a standardization system that makes the detection of hardware in a system easier. More Information
Vendors should incorporate unique ID’s into hardware components. These consist of several sections of ID. (Hardware ID, Vendor ID, SubSystem ID).

e.g. PCI\VEN_1000&DEV_0001&SUBSYS_00000000&REV_02

Woah – Slow Down, PNP ID?
To see the hardware id of a device in a system – do the following…

  • Open Device Manager
  • Right Click on a Device from the Tree and Select Properties
  • Change to the Details Tab
  • Select Hardware ID for the Property

Hardware IDs

How Does Windows Match Drivers and Hardware IDs?
The simple answer to this, is that each driver has a list of Hardware ID’s that it is compatible with integrated into the files of the driver (the *.inf files).

Extract from an *.inf file.  For the geeks out there - Intel's Vendor ID = 8086 :-)
Extract from an *.inf file. For the geeks out there – Intel’s Vendor ID = 8086 🙂

I’m Confused!
You are not alone… The OS get’s confused as well, what with all these ID’s, OEM’s, IHV’s etc… So how do Microsoft handle the issue? – Driver ranking!

Driver Ranking is used to choose an appropriate driver from a list, when there may be multiple drivers applicable. To do this, Windows sorts the drivers and gives them a rank.

What Criteria does it use?
I’m not going to go into detail about this, but the following is the basic guide for more information see – How Does Windows Rank Drivers

  • Signing
  • Plug and Play ID Match
  • Driver Date
  • Driver Version

Before any drivers are loaded by the operating system, they must be ‘staged’ into the DriverStore. The driverstore is a secure location of drivers, which the operating systems dip’s into to find drivers for devices which require them. DPInst.exe can be used to ‘stage’ the drivers – once staged they will be ranked and if they are the lowest rank will be loaded by the OS.

DPInst.exe

I have a found a utility that makes automated driver updates on machines via SCCM (or other methods) very easy. I will publish another article later in the week about it, with a Hot-To guide on updating drivers safely.

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