Device Driver Basics

Most people understand that the "hardware" part of their computer is the real physical parts, like the keyboard, mouse, modem, hard drive and so on. They understand that the "software" is computer bits stored on the hard drive, CD-ROM, or other storage media. But most people are a little hazy about exactly what a "driver" is.

In this article, I'm going to reveal in plain English what a driver is, why we need drivers, and exactly where the drivers are hiding. To give you a basic understanding, I'm going to go back, way back, to the early days of computers.

The Early Days

The year is 1981 and the world is in the midst of a severe resession. IBM's main frame business has slowed and the company is losing money. Up until now they had been laughing at the array of microcomputers on the market: Atari, Commodore, sinclair. Toys really, mostly used to play computer games.

The problem was, these "toys" were selling like hot cakes. IBM had to get into that market and get into it fast. They didn't have time to design and build a computer complete enough to compete in the market, so they built an "open system". They used commonly available electronic components and they published every design detail (including the code), and they even provided plug in slots so that others could build components for their computer.

And people did provide components for the IBM PC. They provided video cards, memory expansion cards, input-output port cards, game port cards, hard disk interface cards, and much more. How were all these various devices able to interface with the PC's operating system? That's where a "driver" comes in.

A hardware device is constructed with various electronic components using various control signals, but the software interface to the operating system is standardized. A device's interface to the operating system must follow the interface specification. A driver is a piece of software that translates the hardware's control signals to signals that the operating system expects, and translates signals from the operating system to the hardware's control signals.

When the computer is started up, it would look in the "system" directory for files with the extension ".drv" and load them into memory. Specific files like autoexec.bat, config.sys, and win.ini were used to inform the operating system about drivers. Hardware would be configured through these files, or through jumpers located on the device itself.

The driver specification evolved along with the PC. Today when a PC starts, it executes the program ntdetect.com which queries the hardware components and builds the registery key HKEY_LOCAL_MACHINEHARDWARESYSTEMCurrentControlSet. This key exists only in memory and is created each time the computer boots. If all the drivers are loaded successfully, a copy of the key is saved as ControlSet00X.

Under the registery key CurrentControlSet, the subkey "Enum" contains a subkey for each harware device on the computer. Each device key contains fields for Hardware ID, Driver ID, Device Parameters, and other configuration data. The 32-bit drivers are files with the extension ".sys" and can be found in the folder C:/winnt/system32.

Driver Signing

Microsoft has been the brunt of much criticism because of the poor reliability of the Windows Operating System. I feel that much of this criticism is justified. On the other hand, as I described in part 1 of this article, the PC was designed by IBM as an "open" system. Anyone can sell a hardware device (or software) for the PC. Should Microsoft be held responsible for the quality from a third-party?

As I described in Part 1 of this article, the operating system doesn't interface directly to a hardware device. There is a piece of software called a "driver" that translates the hardware's control signals to signals that the operating system expects, and translates signals from operating system to the hardware's control signals. Obviously, the hardware manufacturer provides the driver.

Because the driver works between the operating system and the hardware, a bug in the driver can cause a serious problem. Many of the problems with Windows have come from bugs in third-party drivers that Microsoft had nothing to do with. For this reason, Microsoft created a Hardware Quality Lab to test drivers. A hardware manufacturer can submit their driver for testing, and if it is passes rigorous compatibility testing, it receives Microsoft's digital signature.

You may have received a message during the installation of a hardware device warning that the driver was not signed. Why would a hardware manufacturer fail to have their driver certified by Microsoft? The computer hardware market is very competitive and the manufacturer might want to bring a new product to market before thorough testing can be completed. Or maybe they don't want to or can't afford to pay Microsoft for certification. The question is, should you click on the "Continue" button to install the unsigned driver?

In my experience, I have never been able to trace a problem to an unsigned driver. If it's your home computer and you performed a back-up recently, go ahead and install the unsigned driver. If it's a computer on a corporate network, you may want to back-out of the installation and see if you can locate a signed driver first. Many times a manufacturer will release a product with an unsigned driver, then later provide a signed driver as a free download from their website.

If you decide to go ahead and install an unsigned driver, you can always update the driver later. If your computer works with the unsigned driver, I would not update the driver. When it comes to updating drivers (or the computers BIOS) I go by the old saying, "if it ain't broke don't fix it".

To update a driver, select Start | Settings | Control Panel and double-click on the "System Properties" Utility. In the "System Properties" Utility, select the "Hardware" tab and click on the "Device Manager" button. In the "Device Manager" window, right-click on the device in the list and select "Properties" in the popup menu. In the "Properties" dialog box, select the driver tab and click on the "Update Driver..." button.

In the "Properties" dialog box driver tab, you may have noticed the "Roll Back Driver" button. If your computer has problems with the new drive, you can click on the "Roll Back Driver" button to roll back to the previous the driver. Driver roll back saves only one previous driver, so if you update a driver, then update it again, the original driver is gone. If the computer has problems with the new driver, always roll back to the original driver before trying a different one. That way you'll always have the original driver to roll back to.

Copyright(C) Bucaro TecHelp.

Permission is granted for the below article to forward, reprint, distribute, use for ezine, newsletter, website, offer as free bonus or part of a product for sale as long as no changes are made and the byline, copyright, and the resource box below is included.

About The Author

Stephen Bucaro

To learn how to maintain your computer and use it more effectively to design a Web site and make money on the Web visit bucarotechelp.com To subscribe to Bucaro TecHelp Newsletter visit http://bucarotechelp.com/search/000800.asp

---

What is a Document Manager without Version History?

Document Manager and Version HistoryIn previous articles I have discussed... Read More

Linux for Home Users

Hey Guys! Don't raise your eyebrows or fear by hearing... Read More

Programming Language Migration Path

While I was preparing some personal background information for a... Read More

Five Reasons for Using an O/R Mapping Tool

So, why should you use any O/R mapping tool? I... Read More

Secure File Transfer Using SSH Plus Additional Audit & Automation - FSA Reporting

In order to meet regulatory and corporate compliance requirements reporting... Read More

Crystal Reports for Microsoft Great Plains ? Overview for Developer

Microsoft Great Plains is main accounting / ERP application... Read More

Open Source Concepts: Dual Licensing Explained

We were recently faced with a decision: either to let... Read More

Kick-Ass Performance For Your PC? Its Easy

Is your PC is slow and wimpy? Then you need... Read More

Lotus Domino Implementation and Development: Infrastructure ? Present and Future

Domino server is a buffer between the operation system and... Read More

Microsoft Great Plains: Government & Non-Profit Organization ? Workflow Implementation

Usually workflow & messaging is realized in CRM and then... Read More

Microsoft Great Plains - Typical Problems And Fixes ? Overview For IT Administrators

How to delete the user? This is the first problem... Read More

Free Preventive Maintenance Software

While several preventive maintenance software manufacturers offer free trials for... Read More

Microsoft Great Plains Payroll Module Customization Scenarios

It is now common thing when large corporation selects mid-market... Read More

Microsoft Great Plains Implementation: Verticals - Wholesale Order Entry center ? overview

Microsoft Business Solutions Great Plains has substantial market share and... Read More

Mozilla Vs. Firefox

For those who are unclear on the differences between the... Read More

What is Fleet Maintenance Software?

Simply put, fleet maintenance allows companies to monitor and maintain... Read More

Microsoft CRM Implementation & Customization: MS CRM Fax Gateway

With this small article we are continuing Microsoft Business Solutions... Read More

Begun, The Browser Wars Have

As Mozilla Firefox nears 10% market share, with well over... Read More

CROOK: A Methodology for the Refinement of Forward-Error Correction

Table of Contents1) Introduction 2) Related Work 3) Framework 4)... Read More

eCommerce development for Microsoft Great Plains: tools and highlights for programmer

Microsoft Business Solutions Great Plains, former Great Plains Software Dynamics... Read More

Microsoft Navision Customization Upgrade ? Tips For Programmer/IT Specialist

Currently Microsoft Business Solutions is on the way of creating... Read More

Microsoft Great Plains e-Commerce ? additional considerations for programmer

Microsoft Great Plains, designed back in 1990th as database transferable... Read More

Navision Attain Database access via C/ODBC in ASP.NET Application

Navision Software was purchased by Microsoft and now it is... Read More

10 Programming Tips

(1) Avoid using the same variable again and again for... Read More

Understanding XML Server

XML Server can be a Web Server that stores the... Read More

Basic Tips and tricks for Windows XP

Running Applications in Compatibility Mode With Windows XP, you can... Read More

Know Linux

Linux essentials:It's free for download but you have to pay... Read More

Are You Waiting for Microsoft Longhorn Operating System

I love new technology. I am still ready to wait... Read More

Review of TikiWiki Content Management System

TikiWiki is open source software - it is written in... Read More

Microsoft Great Plains Implementation in Russia ? Overview for Consultant

Microsoft Business Solutions Great Plains is very popular ERP platform... Read More

Great Plains Dexterity ? Microsoft Great Plains Customization Overview

Microsoft Business Solutions Great Plains, former Great Plains Software Dynamics... Read More

Linux Dual Boot-How To Format

Just the thought of a duel-boot scares many people away,... Read More

The Death of Windows

I have always regretted how Microsoft price gouges and rips... Read More