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

In The News:


pen paper and inkwell


cat break through


Microsoft Blues

With the advent of 'Service Pack 2' for Windows XP... Read More

C++ Tutorial 1, Introduction to C++

Introduction to C++Why Learn C++?C++ may at first seem like... Read More

Free Software - Powerful Alternatives to Budget-Busting Software

When you buy a computer, it most likely comes with... Read More

Crystal Reports For Microsoft RMS ? Overview For Developer/Report Designer

If you are software developer or database administrator - we... Read More

Microsoft Great Plains Distribution, Barcoding, Consignment ? overview for consultant

Microsoft Great Plains ? ERM from Microsoft Business Solutions and... Read More

Microsoft CRM Implementation & Customization: MS CRM Fax Gateway

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

Accessing XML Using Java Technologies

The most important benefit of XML is its simplicity. Though... Read More

Introduction To ISDN, Part II

In the previous ISDN article, we looked at how and... Read More

Artificial Intelligence And Intuition

The intuitive algorithm.Roger Penrose considered it impossible. Thinking could never... Read More

Who Is Minding Your Sensitive Data?

Stealing company information used to be the specialty of spies... Read More

Software Upgrades Arent Always the Best Move

When my daughter was getting into AOL instant messaging (AIM)... Read More

Protect Your Most Vital Business Asset with Security Software

Homeland security, airport security, Internet security â?" these days weâ??re... Read More

Why do Manufacturers Invest in Business Management Software?

With many manufacturing shops heading over seas in favor of... Read More

Cisco Certification: Introduction To ISDN, Part III

Configuring PPP PAP AuthenticationNow we know how the ISDN link... Read More

A Symons Mark II Function Point Counting Example

I provide, here clear explanations and a count of function... Read More

Adware and Spyware Blockers

The most important things you can do for your computer... Read More

Top Questions to Ask Before Buying a Help Desk & Asset Management Software

#5 All your hardware components like Printers, PCs etc come... Read More

Microsoft Great Plains Implementation for Midsize & Large Corporation: Lockbox Processing

Microsoft Great Plains is now targeting large and midsize businesses... Read More

Selecting Corporate ERP: Microsoft Business Solutions Great Plains ? Estimation Parameters

As we could imagine, if you are reading this article... Read More

Antivirus Software ? Get The Bugs Before They Get You!

You turn on your computer, and it doesn't look quite... Read More

Bridging the Gap between Paper and Data

The cornerstone of successful automated office systems is the ability... Read More

Microsoft Great Plains eCommerce ? Stored Procedures Approach

Since Version 8.0 Microsoft Business Solutions Great Plains & Great... Read More

Microsoft CRM and No-Frills Cadillacs

In today's business world it's all but impossible to escape... Read More

SQL: Querying Microsoft Great Plains ? Overview for Database Administrator/Developer

Looks like Microsoft Great Plains becomes more... Read More

The End of Spyware?

The US House of Representatives has recently passed the "Spy... Read More

Microsoft CRM Data Conversion FAQ

Microsoft Business Solutions CRM data conversion deserves FAQ type of... Read More

Microsoft Great Plains Furniture & Fixtures ? Implementation & Customization Highlights

Microsoft Great Plains, former Great Plains Software Dynamics / eEnterprise... 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

Upgrading Great Plains Dexterity Customization ? switching to new technologies: SQL, Crystal, eConne

1. Replace Dexterity cursor with SQL Stored Procedure Dexterity... Read More

Is Your Small Business Ready For A CRM Software Solution?

I have yet to see a business that, sometimes in... Read More

40/sec to 500/sec

IntroductionSurprised, by the title? well, this is a tour of... Read More

Oracle Development: JDeveloper 10G ? Java, J2EE, EJB, MVC, XML - Overview For Programmer

In 2004 Oracle, Inc. made its new step toward J2EE... Read More

How To Identify, Cure and Prevent Spyware/Adware Infections

Just when you thought you were Web savvy, one more... Read More