Do-it-yourself BIOS binary modification
OEMs using COMs in many cases can not use the standard BIOS that is provided by the module supplier. Special utilities and a BIOS with built-in support allow minor modifications to the BIOS binary without dealing with the BIOS source code. The following are three examples of typical BIOS binary changes:

1. OEM CMOS Default Settings. Most designers who utilize an embedded module within their system need to have their own CMOS ROM default settings. An embedded BIOS should provide the ability to store OEM defaults in flash memory thereby reducing the need for customized BIOS versions.

2. OEM Splash Screen. Hiding the PC functionality in an embedded application is often a requirement. The BIOS should instead display a logo rather than the traditional diagnostic output during POST. Users should be able to integrate an OEM logo into the standard BIOS themselves.

3. OEM BIOS. This BIOS feature allows users to integrate their own code into the BIOS POST process. In order to support this the BIOS must be capable of calling OEM code at different times during POST. With this type of OEM BIOS support a user can, for example, initialize carrier board hardware components and add boot loaders.

Although most BIOS vendors offer an utility for binary BIOS modifications, some embedded PC vendors have their own utility. Congatec AG  for example offers a powerful software package that allows a customer to perform the following modifications to the BIOS binary:

* Add OEM CMOS default settings
* Add OEM Splash screen
* Add OEM BIOS code
* Change the BIOS setup screens and add OEM setup screen

The utility can be also used as a:

* BIOS update utility
* Onboard microcontroller firmware update utility
* Flat panel data configuration (create EDID data set from panel data sheet information)

Provided by Congatec AG at no charge is a system utility available in both DOS command line and Windows GUI versions. It works in file mode (patching a BIOS binary) and flash mode (directly modifying the BIOS on the target PC). The utility is provided by congatec AG at no charge. When using this utility for BIOS modifications COM users can configure and customize their BIOS quickly without incurring additional costs.

Conclusion
All BIOS software offerings are not created equal. This is currently a shortcoming within the embedded PC industry. If indeed all BIOS software and the accompanying COMs being offered were created equally then all the features mentioned earlier would be available and the consumer could benefit from uniform functionality.

Unfortunately this is not yet the case within the industry so it's up to the consumer to closely examine the functionality of the COM being offered. With a fully-featured BIOS that is tailored to the extensive needs of embedded engineering and offering true versatility and design flexibility, successfully implementing an x86 computer-on-module application will be easier and faster.

Christian Riesinger is the R&D Manager at congatec AG. He's been working for over 10 years as a BIOS engineer and has been instrumental in implementing new embedded PC features within the industry.