- The x86 BIOS: Its Limits and Capabilities
- 16- and 32-Bit Code
- The BIOS as Driver for DOS
- Modern Uses of the BIOS
- What BIOS Do You Have?
- Add-On Card BIOSs
- Video BIOSs
- Boot BIOSs for SCSI and Networking
- Additional BIOSs
- BIOS Updates
- EIDE and SCSI Hard Disk Handling
- Understanding CHS Geometry Limits
- Getting Around the 1024-Cylinder Limit
- Common BIOS Disk Utilities
- The Handoff to the OS
What BIOS Do You Have?
Up to this point, I've referred to the BIOS, as if there were only one BIOS used, albeit with modifications, in all computers. In fact, there are several. Common BIOSs in use today include the following:
AMI BIOSAmerican Megatrends, Inc. (AMI; http://www.ami.com) produces a popular BIOS that's used on its own and many other companies' motherboards.
Phoenix BIOSThe Phoenix BIOS is another popular one. It closely resembles the AMI BIOS in its layout and options. For more information, see http://www.phoenix.com.
Award BIOSPhoenix purchased Award, so Award BIOSs are being shipped only on systems that were designed prior to the merger. Many existing Award BIOSs exist, however. The Award BIOS was somewhat different in its overall layout than the AMI and Phoenix BIOSs, but comparable in features. As I write this, the Award Web site still exists at http://www.award.com.
MR BIOSMicroid Research (http://www.mrbios.com) sells after-market BIOS upgrades, mostly for older computer systems. These upgrades can be a useful way to add modern BIOS features to an older computer.
Each of these BIOSs can be considered more of a BIOS family than a single product. Each BIOS must be fine-tuned for each type of computer. For example, a BIOS for an Intel Pentium III motherboard must be different from an AMD Athlon motherboard's BIOS. Even within a CPU family, BIOSs differ because of differences in the motherboard chipsetsthe collection of circuitry that mediates between the CPU and the memory, add-in cards, and on-board devices. These two factors (multiple BIOS suppliers and unique modifications for each motherboard design) result in a huge range of BIOS features, some of which might interact with some OSs but not others.