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BIOS Feature "Magic Dates"

There are several important BIOS features or capabilities that have been introduced over the last few years. The only reliable way to ensure that your BIOS supports these is to check your BIOS or motherboard manual, or contact the manufacturer or dealer. However, there are some rules of thumb relating the BIOS date that you can use to give you an idea of whether or not a given machine is likely to support a given feature.

Here are the most common BIOS features and the approximate date that they were introduced. Obviously these are just rules of thumb; don't take all of this as definitive. It is fairly safe to say that if the BIOS date is more than a year earlier than a magic date, the feature almost certainly is not supported, and if it is more than a year after the date, it almost certainly is supported:

• Geometry Translation for IDE/ATA Hard Drives Over 504 MB: The magic date for this feature is around July 1994.
• Plug and Play Specification: Support for PnP was introduced around mid-year in 1995. (I'm not 100% sure on this one.)
• Year 2000 Compliance: For AMI BIOSes, the magic date is July 15, 1995. For Award BIOSes the situation seems more complex. Check out the Year 2000 web site.
• Large IDE/ATA Hard Drives Over 2 GB: Support for very large hard drives seems to have begun with BIOSes dated in January 1996.

See the section on hard disk BIOS barriers for more information on BIOS hard disk size limitations.

Next: BIOS System Boot Operations

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