Learn about the technologies behind the Internet with The TCP/IP Guide!
NOTE: Using robot software to mass-download the site degrades the server and is prohibited. See here for more.
Find The PC Guide helpful? Please consider a donation to The PC Guide Tip Jar. Visa/MC/Paypal accepted.
View over 750 of my fine art photos any time for free at DesktopScenes.com!

[ The PC Guide | Systems and Components Reference Guide | Hard Disk Drives | Hard Disk BIOS and Capacity Factors ]

Hard Disk BIOS Translation Modes

One of the most important techniques used to break the 504 MiB disk size barrier that results from the combination of BIOS and IDE/ATA hard disk restrictions is the use of BIOS translation. This can be a rather confusing subject and so this section discusses in detail the various types of BIOS translation that are used in PCs. A BIOS that supports the extended CHS and/or LBA modes is often said to be an enhanced BIOS.

Note: For completeness, and to assist those working with older hardware, I maintain the descriptions of translation modes in some detail here. Realize however that on most modern systems they are no longer of much relevance. Drives over 8.4 GB in size, which is what modern PCs use, are generally accessed by setting the BIOS to dynamically autodetect their size at boot time, and then using logical block addressing. Most of the issues that PC users once had to deal with in terms of tweaking BIOS translation modes are no longer necessary for modern drives over 8.4 GB in size, because these drives are no longer address using cylinder, head and sector numbers.

Note: Little of this section has any relevance when using only SCSI hard disks. They are not generally subject to the BIOS limitations that are overcome through translation.

Next: Normal / Standard CHS Mode


Home  -  Search  -  Topics  -  Up

The PC Guide (http://www.PCGuide.com)
Site Version: 2.2.0 - Version Date: April 17, 2001
Copyright 1997-2004 Charles M. Kozierok. All Rights Reserved.

Not responsible for any loss resulting from the use of this site.
Please read the Site Guide before using this material.
Custom Search