lotus

previous page: 06.01.  Should I use my interface's device drivers?
  
page up: Enhanced IDE/Fast-ATA/ATA-2 FAQ
  
next page: 06.03.  Can I safely change the BIOS' xlation mode (None, LBA, Large)?

06.02. What should I use: Normal, LBA or Large?




Description

This item is from the Yet Another Enhanced IDE/Fast-ATA/ATA-2 FAQ, by John Wehman and Peter den Haan with numerous contributions by others. (v1.92).

06.02. What should I use: Normal, LBA or Large?

The difference between the three is this.

o 'Normal' causes the BIOS to behave like an old fashioned one without translation. Use this if your drive doesn't need it (ie. has fewer than 1024 cylinders) or if you want to use the drive with an operating system that doesn't understand about translation.

o 'Large' or ECHS or XCHS tells the BIOS to use CHS translation. It uses a different geometry (Cylinders/Heads/Sectors) when accessing the drive than when talking to the software through int13. This type of translation works with all drives.

Note. Some BIOSes have a braindead Large implementation which works only for disks of up to 1GB. Fortunately, all larger disks support LBA.

o 'LBA' differs from 'Large' in that it uses LBA addressing to access the harddisk. The advantage is that it theoretically is a little faster. The disadvantages are that some older drives don't support it, and it often turns out to be slower, depending on the drive.

WARNING. Some BIOSes change the (translated) geometry if you change from Normal or Large to LBA. The same thing may happen if you transfer a disk that has been formatted on an old, non-LBA computer to a new one that uses LBA. This has destroyed data. Don't let it happen to you.

Section 10 tells more about the differences between these three.

 

Continue to:













TOP
previous page: 06.01.  Should I use my interface's device drivers?
  
page up: Enhanced IDE/Fast-ATA/ATA-2 FAQ
  
next page: 06.03.  Can I safely change the BIOS' xlation mode (None, LBA, Large)?