lotus

previous page: 04.01.  What should I look for in an ATA-2 (Fast-ATA, EIDE) interface?
  
page up: Enhanced IDE/Fast-ATA/ATA-2 FAQ
  
next page: 04.03.  Is my 50MHz VL bus system compatible with ATA-2 interfaces?

04.02. Is my BIOS Enhanced? How can I recognize this?




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).

04.02. Is my BIOS Enhanced? How can I recognize this?

Good question.

Unfortunately, I know no easy answer. The mere ability to specify more than 1,024 cylinders in the BIOS setup is not conclusive. In your BIOS setup, drive related settings like "LBA", "ECHS" or even something silly like "Large" are telltale signs of a BIOS with translation support, which should be good for disk capacities of up to 8GB. A copyright before 1994, on the other hand, reduces your chances to something close to zero :-(

o For AMI, I only have reliable information on their HiFlex BIOS; it can be recognized by its characteristically funky orange and green color scheme. There at least two other types: WinBIOS with a Windows like interface, and a custom BIOS used with Intel Pentium boards. Both may translation even if they have a (much) earlier copyright. I have no further information on those.

AMI HiFlex BIOSes dated 7-25-94 and later and support translation. The date is embedded in the long number displayed at the bottom of the screen on bootup; it must be 072594 or later to support LBA.

40-0100-00101111-111192-486-ABC-F (111192 will not support LBA)

50-0100-001292-00101111-072594-ABCDEF-F (072594 will support LBA)

o Award seems to call all its BIOSes 4.50G :-) Some have translation support, some don't, some have buggy support (see 8.2). With a BIOS dated 12/31/1994 or later you have full translation support, with one dated earlier (7/29/1994, perhaps earlier than that as well) buggy support only.

o Phoenix BIOS v4.03 and later are reported to support translation. Some revisions of Phoenix v4.03 may not support it, though, depending on the computer or system board manufacturer.

o MR BIOS incorporated CHS translation--roughly the same as today's Large mode--as early as 1990!

Note that only BIOSes fully implementing the IBM/Microsoft/Phoenix standards will allow access to disks larger than 8GB. Fortunately, these are becoming more and more common these days. We are not aware of utilities that will detect the presence of such a BIOS.

Western Digital has a utility available by ftp that examines the Enhanced Disk Parameter Table (EDPT), if present. If it finds one on your system, your BIOS has all the bells and whistles to go up to 8GB <ftp://ftp.wdc.com/drivers/hdutil/>. Beware that BIOSes conforming to the WD Enhanced BIOS specification won't build an EDPT unless LBA is enabled. Beware also that with a WD EBIOS it is highly unsafe to enable LBA on a disk that already contains data. This is due to a flaw in the specification.

 

Continue to:













TOP
previous page: 04.01.  What should I look for in an ATA-2 (Fast-ATA, EIDE) interface?
  
page up: Enhanced IDE/Fast-ATA/ATA-2 FAQ
  
next page: 04.03.  Is my 50MHz VL bus system compatible with ATA-2 interfaces?