Clarification of Enhanced IDE Under Windows NT 4.0

• Microsoft Windows NT Workstation version 4.0
• Microsoft Windows NT Server version 4.0

SUMMARY

This article provides clarification of issues relating to enhanced integrated development environment (EIDE) devices under Windows NT 4.0. It addresses the most common questions asked by customers and hardware vendors.

MORE INFORMATION

1. Q. Is bus-mastering IDE disk access (DMA 0 & 2) available under Windows NT 4.0?
   
   A. This feature is planned for release in the Service Pack 1 or 2 for Windows NT 4.0.



2. Q. Does Windows NT use 32-bit I/O accesses (also known as HDD Block Mode)?
   
   A. To date, this has been seen to corrupt data in some cases. Therefore, it is not used.



3. Q. Does Windows NT support Advanced PIO/DMA programming modes (PIO Mode 3 or 4)?
   
   A. If the BIOS programs the part for advanced PIO modes, then it is left in those modes.



4. Q. Does Windows NT support multiple sector disk transfers for hard drives and removable media devices such as Ez-Drive, ATAPI Jaz, or ATAPI Zip drives?
   
   A. Windows NT 4.0 supports multi-sector transfers for hard drives, CD-ROM drives, and for removable media.



5. Q. Does Windows NT support ATAPI CD-ROM drives supporting DMA and multiple sector disk transfers?
   
   A. This feature is currently in Windows NT 3.51 and 4.0.



6. Q. Does Windows NT have the ability to boot from a drive other than a floppy or hard drive device (also called El Torrito capability)?
   
   A. El Torrito is supported under NT 4.0 for both ATAPI and SCSI formats. The bios must be capable of using El Torrito in NonEmulation mode.



7. Q. What is the recommended configuration for my IDE devices?
   
   A. You should put your hard drives on the primary channel, and your slower devices (such as IDE CD-ROMs or IDE tape drives) on the secondary channel. This is because high speed PIO or DMA transfers are recommended, but are not required for the secondary channel.
   
   The other benefit of this configuration is that both channels can operate simultaneously. This is not the case if two IDE devices are on the same chain, because they must alternately share the interrupt.
   
   Many of the high speed features of Enhanced IDE such as bus- mastering, DMA scatter/gather transfers, 32-bit PIO transfers, and high speed DMA transfers, are not required and not present on the secondary channel.
   
   Many of the current Enhanced IDE controllers do not support separate transfer speeds of the slave and master, so if you have a fast master device and a slow slave device on the same channel, your controller may reduce the maximum transfer speed to the speed of slowest device.

Additional query words: sur ATA2 ATA

Keywords          : kbenv kbsetup ntsetup ntconfig NTSrvWkst 
Version           : WinNT:4.0
Platform          : winnt 
Issue type        : kbinfo 

Last Reviewed: February 20, 1999