This message is from the T13 list server.
On 08 Mar 2004 21:06:49 -0700, Pat LaVarre wrote: >This message is from the T13 list server. >How commonly do boot BIOS actually leave BSY and/or DRQ set? Not very often we hope. >I ask because lately I saw the bus trace: >... >That's right, this boot BIOS chooses to leave the device waiting >indefinitely for Command Out bytes, and then gleefully proceeds to write >DEV while BSY|DRQ. Broken host. It is clearly illegal to write a Command Block register while BSY=1 or BSY=0 and DRQ=1. Once upon a time (like 1992) there was discussion that whenever the host did a write to the DEV bit and the DEV value was changed that was in effect a "reset". This discussion never resulted in any change to the ATA documents. The problem is this would be yet another type of reset, different from the two resets that existed in ATA-x (in 1992) and different from the three resets in ATA/ATAPI-x. Hale *** Hale Landis *** www.ata-atapi.com ***
