At 9:06 PM -0700 3/8/04, Pat LaVarre wrote:
This message is from the T13 list server.
How commonly do boot BIOS actually leave BSY and/or DRQ set?
Do Linux/ Mac/ Windows/ etc. always begin life by repeating the resets that the t13.org texts say may complete slowly?
Curiously yours, thanks in advance, Pat LaVarre
P.S.
I can't answer for anyone else, but the Mac OS generally expects the device to be reset before control is turned over to the OS. If a device is touched during the scan or boot-loading process, the code that does the boot search/load is required to leave the device in a clean condition prior to turning over control to the Mac OS.
The Mac OS ATA family code in IOKit does the right thing, waits for busy clear, looks at protocol signatures, etc before banging on the hardware.In some cases, a reset may be applied at start, but that is specific to some hardware.
We try to avoid gratuitous resetting whenever possible. --
--------------------- I make stuff go. --------------------- Larry Barras ATA CPU Software Apple Computer Inc.
