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Michael E:

> "Wait Blindly" ... you believe there is a better way ...?

I don't think I meant to imply so much.

Aye, I'm leery of any unbounded wait.

Aye, I'm leery of waiting for bits to go lo that shouldn't be hi.

But on an issue like this I suppose as a matter of personal style I'm more in favour 
of accreting features over time as needed to make the host as widely compatible as 
possible.

I know just a few months back I taught my own host to look twice before it will 
believe BSY is lo, and working out how far beyond the spec I want to go in this area 
remains on my to-do list.

Pat LaVarre

>>> [EMAIL PROTECTED] 05/04/01 10:29AM >>>
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Pat,  

Based on observation, most Microsoft drivers wait for busy to clear after
selecting the device and before writing the command (and rest of task file).
I know my drivers do this too.

When you say "Wait Blindly", I get the feeling that you believe there is a
better way...do you have one?

Thanks, Michael K. Eschmann.



-----Original Message-----
From: Pat LaVarre [mailto:[EMAIL PROTECTED]] 
Sent: Thursday, May 03, 2001 7:33 AM
To: [EMAIL PROTECTED] 
Subject: [temp t13] BSY spontaneously hi


  ** This is the quasi-official and semi-temporary T13 email list server. **

> (((...
Thought number two...)))

The discussion of trying to eliminate the check for either of x88 BSY|DRQ hi
in x3F6 AlternateStatus before writing parameters and in particular before
writing x1F7 Command did not reproduce all of my personal history of pain.
I saw no discussion of the case where ...

Writing x1F6 Device/Head raises BSY as a side effect.  I hear this is
popular among a significant population CompactFlash cards we can expect to
stay in circulation for at least the next five years.  I hear the
device-side people were tempted into this evil by observing that both the
Ansi texts and Microsoft either blindly wait for BSY|DRQ clear or else
immediately write x1F7 Command after writing x1F6 Device/Head.  When they
wait blindly, everything eventually works.  When they immediately write x1F7
Command, well, that's a write of x1F7 Command while BSY|DRQ set, which by
and large quietly without notice cancels any command in progress and begins
anew ... which in this case works.

Pat LaVarre


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