UBF Timeout Function

gop at us.ibm.com gop at us.ibm.com
Wed Dec 9 09:03:17 PST 1998


* From the T10 Reflector (t10 at symbios.com), posted by:
* gop at us.ibm.com
*
Larry,
I think the timer start/clear should be a little different then what you
have described. I would suggest the following wording:

The unexpected bus free timeout is intended to clear the bus in the event
of a bus hang.  The device starts the UBF timeout function on the
transition of the first REQ and restarts it on each ACK transition. When
the device receives the last ACK transition the UBF timeout function
stopped.  If the UBF timeout expires anytime before the last ACK transition
the device goes to unexpected bus free.  The existing rules related to
unexpected bus free behavior apply.

Bye for now,
George Penokie

Dept EGB  114-2 N212
E-Mail:    gop at us.ibm.com
Internal:  553-5208
External: 507-253-5208   FAX: 507-253-5208




"Lawrence J. Lamers" <ljlamers at ix.netcom.com> on 12/09/98 09:16:38 AM

To:   t10 at symbios.com
cc:    (bcc: George Penokie/Rochester/IBM)
Subject:  UBF Timeout Function





* From the T10 Reflector (t10 at symbios.com), posted by:
* "Lawrence J. Lamers" <ljlamers at ix.netcom.com>
*
To:     T10 Membership
From:   Lawrence J. Lamers
Subject:        UBF Timeout Function
Date:   Wednesday, December 09, 1998

This proposal adds a UBF timeout field to the Control Mode page. The UBF
timeout field is a sixteen-bit value in one millisecond increments.  A
value of
0000h indicates that the function is disabled.  A value of FFFFh indicates
an
unlimited period.   (See also the busy timeout period definition in SPC-2).

This proposal adds a bit to the INQUIRY data to indicate that the device
supports a UBF timeout function.

Note:  The specific bytes/bits location in the Control Mode page and
INQUIRY
data are left to the discretion of Ralph

The unexpected bus free timeout is intended to clear the bus in the event
of a
bus hang.  The device starts the UBF timeout function on the transition of
REQ
and clears it on the transition of ACK.  If the UBF timeout expires without
the
assertion of ACK the device goes to unexpected bus free.  The existing
rules
related to unexpected bus free behavior apply.

Regards,

==========================================
Lawrence J. Lamers                     Adaptec, Inc
email:   ljlamers at ieee.org            691 South Milpitas Blvd.
Phone: (408) 578-1709                 Milpitas, CA  95035


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