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RE: Re: Hub Operations
- Subject: RE: Re: Hub Operations
- From: "Patrick Lidstone \(Personal e-mail\)" <patrick@xxxxxxxxxxxx>
- Date: Mon, 18 Oct 2004 10:06:20 +0100
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Horses for courses, I guess Michael. 2 mins is a jolly long time to sit
in the dark when you press a light switch... I'm not going to implement
a system which has a fail-over mechanism that includes a two minute
period of deafness as a feature, it wouldn't work for me - although I
guess it's ok for you and your intended applications.
Patrick
-----Original Message-----
From: Michael McSharry [mailto:mcs101main@xxxxxxx]
Sent: 17 October 2004 18:46
To: xAP_developer@xxxxxxx
Subject: Re: [xAP_developer] Re: Hub Operations
In flight-critical applications the decision time for failure detection
and reconfiguration is typically under one second. The speed of my
house, however is measured in geological time as it is attached to the
North American tetonic plate. A two minute period of silence will
hardly ever be noticed and it sure beats the alternative of an
indefinite period of silence. From an implementation perspective the
hub is the easiest thing to manage in Windows since the hard work of
actually allocating the port to exactly one user is handled by the OS.
A backup hub simply needs to try to acquire 3639 periodically and when
successful it just keeps running with it in the role of a hub. In the
Role schema I proposed for this awhile back, this new hub would simply
change it's role status from backup to primary and another instance of
the hub app spawned. The new instance would start as a backup since it
would not be successful at acquiring 3639.
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<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=742130109-18102004>Horses
for courses, I guess Michael. 2 mins is a jolly long time to sit in the
dark
when you press a light switch... I'm not going to implement a system which
has a
fail-over mechanism that includes a two minute period of deafness as a
feature,
it wouldn't work for me - although I guess it's ok for you and
your
intended applications.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=742130109-18102004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=742130109-18102004>Patrick</SPAN></FONT></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px
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<DIV></DIV>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr
align=left><FONT
face=Tahoma size=2>-----Original
Message-----<BR><B>From:</B> Michael McSharry
[mailto:mcs101main@xxxxxxx]
<BR><B>Sent:</B> 17 October 2004
18:46<BR><B>To:</B>
xAP_developer@xxxxxxx<BR><B>Subject:</B> Re:
[xAP_developer] Re: Hub
Operations<BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2>In flight-critical applications
the decision time
for failure detection and reconfiguration is typically under one
second. The speed of my house, however is measured
in geological
time as it is attached to the North American tetonic
plate. A two
minute period of silence will hardly ever be noticed and it sure
beats
the alternative of an indefinite period of silence. From an
implementation perspective the hub is the easiest thing to manage in
Windows
since the hard work of actually allocating the port to exactly one user is
handled by the OS. A backup hub simply needs to try to acquire
3639
periodically and when successful it just keeps running with it in the role
of
a hub. In the Role schema I proposed for this awhile back,
this
new hub would simply change it's role status from backup to primary and
another instance of the hub app spawned. The new instance would
start as
a backup since it would not be successful at acquiring
3639.</FONT></DIV>
<DIV><FONT face=Arial color=#0000ff
size=2></FONT> </DIV></BLOCKQUOTE>
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