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LSAM OBJECT SCHEDULING
======================
LSAM Authors: Lars Eggert, Amy S. Hughes
$Revision: 1.20 $ ($Date: 1998/08/27 00:15:47 $)
More Information: http://www.isi.edu/lsam/scheduling


Introduction
------------
The LSAM server supports different service classes for requests. Requests may
either be foreground (FG) or background (BG) requests. Responses to requests
may be sent in the FG or BG as well. This can be thought of as a form of
differentiated services.

FG requests and responses are being received, processed and/or sent out using
the normal apache methods. BG requests and responses, however, are dealt with
in a special way as to minimize their impact on FG performance.  This may
include delaying them longer or maybe not processing them altogether,
depending on the FG load.

The current version of the object scheduler is limited in the following ways:

Distinguishing between FG and BG requests:
	There is currently no inherent way to distinguish a FG from a BG
	request. Instead, the server listens on two ports, a "FG port" and
	a "BG port". All requests arriving on the FG port are assumed to
	be FG requests and treated as such, while all requests arriving at
	the BG port are treated as BG requests.


Demonstration
-------------
Performance of the object scheduling system can be monitored on the
"Foreground/Background Response Scheduling" status web page.


Acknowledgments
---------------
      Portions copyright 1994, 1995, 1996, 1997, 1998, by Cold
      Spring Harbor Laboratory. Funded under Grant
      P41-RR02188 by the National Institutes of Health. 

      Portions copyright 1996, 1997, 1998, by Boutell.Com, Inc. 

      GIF decompression code copyright 1990, 1991, 1993, by David
      Koblas (koblas@netcom.com). 

      Non-LZW-based GIF compression code copyright 1998, by
      Hutchison Avenue Software Corporation
      (http://www.hasc.com/, info@hasc.com). 

      Permission has been granted to copy and distribute
      gd in any context, including a commercial application,
      provided that this notice is present in user-accessible
      supporting documentation. 

      This does not affect your ownership of the derived work itself,
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