Browse Prior Art Database

Automatic Re-Issue of Spi Listen Request

IP.com Disclosure Number: IPCOM000101304D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Hoegh, BT: AUTHOR [+2]

Abstract

Disclosed is a method to prevent an empty receive data buffer from being passed by to the Server Requestor Programming Interface (SRPI). This enhancement to the OS/2* Extended Edition Low Level Programming Interface (LLAPI) Define Buffer verb functions prevents performance degradation, as well as unpredictable results, in the SRPI code.

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Automatic Re-Issue of Spi Listen Request

       Disclosed is a method to prevent an empty receive data
buffer from being passed by to the Server Requestor Programming
Interface (SRPI).  This enhancement to the OS/2* Extended Edition Low
Level Programming Interface (LLAPI) Define Buffer verb functions
prevents performance degradation, as well as unpredictable results,
in the SRPI code.

      When the SRPI applications CMSSERV and MVSSERV receive
destination/origin structured field data from SRPI on the pc side,
they send back a structured field that serves as a host
acknowledgment.  This particular destination/origin structured field
contains only routing information and has nothing of any value for
SRPI.  The only information SRPI would receive from the LLAPI would
be an empty data buffer.

      Technically, SRPI has received information from the host -
acknowledgement of received data (see figure).  LLAPI could tell SRPI
that data has arrived.  However, SRPI resides in another process, and
since the data arrived, notification is of no value to SRPI; system
performance would suffer while LLAPI performs a useless task.  Upon
receipt of a 'data available' notice in this case, SRPI would first
have to look at the request, and finding that there is no real data
to process, build and issue another Define Buffer to catch the real
data that SRPI is expecting.

      LLAPI has solved this problem by checking the number of bytes
received in the returned SPI...