Browse Prior Art Database

Method to Enhance Concurrency Control of Access to a Remote Server Via Netbios in a Microsoft Windows Environment

IP.com Disclosure Number: IPCOM000121663D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 79K

Publishing Venue

IBM

Related People

Arnold, HH: AUTHOR [+2]

Abstract

A method is disclosed to allow multiple database applications executing in a Microsoft WINDOWS 3.0 operating environment to concurrently access a remote database via NETBIOS without overutilizing the memory that is managed by Microsoft WINDOWS 3.0 in the address space below 640K (the address space known to the DOS operating system).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Method to Enhance Concurrency Control of Access to a Remote Server
Via Netbios in a Microsoft Windows Environment

      A method is disclosed to allow multiple database
applications executing in a Microsoft WINDOWS 3.0 operating
environment to concurrently access a remote database via NETBIOS
without overutilizing the memory that is managed by Microsoft WINDOWS
3.0 in the address space below 640K (the address space known to the
DOS operating system).

      Multiple applications using NETBIOS in a Microsoft WINDOWS 3.0
environment are severely constrained by the following problem.  When
an Input/Output request is made to NETBIOS, the control block
describing the operation to be performed, (NCB), and the storage
buffers containing data to be sent or to be used for receiving data
must be copied to memory addresses below 640K (known as low memory)
by Microsoft WINDOWS so that they can be accessed by the DOS (Real
Mode) device driver that comprises the NETBIOS support.  If multiple
applications are allowed to access NETBIOS concurrently (i.e.,
NETBIOS is accessed in No Wait or asynchronous mode), space must be
provided in low memory for all of these concurrent requests and the
memory available is quickly exceeded.     If the NETBIOS Wait option
is used, only space for one application's NCB and buffer is required
to be in low memory and the space available is not exceeded.  In this
mode, however, for the duration of the NETBIOS (synchronous) call, no
Microsoft WINDOWS applications are allowed to run.  In the case of a
database client application, a call to the host server may take up to
several minutes to satisfy and, during this time, no other
applications are allowed to run, a terrible response problem.

      This problem is addressed in the following manner.  The memory
constraint cannot be overcome by adding memory,...