Browse Prior Art Database

Blocked Data Transfer with Virtual Memory Queues

IP.com Disclosure Number: IPCOM000109389D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 4 page(s) / 145K

Publishing Venue

IBM

Related People

Holley, EL: AUTHOR

Abstract

This article describes a transfer method between computing systems or subsystems which allows data records of varying size to be queued on the transmitting system, transmitted in fixed size blocks, placed on a queue in the receiving system without recalculating record to record link pointers, and provide the receiving program with complete data which directly matches the format of the transmitted records.

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

Blocked Data Transfer with Virtual Memory Queues

       This article describes a transfer method between
computing systems or subsystems which allows data records of varying
size to be queued on the transmitting system, transmitted in fixed
size blocks, placed on a queue in the receiving system without
recalculating record to record link pointers, and provide the
receiving program with complete data which directly matches the
format of the transmitted records.

      The technique of this article maintains its own virtual memory
space for each queue on each system.  The variable length records are
linked together with header records which precede the data.  The
links are relative displacements rather than fixed memory locations
so that the links remain valid from the transmitting system to the
receiving system.  Multiple data records can be blocked in a single
fixed size data packet and can span one or more fixed size data
packets.

      The combination of fixed size packet transfers, virtual memory
management of queue space, and relative displacement provides for a
data queuing and transfer technique which provides efficient transfer
for large quantities of data between computing systems or subsystems
with efficient utilization of memory on each system, while
maintaining a minimum of inter-system protocol overhead.

      Data is sent by a program on the transmitting system as a
string of bytes which will be called a 'data record.'  The data
record can be of varying sizes.  The data record is placed in system
memory buffer space with a preceding header record which contains the
length of the record and a pointer to the next record in the queue.
This pointer is a relative pointer which represents the displacement
in bytes from the current header to the next header in the queue.
Data records are added to the 'tail' of the queue.  Since the queue
is maintained in its own virtual memory space, the queue can be
thought of as residing in a contiguous but not unlimited memory space
which is used exclusively by this queue.  If the end of the memory
space is reached as the result of data being added to the queue, data
addition is resumed at the beginnin...