International Business Machines Corporation

David C Wu

Victor S Moore

William Edward Atherton

Douglas M O'Neal

David James Rudda, Jr

Jan W Van Den Berg

Donald V Wildes

Paul W Petroskey

Raghunath Reddy Kallem

Dennis M Nagel

Richard G Van Duren

A method and system for allocating pre-selected physical memory locations to an application executing on a data processing system. Memory allocation subroutines, interacting with the programming interfaces of the operating system (OS), allocates and looks down blocks of memory. The memory allocation subroutines then de-allocates the memory blocks based on whether or not the memory blocks fall within the pre-selected range of physical memory locations. The physical memory locations of the blocks locked down are discovered using the driver. The driver takes the virtual address of the specified memory locations and returns with a corresponding physical address. The memory allocation subroutines provide functions that allow the program developer to specify the number of physical pages to allocate and a range of physical addresses and comprises algorithm(s) that allocates the physical memory within the selected range.

Programmatically pre-selecting specific physical memory blocks to allocate to an executing application

A method and system for maintaining a routing path between a selected workstation within a multisegment local area network and a mobile workstation wherein individual segments within the multisegment local area network are interconnected by a router device and wherein selected segments within the multisegment local area network include radio frequency transceivers adapted to provide a wireless communications link with mobile workstations. Each time communication is established between a mobile workstation and a selected workstation within the multisegment local area network via a radio frequency transceiver a routing table entry is established which identifies a segment location for the mobile workstation within a routing table associated with each router device within the multisegment local area network. A routing table entry is also established which identifies a segment location for the selected workstation within the routing table associated within each router device within the multisegment local area network in response to each attempt at establishment of communication between the selected workstation and the mobile workstation. Thereafter, all routing table entries which identify the segment location for a mobile workstation are automatically deleted in response to a termination of communications between the mobile workstation and the radio frequency transceiver. Routing path determination for communications between a mobile workstation and any workstation within the multisegment local area network may then be determined by reference to a routing table associated with each router device within a multisegment local area network without requiring the maintenance of routing path information at each workstation within the multisegment local area network.

Method and system for maintaining routing between mobile workstations

A micro processor controlled user programmable communications multiplexer subsystem (herein referred to by the symbol PCS) capable of transmitting and receiving data on any one or more of 32 communications lines simultaneously. Each line may be dynamically assigned to a variety of communication characteristics, such as line speeds, character lengths, synchronous, or asynchronous operation, and code structures as well as protocol selections. The system of the invention provides the capability for the user to write his communications programs using novel operations commands that provide code structure and protocol independence as well as communication line independence. Various hardware features and queuing techniques are employed in order to maintain high transmission rates. Variable line scanning in the Teleprocessing Time Division Multiplexer of the PCS is programmably permissible; i.e., the time base for line scanning is fixed and is a multiple of the communication line rate, although the actual line to be scanned is programmably variable. The program ability is provided by a continuously scanned storage array which contains physical line addresses of the time division multiplexer. The scanning mechanism, while running, prioritizes the transmit buffer servicing of the individual lines.

Programmable communications subsystem

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Apex, NC, United States of America

David C Wu