Automatic Persistent Memory Management for the SpotlessTM Virtual Machine on the Palm Connected Organizer

Palm organizers are widely used in a multi-tasking fashion. Users switch from one application to another without losing the context established in either of them. Despite its obvious usefulness, there is no automatic support for this convenience in the organizer’s operating system, PalmOS. Programmers must implement event callbacks that have to operate on a PalmOS database API to save and reload specific application state. In this report, we describe how this burden can be eliminated. We enhanced the Spotless JavaTM virtual machine for the Palm organizer with transparent multi-tasking support that automates persistence. As a consequence, running Java programs can be beamed between the infra-red links of two Palm organizers. A beamed program will resume on the receiving organizer in the exact same state as on the sending device. A HotSync operation effectively establishes a checkpoint for each involved Java program. The original Spotless JVM’s address range for running programs is limited to a few tens of KB in the dynamic RAM area. By directly addressing the much larger static RAM area, our modified VM supports address ranges of several MB. We provide an easy-to-use protocol that leverages persistent threads for automatic life cycle control of external resources (e.g., windows, forms and databases). When applied at the library level, this protocol maintains complete persistence transparency for the application programmer. email address: [email protected] [email protected] © 2000 Sun Microsystems, Inc. All rights reserved. The SML Technical Report Series is published by Sun Microsystems Laboratories, of Sun Microsystems, Inc. Printed in U.S.A. Unlimited copying without fee is permitted provided that the copies are not made nor distributed for direct commercial advantage, and credit to the source is given. Otherwise, no part of this work covered by copyright hereon may be reproduced in any form or by any means graphic, electronic, or mechanical, including photocopying, recording, taping, or storage in an information retrieval system, without the prior written permission of the copyright owner. TRADEMARKS Sun, Sun Microsystems, the Sun logo, and Java are trademarks or registered trademarks of Sun Microsystems, Inc. in the U.S. and other countries. All SPARC trademarks are used under license and are trademarks or registered trademarks of SPARC International, Inc. in the U.S. and other countries. Products bearing SPARC trademarks are based upon an architecture developed by Sun Microsystems, Inc. For information regarding the SML Technical Report Series, contact Jeanie Treichel, Editor-in-Chief .Reports in this series are also available online on the World Wide Web at http://www.sun.com/research/. Automatic Persistent Memory Management for the Spotless JavaTM Virtual Machine on the Palm Connected Organizer Bernd Mathiske Sun Microsystems, Inc. 901 San Antonio Road, MS MTV29-112 Palo Alto, CA 94303-4900 [email protected] Daniel Schneider Universität Hamburg Vogt-Kölln-Straße 30 D-22527 Hamburg [email protected]