User System Performance Research Articles

MICO, An Open Source CORBA Implementation

Arno Puder and Kay Romer Third Edition, MKF, San Francisco, CA, 2000, 195 pp. ISBN 1-55860-666-1, $39.95 I would like to recommend this book to all people wanting to start learning about CORBA and interested in implementing this standard to build distributed systems. It, in a short and easy way presents ORB and the ways it can be implemented. Object Request Broker is the central piece of the CORBA architecture, serving as a carrier for invocations from the client (querying object) to other object implementations. MICO ( Mico Is COrba ) is one of the ORBs fully complying with the CORBA standard, and it was initially created as a didactic tool. It is an Open Source project presented in public for the first time in April 1997. MICO sources are at present freely offered under the GNU General Public License, and are used successfully in both academic and commercial applications (for more information about software you may want to look at: http://www.mico.org/ ). The book is offered with a CD that contains precompiled binaries as well as the complete sources for MICO, version 2.3.2 compliant to CORBA version 2.3. The software is offered for Solaris 2.6, AIX 4.2, Linux 2.2.x, Unix 4.x, HP-UX 10.20, Windows NT and 95 platforms. The book is partly an installation guide, tutorial, as well as a user and reference manual. Additionally, it includes lots of general information about CORBA with a more detailed ORB description. The first part of the book is very short and contains a simple preamble to the standard of CORBA and introduces readers to the MICO project. The second chapter explains the procedure of installation of MICO on the user's operating system (with the use of the CD which accompanies this book). In addition, it contains many tips concerning a compilation of source code, unquestionably useful for all persons who would come to the challenge of making some modifications in the original codes. The third section consists of a full guide through MICO, enriched with some characteristics from the CORBA acquaintance, implemented in the context of distributed computer systems. This part is enhanced with the practical example, showing how to use MICO to modify one-address-space application to a distributed application, running on different remote hosts. The fourth chapter embraces an implementation overview; it is generally a description of different tools, being offered with the MICO software. The practical example, as mentioned in the third section, is presented here once again, this time in much more complicated scenarios, in order to present more advanced CORBA activation modes. The fifth part of the book explains an implementation of IDL (Interface Definition Language) to C++ mapping. Interface Definition Language is a notation used by the OMG group in the CORBA standard to describe object interfaces. Description presented in this book includes rules about how to map an IDL specification to C++, and also mentions some design matters specific to MICO solution. The sixth chapter, titled Interoperability , demonstrates how to implement MICO's cooperation with other ORB implementations. The examples used here by the authors are very popular commercial tools: Orbix (a CORBA compliant ORB for C++ and Java, made by IONA Technologies: http://www.iona.com/ ) and VisiBroker (a support for CORBA with C++ and Java language bindings, implemented by Borland Software Corporation: http://www.borland.com/us/products/visibroker/ ). The seventh chapter describes a naming service, which was implemented as a fully CORBA-compliant module, and presents additionally how to practically employ it in the users' own applications. The penultimate chapters of the book include description of the Interface Repository Browser, and the ninth and final chapter contains GNU License usage rules, which close the presentation of the MICO software included inside this book. This book is obviously not a complete CORBA manual, and it looks like the authors did not want to achieve the goal in producing it as such. However, the book presents an exceptional value for its price, including many practical solutions supported by nice theoretical explanations. I personally believe it could be very helpful in initial studies of Distributed Systems as well as it could be successfully used in preliminary lecture for people interested in CORBA standard. Rafal Angryk Tulane University New Orleans, Louisiana

BMS: A KNOWLEDGE-BASED TOOL FOR UNIX PERFORMANCE TUNING

This paper presents the design and implementation of a knowledge-based tool for performance tuning of the UNIX operating system. The tool, called BMS, provides an intelligent support and maintenance for identifying performance bottlenecks in UNIX and recommending solutions to the problems. Currently, it handles problems in UNIX resource management, such as memory utilization, disk utilization, CPU scheduling and I/O devices. BMS has been implemented in the EXSYS environment and tested on UNIX V.3. Preliminary results have indicated that such a knowledge-based tool to operating system performance tuning (1) is viable; (2) increases the productivity of system maintenance personnel and reduces the cost of training; and (3) offers a better service to operating system users by providing prompt recommendations to solutions of their system performance problems.

Book review: MS-DOS User's Guide, Special Ed. by David W. Solomon, Caroline M. Halliday, David D. Busch, & Timothy S. Stanley (Que Corporation, 1989)

All MS-DOS users can find an abundance of helpful and often needed information in the MS-DOS User's Guide. This is a very complete guide to MS-DOS and PC-DOS versions 3 and 4. References are made to versions 1 and 2 of the operating system, however the emphasis of book is on versions 3 (with more attention to version 3.3) and 4. The guide does not include references to the DEBUG or LINK commands. Also, the guide does not try to explain GW-BASIC nor any other application software. This is a book about the operating system for operating system users, i.e. all users.

Surreptitious security violation in the MVS operating system

Even in the well-protected IBM MVS operating system users can force breaches in the standard protection mechanisms and obtain control over the entire installation regardless of RACF or TOP SECRET protection software. This paper encourages computing center management to appoint security officers to prevent and detect security violations. The need for these officers will be demonstrated as a consequence of the violations shown.

Computer System Response Time and Psychophysiological Stress II

With the advent of time-shared interactive systems, the psychological impact of system response time (SRT) and SRT variability (SRTV) has become an important issue. Carbonell, et. al. (1968) have suggested that both SRT and SRTV may influence system user performance and satisfaction. A number of studies have been reported that address this issue, but results have been mixed. In this experiment, twenty subjects ( Ss) executed keyboard entries to control the temperature of a simulated industrial process via time-shared process control computer. Temperature was displayed in analog form on a CRT. The task was to maintain the temperature within upper and lower bounds that were clearly indicated on the display. The experimental design consisted of repeated measures with SRT and SRTV as experimental factors. Three SRT's were employed (2, 6 and 10 seconds) with two levels of SRTV (σ2 = 0 and σ2 = 0.33 seconds). Mean blood pressure (MBP) and heart rate (HR) were continuously monitored during experimental conditions. Task errors were defined as temperature excursions beyond the displayed bounds. Significant main effects were not obtained for MBP or HR. Significant differences for error rate (performance) were noted for SRT ( F(2, 15) = 23.10, p < .05), subjects x SRT ( F37, 15) = 1.66, p < .001), and SRT x SRTV ( F(1, 15) = 13.14, p < .05). Error data are consistent with the Carbonell et. al. suggestion that long and variable SRT may affect user performance. The results are discussed in terms of their incongruity with current literature.

STRUCT programming analysis system

The STRUCT system utilizes the flexibility of a powerful graphics display system to provide a set of tools for program analysis. These tools allow the analysis of the static program structure and the dynamic execution behaviour of programs within the entire operating system user program environment of the Brown University Graphics System (BUGS). Information is collected and presented in a manner which fully exploits two aspects of this environment. First, the operating system has been developed in a well-structured hierarchical manner following principles laid down by other researchers. Second the programs under analysis have been written in a structured programming language following coding conventions which make available, at the source code level, valuable program control information. This system is currently being used to predict and analyze the performance advantages available through the migration of function between levels of software and between software and firmware within the BUGS.