Version Of Operating System Research Articles

GENESIS: an efficient, transparent and easy to use cluster operating system

Present operating systems are not built to support parallel computing––they do not provide services to manage parallelism, i.e., to globally manage parallel processes and computational resources. The cluster operating environments that are used to assist the execution of parallel applications do not provide support for both programming paradigms, message passing (MP) or distributed shared memory (DSM)––they are mainly offered as separate components implemented at the user level as library and independent server processes. Due to poor operating systems users must deal with clusters as a set of independent computers rather than to see this cluster as a single powerful computer. A single system image (SSI) of the cluster is not offered to users. There is a need for an operating system for clusters. We claim and demonstrate in this paper that it is possible to develop a cluster operating system that is able to efficiently manage parallelism; use cluster resources efficiently; support MP in the form of standard MP and PVM, and DSM; offer SSI; and make it easy to use. We show that to achieve these aims this operating system should inherit many features of a distributed operating system and provide new services which address the needs of parallel processes, cluster's resources, and application developers. In order to substantiate the claim the first version of a cluster operating system managing parallelism and offering SSI, called GENESIS, has been developed.

Implementing a dynamic processor allocation policy for multiprogrammed parallel applications in the SolarisTM

AbstractParallel applications typically do not perform well in a multiprogrammed environment that uses time‐sharing to allocate processor resources to the applications' parallel threads. Co‐scheduling related parallel threads, or statically partitioning the system, often can reduce the applications' execution times, but at the expense of reducing the overall system utilization. To address this problem, there has been increasing interest in dynamically allocating processors to applications based on their resource demands and the dynamically varying system load. The Loop‐Level Process Control (LLPC) policy (Yue K, Lilja D. Efficient execution of parallel applications in multiprogrammed multiprocessor systems. 10th International Parallel Processing Symposium, 1996; 448–456) dynamically adjusts the number of threads an application is allowed to execute based on the application's available parallelism and the overall system load. This study demonstrates the feasibility of incorporating the LLPC strategy into an existing commercial operating system and parallelizing compiler and provides further evidence of the performance improvement that is possible using this dynamic allocation strategy. In this implementation, applications are automatically parallelized and enhanced with the appropriate LLPC hooks so that each application interacts with the modified version of the Solaris operating system. The parallelism of the applications are then dynamically adjusted automatically when they are executed in a multiprogrammed environment so that all applications obtain a fair share of the total processing resources. Copyright © 2001 John Wiley & Sons, Ltd.

A Cluster Operating System Supporting Parallel Computing

The single factor limiting the harnessing of the enormous computing power of clusters for parallel computing is the lack of appropriate software. Present cluster operating systems are not built to support parallel computing – they do not provide services to manage parallelism. The cluster operating environments that are used to assist the execution of parallel applications do not provide support for both Message Passing (MP) or Distributed Shared Memory (DSM) paradigms. They are only offered as separate components implemented at the user level as library and independent servers. Due to poor operating systems users must deal with computers of a cluster rather than to see this cluster as a single powerful computer. A Single System Image of the cluster is not offered to users. There is a need for an operating system for clusters. We claim and demonstrate that it is possible to develop a cluster operating system that is able to efficiently manage parallelism, support Message Passing and DSM and offer the Single System Image. In order to substantiate the claim the first version of a cluster operating system, called GENESIS, that manages parallelism and offers the Single System Image has been developed.

Towards an operating system managing parallelism of computing on clusters

Parallelism management is a difficult task, in particular in parallel systems based on clusters (of PCs or workstations). We claim in this paper that parallelism management should be provided by an operating system that inherits many features of a distributed operating system and provides new services that address the needs of parallel processes, cluster’s resources, and application programmers. This system, in order to allow parallel programs to achieve high performance, transparency and ease of use, should provide services such as establishment of a virtual machine; mapping processes to computers; concurrent process creation and process duplication supported by process migration; computation co-ordination; group communication; and distributed shared memory. In order to substantiate the claim the first version of a cluster operating system managing parallelism, called GENESIS, has been developed and presented in this paper. The results of the execution of some parallel applications, that further substantiate our claim, are shown.

Performance evaluation of two operating systems

This report compares the performance of two radically different versions of MacOS™ operating system. In particular, we are interested in the study that focuses primarily on the emulation code related aspect of the performance of two version of the aforementioned operating system. ALPS (Application Level Performance Measurement Suite) benchmarks [1] were used as test cases due to the fact that they contains scenarios which stresses the operating system (OS) related activities.

Enhancing Web applications in radiology with Java: estimating MR imaging relaxation times.

Java is a relatively new programming language that has been used to develop a World Wide Web-based tool for estimating magnetic resonance (MR) imaging relaxation times, thereby demonstrating how Java may be used for Web-based radiology applications beyond improving the user interface of teaching files. A standard processing algorithm coded with Java is downloaded along with the hypertext markup language (HTML) document. The user (client) selects the desired pulse sequence and inputs data obtained from a region of interest on the MR images. The algorithm is used to modify selected MR imaging parameters in an equation that models the phenomenon being evaluated. MR imaging relaxation times are estimated, and confidence intervals and a P value expressing the accuracy of the final results are calculated. Design features such as simplicity, object-oriented programming, and security restrictions allow Java to expand the capabilities of HTML by offering a more versatile user interface that includes dynamic annotations and graphics. Java also allows the client to perform more sophisticated information processing and computation than is usually associated with Web applications. Java is likely to become a standard programming option, and the development of stand-alone Java applications may become more common as Java is integrated into future versions of computer operating systems.

Computer-aided identifications of thin-layer chromatographic patterns in broad-spectrum drug screening

We have developed a systematic thin-layer chromatographic (TLC) technique for detecting and identifying drugs and drug metabolites on 10-cm-long silica-gel plates with organic binder (fluorescent indicator); a computer program (SPOT CHEK) assists in matching the data from a particular chromatogram with those obtained for known drugs recovered from serum, urine, or other specimens. The plates are developed in a single mobile phase. Visualization and detection reagents used to characterize unknowns include fluorescamine, ferric chloride/perchloric acid/nitric acid, Dragendorff, Marquis, Mandelin, and iodinated Dragendorff solutions, 254 nm ultraviolet light, and vapor from chlorine or hydrochloric acid. Detection limits of 5-200 ng per sample spot were obtained for drugs in the database. The computer program database is based on nine reaction responses plus the plate zone locations for 243 drug substances but requires entry of only one TLC property to generate a matching list. We ran the program with an IBM-compatible 386/486 PC using an MS-DOS operating system (version 6.2).

Faster, better, cheaper-NASA visualizes the solar system

Pathfinder is the first of many planned Program missions by NASA. The Discovery program is based on the concept of using industry spacecraft comprised of near commodity components built from generic parts that cost orders of magnitude less than the custom built equipment of earlier phases of space exploration. Daniel Goldin, administrator of NASA, has given his agency a mandate to explore the solar system faster, better, and cheaper than in the past. How do you build an industry spacecraft? First, use as much COTS (commercial off the shelf) hardware and software as possible. That eliminates the need for NASA to build every part and write all the software. Instead of building a custom computer, at a cost of millions, now NASA finds a commercial system (on Pathfinder, an IBM RS6000) and modifies it as needed. And the computer will probably run some version of a commercial operating system, saving thousands or millions more dollars in development costs. Other COTS components include the Motorola modem used to communicate between the rover and lander, and the real time operating system used in the lander. Second, make everything as small and light as possible. Launch costs-the cost of a rocket and fuel-still account for 30 to 40 percent of the total cost of a mission. Every gram of weight shaved off a payload reduces the cost of launch or adds to the number of scientific instruments that can go on board. Image processing equipment and methods used in Pathfinder are discussed.

Network firewalls

Computer security is a hard problem. Security on networked computers is much harder. Firewalls (barriers between two networks), when used properly, can provide a significant increase in computer security. The authors classify firewalls into three main categories: packet filtering, circuit gateways, and application gateways. Commonly, more than one of these is used at the same time. Their examples and discussion relate to UNIX systems and programs. The majority of multiuser machines on the Internet run some version of the UNIX operating system. Most application-level gateways are implemented in UNIX. This is not to say that other operating systems are more secure; however, there are fewer of them on the Internet, and they are less popular as targets for that reason. But the principles and philosophy apply to network gateways built on other operating systems as well. Their focus is on the TCP/IP protocol suite, especially as used on the Internet. >

Book Reviews : MacWeek Guide to System 7 Don CrabbPublisher: Ziff-Davis Press, 5903 Christie Ave., Emeryville, cA 94608 Year of Publication: 1992 Length: 296 pages Price: $24.95

MacWeek columnist Don Crabb provides a manager's view of the impact of Apple's new version of the Macintosh operating system. His comments on the strengths and weaknesses of Apple's and other vendors' hardware and software are especially insightful. This book would be a valuable resource for anyone who is concerned with the care and feeding of a group of Macintosh systems.

An evaluation of HP-UX (UNIX) for database protection using the European ITSEC

This paper describes an evaluation of the effectiveness of two versions of Hewlett Packard's UNIX operating system, HP-UX, to protect a sensitive database set up under the ORACLE Data Base Management System, using Version 1.0 of the European Information Technology Security Evaluation Criteria (ITSEC) as the basis for the evaluation. An outline of these criteria is given, along with mention of the US Trusted Computer System Evaluation Criteria (TCSEC) for comparison purposes. The research project reported in this paper was aimed at determining the level of effort required to perform such an evaluation and also the relevance of the ITSEC to commercial environments where information systems security, incorporating authenticity, integrity and privacy, are of paramount concern. Two successive releases of the HP-UX operating system were found to be markedly different when evaluated from the ITSEC point of view, with the latter version being quite effective in maintaining security parameters. It was also concluded that evaluations are time consuming but can have positive implications for commercial systems developers.

A distributed real-time operating system

Two versions of the HARTS operating system, which is based on Software Components Group's pSOS uniprocessor kernel, are presented. In one version, pSOS services are enhanced to provide interprocessor communication and a distributed naming service. In the second version, real-time fault-tolerant communication, including reliable broadcasting, clock synchronization, and group communication are added to the HARTS operating system. Three tools to evaluate the performance and fault tolerance dependability of HARTS hardware and software-a synthetic-workload generator, a monitor, and a fault injector-are described. The generator produces a synthetic workload, the monitor collects the performance data, and the fault injector simulates faulty behavior for further study. Together these tools create a facility that lets the user perform a wide range of experiments. The tools are independent, so they are equally effective separately or together, depending on the requirements.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Human HPRT mutant database: software for data entry and retrieval.

We have developed a computer database containing information on over 1,000 human hypoxanthine guanine phosphoribosyl transferase (HPRT) mutants. Both published and unpublished data are present. The database itself is maintained in a dBASE format (.DBF) and we provide a set of programs to examine and extract information from the database. A program to input information into the database is also supplied. The database and programs are available directly from us or via remote FTP (file transfer protocol) using BITNET/INTERNET. All programs require an IBM-compatible computer, the MS-DOS operating system (version 3.3 or greater), and a hard disk with about 5 megabytes of free disk space. The purpose of the database is 1) to allow investigators to contribute their HPRT mutants directly to the database in a standardized fashion, and 2) to allow access to the entire database with a set of programs that allows manipulation and extraction of data. For example, using our programs it is possible to i) order the database by base pair position, ii) examine only information regarding mutagenesis by a particular agent, iii) search for a particular author, iv) create a report which contains selected portions of the database, the report can be printed or saved as a file. The database will be updated every several months and distributed.

The Economics of UNIX

The emergence of a commercially feasible version of the UNIX operating system portends considerable change for the economics of both production and consumption in the MIS industry. UNIX has been around for 20 years and has drawn periodic attention from the MIS community, but the significance of this innovative operating system is just beginning to be felt among MIS professionals. Although it is tempting to dismiss UNIX as just another fad in information technology, the technical, economic, and social forces behind the UNIX innovation indicate that its effects will be far-reaching. This column discusses the origins and characteristics of UNIX, explores some important differences between UNIX and conventional operating systems, and presents the likely economic implications of the UNIX phenomenon for MIS management.

On distributed fault simulation

The authors examine the computational aspects of fault simulation of digital circuits and address issues related to the efficient partitioning of a fault simulation task to a number of subtasks assignable for execution to the nodes of a distributed system. They review the basic concepts involved in the operation of fault simulation. They describe the implementation of a distributed fault simulation facility, called DFSim, using a heterogeneous local area network consisting of a number of workstations with different computing resources and different versions of Unix operating systems. >

Low-synchronization translation lookaside buffer consistency in large-scale shared-memory multiprocessors

Operating systems for most current shared-memory multiprocessors must maintain translation lookaside buffer (TLB) consistency across processors. A processor that changes a shared page table must flush outdated mapping information from its own TLB, and it must force the other processors using the page table to do so as well. Published algorithms for maintaining TLB consistency on some popular commercial multiprocessors incur excessively high synchronization costs. We present an efficient TLB consistency algorithm that can be implemented on multiprocessors that include a small set of reasonable architectural features. This algorithm has been incorporated in a version of the MACH operating system developed for the IBM Research Parallel Processor Prototype (RP3).

Technology '89: software

Software developments during 1988 are examined. Among them are: competition among various versions of Unix; the Mach operating system, in both Unix and non-Unix versions; efforts to standardize parallel Fortran; and supercompilers.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

DOS‐tips

The tips in this issue's column are directed to users of the WYSEpc 286 Model 2112, manufactured by Wyse Technology of San Jose, CA, a.k.a. the OCLC M310 Workstation. The M310 Workstation comes with an “enhanced” version of the MS DOS operating system. This version of DOS contains some interesting new commands that correspond to special features of the M310 hardware. Let's take a look.

MULTILIS: A Description of the System Design and Operational Features

MultiLIS is an integrated library software product that can be purchased on a modular basis or as a turnkey system encompassing both hardware and software. Acquisitions, cataloging, online public access, circulation, book exchange, local policy management, management and statistical report modules, and a report generator are currently available. An enhanced serials management module will be released in 1989. The software is written in PASCAL and C languages, and is available in either VMS or EUNIX V operating system versions. The VMS version is designed to run on Digital VAX computers, while UNIX V will run on a wider range of machines, including NCR Tower machines. MultiLIS features a strong network option, as well as a low cost annual software support agreement, providing users with telephone support services and all software updates.

DPUP: a distributed processing utilities package

DPUP is a library of utilities that support distributed concurrent computing on a local area network of computers. The library is built upon the interprocess communication facilities in Berkeley Unix 4.2bsd. Thus it will run on any network, connected by an Ethernet, where each computer runs a version of the Unix operating system that supports the Berkeley Unix interprocess communication facilities. DPUP supports two models of distributed concurrent computation, a master-slave model based upon stream sockets, and a broadcast model based upon datagram sockets. With each model, facilities for creating and terminating remote processes, establishing communications between them, and sending and receiving data between these processes are provided. This paper describes the facilities provided in DPUP and gives examples of their use.