A method for the recovery of data after a computer system failure: the development of Constant Random Access Memory (CRAM) Recovery System

An experimental design study was done to investigate three research questions: (1) Can a software system be developed that will provide recovery from a system failure? (2) What problems exist in achieving a software-only recovery system? (3) What is the degradation in application program performance when utilizing a software recovery system?;A software was developed for recovering data that was in memory before a catastrophic failure. It allows for memory retrieval after unfortunate incidents such as keyboard lock-up, software failures, and power outages. The software, named CRAM, (Constant Random Access Memory) operates by using Undocumented DOS functions, memory management tools, disk management, context switching and the timely backup of the system to the hard disk. The main task of CRAM is to operate in the background of the computer, transferring the computer system\u27s memory to disk at specified intervals of time, with limited interruption of the foreground process;Most of the coding was done in the high-level language C . Some codes were done in assembly language to access low level interface to DOS that were either not available in C or provided better data access speed. The most interesting and challenging part of the project was context switching during restoration of the system\u27s memory. Restoration was accomplished through the ingenious use of the information stored in each program\u27s PSP and data in the DOS swappable Data Area. Saving and restoring of data was accomplished by utilizing DOS hardware and software interrupts and replacing some of these routines with new code that do some operations that are specific to CRAM while also allowing other programs to have access to the original routines. The major interrupts used by CRAM are the keyboard interrupt (9h), the clock interrupt (1Ch), and the DOS idle interrupt (28h);The software was tested and analyzed for conflict by executing nine commercial programs. It was noted that about 75% of the time the system was restored and 33% were full restoration. Another analysis was done for the speed degradation. A degradation of 3.3% for the sieve numerical calculation, 1.3% for the random number generation, 5.2% for the disk I/O write operation, and 10.6% for the video display operation was observed. Less than 1% change was noted for most of the other operation except for times when CRAM\u27s presence may delay the clock interrupt by 0.05 seconds

Sixth Annual Users' Conference

Conference papers and presentation outlines which address the use of the Transportable Applications Executive (TAE) and its various applications programs are compiled. Emphasis is given to the design of the user interface and image processing workstation in general. Alternate ports of TAE and TAE subsystems are also covered

Програмне забезпечення: практикум з англійської мови для студентів фізико-математичного факультету спеціальностей: «Інформатика», «Математика та інформатика», «Фізика та інформатика»

Практикум складається з 8 розділів, текстів для самостійного опрацювання, додаткового читання та додатків. Тексти підібрані з оригінальної науково-технічної літератури та містять необхідну термінологію зі спеціальності. До складу розділів входять вправи на закріплення лексико-граматичного матеріалу, тести, запитання. Вправи та тести побудовано на мовному матеріалі, який використовується в текстах розділів. Додається підсумковий тест для перевірки знань всього курсу. Для студентів неспеціальних факультетів денної, заочної та дистанційної форми навчання, які вивчають інформатику. Пізнавальний характер текстів зацікавить не лише зазначене коло студентів, але й усіх тих, хто поглиблено вивчає англійську мову

Mission and data operations IBM 360 user's guide

The M and DO computer systems are introduced and supplemented. The hardware and software status is discussed, along with standard processors and user libraries. Data management techniques are presented, as well as machine independence, debugging facilities, and overlay considerations

SEAPAK user's guide, version 2.0. Volume 1: System description

The SEAPAK is a user interactive satellite data analysis package that was developed for the processing and interpretation of Nimbus-7/Coastal Zone Color Scanner (CZCS) and the NOAA Advanced Very High Resolution Radiometer (AVHRR) data. Significant revisions were made to version 1.0 of the guide, and the ancillary environmental data analysis module was expanded. The package continues to emphasize user friendliness and user interactive data analyses. Additionally, because the scientific goals of the ocean color research being conducted have shifted to large space and time scales, batch processing capabilities for both satellite and ancillary environmental data analyses were enhanced, thus allowing large quantities of data to be ingested and analyzed in background

PC-SEAPAK user's guide, version 4.0

PC-SEAPAK is designed to provide a complete and affordable capability for processing and analysis of NOAA Advanced Very High Resolution Radiometer (AVHRR) and Nimbus-7 Coastal Zone Color Scanner (CZCS) data. Since the release of version 3.0 over a year ago, significant revisions were made to the AVHRR and CZCS programs and to the statistical data analysis module, and a number of new programs were added. This new version has 114 procedures listed in its menus. The package continues to emphasize user-friendliness and interactive data analysis. Additionally, because the scientific goals of the ocean color research being conducted have shifted to larger space and time scales, batch processing capabilities were enhanced, allowing large quantities of data to be easily ingested and analyzed. The development of PC-SEAPAK was paralled by two other activities that were influential and assistive: the global CZCS processing effort at GSFC and the continued development of VAX-SEAPAK. SEAPAK incorporates the instrument calibration and support all levels of data available from the CZCS archive

Database machines in support of very large databases

Software database management systems were developed in response to the needs of early data processing applications. Database machine research developed as a result of certain performance deficiencies of these software systems. This thesis discusses the history of database machines designed to improve the performance of database processing and focuses primarily on the Teradata DBC/1012, the only successfully marketed database machine that supports very large databases today. Also reviewed is the response of IBM to the performance needs of its database customers; this response has been in terms of improvements in both software and hardware support for database processing. In conclusion, an analysis is made of the future of database machines, in particular the DBC/1012, in light of recent IBM enhancements and its immense customer base

Guardian: Hypervisor as Security Foothold for Personal Computers

Abstract. Personal computers lack of a security foothold to allow the end-users to protect their systems or to mitigate the damage. Existing candidates either rely on a large Trusted Computing Base (TCB) or are too costly to widely deploy for commodity use. To fill this gap, we propose a hypervisor-based security foothold, named as Guardian, for commodity personal computers. We innovate a bootup and shutdown mechanism to achieve both integrity and availability of Guardian. We also propose two security utilities based on Guardian. One is a device mon-itor which detects malicious manipulation on camera and network adaptors. The other is hyper-firewall whereby Guardian expects incoming and outgoing network packets based on policies specified by the user. We have implemented Guardian ( ≈ 25K SLOC) and the two utilities ( ≈ 2.1K SLOC) on a PC with an Intel pro-cessor. Our experiments show that Guardian is practical and incurs insignificant overhead to the system.

Development of Software to Model AXAF-I Image Quality

This draft final report describes the work performed under the delivery order number 145 from May 1995 through August 1996. The scope of work included a number of software development tasks for the performance modeling of AXAF-I. A number of new capabilities and functions have been added to the GT software, which is the command mode version of the GRAZTRACE software, originally developed by MSFC. A structural data interface has been developed for the EAL (old SPAR) finite element analysis FEA program, which is being used by MSFC Structural Analysis group for the analysis of AXAF-I. This interface utility can read the structural deformation file from the EAL and other finite element analysis programs such as NASTRAN and COSMOS/M, and convert the data to a suitable format that can be used for the deformation ray-tracing to predict the image quality for a distorted mirror. There is a provision in this utility to expand the data from finite element models assuming 180 degrees symmetry. This utility has been used to predict image characteristics for the AXAF-I HRMA, when subjected to gravity effects in the horizontal x-ray ground test configuration. The development of the metrology data processing interface software has also been completed. It can read the HDOS FITS format surface map files, manipulate and filter the metrology data, and produce a deformation file, which can be used by GT for ray tracing for the mirror surface figure errors. This utility has been used to determine the optimum alignment (axial spacing and clocking) for the four pairs of AXAF-I mirrors. Based on this optimized alignment, the geometric images and effective focal lengths for the as built mirrors were predicted to cross check the results obtained by Kodak