NASA Scientific and Technical Aerospace Reports

20040121062 California Univ., Santa Cruz, CA, USA
OBFS: A File System for Object-Based Storage System Devices
Wang, Feng; Brandt, Scott A.; Miller, Ethan L.; Long, Darrell D. E.; NASA/IEEE MSST 2004 Twelfth NASA Goddard
Conference on Mass Storage Systems and Technologies in cooperation with the Twenty-First IEEE Conference on Mass
Storage Systems and Technologies; April 2004, pp. 283-300; In English; See also 20040121020
Contract(s)/Grant(s): B520714; No Copyright; Avail: CASI; A03, Hardcopy
The object-based storage model, in which files are made up of one or more data objects stored on self-contained
Object-Based Storage Devices (OSDs), is emerging as an architecture for distributed storage systems. The workload presented
to the OSDs will be quite different from that of general purpose file systems, yet many distributed file systems employ
general-purpose file systems as their underlying file system. We present OBFS, a small and highly efficient file system
designed for use in OSDs. Our experiments show that our user-level implementation of OBFS outperforms Linux Ext2 and
Ext3 by a factor of two or three, and while OBFS is 1/25 the size of XFS, it provides only slightly lower read performance
and 10%-40% higher write performance.
Author
Memory (Computers); Architecture (Computers); Object-Oriented Programming
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COMPUTER PROGRAMMING AND SOFTWARE
Includes software engineering, computer programs, routines, algorithms, and specific applications, e.g., CAD/CAM. For computer
software applied to specific applications, see also the associated category.
20040111037 NASA Marshall Space Flight Center, Huntsville, AL, USA
The Electric Propulsion Interactions Code (EPIC)
Mikellides, I. G.; Mandell, M. J.; Kuharski, R. A.; Davis, V. A.; Gardner, B. M.; Minor, J.; 8th Spacecraft Charging Technology
Conference; March 2004; 19 pp.; In English; See also 20040111031
Contract(s)/Grant(s): NAS8-02028; No Copyright; Avail: CASI; A03, Hardcopy
Science Applications International Corporation is currently developing the Electric Propulsion Interactions Code, EPIC,
as part of a project sponsored by the Space Environments and Effects Program at the NASA Marshall Space Flight Center.
Now in its second year of development, EPIC is an interactive computer tool that allows the construction of a 3-D spacecraft
model, and the assessment of a variety of interactions between its subsystems and the plume from an electric thruster. These
interactions may include erosion of surfaces due to sputtering and re-deposition of sputtered materials, surface heating, torque
on the spacecraft, and changes in surface properties due to erosion and deposition. This paper describes the overall capability
of EPIC and provides an outline of the physics and algorithms that comprise many of its computational modules.
Author
Aerospace Environments; Algorithms; Electric Propulsion; Spacecraft Models; Three Dimensional Models
20040111054 Air Force Research Lab., Hanscom AFB, MA, USA
AF-Geospace 2.0
Hilmer, R. V.; Ginet, G. P.; Hall, T.; Holeman, E.; Tautz, M.; 8th Spacecraft Charging Technology Conference; March 2004;
14 pp.; In English; See also 20040111031
Contract(s)/Grant(s): F19628-00-C-0073; F19628-98-C-0054; No Copyright; Avail: CASI; A03, Hardcopy
The capabilities of the newest AF-GEOSpace space environment software program are reviewed. Released in 2002,
AF-GEOSpace Version 2.0 is a graphics-intensive software program with space environment models and applications
developed and distributed by the Space Weather Center of Excellence at the Air Force Research Laboratory (AFRL). A wide
range of physical domains is addressed including solar disturbance propagation, radiation belt configuration, and ionospheric
auroral particle precipitation and scintillation. The software is currently being used to aid with the design, operation, and
simulation of a wide variety of communications, navigation, and surveillance systems. Building on the success of previous
releases, AF-GEOSpace has become a platform for the rapid prototyping of automated operational and simulation space
weather visualization products and helps with a variety of tasks, including: orbit specification for radiation hazard avoidance;
satellite design assessment and post-event anomaly analysis; solar disturbance effects forecasting; frequency and antenna
management for radar and HF communications; determination of link outage regions for active ionospheric conditions;
scientific model validation and comparison, physics research, and education. Version 2.0 provides a simplified graphical user
interface, improved science and application modules, and significantly enhanced graphical performance. Common input data
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