16,506 research outputs found
Energy-Efficient Streaming Using Non-volatile Memory
The disk and the DRAM in a typical mobile system consume a significant fraction (up to 30%) of the total system energy. To save on storage energy, the DRAM should be small and the disk should be spun down for long periods of time. We show that this can be achieved for predominantly streaming workloads by connecting the disk to the DRAM via a large non-volatile memory (NVM). We refer to this as the NVM-based architecture (NVMBA); the conventional architecture with only a DRAM and a disk is referred to as DRAMBA. The NVM in the NVMBA acts as a traffic reshaper from the disk to the DRAM. The total system costs are balanced, since the cost increase due to adding the NVM is compensated by the decrease in DRAM cost. We analyze the energy saving of NVMBA, with NAND flash memory serving as NVM, relative to DRAMBA with respect to (1) the streaming demand, (2) the disk form factor, (3) the best-effort provision, and (4) the stream location on the disk. We present a worst-case analysis of the reliability of the disk drive and the flash memory, and show that a small flash capacity is sufficient to operate the system over a year at negligible cost. Disk lifetime is superior to flash, so that is of no concern
Rewriteable optical disk recorder development
A NASA program to develop a high performance (high rate, high capability) rewriteable optical disk recorder for spaceflight applications is presented. An expandable, adaptable system concept is proposed based on disk Drive modules and a modular Controller. Drive performance goals are 10 gigabyte capacity are up to 1.8 gigabits per second rate with concurrent I/O, synchronous data transfer, and 2 to 5 years operating life in orbit. Technology developments, design concepts, current status, and future plans are presented
EChO Payload electronics architecture and SW design
EChO is a three-modules (VNIR, SWIR, MWIR), highly integrated spectrometer,
covering the wavelength range from 0.55 m, to 11.0 m. The baseline
design includes the goal wavelength extension to 0.4 m while an optional
LWIR module extends the range to the goal wavelength of 16.0 m.
An Instrument Control Unit (ICU) is foreseen as the main electronic subsystem
interfacing the spacecraft and collecting data from all the payload
spectrometers modules. ICU is in charge of two main tasks: the overall payload
control (Instrument Control Function) and the housekeepings and scientific data
digital processing (Data Processing Function), including the lossless
compression prior to store the science data to the Solid State Mass Memory of
the Spacecraft. These two main tasks are accomplished thanks to the Payload On
Board Software (P-OBSW) running on the ICU CPUs.Comment: Experimental Astronomy - EChO Special Issue 201
Preliminary Candidate Advanced Avionics System (PCAAS)
Specifications which define the system functional requirements, the subsystem and interface needs, and other requirements such as maintainability, modularity, and reliability are summarized. A design definition of all required avionics functions and a system risk analysis are presented
iDataCool: HPC with Hot-Water Cooling and Energy Reuse
iDataCool is an HPC architecture jointly developed by the University of
Regensburg and the IBM Research and Development Lab B\"oblingen. It is based on
IBM's iDataPlex platform, whose air-cooling solution was replaced by a custom
water-cooling solution that allows for cooling water temperatures of 70C/158F.
The system is coupled to an adsorption chiller by InvenSor that operates
efficiently at these temperatures. Thus a significant portion of the energy
spent on HPC can be recovered in the form of chilled water, which can then be
used to cool other parts of the computing center. We describe the architecture
of iDataCool and present benchmarks of the cooling performance and the energy
(reuse) efficiency.Comment: 12 pages, 7 figures, proceedings of ISC 201
Data communication network at the ASRM facility
The main objective of the report is to present the overall communication network structure for the Advanced Solid Rocket Motor (ASRM) facility being built at Yellow Creek near Iuka, Mississippi. This report is compiled using information received from NASA/MSFC, LMSC, AAD, and RUST Inc. As per the information gathered, the overall network structure will have one logical FDDI ring acting as a backbone for the whole complex. The buildings will be grouped into two categories viz. manufacturing critical and manufacturing non-critical. The manufacturing critical buildings will be connected via FDDI to the Operational Information System (OIS) in the main computing center in B 1000. The manufacturing non-critical buildings will be connected by 10BASE-FL to the Business Information System (BIS) in the main computing center. The workcells will be connected to the Area Supervisory Computers (ASCs) through the nearest manufacturing critical hub and one of the OIS hubs. The network structure described in this report will be the basis for simulations to be carried out next year. The Comdisco's Block Oriented Network Simulator (BONeS) will be used for the network simulation. The main aim of the simulations will be to evaluate the loading of the OIS, the BIS, the ASCs, and the network links by the traffic generated by the workstations and workcells throughout the site
Comparing SSD Forensics with HDD Forensics
The technological industry is growing at an unprecedented rate; to adequately evaluate this shift in the fast-paced industry, one would first need to deliberate on the differences between the Hard Disk Drive (HDD) and Solid-State Drive (SSD). HDD is a hard disk drive that was conventionally used to store data, whereas SSD is a more modern and compact substitute; SSDs comprises of flash memory technology, which is the modern-day method of storing data. Though the inception of data storage began with HDD, they proved to be less accessible and stored less data as compared to the present-day SSDs, which can easily store up to 1 Terabyte in a minuscule chip-size frame. Hence, SSDs are more convenient and user-friendly, where, in contrast, HDDs often require some degree of technical knowledge. However, since SSDs are still a relatively new phenomenon, it has proved to create myriads of problems in the digital forensics department. Since, SSDs are still a more modern concept, the tools that digital forensics employ to investigate evidence obtained from HDDs are not proving to be as efficient; this is primarily due to the fact that data in flash memory drives can only be written if the data unit or data block is erased, ergo, an erase operation occurs every time before something is written into the flash memory. Therefore, the aim of this research is to critically analyze the results obtained by running forensic tools on an HDD and SSD; the results would pertain to the image generated from the HDD and SSD
GRAPE-6: The massively-parallel special-purpose computer for astrophysical particle simulation
In this paper, we describe the architecture and performance of the GRAPE-6
system, a massively-parallel special-purpose computer for astrophysical
-body simulations. GRAPE-6 is the successor of GRAPE-4, which was completed
in 1995 and achieved the theoretical peak speed of 1.08 Tflops. As was the case
with GRAPE-4, the primary application of GRAPE-6 is simulation of collisional
systems, though it can be used for collisionless systems. The main differences
between GRAPE-4 and GRAPE-6 are (a) The processor chip of GRAPE-6 integrates 6
force-calculation pipelines, compared to one pipeline of GRAPE-4 (which needed
3 clock cycles to calculate one interaction), (b) the clock speed is increased
from 32 to 90 MHz, and (c) the total number of processor chips is increased
from 1728 to 2048. These improvements resulted in the peak speed of 64 Tflops.
We also discuss the design of the successor of GRAPE-6.Comment: Accepted for publication in PASJ, scheduled to appear in Vol. 55, No.
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