Changes between Version 23 and Version 24 of Installation_and_Configuration


Ignore:
Timestamp:
11/16/11 15:43:04 (9 years ago)
Author:
branden
Comment:

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  • Installation_and_Configuration

    v23 v24  
    1717Earthworm currently offers the following general features: 
    1818 
    19 === Analog data acquisition === 
     19=== Analog Data Acquisition === 
    2020(e.g., [wiki:adsend adsend]) 
    2121 
    222212 or 16 bit A/D conversion, up to 256 channels per Windows 2000 machine, any number of such machines per system. 
    2323 
    24 === Digital acquisition === 
     24=== Digital Acquisition === 
    2525(e.g., [wiki:slink2ew slink2ew]) 
    2626 
     
    6262All acquired trace data can be made available via an IP server for a configurable time period, ranging from hours to weeks. 
    6363 
    64 === Distributed systems === 
     64=== Distributed Systems === 
    6565(XXX) 
    6666 
    6767Any number of Earthworm systems can be linked via IP communication links. The extend of such linkages is configurable. Possible configurations include a 'master' central site and any number of remote nodes operating as one integrated system, as well as limited, negotiated linkages between two sovereign central systems. 
    6868 
    69 === Multi-machine configurations === 
     69=== Multi-Machine Configurations === 
    7070(XXX) 
    7171 
     
    7777Any type of internal data can be exchanged in real time with other Earthworm systems. This exchange mechanism has proved to be quite reliable, and has performed well in numerous applications. It requires a communications link capable of physically interfacing to a computer's ethernet port and capable of carrying IP messages. It functions over the public internet as well as private dedicated links. 
    7878 
    79 === Long period Events === 
     79=== Long-Period Events === 
    8080(XXX) 
    8181 
     
    8888Earthworm has been developed under the mandate of speed and reliability. It therefore tends to use fast, low-level operating system services rather than high-level end-user packages. A positive side effect of this is that Earthworm is fairly economical in terms of hardware requirements. In general, a contemporary Pentium- or Ultra- class machine is adequate for most regional network loads. Specifically, the hardware requirements can be divided into four categories: 
    8989 
    90 === Data acquisition === 
     90=== Data Acquisition === 
    9191This can be via the ethernet network port, system bus, or serial ports. In practice, we have not observed problems in the first two cases. We have observed problems with serial port acquisition, especially when running on the same machine as the bus-based A/D acquisition. The symptoms are intermittent data loss from the serial ports, and warning messages from the A/D subsystem. 
    9292 
    93 === Numeric processing === 
     93=== Numeric Processing === 
    9494This is not generally a problem when the current, common processing features are enabled. A contemporary machine (PentiumII or Sparc Ultra) has been demonstrated to be capable of supporting the numeric and I/O requirements of processing a large events on over 500 channels in rear-real time. However, modules are currently being worked on which may require considerable numeric resources. 
    9595 
     
    9999Network bandwidth requirements are critical on the input side, as the trace input streams are real-time. The server-side responses, or course, are not. In situations where this is a concern, a second, dedicated ethernet subnet is usually established to carry real-time trace data, and the participating machines are equipped with two (or more) network adapters. 
    100100 
    101 === Event storage and processing === 
     101=== Event Storage and Processing === 
    102102As mentioned above, Earthworm can produce directories of event files from various triggers in various formats. Adequate disk space has to be provided to hold such events until they are moved to off-line media. Considerations there include the expected worst-case seismicity levels, time of storage, and off-line media capacity and life-time. 
    103103