The Space Science and Engineering Center (SSEC) of the University of Wisconsin has developed the Man-computer Interactive Data Access System (McIDAS) over the past two decades. McIDAS consists of over 1.5 million lines of code contained in nearly two thousand modules. The current version of the system views the mainframe, which acquires the satellite data, as being a database builder and manager. Remote users can download data from the mainframe, disconnect communications, and operate independently until additional data are needed. The data are compressed before transmission.
The SSEC is the national archive for GOES data in digital form. The archive contains a global collection for 1978 and all U.S. data since then.
The present mainframe supports a multitude of tasks, including ingesting real-time imagery from GOES, METEOSAT, and NOAA POES HRPT; Kavouras and Weather Services Inc. radar; ingesting GOES data from the archive to satisfy user requests; ingesting and decoding conventional data from the FAA 604, NWS IDS, PPS, and DDS circuits; ingesting NMC model grids; and providing interactive support for connected terminals.
McIDAS operates using IBM's MVS operating system, SP, XA or ESA. McIDAS is currently installed on IBM 43XX and 3090 systems as well as a few IBM mainframe clones.
McIDAS currently supports workstations which use an IBM PS/2 as the user interface. Cost varies based on the type of display chosen. All the workstations operate under the OS/2 operating system. Workstations can be a part of the mainframe's Local Area Network if within the mainframe's site or can communicate remotely. The remote workstations currently communicate with the mainframe via the Trailblazer Plus modem at a maximum rate of 9,600 bps. Transmission Control Protocol/Internet Protocol (TCP/IP) communications, which should improve throughput by a factor of 2 to 10, should be available within the next few months. The SSEC is also developing a workstation based on the IBM RISC 6000 running the UNIX (AIX) operating system.
The McIDAS OS/2 system incorporates most of the software capability of the mainframe, as will McIDAS AIX when available.
The Bureau of Meteorology (BOM) in Melbourne, Australia, has established a system for use in Antarctica. HRPT data are captured using a PS/2 Model 80. The same PS/2 converts the data to McIDAS format and then transfers it to another PS/2 Model 80 via TCP/IP. The second PS/2 runs McIDAS processing and visualization software. The BOM staff has developed software to convert the direct broadcast HRPT data to McIDAS format.
The SSEC people intend to bring the IBM RISC 6000 workstation up to full mainframe capability (i.e., able to capture direct readout satellite data) but envision this will take another 2-3 years.
There is no charge for the McIDAS software for federal government agencies. However, users are expected to join the McIDAS User's Group (MUG), and there is a fee for access to a McIDAS mainframe. Both fees are annual. The mainframe fee is based on actual usage. Remote terminal users must arrange access to McIDAS mainframes themselves.
The SSEC recommends a training period of 3-5 days for a meteorologist to become familiar with the system. Training is provided at the SSEC; they recommend two people in a training session and will not accept more than three.
Lists of the current mainframes running McIDAS, the remote workstations which are running McIDAS software while being connected to the SSEC, and the remote workstations which are connected to other McIDAS mainframes are included in Appendix A to this report.