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Breaking Up the Data Data will be recorded on high-density tapes at the Arecibo telescope in Puerto Rico, filling about one 35 Gbyte DLT tape per day. Because Arecibo does not have a high bandwidth Internet connection, the data tape must go by snail-mail to Berkeley. The data is then divided into 0.25 Mbyte chunks (which we call "work-units"). These are sent from the Seti@Home server over the Internet to people around the world to analyze. Extra Credit Section: How the data is broken up
SETI@home looks at 2.5 MHz of data, centered at 1420 MHz. This is still too broad a spectrum to send to you for analysis, so we break this spectrum space up into 256 pieces, each 10 kHz wide (actually 9766 Hz, but we'll simplify the numbers to make calculations easier to see). This is done with a software program called the "splitter". These 10 kHz pieces are now more managable in size. To record signals up to 10 KHz you have to record the bits at 20,000 bits per second (kbps). (This is called the Nyquist frequency.) We send you about 107 seconds of this 10 kHz (20kbps) data. 100 seconds times 20,000 bits equals 2,000,000 bits, or about 0.25 megabyte given that there are 8 bits per byte. Again, we call this 0.25 megabyte chunk a "work-unit." We also send you lots of additional info about the work-unit, so the total comes out to about 340 kbytes of data.
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