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APPENDIX A Semiconductor Memories Semiconductor memories were examined as possible candidates for archival storage and were dismissed summarily because of cost, size, power, and especially volatility. Given cost projections of $5 for a 256,000-bit CMOS random access memory {RAM) chip, the cost per bit is 2 x 10-3 cents. For large data storage systems of 10~2 bits, the chip cost alone would be $20 million, which is only a fraction of the total system cost. The density of bits on a chip may be as high as 5 x 106 bits per square inch, but chip size takes only a minute portion of a semiconductor memory system. There- fore, the system would be very large. The operating power per chip is low {200 mw), but using approximately 5 x 106 chips for a large system means that 1 megawatt of power would be required. Even if cost, size, and power were not a problem, no one would want to commit archival records to a memory that would be erased if power were interrupted. 93