Nanomedicine, Volume I: Basic Capabilities

© 1999 Robert A. Freitas Jr. All Rights Reserved.

Robert A. Freitas Jr., Nanomedicine, Volume I: Basic Capabilities, Landes Bioscience, Georgetown, TX, 1999


7.2.6 Communicytes

A useful supplemental means of information transport throughout the body is a mobile mass-storage memory device called a communicyte. Communicytes may serve an analogous function to postal carriers -- messages are delivered to them, passed among them, and eventually delivered by them to the intended recipients. Mass mailings to selected recipient subpopulations are also possible. Classes of communicyte mass memory may include rapidly spooled hydrofluorocarbon memory tape (Section, dense banks of diamondoid register rods forming a random access memory (RAM) (Fig. 10.2), or other means (Section 10.2).

In the first case, a 1 micron3 storage block could contain a 1010 bit, 0.4-micron3, 3-meter length of memory tape, with the remaining 0.6-micron3 volume occupied by read/write heads, spool drivers, housing and the like. With a read speed10 of ~30 cm/sec (~109 bits/sec) the entire data cache may be offloaded in ~10 sec. The energy cost to rewrite the tape is 1-1000 zJ/bit (Sections 6.5.6 (B) and, hence the entire tape may be erased and overwritten in 1-1000 sec assuming a 10 pW tape-handling power budget, giving a write speed of 107-1010 bits/sec.

In the second case, register rods of cross-section ~1 nm2 (described in Drexler10) require ~4 nm of length to accommodate a single input/output rod pair and can store at least ~1 bit/40 nm3. Thus a 0.4 micron3 block of tightly-packed register-rod RAM may hold 107 bits, with the remaining 0.6 micron3 of the 1 micron3 storage block reserved for springs, latches, and other essential mechanisms (including address-decoding logic) to access the stored data, and housings. Read and write speeds are ~1010 bits/sec; full-cycle energy losses are ~5 zJ/bit assuming 1 bit/register,10 a ~50 pW power draw during the ~1 millisec required to read or write the entire onboard data cache.

Communicytes may also incorporate mechanisms allowing data transfers among themselves or between themselves and living or artificial entities (Section 7.4). Communicytes will normally be deployed as components of a communication network of such devices, as described in Section 7.3.2, although they may also serve as mobile data repositories or software libraries.


Last updated on 19 February 2003