The SystemConfiguration value specifies a global state of the
computer which determines how the Arithmetic Element (in modern
wording, arithmetic unit) communicates with memory. The basic
outline is given in Fig. 9 (page 20) of “A Functional Description
of the Lincoln TX-2 Computer” by John M. Frankovitch and H. Philip
Peterson. A more complete description (including the
corresponding F-memory values) is given in tables 7-2 and 7-2A of
the TX-2 User’s Handbook (pp 192-193 in my PDF copy).
The system configuration is a 9-bit value. While Frankovitch and
Peterson describe most significant bit as being spare, table 7-2
appears to use it.
Figure 12-39 (“Configuration Block Diagram”) (page 250) in Volume
2 of the TX-2 Technical manual describes how a word from the CF
memory (a QKIRcf value) is decoded into permutation, activity
(which quarters are active) and fracture (which quarters are
considered to be separate).
Extract a QuarterActivity value from the activity field of a
system configuration value.
Active quarters are signaled by a 0 in the appropriate bit
position of the system configuration value. A 1 signals that
the corresponding quarter is inactive.
The mapping between configuration values and which quarter is
active is given in Table 12-4 in the technical manual (volume
2, page 12-22).