Control Data Cyber 170 State Hardware Reference Manual page 46

Central Memory
Central Memory
The CM performs t h e following f u n c t i o n s .
The e i g h t memory banks s t o r e from
2097K
t o 16 7763 of 64-bit words ( t h e
l e f t m o s t 4 b i t s a r e undefined) and an 8-bit SECDED code.
The two p o r t s make CM a c c e s s i b l e t o t h e CP and every PP.
A bounds r e g i s t e r limits a c c e s s t o CM from e i t h e r o r both p o r t s .
The SECDED g e n e r a t o r s g e n e r a t e t h e SECDED code b i t s s t o r e d with each word.
SECDED checks c i r c u i t s , c o r r e c t s s i n g l e - b i t e r r o r s , and d e t e c t s double-bit
e r r o r s .
The maintenance channel i n t e r f a c e g i v e s a PI? i n t h e I O U a c c e s s t o t h e CM
maintenance r e g i s t e r s f o r system i n i t i a l i z a t i o n , c o r r e c t i v e a c t i o n , e r r o r
r e p o r t i n g and d i a g n o s t i c s , and s e t t i n g t h e p o r t bounds r e g i s t e r .
Address Format
Figure 2-2 i l l u s t r a t e s t h e a d d r e s s format f o r t h e computer system.
23
22 21 20
12 11 3
2
0
r
I I
COLUMN ADDRESS
I
R o w ADDRESS
I
I
I
SELECT
1 ,
I
L
CHlP ADDRESS
CHlP SELECT
QUADRANT SELECT BANK SELECT
Figure 2-2. Address Format