Lect 15 Errors in Crossbars
CSCI 2570
@John E Savage
21
Defect Tolerance
lNW sparing
lBoth OR output and restoration NWs must work correctly.
lIf Pw is prob NW is not defective, (Pw)2 is prob that OR output is useable
lHow many NW pairs needed for correct operation?
lNW failure
lPc = prob NW makes good contact on one end
lPj = prob no break in NW of length L0.
lPctrl = prob NW aligned adequately
lFor NW length L = ρ L0, Pw = (Pc)2 x (Pj)ρ x Pctrl
lPw = .8 is typical.