ABSTRACT
CMUA PDP-10, ECL Parity 44 800-1600 0.03-0.06 C M * LSI-11, NMOS Diagnostics 128 4200 0.03 C.vmp TMR LSI-11 Crash 97-328 4900 0.02-0.07 Telettra, TTL Mismatch 80-170 1300 0.06-0.13 SUN-2, TTL, MOS Crash 689 6552 0.11 IM x 37 RAM, Parity 106 1450 0.07
MOS
FIGURE 2 -2 Operational life er ror rate as function of RAM densities [From Geilhufe, 1979; ©1979 IEEE]
Memory size in bits
Source of Number of Mean Time to Error Occurrences Occurrence (hrs)
Permanent fault 29 6552 Intermittent fault 610 58 Transient fault 446 354 System crash 298 689
w ith in less than a w e e k of the previous error, the e rro r was d ee m e d to be caused by an in te rm itten t fault. Since the mean tim e to a transient fau lt was over tw o w eeks , it was fe lt that the re was little probability of inadvertently m ixing in te rm itte n t and tran sient faults.
