On Gaver's parallel system sustained by a cold standby unit and attended by two repairmen (Q5915533)

In a landmark paper, \textit{D. P. Gaver jun.} [ IEEE Trans. Reliab. R-12, 30--38 (1963)] introduced a two-unit parallel system sustained by a cold or warm standby unit and attended by a single repair facility. As a variant, one of the authors of this paper [\textit{E. J. Vanderperre}, J. Oper. Res. Japan 41, 171--180 (1998; Zbl 0998.90029)] considered a cold standby unit attended by two identical repairmen. In this paper, the authors study the total joint idle time of both repairmen assuming that each operating unit has a constant failure rate and a deterministic repair time. They use the solution of a delay-differential equation.