Evolution of an LMXB consisting of a 1.6 M_⊙ NS and a 1.0 M_⊙ MS donor star with an initial orbit of 0.35 days in the orbital period vs. stellar age diagram (top panel), and the donor-star mass vs. stellar age diagram (bottom panel). The horizontal short dashed line in the top panel indicates the orbital period of 2A 1822-371, and the horizontal short dashed lines in the bottom panel represent the inferred upper and lower limits of the donor star mass.