We recently reported the results of molecular dynamics simulations for a binary liquid mixture in porous glass. The results for the concentration-fluctuation autocorrelation function showed that the mutual diffusion and the self-diffusion are different. Unfortunately, the linear size of the three-dimensional system used for this simulation was rather small. We carry out the same simulations here using a relatively large two-dimensional system. The results are the same as those for the small three-dimensional system. The self-diffusion departs from the q(2) Fick's pattern while the mutual diffusion follows it more closely.