Answers for Homework 6
  1. single-level paging, 90% hit ratio

    2. 90%*(40+3)+(1-90%)*(40+40+3)=47ns

    single-level paging, 98% hit ratio

    98%*(40+3)+(1-98%)*(40+40+3)=43.8ns

    four-level paging, 90% hit ratio

    90%*(40+3)+(1-90%)*(40*4+40+3)=59ns

    four-level paging, 98% hit ratio

    98%*(40+3)+(1-98%)*(40*4+40+3)=46.2ns

     

  2. Assume x is the hit ration and y is the effective access time

One-level paging

(y-40)/40<=15%

x*(40+3)+(1-x)*(40+40+3)<=y

we got y<=46 x>=92.5%

four-level paging

(y-40)/40<=15%

x*(40+3)+(1-x)*(40*4+40+3)<=y

we got y<=46 x>=98.1%