Solución de los ejercicios de memoria virtual
De Wiki de Sistemas Operativos
Revisión del 18:39 30 dic 2015 de Juautrmar (discusión | contribuciones) (→Sustitución por envejecimiento)
NRU
Acceso a 1(R) 3(R) 3(W) 3(R) 4(R) 5(R) 1(R) 2(W) 5(W) 1(W) 3(R) 4(R) página +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ | 1 | = | = | = | = | = | = | = | = | = | = | = | Marco 1 | R=1 | = | = | = | = | = | = | = | = | = | = | = | | M=0 | = | = | = | = | = | = | = | = | M=1 | = | = | +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ | | 3 | = | = | = | = | = | = | = | = | = | = | Marco 2 | | R=1 | = | = | = | = | = | = | = | = | = | = | | | M=0 | M=1 | = | = | = | = | = | = | = | = | = | +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | 4 | = | = | 2 | = | = | = | 4 | Marco 3 | | | | | R=1 | = | = | R=1 | = | = | = | R=1 | | | | | | M=0 | = | = | M=1 | = | = | = | M=0 | +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | 5 | = | = | = | = | = | = | Marco 4 | | | | | | R=1 | = | = | = | = | = | = | | | | | | | M=0 | = | = | M=1 | = | = | = | +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ Fallo | | | | | | | | | | | | | de | x | x | | | x | x | | x | | | | x | página | | | | | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ Tiempo 1 2 3 4 5 6 7 8 9 10 11 12 nº fallos de página 6 Tasa de fallos de página = --------------------- = ---- = 0,5 nº accesos a páginas 12
Sustitución por envejecimiento
Periodo = 4
Registro R de 3 bits.
En caso de empate = LRU
Acceso a 2 3 3 1 - 4 5 4 1 - 5 2 3 4 página +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ Marco 1 | 2 | = | = | = | = | = | 5 | = | = | = | = | = | = | = | Bit R | 100 | = | = | = | 010 | = | 100 | = | = | 010 | 110 | = | = | = | +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ Marco 2 | | 3 | = | = | = | = | = | = | = | = | = | 2 | = | = | Bit R | | 100 | = | = | 010 | = | = | = | = | 001 | = | 100 | = | = | +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ Marco 3 | | | | 1 | = | = | = | = | = | = | = | = | = | 4 | Bit R | | | | 100 | 010 | 010 | = | = | 110 | 011 | = | = | = | 100 | +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ Marco 4 | | | | | | 4 | = | = | = | = | = | = | 3 | = | Bit R | | | | | | 100 | = | = | = | 010 | = | = | 100 | = | +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ Fallo | | | | | | | | | | | | | | | de | x | x | | x | - | x | x | | | - | | x | x | x | página | | | | | | | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ Tiempo 1 2 3 4 - 5 6 7 8 - 9 10 11 12 Periodo 4 3 2 1 0 4 3 2 1 0 4 3 2 1 8 nº fallos de página 8 Tasa de fallos de página = --------------------- = ---- = 0,6666666666666667 nº accesos a páginas 12