soluzioni


Si guarda quanto tempo occorre per scrivere 51MBytes su un file, quando la macchina non ha altri utenti e non ci sono altri processi pesanti in corso:
steffe@dida1 /net/data/home/steffe$w
 11:35pm  up 3 days, 11:34,  1 user,  load average: 0.00, 0.00, 0.00
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU  WHAT
steffe   pts/0    volterra.dm.unip 11:35pm  0.00s  0.15s  0.04s  w 
steffe@dida1 /net/data/home/steffe$time dd if=/dev/zero of=/tmp/prova count=100000
100000+0 records in
100000+0 records out
1.36user 6.97system 0:10.38elapsed 80%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (138major+18minor)pagefaults 0swaps
steffe@dida1 /net/data/home/steffe$ls -la /tmp/prova
-rw-rw-r--    1 steffe   steffe   51200000 Apr 10 23:36 /tmp/prova
steffe@dida1 /net/data/home/steffe$rm /tmp/prova
------------------------------
steffe@dida12 /net/data/home/steffe$w
 11:36pm  up 1 day, 12:45,  1 user,  load average: 0.00, 0.00, 0.00
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU  WHAT
steffe   pts/0    volterra.dm.unip 11:36pm  0.00s  0.06s  0.02s  w 
steffe@dida12 /net/data/home/steffe$time dd if=/dev/zero of=/tmp/prova count=100000
100000+0 records in
100000+0 records out
0.11user 1.40system 0:02.14elapsed 70%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (138major+18minor)pagefaults 0swaps
steffe@dida12 /net/data/home/steffe$ls -la /tmp/prova
-rw-rw-r--    1 steffe   steffe   51200000 Apr 10 23:37 /tmp/prova
steffe@dida12 /net/data/home/steffe$rm /tmp/prova 

Dunque: 10.4 secondi su dida1 e 2.1 secondi su dida12, che risulta molto più veloce.  
CHIUDI

Laboratorio di Comunicazione mediante Calcolatore - Sergio Steffè - AA 2001/2002 - PISA