Thank you very much for your time, even in the after hours.
I ran top in one putty window, logged in on another and ran:
dd if=/dev/zero of=/mnt/esata/test bs=1M count=256
This is what top said:
top - 06:45:12 up 9:42, 2 users, load average: 1.03, 0.46, 0.17
Tasks: 77 total, 1 running, 76 sleeping, 0 stopped, 0 zombie
Cpu(s): 1.7%us, 6.6%sy, 0.0%ni, 0.0%id, 90.7%wa, 0.3%hi, 0.7%si, 0.0%st
Mem: 513948k total, 207080k used, 306868k free, 6772k buffers
Swap: 0k total, 0k used, 0k free, 89760k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1862 root 20 0 4408 1616 508 D 7.3 0.3 0:00.46 dd
1555 squeezeb 20 0 85104 74m 5208 S 2.3 14.8 13:49.53 squeezeboxserve
870 root 20 0 0 0 0 S 0.7 0.0 0:00.09 jbd2/sda1-8
1861 root 20 0 2548 1168 932 R 0.7 0.2 0:00.11 top
141 root 20 0 0 0 0 S 0.3 0.0 0:00.22 ata/0
1151 mysql 20 0 124m 16m 4736 S 0.3 3.3 0:58.81 mysqld
1 root 20 0 2004 684 596 S 0.0 0.1 0:02.43 init
2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd
3 root 20 0 0 0 0 S 0.0 0.0 0:00.02 ksoftirqd/0
4 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/0
5 root 20 0 0 0 0 S 0.0 0.0 0:00.11 events/0
6 root 20 0 0 0 0 S 0.0 0.0 0:00.01 khelper
9 root 20 0 0 0 0 S 0.0 0.0 0:00.00 async/mgr
131 root 20 0 0 0 0 S 0.0 0.0 0:00.04 sync_supers
133 root 20 0 0 0 0 S 0.0 0.0 0:00.10 bdi-default
135 root 20 0 0 0 0 S 0.0 0.0 0:00.08 kblockd/0
142 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ata_aux
And I tried the same with reading but the command goes too fast to copy the screen in my second putty