I read this SO question on 'real', 'user', and 'sys' descriptions and thought I'd play a little. Can someone explain why
[root@lux ~]# time dd if=/dev/zero of=del.large bs=10K count=32768 32768+0 records in 32768+0 records out 335544320 bytes (336 MB) copied, 0.623293 seconds, 538 MB/s real 0m0.717s user 0m0.007s sys 0m0.709s [root@lux ~]# time dd if=/dev/zero of=del.large bs=100K count=32768 19838+0 records in 19838+0 records out 2031411200 bytes (2.0 GB) copied, 47.31 seconds, 42.9 MB/s real 0m47.401s user 0m0.009s sys 0m3.395s
Clearly real = user + sys in the first trial. Why isn't is the same in the second test?