I tested it on an R4600SC (SGI Indy) running Debian unstable: indy 2.4.17-r4k-ip22 I ran it twice with and without the fragile argument.
No arguments gave: read #66 of 8192 bytes the first time, read #73 of 8192 bytes the second time. With fagile argument: Reading data from (fragile) /dev/mem... both times.