[Coco] megaread HOW TO ?

[coco at jechar.ca]

  The command help megaread gives:

  Syntax: megaread {#####} </dev

  but when I type

  megaread 100 </dd

  I get Error 214 - No Permission

  Same for megaread 100 </x0

  /dd is an IDE hard drive. And /x0 I have tried
  with both the traditional JAVA and the new Python
  drivewire server.

  What am I doing wrong?
  Is there a better disk I/O bench-marking tool.

  Charles