object Test
{
  def log(item: _) : Unit = 
    println("you logged " + item)
 
  def main(args: Array[String]) : Unit =
  {
    log(42)
  }
}

The error message wasn’t not helping that much at the first glance:

/home/niels/tmp/test.scala:3: error: unbound wildcard type
	def log(item: _) : Unit = 
                      ^

To fix it, change the prototype of the log function like this:

	def log(item: Any) : Unit =

There is a pretty good overview of the Scala type hierarchy on the Scala homepage. In short, Scala Objects are subtypes of AnyRef. Primitive types (Int, Boolean, …) are subtypes of “AnyVal”. Both “AnyRef” and “AnyVal” are subtypes of “Any”, and substituting “Any” with “_” in prototypes and templates is not allowed in Scala 2.8.

But why is Samba such a pain suddenly?

The short version: because Vista and Leopard have a different behind-the-scenes network config than XP and Tiger.

The long version: when you receive a file over a network, the file is chopped in packets, which are sent to your system one after the other. Whenever you have received a packet, you will send a notice of receipt to the server (“ok, I got packet XYZ, and it is intact”). Obviously, sending all these acknowledgments creates quite some traffic. That’s why Vista and Leopard use bulk acks: you don’t send an ack for every packet, but you wait until you have received (let’s say) 10 packets and send one ack for all of them.

And that “you wait until” is the tricky part. Because Samba is a synchronous protocol, the server won’t send the next packet until it has received the ack for the last.

Get the picture?
There’s a timeout, of course – your system won’t wait for eternity until it sends an ack for the < 10 packets it had received. The timeout should be ~100ms on your system. But 1/10 of a second between each small packet sums up to a hell of a time.

And that’s why Samba can be really slow.

Now, the obvious solution to this problem is to use a shorter delayed ack. BUT DON’T PLAY WITH YOUR SYSTEM IF YOU DON’T KNOW EXACTLY WHAT YOU ARE DOING!

If you are running Windows, try this: set a delayed ack value in your registry.

You are happily working on Mac OS X? Then enter this command:

sudo sysctl -w net.inet.tcp.delayed_ack=0

Learn more about it at his blog.