I/O-bound tasks for experimenting in the Scala REPL

IOboundTasks.scala

def p(s: String) = 
  for (i <- 1 to 10) { 
    Thread.sleep(500)
    println(i + ": " + s) 
  } 

// running two tasks sequentially
// about 20 seconds by design
val t0 = System.currentTimeMillis
p("a")
p("b")
p("c")
p("d")
System.currentTimeMillis - t0
 
// running two tasks concurrently
// down to about about 5 seconds
val p1 = new java.lang.Thread { override def run() = { p("a") } }
val p2 = new java.lang.Thread { override def run() = { p("b") } }
val p3 = new java.lang.Thread { override def run() = { p("c") } }
val p4 = new java.lang.Thread { override def run() = { p("d") } }
val t0 = System.currentTimeMillis
p1.start()
p2.start()
p3.start()
p4.start()
p1.join()
p2.join()
p3.join()
p4.join()
System.currentTimeMillis - t0