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

IOboundTasks.scala

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

// running two or more 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 or more concurrently
// down to about about 5 seconds
def makeP(label: String) = new java.lang.Thread:
  override def run() = p(label)

val p1 = makeP("a")
val p2 = makeP("b")
val p3 = makeP("b")
val p4 = makeP("b")

val t1 = System.currentTimeMillis
p1.start()
p2.start()
p3.start()
p4.start()
p1.join()
p2.join()
p3.join()
p4.join()
System.currentTimeMillis - t1