function scheduler_schedule() {
  this.currentTcb = this.list;
  while (this.currentTcb != null) {
    if (tcb_isHeldOrSuspended.call(this.currentTcb)) {
      this.currentTcb = this.currentTcb.link;
    } else {
      this.currentId = this.currentTcb.id;
      this.currentTcb = tcb_run.call(this.currentTcb);
    }
  }
}
Execute the tasks managed by this scheduler.