Can any one explain the code given below??... Its about the scheduling

Code:

<%@ LANGUAGE="VBScript" %>
<% Option Explicit %>
<%
'+---------------------------------------------------+
'| Scheduled Task in Active Server Pages             |
'| Nick Sumner 06.2004                               |
'| [url]http://www.tele-pro.co.uk/[/url]                        |
'| [email]dev@nicksumner.com[/email]                                |
'+---------------------------------------------------+
'| asp_schedule_task.asp
'| schedule a task in an ASP application
'+---------------------------------------------------+


'call AnyFunction() once every 6 hrs
If (ScheduleTask("MyTaskName", "h", 6)) Then 
  Call AnyFunction()
end If

FUNCTION ScheduleTask(task_name, period, qty)
  Dim RunNow
  Dim last_date
  Dim diff

  'boolean result
  RunNow = False

  'chcek the value of app setting
  last_date = Trim(Application("Sched_" & task_name))

  'is value empty? maybe app just started
  If (last_date = "") Then
    RunNow = True
  Else
    'is value old?
    diff = DateDiff(period, last_date, Now())
    If (diff>=qty) Then RunNow = True
  End if

  'if scheduled to run now, set the app last run time
  If (RunNow) Then Application("Sched_" & task_name) = Now()

  'return result
  ScheduleTask = RunNow 
END FUNCTION 

%>