OSのスケジューリングに関するコードの理解について

前提・実現したいこと

スケジューリングに関するPython2系で書かれたコードが理解できずに困っています。
オペレーティングシステムに関するコードで、以下のページからコードは引用しました。
コードの引用元　Scheduling Basics

①
実行し問題なく結果が表示されましたが、
元のコードが何を要求して、何が返されているのかわからないため、
教えていただけますと幸いです。

②
実行結果に表示されたメッセージをGoogleTranslateにかけたものです。

各ジョブのターンアラウンドタイム、応答時間、および待機時間を計算します。
完了したら、同じ引数でこのプログラムを再度実行し、
-cを指定すると、答えが得られます。あなたは使うことができます
-s <somenumber>または自分のジョブリスト（-l 10,15,20など）
あなた自身のために異なる問題を生成する。

この

完了したら、同じ引数でこのプログラムを再度実行し、-cを指定すると、答えが得られます。

の部分を実行するにはターミナルで

$ python scheduler.py

以外に何を行う必要があるかも知りたいです。

該当のソースコード

実行結果


ARG policy FIFO
ARG jobs 3
ARG maxlen 10
ARG seed 0

Here is the job list, with the run time of each job: 
  Job 0 ( length = 9 )
  Job 1 ( length = 8 )
  Job 2 ( length = 5 )


Compute the turnaround time, response time, and wait time for each job.
When you are done, run this program again, with the same arguments,
but with -c, which will thus provide you with the answers. You can use
-s <somenumber> or your own job list (-l 10,15,20 for example)
to generate different problems for yourself.

python
1#! /usr/bin/env python
2
3import sys
4from optparse import OptionParser
5import random
6
7parser = OptionParser()
8parser.add_option("-s", "--seed", default=0, help="the random seed", 
9                  action="store", type="int", dest="seed")
10parser.add_option("-j", "--jobs", default=3, help="number of jobs in the system",
11                  action="store", type="int", dest="jobs")
12parser.add_option("-l", "--jlist", default="", help="instead of random jobs, provide a comma-separated list of run times",
13                  action="store", type="string", dest="jlist")
14parser.add_option("-m", "--maxlen", default=10, help="max length of job",
15                  action="store", type="int", dest="maxlen")
16parser.add_option("-p", "--policy", default="FIFO", help="sched policy to use: SJF, FIFO, RR",
17                  action="store", type="string", dest="policy")
18parser.add_option("-q", "--quantum", help="length of time slice for RR policy", default=1, 
19                  action="store", type="int", dest="quantum")
20parser.add_option("-c", help="compute answers for me", action="store_true", default=False, dest="solve")
21
22(options, args) = parser.parse_args()
23
24random.seed(options.seed)
25
26print 'ARG policy', options.policy
27if options.jlist == '':
28    print 'ARG jobs', options.jobs
29    print 'ARG maxlen', options.maxlen
30    print 'ARG seed', options.seed
31else:
32    print 'ARG jlist', options.jlist
33
34print ''
35
36print 'Here is the job list, with the run time of each job: '
37
38import operator
39
40joblist = []
41if options.jlist == '':
42    for jobnum in range(0,options.jobs):
43        runtime = int(options.maxlen * random.random()) + 1
44        joblist.append([jobnum, runtime])
45        print '  Job', jobnum, '( length = ' + str(runtime) + ' )'
46else:
47    jobnum = 0
48    for runtime in options.jlist.split(','):
49        joblist.append([jobnum, float(runtime)])
50        jobnum += 1
51    for job in joblist:
52        print '  Job', job[0], '( length = ' + str(job[1]) + ' )'
53print '\n'
54
55if options.solve == True:
56    print '** Solutions **\n'
57    if options.policy == 'SJF':
58        joblist = sorted(joblist, key=operator.itemgetter(1))
59        options.policy = 'FIFO'
60    
61    if options.policy == 'FIFO':
62        thetime = 0
63        print 'Execution trace:'
64        for job in joblist:
65            print '  [ time %3d ] Run job %d for %.2f secs ( DONE at %.2f )' % (thetime, job[0], job[1], thetime + job[1])
66            thetime += job[1]
67
68        print '\nFinal statistics:'
69        t     = 0.0
70        count = 0
71        turnaroundSum = 0.0
72        waitSum       = 0.0
73        responseSum   = 0.0
74        for tmp in joblist:
75            jobnum  = tmp[0]
76            runtime = tmp[1]
77            
78            response   = t
79            turnaround = t + runtime
80            wait       = t
81            print '  Job %3d -- Response: %3.2f  Turnaround %3.2f  Wait %3.2f' % (jobnum, response, turnaround, wait)
82            responseSum   += response
83            turnaroundSum += turnaround
84            waitSum       += wait
85            t += runtime
86            count = count + 1
87        print '\n  Average -- Response: %3.2f  Turnaround %3.2f  Wait %3.2f\n' % (responseSum/count, turnaroundSum/count, waitSum/count)
88                     
89    if options.policy == 'RR':
90        print 'Execution trace:'
91        turnaround = {}
92        response = {}
93        lastran = {}
94        wait = {}
95        quantum  = float(options.quantum)
96        jobcount = len(joblist)
97        for i in range(0,jobcount):
98            lastran[i] = 0.0
99            wait[i] = 0.0
100            turnaround[i] = 0.0
101            response[i] = -1
102
103        runlist = []
104        for e in joblist:
105            runlist.append(e)
106
107        thetime  = 0.0
108        while jobcount > 0:
109            # print '%d jobs remaining' % jobcount
110            job = runlist.pop(0)
111            jobnum  = job[0]
112            runtime = float(job[1])
113            if response[jobnum] == -1:
114                response[jobnum] = thetime
115            currwait = thetime - lastran[jobnum]
116            wait[jobnum] += currwait
117            if runtime > quantum:
118                runtime -= quantum
119                ranfor = quantum
120                print '  [ time %3d ] Run job %3d for %.2f secs' % (thetime, jobnum, ranfor)
121                runlist.append([jobnum, runtime])
122            else:
123                ranfor = runtime;
124                print '  [ time %3d ] Run job %3d for %.2f secs ( DONE at %.2f )' % (thetime, jobnum, ranfor, thetime + ranfor)
125                turnaround[jobnum] = thetime + ranfor
126                jobcount -= 1
127            thetime += ranfor
128            lastran[jobnum] = thetime
129
130        print '\nFinal statistics:'
131        turnaroundSum = 0.0
132        waitSum       = 0.0
133        responseSum   = 0.0
134        for i in range(0,len(joblist)):
135            turnaroundSum += turnaround[i]
136            responseSum += response[i]
137            waitSum += wait[i]
138            print '  Job %3d -- Response: %3.2f  Turnaround %3.2f  Wait %3.2f' % (i, response[i], turnaround[i], wait[i])
139        count = len(joblist)
140        
141        print '\n  Average -- Response: %3.2f  Turnaround %3.2f  Wait %3.2f\n' % (responseSum/count, turnaroundSum/count, waitSum/count)
142
143    if options.policy != 'FIFO' and options.policy != 'SJF' and options.policy != 'RR': 
144        print 'Error: Policy', options.policy, 'is not available.'
145        sys.exit(0)
146else:
147    print 'Compute the turnaround time, response time, and wait time for each job.'
148    print 'When you are done, run this program again, with the same arguments,'
149    print 'but with -c, which will thus provide you with the answers. You can use'
150    print '-s <somenumber> or your own job list (-l 10,15,20 for example)'
151    print 'to generate different problems for yourself.'
152    print ''