def loaddata(fileName): # 读取数据
f = open(fileName)
start = f.readline() # 读入data文件的第一行作为起始磁道
data = f.readline() # 依次读入数据作为下一个被访问的磁道号
return start, data
def loadnext(now, next): # 输出下一个被访问的磁道号和移动距离
length = abs(int(now) - int(next)) # 移动距离
str_length =str(length)
if len(next) == 3:
if len(str_length) == 1:
print("| ", end="")
print(next, end="")
print(" | ", end="")
print(" ", end="")
print(length, end="")
print(" |")
elif len(str_length) == 2:
print("| ", end="")
print(next, end="")
print(" | ", end="")
print(" ", end="")
print(length, end="")
print(" |")
else:
print("| ", end="")
print(next, end="")
print(" | ", end="")
print(" ", end="")
print(length, end="")
print(" |")
elif len(next) == 2:
if len(str_length) == 1:
print("| ", end="")
print(next, end="")
print(" | ", end="")
print(" ", end="")
print(length, end="")
print(" |")
elif len(str_length) == 2:
print("| ", end="")
print(next, end="")
print(" | ", end="")
print(" ", end="")
print(length, end="")
print(" |")
else:
print("| ", end="")
print(next, end="")
print(" | ", end="")
print(" ", end="")
print(length, end="")
print(" |")
elif len(next) == 1:
if len(str_length) == 1:
print("| ", end="")
print(next, end="")
print(" | ", end="")
print(" ", end="")
print(length, end="")
print(" |")
elif len(str_length) == 2:
print("| ", end="")
print(next, end="")
print(" | ", end="")
print(" ", end="")
print(length, end="")
print(" |")
else:
print("| ", end="")
print(next, end="")
print(" | ", end="")
print(" ", end="")
print(length, end="")
print(" |")
return length
def FCFS():
l = 0
start, data = loaddata('data')
print("|--------------------------------------|")
print("| 被访问的下一个磁道号 | 移动距离 |")
print("|--------------------------------------|")
for d in data.split():
l += loadnext(start, d) # 循环输出下一个磁道号和移动距离，并将寻道距离累加
start = d # 将刚访问的磁道作为下次访问的起始磁道
n = len(data.split())
print("|--------------------------------------|")
print("| 先来先服务(FCFS)的平均寻道长度：%.1f |" % (l / n))
print("|--------------------------------------|")
def findnextindex(start, datas): # SSTF算法
length = []
for data in datas:
l = abs(int(start) - int(data)) # 计算磁道间要移动的距离
length.append(l) # 计算的将每个距离放入距离数组
minIndex = length.index(min(length)) # 在数组中选出最小的距离在数组中位置
return minIndex
def SSTF():
l = 0
start, data = loaddata('data')
data2 = data.split().copy()
n = len(data2)
print("|--------------------------------------|")
print("| 被访问的下一个磁道号 | 移动距离 |")
print("|--------------------------------------|")
for d in data.split():
nextIndex = findnextindex(start, data2) # 获取每次的最小寻道距离
l += loadnext(start, data2[nextIndex])
start = data2[nextIndex]
data2.remove(data2[nextIndex])
print("|--------------------------------------|")
print("|最短寻道时间优先(SSTF)的平均寻道长度：%.1f |" % (l / n))
print("|--------------------------------------|")
def findnext1(now, data): # SCAN
biggerList = []
smallerList = []
for d in data:
if int(d) > int(now): # 判断初始磁道和下一磁道的大小关系
biggerList.append(d) # 如果下一磁道号更大则将其放入大数组中
if (len(biggerList) == 0): # 否则则开始寻找比初始磁道小的磁道号
if len(data) != 0:
for d2 in data:
if int(d2) < int(now):
smallerList.append(d2) # 将其加入小数组中
return max(smallerList)
else:
return None
return min(biggerList)
def SCAN():
l = 0
start, data = loaddata('data')
data2 = data.split().copy()
print("|--------------------------------------|")
print("| 被访问的下一个磁道号 | 移动距离 |")
print("|--------------------------------------|")
n = len(data2)
for d in data:
next = findnext1(start, data2) #
if next == None:
break
l += loadnext(start, next)
start = next
data2.remove(next)
print("|--------------------------------------|")
print("|电梯调度算法(SCAN)平均寻道长度：%.1f |" % (l / n))
print("|--------------------------------------|")
def findnext2(now, data): # CSCAN
biggerList = []
smallerList = []
for d in data:
if int(d) > int(now):
biggerList.append(d)
if (len(biggerList) == 0):
if len(data) != 0:
now = 0
return (findnext2(now, data))
else:
return None
return min(biggerList)
def CSCAN():
l = 0
start, data = loaddata('data')
data2 = data.split().copy()
n = len(data2)
print("|--------------------------------------|")
print("| 被访问的下一个磁道号 | 移动距离 |")
print("|--------------------------------------|")
for d in data:
next = findnext2(start, data2)
if next == None:
break
l += loadnext(start, next)
start = next
data2.remove(next)
print("|--------------------------------------|")
print("|循环扫描算法(CSCAN)平均寻道长度：%.1f |" % (l / n))
print("|--------------------------------------|")
def main():
num4 = int(input("恢复原磁道(1、是；0、否)："))
if num4 == 1:
filename = 'data'
with open(filename, 'w') as f:
first = "100"
second = "55 58 39 18 90 160 150 38 184"
f.write(first)
f.write("\n")
f.write(second)
else:
print("")
start, data = loaddata('data')
print("|------------磁盘调度算法程序-------------|")
print("|------1、先来先服务 (FCFS )算法-----|")
print("|------2、最短寻道时间优先 (SSTF )算法-----|")
print("|------3、电梯调度 (SCAN )算法-----|")
print("|------4、循环扫描算法 (CSCAN)算法-----|")
print("|---------------------------------------|")
print("初始磁道为:" + start + data)
num = int(input("请选择要使用的调度算法(1~4):"))
if num == 1:
FCFS()
elif num == 2:
SSTF()
elif num == 3:
SCAN()
elif num == 4:
CSCAN()
else:
num1 = int(input("您没有做出选择，是否需要指定访问的磁道？(1:是 0:否)"))
if num1 == 1:
# 100
# 55 58 39 18 90 160 150 38 184
print("原磁道顺序为：100 \n"+"55 58 39 18 90 160 150 38 184")
filename = 'data'
with open(filename, 'w') as f:
first = int(input("请输入初始访问磁道："))
second = input("请输入被访问的下一个磁道号序列(用空格分开)：")
f.write(str(first))
f.write("\n")
f.write(str(second))
else:
num3 = int(input("是否选择关闭程序？(1:是 0:否)"))
if num3 == 1 :
print("程序结束！谢谢使用。")
exit()
elif num3 == 0:
main()
else:
print("选择错误！")
main()
num2 = int(input("是否继续选择？(1:是 0:否,关闭程序)"))
if num2 == 1:
main()
elif num2 == 0:
print("程序结束！谢谢使用。")
exit()
else:
print("选择错误！")
main()
if __name__ == "__main__":
main()
