class cscanMode:
def __init__(self, queue, headpos):
self.headPos = headpos
if not isinstance(queue, list):
raise TypeError("queue must be set to an list")
self.name = "c-scan algorithm"
print(self.name)
self.requestList = queue.copy()
self.direction = 1 #direction modifier
def run(self):
print("starting run")
self.records = Records()
print(len(self.requestList))
print(self.requestList)
self.startIndex = 0
self.requestList.sort()
finished = False
endPos = cylinders
direction = 1 # values 1 or -1
hp = self.headPos
while len(self.requestList) > 0:
for track in range(hp, endPos, direction):
if track in self.requestList:
print(track)
self.nextTrack = track
self.requestList.remove(track)
self.records.addRecord(self.headPos, self.nextTrack)
self.headPos = self.nextTrack
if track == 199:
hp = 0
print(self.records)
class FIFO:
def __init__(self, queue, trackStartPos):
self.currentTrack = trackStartPos
if not isinstance(queue, list):
raise TypeError("queue must be set to an list")
self.name = "first in first out"
print(self.name)
self.queue = queue.copy()
self.pos = 0
def getQueue(self):
return self.queue
def accessNextTrack(self):
self.pos += 1
return self.queue.pop(0)
def run(self):
print("starting run")
self.records = Records()
print(len(self.queue))
for i in range(len(self.queue)):
self.nextTrack = self.accessNextTrack()
self.records.addRecord(self.currentTrack, self.nextTrack)
self.currentTrack = self.nextTrack
print(self.records)
class nstepscan:
def __init__(self, queue, headpos, queuesize):
self.headPos = headpos
self.queueSize = queuesize
if not isinstance(queue, list):
raise TypeError("queue must be set to an list")
self.name = "n-scan step scan algorithm"
print()
print(self.name)
self.requestList = queue.copy()
def run(self):
print("starting run")
self.records = Records()
# print(len(self.requestList))
# print(self.requestList)
self.startIndex = 0
hp = self.headPos
endPos = cylinders
direction = 1 # values 1 or -1
while len(self.requestList) > 0:
self.activeRequestQueue = []
for i in range(self.queueSize):
#print(i)
if len(self.requestList) > 0:
self.activeRequestQueue.append(self.requestList.pop(0))
while len(self.activeRequestQueue) > 0:
for track in range(hp, endPos, direction):
if track in self.activeRequestQueue:
#print("while " + str(track))
self.nextTrack = track
self.activeRequestQueue.remove(track)
self.records.addRecord(self.headPos, self.nextTrack)
self.headPos = self.nextTrack
if track == 199:
direction = -1
endPos = -1
hp = cylinders - 1
elif track == 0:
endPos = cylinders
hp = 0
direction = 1
print(self.records)
class LIFO:
def __init__(self, queue, trackStartPos):
self.currentTrack = trackStartPos
if not isinstance(queue, list):
raise TypeError("queue must be set to an list")
self.name = "last in first out"
print()
print(self.name)
self.queue = queue.copy()
self.pos = 0
def copyList(self, in_List):
self.out_list = []
for i in in_List:
self.out_list.append(i)
return self.out_list
def getQueue(self):
return self.queue
def accessNextTrack(self):
self.pos += 1
return self.queue.pop(0)
def run(self):
self.queue.reverse()
print("starting run")
self.records = Records()
print("length of request list: " + str(len(self.queue)))
for i in range(len(self.queue)):
self.nextTrack = self.accessNextTrack()
self.records.addRecord(self.currentTrack, self.nextTrack)
self.currentTrack = self.nextTrack
print(self.records)
class SSTF:
def __init__(self, queue, trackStartPos):
self.currentTrack = trackStartPos
if not isinstance(queue, list):
raise TypeError("queue must be set to an list")
self.name = "shortest seek time first"
print(self.name)
self.queue = queue.copy()
def selectClosetTrack(self):
self.minIndex = 0 #setting to first index and assuming there is atleast one
self.diff = abs(self.queue[0] -
self.currentTrack) #using first index to start with
for i in range(len(self.queue)):
print("index: " + str(i) + ", diff: " +
str(abs(self.currentTrack - self.queue[i])) + ", value: " +
str(self.queue[i]))
if abs(self.currentTrack - self.queue[i]) < self.diff:
self.diff = abs(self.currentTrack - self.queue[i])
self.minIndex = i
print("removing: " + str(self.minIndex))
return self.queue.pop(self.minIndex)
def run(self):
print("starting run")
self.records = Records()
for i in range(len(self.queue)):
self.nextTrack = self.selectClosetTrack()
self.records.addRecord(self.currentTrack, self.nextTrack)
self.currentTrack = self.nextTrack
print(self.records)
