操作系统Python

Question

def is_safe_state(processes, available, allocation, need):
    work = available.copy()
    finish = [False] * len(processes)
    safe_sequence = []

    while len(safe_sequence) < len(processes):
        allocated_this_round = False
        for i in range(len(processes)):
            if not finish[i] and all(need[i][j] <= work[j] for j in range(len(available))):
                # 如果进程i可以完成
                for j in range(len(available)):
                    work[j] += allocation[i][j]
                finish[i] = True
                safe_sequence.append(i)
                allocated_this_round = True
                break
        if not allocated_this_round:
            # 如果没有进程可以完成，则系统处于不安全状态
            return False, []

    return True, safe_sequence

def can_allocate_resources(processes, available, allocation, need, request, process_index):
    # 尝试分配资源给指定的进程
    temp_available = available.copy()
    temp_allocation = [list(a) for a in allocation]
    temp_need = [list(n) for n in need]

    for i in range(len(request)):
        if request[i] > temp_available[i]:
            return False, "资源不足，无法分配"

    # 尝试分配
    for i in range(len(request)):
        temp_available[i] -= request[i]
        temp_allocation[process_index][i] += request[i]
        temp_need[process_index][i] -= request[i]

    # 检查分配后的状态是否安全
    is_safe, _ = is_safe_state(processes, temp_available, temp_allocation, temp_need)
    if is_safe:
        return True, temp_allocation
    else:
        return False, "分配资源后状态不安全"

# 定义进程、可用资源、已分配资源和需求矩阵
processes = [
    (0, [0, 1, 2, 2], [1, 6, 5, 2]),  # P0
    (1, [1, 3, 5, 4], [2, 3, 5, 6]),  # P1，根据图片信息补全
    (2, [1, 2, 2, 2], [3, 5, 6, 0]),  # P2
    (3, [0, 3, 3, 2], [0, 6, 5, 6]),  # P3，根据图片信息补全
    (4, [0, 1, 4, 6], [0, 1, 5, 0]),  # P4，根据图片信息补全，但注意需求应为非负整数
]

available = [3, 3, 2, 2]  # 根据图片信息补全
allocation = [
    [0, 1, 0, 2],  # P0
    [2, 0, 0, 0],  # P1
    [0, 3, 3, 2],  # P2
    [0, 0, 2, 4],  # P3
    [0, 1, 0, 0],  # P4
]  # 根据图片信息补全

need = [
    list(p[2]) - list(a) for p, a in zip(processes, allocation)
]

# (1) 检查当前状态是否安全
is_safe, safe_sequence = is_safe_state(processes, available, allocation, need)
print(f"(1) 该状态是否安全？ {'安全' if is_safe else '不安全'}")
if is_safe:
    print(f"    安全序列为：{safe_sequence + 1}（注意：进程编号从1开始）")

# (2) 检查P2提出请求Request(1,2,2,2)后，系统能否将资源分配给它
can_allocate, result = can_allocate_resources(processes, available, allocation, need, [1, 2, 2, 2], 2)
print(f"(2) 若进程P2提出请求Request(1,2,2,2)后，系统能否将资源分配给它？ {'可以' if can_allocate else '不可以'}")
if can_allocate:
    print(f"    分配后的资源情况为：{result}")
else:
    print(f"    {result}")

Answer 1

# -*- coding: utf-8 -*-
"""
Created on Wed Oct  9 15:11:29 2024

@author: H3C
"""



import numpy as np
 
allocation = np.array([[0, 0, 3, 2], [1, 0, 0, 0], [1, 3, 5, 4], [0, 3, 3, 2], [0, 0, 1, 4]])
need = np.array([[0, 0, 1, 2], [1,7, 5, 0], [2, 3, 5, 6], [0, 6, 5, 2], [0, 6 ,5 ,6]])
available = np.array([1, 6, 2, 2])

 
def list_convert_nparray(arg):
    return np.array(list(map(int, arg.split(','))))
 
 

def banker(index, request, allocation, need, available):
    print(index, '  request:', request)
    if np.all(request <= need[index, :], axis=0) and np.all(request <= available, axis=0):
        saftySeq = []
        available -= request
        allocation[index, :] += request
        need[index, :] -= request
        work = workPlusAllocation = available
        sumOfProcess = len(allocation) 
        while len(saftySeq) < sumOfProcess:
            for i in range(0, sumOfProcess):
                cnt = 0
                if len(saftySeq) == sumOfProcess:
                    break
                if i not in saftySeq and np.all(need[i, :] <= workPlusAllocation, axis=0):
                    if len(saftySeq) != 0:
                        work = workPlusAllocation
                    workPlusAllocation = work + allocation[i, :]
                    saftySeq.append(i)
                    print('Process:', i, '  Work:', work, '  Need:', need[i], '  Allocation:', allocation[i],
                          '  Work+Allocation:', workPlusAllocation)
                    cnt += 1
                if i == sumOfProcess - 1 and cnt == 0:
                    available += request
                    allocation[index, :] -= request
                    need[index, :] += request
                    return False
        print('Safty Sequence: ', saftySeq)
        return True
    else:
        return False
 
 
if __name__ == '__main__':
    while True:
        print('Need:\n',need)
        print('Allocation:\n',allocation)
        print('Available:',available)
        if banker(int(input("index:")), list_convert_nparray(input("request(split by ,):")), allocation, need, available):
            print("Allocate Successfully")
        else:
            print('Can not Allocate')
        print('-------------------------------')