操作系统行为模拟[内存分配算法&银行家算法&进程管理]

【实例简介】

模拟内存分配算法
模拟银行家算法
模拟进程管理

讲解操作系统基本算法的小例子~
给朋友做示例时写的，时间有限，功能有限，不可用于生产环境

【实例截图】

【核心代码】

        //申请内存
        public Boolean request(int pid, int memory)
        {
            if (memoryTable.ContainsKey(pid))
                return false;

            if (getMaxAvailaleMemory() - memory < 0)
                return false;

            if (freeList.Count == 0)
                return false;

            int minWaste = memoryTotal   1;
            int addressAloc = 0;
            Node cur = null, nxt = null, minPre = null, minNode = null;

            //处理首节点
            cur = freeList[0];
            if(cur.size > memory)
            {
                    minWaste = cur.size - memory;
                    minPre = null;
                    minNode = cur;
            }

            //处理后续节点
            for (nxt = cur.next; nxt != null ; cur = nxt, nxt = nxt.next)
            {
                if (nxt.size > memory && nxt.size - memory < minWaste)
                {
                    minWaste = nxt.size - memory;
                    minPre = cur;
                    minNode = nxt;
                }
            }

            if (minNode == null)
                return false;

            if (minNode.size > memory)
            {
                addressAloc = minNode.address;
                minNode.address = minNode.address   memory;
                minNode.size = minNode.size - memory;
            }
            else if (minNode.size == memory)
            {
                addressAloc = minNode.address;
                freeList.Remove(minNode);
            }

            MemoryAloc memAloc = new MemoryAloc();
            memAloc.address = addressAloc;
            memAloc.size = memory;

            memoryTable.Add(pid, memAloc);
            memoryUsed  = memory;

            return true;
        }

        //释放内存
        public Boolean free(int pid)
        {
            if (!memoryTable.ContainsKey(pid))
                return false;

            MemoryAloc memAloc = (MemoryAloc)memoryTable[pid];
            memoryUsed -= memAloc.size;

            Node freeNode = new Node();
            freeNode.address = memAloc.address;
            freeNode.size = memAloc.size;

            int count = freeList.Count;
            for (int i = 0; i < count; i  )
            {
                Node node = freeList[i];
                if (memAloc.address < node.address)
                {
                    freeNode.next = node;
                    if (i > 0)
                        freeList[i - 1].next = freeNode;
                    if (i < freeList.Count - 1)
                        freeNode.next = freeList[i   1];
                    freeList.Insert(i, freeNode);
                    break;
                }
            }

            coalesce();
            memoryTable.Remove(pid);

            return true;
        }