Research On I/O Management Supporting Transparent Computing Oriented Information Management

Information technologies such as computer and network have provided measures and supporting environments for Management. Management information systems which were produced with the integration of management science and information technologies have been widely applied to enterprises, governments, et al. However, in the computer systems based on Von Neumann architecture, software binding hardware closely has brought forth a series of problems including operating complexly, the high cost of management, maintenance and upgrade, and can't provide stable and reliable supporting environments for management information systems, which lead to the total ownership of cost higher. Therefore, it has been an important area in information management that how to reduce the complexity of management and maintenance to provide the high reliable and low cost supporting environments for management information systems which is easy to install, use, maintain, and reduce the total cost of ownership.With the development of information technologies, there are some computing paradigms proposed to reduce the total cost of ownership, such as Network Computer, NetPC, Thin Client, Diskless Workstation and Transparent Computing, et al. Among these computing paradigms, transparent computing based on ubiquitous computing has the I/O of Von Neumann architecture between the CPU and disks extended to the network to realize the "stored program concept" model in networking environments programs. Transparent computing released the binding relationship of the software and hardware in Von Neumann architecture, and can provide a stable and reliable and easy to manage and maintain computer system as supporting environment for management information systems, and effectively reduce the total cost of ownership.Aiming at the problems produced by transparent computing extending the I/O between the CPU and disks to the network, based on ubiquitous computing and Von Neumann architecture, the dissertation studies systematically I/O management supporting transparent computing and realizes a transparent computing system which is applied to information management. The following is the detail:(1) The dissertation proposes an I/O management method supporting multi-OS remote and run in LAN environment to support transparent computing. It provides a storage view similar to the real hard disk for clients by creating a virtual block device, which transparently redirects I/O requests accessing the disk to the server to complete I/O processing and realizes the scheduling and swapping of instructions and data of programs on demand.(2) The dissertation designs a network storage access protocol for transmitting the I/O requests and data in transparent computing. It defines the types and formats of datagram transmitting I/O requests and data, and also proposes a retransmission timeout algorithm to insure the reliability and safety of the virtual I/O requests transmitting.(3) The problems of the data coherence destroyed when multi-user do remote operations in transparent computing are discussed. The dissertation proposes a block-based write redirection mechanism, which respectively creates an initially empty temporary swap area for every user aim at the programs image accessed on the server hard disk, and then redirects the data written back by the programs running on every client to its temporary swap area at the granularity of a disk block. It not only protects the programs images contents integrality but also completely supports multi-user remote reading or writing any data of the same one programs image, and effectively solves the problems of the data coherence destroyed on multi-user remote operation.(4) To improve the response time of the server, the dissertation analyzes the access pattern of I/O requests accessing the server in transparent computing and proposes a buffer cache replacement algorithm: frequency-based multi-priority queues. It distinguishes the block and endows it with different priority according to its access frequency. The higher priority is, the longer its lifetime is in the buffer cache. It increases the buffer hit ratio and reduces the times accessing the server disk in order to reduce the response time of the server and improve the programs remote load.(5) The dissertation describes the implementation of a transparent desktop computing platform: TransCom, and applies the I/O management methods and protocol into the real design of TransCom system. The results of performance evaluation and deployment experience of TransCom and the contrast between TransCom and other similar systems show that TransCom system has preferable performance and can satisfy the user demand.(6) The dissertation gives the feasibility analysis and applied example of TransCom in the informatization construction of China National Petroleum Corporation. The result shows that TransCom is able to provide the reliable and easy to manage and maintain supporting environment for management information system, and effectively decrease the total cost of the enterprise informatization construction and enhance information management efficiency and quality.