The Design And Implementation Of The Virual Disk System For Flash Storage Management

I internships where the company is a focus on mobile communication and multimedia terminal Soc design of high-tech foreign-owned enterprises. Companies have a number of the mobile communications and multimedia aspects of the core technology, a number more than 10 years in Silicon Valley senior IC design experts to provide chip design; accumulated from the algorithm simulation, system design, protocol, software platform and production test tools The development, until the end of the multifaceted, mature industries and professional experience, for the majority of the manufacturer provides a wide range of solutions, has won high reputation. Company products are mainly related to GSM / GPRS mobile terminals, CD/MP3/WMA player. At the same time, the company's product line also covers the WCDMA / TD-SCDMA mobile phones and multimedia mobile phones.This topic comes from the actual development of a project: CSW Platform, this project is to develop a GSM / GPRS communications software platform, which are mainly used in mobile phones and AT module. I of the development team in the project is responsible for the file system for the Flash memory module and the abstract management. With the phone's Flash memory and the expansion of capacity to deal with the object (audio, video, pictures, ringtones, etc.) increase, and embedded file system is an inevitable trend. Documents within the system and into the upper VFS (Virtual File System) and the lower deck of the FAT. The file system has the support of Microsoft FAT12/16/32 file system, and to mount a number of different types of file systems and storage devices. Flash memory is different from the disk hardware features, and we design the Flash storage management system will draw on the virtual memory management and Java's garbage collection mechanism, through all the different types of Flash memory to the abstract and package, so that File system (or other applications) can be as hard as access to Flash memory, and to ensure the safety and integrity of the data.CSW Platform design is the first Flash storage medium for the Application (SMS, Reg, FS, etc.) have a direct operation Flash, which means that they need to consider the Application flash hardware features. This has brought the two areas: duplication of work (each Application must be completed similar work), resulting in relatively high maintenance costs; difficult to achieve stability, lower (Flash and the realization of related hardware). To address these two issues, our virtual disk system (VDS, Virtual Disk System) programme. VDS is in the Application (SMS, Reg, FS) and Flash storage medium between the introduction of a level of abstraction, this upper layer user interface to shield the physical characteristics of Flash memory, when the upper Application came to write data order, VDS for the Application The provision known as the Virtual Disk storage media access interface. In other words, the Application for, Vritual Disk and really no difference between the Hard Disk (or not distinguish between):(1) the Virtual Disk is divided into several block, Application according to the index to block access block; multiple consecutive constitute a sub-block (partition);(2) Application to block the smallest unit of the block;(3) in the same block, can repeat write.VDS programmes on the management and storage medium for the Application of the object itself separated from the management, shielding the Flash equipment hardware features, enhance the entire CSW Platform module; easy to transplant based on the Application Hard Disk to our system. At the same time so can the Flash storage space fully utilized, can guarantee that the average wear block Flash, Flash to extend the useful life of equipment.In this paper, I will elaborate on how to manage the Flash memory of virtual disk system (VDS) Design and Implementation. In this virtual disk system, we have the upper provides a virtual disk, the upper Flash users can not consider the characteristics, but we provide a virtual disk on the operation of its operation and data storage, thus greatly improving the compatibility of the CSW Plattform Sexual. All the VDS application interface is used coded language to C, and in the paper I will describe in detail the interface process, and on garbage collection mechanism, power protection mechanisms to achieve.