A Method of Direct I/O Access to Disk Based on JVM

Abstract

The invention relates to a method for disk direct I / O access based on a JVM (Java Virtual Machine). An API layer for providing a file operating function, an adaptation layer for shielding operating system file system access difference, a language transformation layer for supporting multiple programming language transformation, and a direct call I / O layer for executing disk access operation are configured, page cache supporting any operating language and capable of crossing an operating system is realized, and an ability of directly controlling a disk file is obtained. The method comprises the steps of (1) calling a file opening function of the API layer, passing a file path name in a file operating order, and returning a file handle fd; (2) calling a file reading function or a file writing function of the API layer, and providing the passed file handle fd, file offset and other parameters; (3) reading configuration information of a currently running operating system through the adaption layer, judging the type of the operating system according to the configuration information, utilizing functional characteristics of the JVM for calling a language transformation function prestored in the language transformation layer and corresponding to the operating system, and enabling the file operation order to be executed in the current operating system.

Description

technical field [0001] The invention belongs to the technical field of system file input and output, and specifically relates to a method for direct I / O access of disks based on JVM. Background technique [0002] General file read and write operations inevitably use the page cache (Page Cache) of the file system of the operating system. Page Cache has several characteristics: First, it is a global memory space at the operating system level, which is shared among all applications. Because physical memory is limited, there is resource contention. Secondly, the page cache is managed uniformly by the operating system, and applications cannot directly control and interfere with the Page Cache. In actual work, this will bring the following problems: [0003] First, the overall performance of the system is reduced when operating large files. When reading and writing large files, such as when performing operations such as reading, writing, copying, moving, and compressing large ...

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Problems solved by technology

[0007] In order to solve the limitations and deficiencies existing in the prior art, the purpose of the present invention is to provide an API layer for file manipulation functions, an adaptation layer for shielding operating system file system access differences, and support multiple types of programming languages ​​by utilizing JVM functional characteristics. The language conversion layer for conversion and the direct call I / O layer for performing disk access operations can realize any operation language that can cross the page cache of the operating system, obtain the ability to directly manipulate disk files, and fundamentally solve the problem of system downtime. The resulting data loss problem also helps to reduce the consumption of global system resources, and helps to solve the problem of I / O performance degradation of other programs caused by the operation of large files

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