#DIFFERENT MAC OS SYSTEMS DRIVER#

The process of disk I/O goes through the generic block layer of the kernel, the I/O scheduling layer, the device driver layer, and finally to the specific hardware device for processing. If it is found that the data the application wants to read is not in the page cache, it is time to actually initiate an I/O request to the disk. Most current Linux filesystems use the ext4 filesystem by default, just as previous Linux distributions used ext3, ext2, and the older ext by default.ĭisk refers to the system’s storage device, commonly mechanical hard drives, solid state drives, etc. Thus VFS encapsulates all the functionality and abstractions of the underlying file system, and VFS is responsible for forwarding requests from the application layer to a specific file system. VFS provides as large a generic model of the underlying file system as possible, making this model contain an ensemble of all file system functions. Downward, it provides a standard interface to file systems so that file systems from other operating systems can be easily ported to Linux. VFS, upwards, provides a standard file manipulation interface to the application layer. Linux provides support for these file systems through VFS, an intermediate layer. In addition to the standard Linux file systems Ext2/Ext3/Ext4, Windows’ vfat NTFS, etc., there are many other file systems such as reiserfs, xfs, and the network file system nfs. All file systems in the system not only rely on VFS to coexist, but also to work together.

#DIFFERENT MAC OS SYSTEMS SOFTWARE#

VFS, a software layer in the Linux kernel, is used to provide a file system interface to user-space programs it also provides an abstraction in the kernel that allows different file systems to coexist. If we want to find the directory structure of the device files through the root directory on Linux, we have to merge these two file system directories into one, and that is what mounting really means. We know that Linux itself has a file directory structure with the root directory as the root of the tree, and so does each device, which is independent of each other. The disadvantage of everything being a file is that to use any hardware device you have to perform a mount operation with a directory in the root directory, otherwise you can’t use it. Further, operations on files can also be performed across file systems. Although the types are different, the same set of interface is provided for them. The hardware distinction is masked, and all devices are abstracted into files, providing a unified interface to the user. you can use the same set of api’s (read, write) and tools (cat, redirect, pipe) for most resources in unix.Įverything is a file means that for all file (directories, character devices, block devices, sockets, printers, etc.) operations, reading and writing can be handled with functions like fopen()/fclose()/fwrite()/fread(). The most significant benefit of everything being considered a file is that for the input/output resources listed above, only the same set of Linux tools, utilities and APIs are required.

#DIFFERENT MAC OS SYSTEMS MAC OS X#

Things in Linux like documents, directories (called folders under Mac OS X and Windows), keyboards, monitors, hard disks, removable media devices, printers, modems, virtual terminals, and input/output resources like inter-process communication (IPC) and network communication are all streams of bytes defined in file system space. The basic components of Linux I/O: everything is a file Strictly speaking, a file system is a set of abstract data type that implements operations such as storage, hierarchical organization, access and retrieval of data.

Before writing new data, the user does not have to care about which block address on the hard disk is not used, the storage space management (allocation and release) function on the hard disk is done automatically by the file system, the user only needs to remember which file the data is written to. A file system uses the abstract logical concept of files and tree directories instead of using the concept of data blocks for physical devices such as hard disks and CD-ROMs, so that users using a file system to save data do not have to care about how much data is actually saved on the hard disk (or CD-ROM) at the address of the data block, but only need to You only need to remember the directory and file name of the file. A computer’s file system is a method of storing and organizing computer data, which makes it easy to access and find.

Different mac os systems