What Is File Spanning?

A computer file is a stream of data stored in a long-term storage device or a temporary storage device, and is under the management of a computer file system. Creating a file means that the user, the operating system, or a program creates related files according to requirements. The newly created file generally contains basic attributes such as file name, file type, file creation time, and file physical location.

Users implement file operations through system calls provided by the file system. The most basic file operations are: create a file, delete a file, read a file, write a file, truncate a file, and set the read / write location of a file. But for an actual OS, in order to facilitate the user to use the file, more operations on the file are provided, such as opening and closing a file and changing the file name.

Create a file. When creating a new file, the system first allocates the necessary external storage space for the new file, and

Files are divided into several types for easy management and control. Because different systems manage files differently, their classification methods for files are also very different. In order to make it easier for the system and users to understand the file type, in many OS, the file type is suffixed with the file name as the extension, and the file name and extension are separated by a "." Sign. The following are several common file classification methods. ^[1]

Create a file data item

In the file system, data items are the lowest level of data organization, which can be divided into the following two types:

(1) Basic data items. This is a character set used to describe an attribute of an object. It is the smallest logical data unit that can be named in a data organization, that is, atomic data, also called a data element or field. Its name is often consistent with its attributes. For example, the basic data items used to describe a student are student number, name, age, class, etc.

(2) Combined data items. It is composed of several basic data items, referred to as group items. For example, a manager is a group item, which consists of two basic items: a manager and an assistant manager. As another example, wages are also a group item, which can be composed of basic items such as basic wages, seniority wages, and reward wages.

Create file record

A record is a collection of related data items that describes the properties of an object in some way. Which data items a record should contain depends on which aspect of the object needs to be described. An object can be treated as a different object due to the different circumstances. For example, when a student is regarded as a student in the class, he should be described using the student number, name, age, and class, and may also include data such as the name and grade of the course he has studied item. However, if a student is treated as a medical object, the data items described by him should be used such as medical record number, name, gender, date of birth, height, weight, blood pressure and medical history.