It is enough to set the size of 2m per page, and no special hardware requirements are needed.
4 Virtual storage management is to set the hard disk into virtual memory! For details, please open the virtual memory in the Performance option of the System in the process control panel, and select the second option: users set the virtual memory settings themselves, point to a hard disk that is rarely used, and set the maximum and minimum values to fixed values, which are about twice the size of physical memory.
Disk scheduling is a part of disk management. Specifically, when multiple processes request access to the disk, an appropriate scheduling algorithm should be adopted to minimize the average access time (mainly seek) of each process to the disk.
First come, first served scheduling algorithm
The simplest mobile scheduling algorithm is the "first come, first served" scheduling algorithm, which actually does not consider the physical location that visitors request to visit, but only considers the order in which visitors request to visit. For example, if the read-write head is currently performing an output operation on cylinder 50, the cylinders waiting for the visitor to visit in turn are 130,199,32, 159, 15,148,61.
It's 50->130 ...-"90 There are also shortest search algorithms and various scanning algorithms (elevator algorithm
)
7. Structure of sequential file: The physical records in the file are sequentially stored in the storage medium according to their logical recording order in the file. There are two structures: 1 is a continuous structure, and 2 is a linked list structure. The characteristics of continuous structure Once the initial address (the first block number) and the length (the total block number) of the file on the file storage device are known, it can be accessed quickly. However, the file information length of the continuous structure file must be determined in the file description information when the file is created, and cannot be dynamically increased in the future; Moreover, after some parts of the file are deleted, it will leave unused odd space. Therefore, the continuous structure is not suitable for storing user files, database files and other frequently modified files. The characteristic of linked list structure is that logically continuous file information is scattered and stored in several discontinuous physical blocks, in which each physical block has a pointer to another physical block connected in turn. When using the chain structure, you don't need to specify the length of the file in the file description information, you only need to specify the first block number of the file to retrieve the whole file according to the chain pointer. Another feature of the chain structure is that the file length can be dynamically increased, and an information block can be inserted or deleted between any information blocks by adjusting the chain pointer.
Firstly, the file allocation table (acronym: FAT) is a partially patented file system invented by Microsoft [1], which is used by MS-DOS with non-NT kernel and Microsoft windows.
The idea is that the FAT file system consists of four different parts.
1 reserve sector 2FAT area 3 Root area 4 data area (see for yourself).
An index file consists of an index table and a main file. A file whose main files are sorted by the main keyword is called an index file (index order file).
In order to make full use of the parallel working characteristics of computer hardware resources, multi-level index is introduced.
Its basic principle is similar to quadtree, which divides the spatial range into multiple levels, and the space divided by each level adopts cell grid index to form a multi-level grid space to adapt to the efficient query of different ranges.