How to write files into memory

How can I write files to the memory in php? how can I write files to the memory instead of the disk? reading variables is to put them into the memory if you want to keep them in the memory for a long time, third-party software can be used for retrieval. you can assign the information to a variable in the class to find out how the memory cache writes files to the memory.
How can php write files into memory instead of disk?
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The Read variable is put into the memory.
If you want to keep it in memory for a long time, you can retrieve it
Third-party software
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You can assign the information to a variable in the class.
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Find the memory cache