When a process opens a file, it exists on disk even if deleted, as long as the process holds the file open.

当进程打开了某个文件时，只要该进程保持打开该文件，即使将其删除，它依然存在于磁盘中。

youdao

Also unique to Red October was its ability to hide on a machine as if deleted, said Prof Woodward.

BBC: 'Red October' cyber-attack found by Russian researchers

Even if they deleted regular cookies, information about their Web-browsing could have been retained by Microsoft.

WSJ: Latest in Web Tracking: Stealthy 'Supercookies'

Parents also need to be able to review their children's data and have these deleted if they so wish.

ECONOMIST: Small children are a big headache for the social network