If you are like me and have a need for information collection, you can use it to create a “personal knowledge center” (collecting and retrieving your own documents and knowledge anytime, anywhere). And if you are a person who is keen to share, you can create a “private cloud” (shared files, multimedia, knowledge) based on the circle of friends. If you are a man with secrets like me, you are very much about the loss of information. If you care: you can use truecrypt+backup4all-pro to create your “secret data base” truecrypt: encryption tool that can perform encryption at the operating system level, partition level, and file level. There is a decoy mode, so you are not even afraid of forcing a confession. Lost the password and cannot be unlocked. Backup4all Professional: a backup tool that supports version management (such as viewing the hard disk 3 days ago, and you are not afraid of accidental deletion of data), differential backup, incremental backup, compression, encryption, multiple backup media, volume duplication (you can back up Open files), task scheduling (automatically scheduled backups). Finally, this system can actually be a low-power personal server (open source, free and practical, you only need to spend two to three hundred to buy a USB port and support NAS A functional router/switch and then connect the USB disk or mobile hard disk. Recently, I have paid attention to several low-end routers that are irresponsible. Do you want to do it yourself? If it is a commercial production, the manufacturer will definitely choose ARM + linux Develop embedded devices. You are at home now, and there is a card-type computer called /, which should be more in line with your requirements. You develop the hard disk-mounted part, run a web service in /, and a card-type USB flash drive. You can develop web programs to complete functions according to your needs. The advantage of using the web is to avoid separate development of the client.