The OS file system is read-only for protection.

处于保护的目的，OS的文件系统是只读的。

youdao

In the 1990s, when Copland was initiated, "next-generation" meant supporting memory protection and preemptive multitasking, both of which classic Mac OS lacked.

Copland始于上世纪90年代，“新一代”是指支持内存保护和抢先式多任务，当时的Mac OS不支持这两项功能。

youdao

F-Secure also offers protection against the Palm OS Phage.963 virus and the Palm Liberty Trojan, both of which have come to the public's attention.

CNN: Company scans for viruses targeting PDAs, WAP devices