Because the passwd program cannot be written to by the user, and is very constrained in what it allows the user to do, this setup is usually safe.
因为用户不能编写passwd程序，而且它对允许用户执行的操作有严格限制，所以这个设置常常是安全的。
2
FOCAL was originally written for the PDP-8 by Richard Merrill and could run in a system with only 3000 words of memory (12 bits), with 1000 words for the userprogram.
FOCAL最初是Richard Merrill为PD P - 8编写的且运行在只有3000字内存(12位)和1000字用于用户程序的系统中。
3
The performance of the federated system is comparable to the performance of some existing user-written application program that implements the same distributed query