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init <BR> <BR>The last step in bootstrapping the kernel starts the /etc/init process. The init process runs as process 1 and always <BR>remains in the background when the system is running. If the system is brought up in a single user mode, init merely <BR>creates a shell on the system console (/dev/console) and waits for it to terminate before running other startup scripts. <BR> <BR>Single User Mode <BR> <BR>Single user shell is always Bourne shell (sh) and it runs as 'root'. It enables the system manager to perform various <BR>administrative functions, such as setting the date, checking the consistency of the file system, reconfiguring the list of <BR>on-line terminals, and so on. At this stage only the root partition is usually mounted. Other file systems will have to be <BR>mounted manually to use programs that do not reside on the root volume. The file system consistency check may be <BR>performed by the command fsck, usually found in the /etc directory. <BR> <BR>Startup Scripts <BR> <BR>The startup scripts are merely shell scripts, so init spawns a copy of sh to interpret them. The startup scripts are defined <BR>and organized differently on different systems. On BSD systems the startup scripts may be found in the /etc directory and <BR>their names begin with rc, e.g., /etc/rc.boot, /etc/rc.single, /etc/rc.local and so on. SVR5 systems define various run levels <BR>in which a specific set of processes are allowed to run. This set of processes is defined in the /etc/inittab file. Each line in <BR>the inittab file describes an action to take. The syntax of inittab entries is: <BR> <BR> id:run-level:action:process <BR> <BR> id uniquely identifies the entry. It may be a one or characters string. <BR> run-level defines the run level in which the entry can be processed. If this field is empty, all run levels are <BR> assumed. <BR> action identifies what actions to take for this entry. These actions may include: <BR> sysinit - perform system initialization, <BR> wait - wait for the process to complete, <BR> once - run the process only once, <BR> respawn - restart the process whenever it dies. <BR> process specifies the shell command to be run, if the entry's run level matches the run level, and/or the action <BR> field indicates such action. <BR> <BR>In general, the following tasks are performed in the startup scripts. <BR> <BR> Set the hostname. <BR> Set the time zone. <BR> Run the file system consistency check. <BR> Mount the system's disk partitions. <BR> Start the daemons and network services. <BR> Configure the network interface. <BR> Turn on the accounting and quotas. <BR> <BR> <BR> <BR>Terms used: boot, bootstrapping kernel, init,swap, virtual memory, run level. <BR> <BR> <BR> <BR> <BR> <BR> <BR> Last modified: Thursday, 21 August 1997 15:09 EST <BR> <URL:<A HREF="http://www.uwsg.indiana.edu/usail/installation/boot-process.html>">http://www.uwsg.indiana.edu/usail/installation/boot-process.html></A> <BR> Copyright 1996, The Trustees of Indiana University <BR> Comments and suggestions to: <A HREF="mailto:usail@indiana.edu">usail@indiana.edu</A> <BR> <BR>-- <BR> 白马带著她一步步的回到中原。白马已经老了,只能慢慢的走, <BR>但终是能回到中原的。江南有杨柳、桃花,有燕子、金鱼…… <BR>汉人中有的是英俊勇武的少年,倜傥潇洒的少年……但这个美 <BR>丽的姑娘就像古高昌国人那样固执: <BR> <BR> 「那都是很好很好的,可是我偏不喜欢。」 <BR> <BR>※ 来源:·BBS 水木清华站 bbs.net.tsinghua.edu.cn·[FROM: 159.226.21.172] <BR><CENTER><H1>BBS水木清华站∶精华区</H1></CENTER></BODY></HTML>
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