UNIX UNIX Maurice J.Bach

UNIX; ,,,UNIX(,),,

UNIX

10.1 UNIX1. UNIX1) 2) 3) 4) 5)

UNIXUNIX

I/O Shell UNIXUNIX

2. UNIX 10-1 UNIX

1) (1) (2) (3) (4)

2) (1) (2) (3)

10.2 UNIX (1) (2) U (3) (4) 2.1

1. (Process Table Entry) (1) (PID) (2) (UID) (3) (4) (5) U (6) (7) (8) (9) nice (10) P-Link (11) U

2. U(U Area) (1) (2) u-ruid(real user ID) (3) u-euid(effective user ID) (4) (5) (6) (7) I/O (8) (9) (10) (11)

3. (System Region Table) (1) (2) (3) (4) (5)

4. (Per Process Region Table) 10-2

2.2 1.

12345

678910-4

1

20#

3

2. UNIX

PCPSWPCB

0#0#1#12n. . .. . .2.3

0# 1# 1# UNIX

1. schedPID=0 UNIX swapmemory() 2. initPID=1 bootlogin ancestor schedancestor 3. vhandPID=2 memoryswap 4. dbflushPID=3 buffer cache 5. kmdaemonPID=4 6. htepi_daemonPID=5 ht filesystem driver

1. fork(1) (2) (3) (4) (5) (6)

main(){pid_t pid;pid=fork();if(pid==0)exec(program);else if(pid>0)wait();}(1) (2) (3) (4) (5) (6)

2. execint execv(path,argv)char *path,*argv[]int execl(path,arg0[,arg1,...,argn], 0)char * path,*arg0,*arg1,.......,*argn

3. exit exitexit(1) (2) (3) (4)

4. wait wait wait

main(){int i;while((i=fork()==-1);if (i) { printf(Its parent process.\n);wait();printf(My child process,Id number%d exited.\n,i);exit();}else printf(It is child process);printf(It is parent or child process);}ID331

1Its parent processIt is child processIt is parent or child processMy child process,Id number 33 exited

2It is child processIt is parent or child processIts parent processMy child process,Id number 33 exited3It is child processIts parent processIt is parent or child processMy child process,Id number 33 exited

2UN IX Amian() /*A*/{fork();fork();fork();}

mian() /*A*/{fork();fork();fork();}mian() /*B*/{fork();fork();fork();}

ABCEDFGH

3#include main(){char command[32];char *prompt=>;while (printf(%s,prompt),gets(command)!=NULL){if (fork()==0) execl(command,command,(char *) 0); else wait(); }}

24 UNIX CPU CPU

UNIX1CPU

0#swtch

Round Robin With Multiple Feedback)

N .....CPU

123) 45cpu

UNIXn+1 0n

Unix sys V,

Ppri= Pcpu/2+PUSER+Pnice+NZERO

Pcpu CPU

Pnice0~40nicePUSERNZERO

Pcpu/2=0

a) :Pcpu

b) :Pcpu2Pcpu/2CPU

,

0CPU0

user

10.3 1 sleepwakeup234UNIX V IPC

a.bc 3.1 sleepwakeup1. sleep

2. wakeup :

3.2 (signal) 1. 1~19PCB19

killint kill(pid,sig);pidpidpid 0 sig

signal(sig,func)func=1sigfunc=0 sigfunc 0/1func

func==1func==0corefunc 0/1

3.3 1. (Unnamed Pipes) pipe() (Named Pipes) mknod

2. pipe 2) 3) 4)

3.4-1

1. key

2) 10-6

msgget()int msgget(key,msgflag)

key: msgflagipc_CREATkeymsgid

msgid

msgsnd()msgsnd(msgid,msgp,msgsz,msgflg)

msgidmsgpmsgszmsgflg

msgrev()msgrev(msgid,msgp,msgsz,msgtpy,msgflg);msgid msgpmsgszmsgtpy msgflg

3.4-2 1. 10-7

UNIX

int shmget(key,size,shmflg);

key:sizeshmflg

shmid

shmatShmat(shmid,shmaddr,shmflg);

ShmidShmaddrShmflg

shmdt()

int shmdt(shmaddr);

shmaddr:

3.4-3 1) UNIXwaitsignalUNIXwaitsignalsemop( )semget( )semctl( )1.

2)

2. 1) semvalsempid

2) 10-8

3. 1) semget( ) semid

2) semop( ) semop semopsemopsemopsemop

10.4 10.4.1 1. 1) 10-9

2. 1) 1 2

2) 10-11

10.4.2 1. 012301231310

2. (1)1 (2) (3)

3. 64 KB1001

10.4.3 1. 2. 3.