SYSTEM PROGRAMMING
CS 350
PROCESSES AND IPC
COMMAND LINE REDIRECTION
cmd > file standard output to file
cmd < file
cmd !" file
cmd n> file
cmd n>&m
file to standard input
append standard output to file
file descriptor n to file
File descriptor n to file descriptor m
PROCESSES AND IPC
TWOWRITERS DEMO
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
OS: Open File Table
Process: FDs
PROCESSES AND IPC
TWOWRITERS DEMO
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
FTE: FILE1
READABLE? WRITABLE? OFFSET
OS: Open File Table
Process: FDs
PROCESSES AND IPC
TWOWRITERS DEMO
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
FTE: FILE1
READABLE? WRITABLE? OFFSET
OS: Open File Table
INODE: FILE1
FILE1
Process: FDs
Disk
PROCESSES AND IPC
TWOWRITERS DEMO
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
FTE: FILE1
READABLE? WRITABLE? OFFSET
FTE: FILE1
READABLE? WRITABLE? OFFSET
OS: Open File Table
INODE: FILE1
FILE1
Process: FDs
Disk
PROCESSES AND IPC
DUPLICATE FILE DESCRIPTOR
int dup(int filedes)
Returns a file descriptor duplicate of the input file descriptor
PROCESSES AND IPC
DUPLICATE FILE DESCRIPTOR
int dup(int filedes)
Returns a file descriptor duplicate of the input file descriptor
The new file descriptor and filedes refer to the same file table entry!
PROCESSES AND IPC
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
FTE: FILE1
READABLE? WRITABLE? OFFSET
OS: Open File Table
INODE: FILE1
FILE1
Process: FDs
Disk
TWOWRITERS-DUP DEMO
PROCESSES AND IPC
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
FTE: FILE1
READABLE? WRITABLE? OFFSET
OS: Open File Table
INODE: FILE1
FILE1
Process: FDs
Disk
TWOWRITERS-DUP DEMO
PROCESSES AND IPC
DUPLICATE FILE DESCRIPTOR
int dup2(int filedes1, int filedes2)
Makes filedes2 a duplicate of filedes1
filedes1 and filedes2 will refer to the same file table entry!
PROCESSES AND IPC
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
FTE: FILE1
READABLE? WRITABLE? OFFSET
OS: Open File Table
INODE: FILE1
FILE1
Process: FDs
Disk
TWOWRITERS-DUP2 DEMO
PROCESSES AND IPC
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
FTE: FILE1
READABLE? WRITABLE? OFFSET
OS: Open File Table
INODE: FILE1
FILE1
Process: FDs
Disk
TWOWRITERS-DUP2 DEMO
PROCESSES AND IPC
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
FTE: FILE1
READABLE? WRITABLE? OFFSET
OS: Open File Table
INODE: FILE1
FILE1
Process: FDs
Disk
TWOWRITERS-DUP2 DEMO
PROCESSES AND IPC
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
FTE: FILE1
READABLE? WRITABLE? OFFSET
OS: Open File Table
Parent: FDs
FORK2 DEMO
PROCESSES AND IPC
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
FTE: FILE1
READABLE? WRITABLE? OFFSET
OS: Open File Table
Parent: FDs Child: FD
FORK2 DEMO
AAACpXicdZHLThsxFIY900Ih3NKyZGMR0bKKZnKZwA7BhgWtAJGAlIkij3OSWHg8I/sMUjTNm/Up2PE2eELaNE05lqX//87x7ThKp TDoeS+O++Hj2vqnjc3S1vbO7l7585eOSTLNoc0TmeiHiBmQQkEbBUp4SDWwOJJwHz1eFPn7J9BGJOoOJyn0YjZSYig4Q4v65V9hBCO hcmRRJpme5j+5HdNwXGxYol+pR8Nw4fwlV1ty9SXXWLgf7asrS5orJFghrRUSDhI0CxqCGvy5bL9c8aqnrcZp4NNCBE0/KESz3mzV qF/1ZlEh87jul5/tdjyLQSGXzJiu76XYy5lGwSVMS2FmIGX8kY2ga6ViMZhePuvylB5ZMqDDRNupkM7o3ytyFhsziSNbGTMcm39zBf xfrpvh8KSXC5VmCIq/HTTMJMWEFl9GB0IDRzmxgnEt7F0pHzPNONqPLdkm/H4pfV90alU/qDZuGpWz83k7NsgBOSTHxCctckYuyTVp E+4cOpfOjXPrfnO/u3du563UdeZr9slSuP1XVKvGzg==
0
1
2
3
4
NULL 5
NULL 6
NULL 7
NULL . . .
PROCESSES AND IPC
PIPES
A unidirectional dataflow (i.e. single channel) communication mechanism
‣ Input into write end
‣ Output from read end: FIFO order
PROCESSES AND IPC
PIPES
int pipe(int fd[2])
Creates a pipe:
‣ fd[0] is read end
‣ fd[1] is write end
PROCESSES AND IPC
PIPES
int pipe(int fd[2])
Common Use:
‣ Redirect sources’s STDOUT to write end
‣ Redirect destination’s STDIN from read end
PROCESSES AND IPC
CLOSING PIPES
A pipe will persist until all associated descriptors are closed.
PROCESSES AND IPC
CLOSING PIPES
A pipe will persist until all associated descriptors are closed.
A pipe whose read or write end has been closed is called widowed.
PROCESSES AND IPC
CLOSING PIPES
A pipe will persist until all associated descriptors are closed.
A pipe whose read or write end has been closed is called widowed.
‣ Widowing a pipe is the only way to read EOF
‣ Reading a widowed pipe returns a zero count
‣ Writing to a widowed pipe causes the writer to receive SIGPIPE
PROCESSES AND IPC
PIPE0 DEMO
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
FTE: PIPEFD[0]
READABLE? WRITABLE? OFFSET
FTE: PIPEFD[1]
READABLE? WRITABLE? OFFSET
OS: Open File Table
Process: FDs
Write end Read end
PROCESSES AND IPC
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
OS: Open File Table
Parent: FDs Child: FD
PIPE1 DEMO
AAACpXicdZHLThsxFIY900Ih3NKyZGMR0bKKZnKZwA7BhgWtAJGAlIkij3OSWHg8I/sMUjTNm/Up2PE2eELaNE05lqX//87x7ThKp TDoeS+O++Hj2vqnjc3S1vbO7l7585eOSTLNoc0TmeiHiBmQQkEbBUp4SDWwOJJwHz1eFPn7J9BGJOoOJyn0YjZSYig4Q4v65V9hBCO hcmRRJpme5j+5HdNwXGxYol+pR8Nw4fwlV1ty9SXXWLgf7asrS5orJFghrRUSDhI0CxqCGvy5bL9c8aqnrcZp4NNCBE0/KESz3mzV qF/1ZlEh87jul5/tdjyLQSGXzJiu76XYy5lGwSVMS2FmIGX8kY2ga6ViMZhePuvylB5ZMqDDRNupkM7o3ytyFhsziSNbGTMcm39zBf xfrpvh8KSXC5VmCIq/HTTMJMWEFl9GB0IDRzmxgnEt7F0pHzPNONqPLdkm/H4pfV90alU/qDZuGpWz83k7NsgBOSTHxCctckYuyTVp E+4cOpfOjXPrfnO/u3du563UdeZr9slSuP1XVKvGzg==
0
1
2
3
4
NULL 5
NULL 6
NULL 7
NULL . . .
FTE: PIPEFD[0]
READABLE? WRITABLE? OFFSET
FTE: PIPEFD[1]
READABLE? WRITABLE? OFFSET
PROCESSES AND IPC
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
OS: Open File Table
Parent: FDs Child: FD
PIPE2 DEMO
AAACpXicdZHLThsxFIY900Ih3NKyZGMR0bKKZnKZwA7BhgWtAJGAlIkij3OSWHg8I/sMUjTNm/Up2PE2eELaNE05lqX//87x7ThKp TDoeS+O++Hj2vqnjc3S1vbO7l7585eOSTLNoc0TmeiHiBmQQkEbBUp4SDWwOJJwHz1eFPn7J9BGJOoOJyn0YjZSYig4Q4v65V9hBCO hcmRRJpme5j+5HdNwXGxYol+pR8Nw4fwlV1ty9SXXWLgf7asrS5orJFghrRUSDhI0CxqCGvy5bL9c8aqnrcZp4NNCBE0/KESz3mzV qF/1ZlEh87jul5/tdjyLQSGXzJiu76XYy5lGwSVMS2FmIGX8kY2ga6ViMZhePuvylB5ZMqDDRNupkM7o3ytyFhsziSNbGTMcm39zBf xfrpvh8KSXC5VmCIq/HTTMJMWEFl9GB0IDRzmxgnEt7F0pHzPNONqPLdkm/H4pfV90alU/qDZuGpWz83k7NsgBOSTHxCctckYuyTVp E+4cOpfOjXPrfnO/u3du563UdeZr9slSuP1XVKvGzg==
0
1
2
3
4
NULL 5
NULL 6
NULL 7
NULL . . .
FTE: PIPEFD[0]
READABLE? WRITABLE? OFFSET
FTE: PIPEFD[1]
READABLE? WRITABLE? OFFSET
PROCESSES AND IPC
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
OS: Open File Table
Parent: FDs Child: FD
PIPE2 DEMO
AAACpXicdZHLThsxFIY900Ih3NKyZGMR0bKKZnKZwA7BhgWtAJGAlIkij3OSWHg8I/sMUjTNm/Up2PE2eELaNE05lqX//87x7ThKp TDoeS+O++Hj2vqnjc3S1vbO7l7585eOSTLNoc0TmeiHiBmQQkEbBUp4SDWwOJJwHz1eFPn7J9BGJOoOJyn0YjZSYig4Q4v65V9hBCO hcmRRJpme5j+5HdNwXGxYol+pR8Nw4fwlV1ty9SXXWLgf7asrS5orJFghrRUSDhI0CxqCGvy5bL9c8aqnrcZp4NNCBE0/KESz3mzV qF/1ZlEh87jul5/tdjyLQSGXzJiu76XYy5lGwSVMS2FmIGX8kY2ga6ViMZhePuvylB5ZMqDDRNupkM7o3ytyFhsziSNbGTMcm39zBf xfrpvh8KSXC5VmCIq/HTTMJMWEFl9GB0IDRzmxgnEt7F0pHzPNONqPLdkm/H4pfV90alU/qDZuGpWz83k7NsgBOSTHxCctckYuyTVp E+4cOpfOjXPrfnO/u3du563UdeZr9slSuP1XVKvGzg==
0
1
2
3
4
NULL 5
NULL 6
NULL 7
NULL . . .
FTE: PIPEFD[0]
READABLE? WRITABLE? OFFSET
FTE: PIPEFD[1]
READABLE? WRITABLE? OFFSET
PROCESSES AND IPC
AAA CoHicd VFbT9s wFHYCG9 BdKPCI kCyqTX uqktKm4 w2NFx7 KTVoBr akqxz1t LRwnsk 8mVVl/ F/+DN/4 NTikQ1 u1Ylr7v Oxcfnx OlUhj0 vAfHXVl 9935tf aPy4eO nz5vVre 0rk2Sa Q5cnMt E3ETMgh YIuCpR wk2pgc SThOro9 LvzXv0 EbkaifO E2hH7O xEiPBG VppUL0L IxgLlS OLMsn0 LP/D7Zm Fk6Jgx aNfaRg uiF8mjT I5KJNm mbQsOe t2Oq9Ks KS0l5R wmKBZVk ENX/oc VGte/b DdPAx8W oCg5Qc FaB202 g3q1725 1cjCLg bVe1uV ZzEo5JI Z0/O9F Ps50yi 4hFklzA ykjN+y MfQsVCw G08/nA 57RL1Y Z0lGi7V VI52o5 I2exMd M4spExw 4n521e I//L1M hx97+dC pRmC4k 8PjTJJ MaHFtuh QaOAop xYwroXt lfIJ04 yj3WnF DuH5p/T /4KpR9 4N687J ZO/qxGM c62SX7 5BvxSZ sckRNyQ bqEO3v OsdNxT t1998Q9 dy+fQl 1nkbND3 pj76xH tRcX8< /latexi t>
0
1
2
3
4
5 NULL
6 NULL
7 NULL
. . . NULL
FTE: TERMINAL
INPUT
FTE: TERMINAL
OUTPUT
OS: Open File Table
Parent: FDs Child: FD
PIPE2 DEMO
AAACpXicdZHLThsxFIY900Ih3NKyZGMR0bKKZnKZwA7BhgWtAJGAlIkij3OSWHg8I/sMUjTNm/Up2PE2eELaNE05lqX//87x7ThKp TDoeS+O++Hj2vqnjc3S1vbO7l7585eOSTLNoc0TmeiHiBmQQkEbBUp4SDWwOJJwHz1eFPn7J9BGJOoOJyn0YjZSYig4Q4v65V9hBCO hcmRRJpme5j+5HdNwXGxYol+pR8Nw4fwlV1ty9SXXWLgf7asrS5orJFghrRUSDhI0CxqCGvy5bL9c8aqnrcZp4NNCBE0/KESz3mzV qF/1ZlEh87jul5/tdjyLQSGXzJiu76XYy5lGwSVMS2FmIGX8kY2ga6ViMZhePuvylB5ZMqDDRNupkM7o3ytyFhsziSNbGTMcm39zBf xfrpvh8KSXC5VmCIq/HTTMJMWEFl9GB0IDRzmxgnEt7F0pHzPNONqPLdkm/H4pfV90alU/qDZuGpWz83k7NsgBOSTHxCctckYuyTVp E+4cOpfOjXPrfnO/u3du563UdeZr9slSuP1XVKvGzg==
0
1
2
3
4
NULL 5
NULL 6
NULL 7
NULL . . .
FTE: PIPEFD[0]
READABLE? WRITABLE? OFFSET
FTE: PIPEFD[1]