Answer:
Charles Babbage, (born December 26, 1791, London, England—died October 18, 1871, London), English mathematician and inventor who is credited with having conceived the first automatic digital computer.
Explanation:
The idea of mechanically calculating mathematical tables first came to Babbage in 1812 or 1813. Later he made a small calculator that could perform certain mathematical computations to eight decimals. Then in 1823 he obtained government support for the design of a projected machine, the Difference Engine, with a 20-decimal capacity. The Difference Engine was a digital device: it operated on discrete digits rather than smooth quantities, and the digits were decimal (0–9), represented by positions on toothed wheels rather than binary digits (“bits”). When one of the toothed wheels turned from nine to zero, it caused the next wheel to advance one position, carrying the digit. Like modern computers, the Difference Engine had storage—that is, a place where data could be held temporarily for later processing.
Answer:
B seems like the best answer to me.
Explanation:
Answer:
This is the complete correct program:
#include <stdio.h>
#include<sys/types.h>
#include<unistd.h>
int value = 128;
int main()
{
pid_t pid;
pid=fork();
if (pid==0) /* child process */
{
value +=8;
return 0; }
else if (pid > 0) {/* parent process */
wait (NULL);
printf ("PARENT: value =%d\n" ,value); /* LINEA */
return 0;
}
}
The output of the LINE A is:
PARENT: value = 128
Explanation:
The fork() function used in the program creates a new process and this process is the child process. The child process is same as the original process having its own address space or memory.
In the child process the value of pid is 0. So the if condition checks if pid==0. Then the child process adds 8 to the value of its variable according to the following statement
value +=8;
Now the original process has value = 128. In else if part the parents process has the value of pid greater than zero and this portion of the program is of the parent process :
else if (pid > 0)
{ wait (NULL);
printf ("PARENT: value =%d\n" ,value);
return 0; }
So the value 128 is printed at the end in the output.
wait(NULL) is used to wait for the child process to terminate so the parent process waits untill child process completes.
So the conclusion is that even if the value of the variable pid is changed in the child process but it will not affect the value in the variable of the parent process.
Gamma rays are not used for communication.
-- We have no safe way to generate them.
-- We have no cheap way to detect them.
-- We have no way to impress information on them (modulate them).
-- They're dangerous.
Otherwise they're ideal for communication.
