Yes, by "loop through" I mean that
is 10,000. 389 is the lux factor passed to the TRandom1 class constructor. It determines the quality and time required to generate the random numbers.
Hello!
First of all, forgive me for bad English.
When I starts new thread (pthread_create), system allocates some memory for it (for example, for thread's stack). I wonder when does it deallocate this memory? The problem is that I have a program which sometimes creates new threads and sometimes... (3 Replies)
Hi all,
I have a HP-UX Server with 4 gigabytes of physical RAM. When I use the 'Glance' utility to see what my memory utilization is, my memory usage shows up maxed out at 99%. I shut off all the known processes that I'm running on that box and the memory utilization is still at 78% (with Swap... (3 Replies)
I have a scenario like the client has to search for the active server.There will be many servers.But not all server are active.And at a time not more than one server will be active.
The client will be in active state always i.e, it should always search for an active server until it gets one.I... (1 Reply)
Hi Experts
I need some help in static memory allocation in C. I have a program in which I declared 2 variables, one char array and one integer. I was little surprised to see the addresses of the variables.
First:
int x;
char a;
printf("%u %u\n', &x, a);
I got the addresses displayed... (2 Replies)
Hello Guys
I have a small confusion in the dynamic memory allocation concept.
If we declare a pointer say a char pointer, we need to allocate adequate memory space.
char* str = (char*)malloc(20*sizeof(char));
str = "This is a string";
But this will also work.
char* str = "This... (2 Replies)
When we dynamically allocate the memory say 100 integers say
int *x = new int(1000);
then does entire chunk of memory gets allocated at once after the completion of the statement?
I mean will the the concept of page fault come into picture over here? (3 Replies)
hello all..
i'm a beginner in shell scripting. I need to know what is really happening when we are creating a variable in shell scripting? how memory is allocated for that variable? (3 Replies)
hi
in the following code, how the memory is allocated for a1 which holds the values of a2 after cpy function call.
#include <stdio.h>
#include <string.h>
void cpy(char* d, const char* s){
while(*d++=*s++);
}
main(){
char* a1;
char* a2="done";
cpy(a1,a2);
... (3 Replies)
I am using ubuntu. I have written a program to calculate prime factors. it works perfectly fine till entered number is less than 9989 (or so ) but when one enters a number higher than that, for example 15000, it does not work. Can anyone guide me whats the problem ? although new codes are welcome,... (2 Replies)
Discussion started by: Abhishek_kumar
2 Replies
LEARN ABOUT OSX
random
RANDOM(4) BSD Kernel Interfaces Manual RANDOM(4)NAME
random , urandom -- random data source devices.
SYNOPSIS
pseudo-device random
DESCRIPTION
The random device produces uniformly distributed random byte values of potentially high quality.
To obtain random bytes, open /dev/random for reading and read from it.
To add entropy to the random generation system, open /dev/random for writing and write data that you believe to be somehow random.
/dev/urandom is a compatibility nod to Linux. On Linux, /dev/urandom will produce lower quality output if the entropy pool drains, while
/dev/random will prefer to block and wait for additional entropy to be collected. With Yarrow, this choice and distinction is not necessary,
and the two devices behave identically. You may use either.
OPERATION
The random device implements the Yarrow pseudo random number generator algorithm and maintains its entropy pool. Additional entropy is fed
to the generator regularly by the SecurityServer daemon from random jitter measurements of the kernel. SecurityServer is also responsible
for periodically saving some entropy to disk and reloading it during startup to provide entropy in early system operation.
You may feed additional entropy to the generator by writing it to the random device, though this is not required in a normal operating envi-
ronment.
LIMITATIONS AND WARNINGS
Yarrow is a fairly resilient algorithm, and is believed to be resistant to non-root. The quality of its output is however dependent on regu-
lar addition of appropriate entropy. If the SecurityServer system daemon fails for any reason, output quality will suffer over time without
any explicit indication from the random device itself.
Paranoid programmers can counteract this risk somewhat by collecting entropy of their choice (e.g. from keystroke or mouse timings) and seed-
ing it into random directly before obtaining important random numbers.
FILES
/dev/random
/dev/urandom
HISTORY
A random device appeared in the Linux operating system.
Darwin September 6, 2001 Darwin