|
|
Sponsored Content
Operating Systems
HP-UX
Shared Memory segments
Post 100111 by Perderabo on Friday 24th of February 2006 12:48:25 AM
02-24-2006
|
|
10 More Discussions You Might Find Interesting
1. UNIX for Advanced & Expert Users
I am running HP-UX B.11.11.
I'm increasing a parameter for a database engine so that it uses more memory to buffer the disk drive (to speed up performance). I have over 5GB of memory not being used.
But when I try to start the DB with the increased buffer parameter I get told.
"Not... (1 Reply)
Discussion started by: cjcamaro
1 Replies
2. Linux
Hi all :confused: ,
I am new to unix.I have been asked to implement shared memory in user's mode.What does this mean?What is the difference it makes in kernel mode and in users mode?What are the advantages of this impemenation(user's mode)?
And also i would like to know why exactly shared... (0 Replies)
Discussion started by: vijaya2006
0 Replies
3. Programming
what i want to do is have an int that can been written into by 2 processes but my code doesn't seem to work.
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include<stdio.h>
#define KEY1 (1492)
int main()
{
int shmid;
volatile int * addr;... (6 Replies)
Discussion started by: ddx08
6 Replies
4. Programming
hi,
this is the problem: i want to swap a linked list between 4 processes (unrelated), is there any way i can do that just by sending a pointer to a structure?
//example
typedef struct node
{
int x;
char c;
struct node *next;
} node;
or i should send the items ( x,c ) by... (9 Replies)
Discussion started by: elzalem
9 Replies
5. Programming
I need to create a shared library to access an in memory DB. The DB is not huge, but big enough to make it cumbersome to carry around in every single process using the shared library. Luckily, it is pretty static information, so I don't need to worry much about synchronizing the data between... (12 Replies)
Discussion started by: DreamWarrior
12 Replies
6. HP-UX
I am fairly new to HP-UX and trying to get a better understanding of the operating system. While poking around a bit I find myself questioning whether I should be concerned about Shared Memory segments with missing CPID and LPID? For example:
ipcs -mp
IPC status from /dev/kmem as of Mon Mar... (2 Replies)
Discussion started by: scotbuff
2 Replies
7. Programming
I am writing a shared library in Linux (but compatible with other UNIXes) and I want to allow multiple instances to share a piece of memory -- 1 byte is enough. What's the "best" way to do this? I want to optimize for speed and portability.
Obviously, I'll have to worry about mutual exclusion. (0 Replies)
Discussion started by: otheus
0 Replies
8. Programming
I have created a shared memory segment (which size is 64 bytes) using shmget, shmat e.t.c and i want to divide it into 2 areas. One area for input data and one area for output? How can i do that?
Furthermore, When i have to write my input data into the shared memory segment i want to write... (3 Replies)
Discussion started by: mae4
3 Replies
9. Programming
Can someone tell me how many bytes are allocated for C segments(text,data,heap,stack). (3 Replies)
Discussion started by: nandumishra
3 Replies
10. Programming
Hello.
I am new to this forum and I would like to ask for advice about low level POSIX programming.
I have to implement a POSIX compliant C shared library.
A file will have some variables and the shared library will have some functions which need those variables.
There is one special... (5 Replies)
Discussion started by: iamjag
5 Replies
LEARN ABOUT HPUX
shmmax
shmmax(5) File Formats Manual shmmax(5) NAME
shmmax - maximum size (in bytes) for a System V shared memory segment VALUES
Default Allowed values DESCRIPTION
Shared memory is an efficient InterProcess Communications (IPC) mechanism. One process creates a shared memory segment and attaches it to its address space. Any processes looking to communicate with this process through the shared memory segment, then attach the shared memory segment to their corresponding address spaces as well. Once attached, a process can read from or write to the segment depending on the permissions specified while attaching it. This tunable sets the maximum size for such a segment within the system, and is dynamic as of HP-UX 11i. Who is Expected to Change This Tunable? Anyone. Restrictions on Changing Changes to this tunable take effect immediately. When Should the Value of This Tunable Be Raised? should be raised if it is below the maximum and user programs are attempting to segments larger than the current value, and receiving an error message. What Are the Side Effects of Raising the Value? The only effect is that user programs can use to get larger segments. When Should the Value of This Tunable Be Lowered? If you wish to enforce behavior on the user's code, limiting the maximum size of System V segments. What Are the Side Effects of Lowering the Value? None. What Other Tunable Values Should Be Changed at the Same Time? and should be considered because enforcing smaller segments may cause the user's code to try to create more segments to accomplish the task. WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its meaning changed in future releases of HP-UX. Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parameter values. After installation, some tunable parameters may no longer be at the default or recommended values. For information about the effects of installation on tun- able values, consult the documentation for the kernel software being installed. For information about optional kernel software that was factory installed on your system, see at AUTHOR
was developed by HP. SEE ALSO
shmem(5), shmmni(5), shmseg(5). Tunable Kernel Parameters shmmax(5)