10 More Discussions You Might Find Interesting
1. UNIX for Beginners Questions & Answers
So, I would ask you a piece of advice about which books or titles could give me comprehensive information about virtual memory in UNIX. Especially, I would found out that virtual address translation corresponds structures of kernel!
Thanks! (2 Replies)
Discussion started by: Fadedfate
2 Replies
2. AIX
Hi
I am running AIX 5.2. My server is running low on memory. It it using about 1307775 file pages on a total of 1511424 (from vmstat -v).
I looked at the memory yesterday morning, and we had plenty of free memory. I did a backup from Windows (ftp mget command) of a large file selection. From... (5 Replies)
Discussion started by: fredrivard
5 Replies
3. HP-UX
Hello! just wanna ask if how UNIX implements virtual memory, and how it handles page faults, working sets, page sizes and how it reconciles thrashing issues? if you know some sources where I can have some idea, just post it here. thx (1 Reply)
Discussion started by: kjcruz
1 Replies
4. UNIX for Dummies Questions & Answers
Hi,
Can anyone please help me workout how much virtual memory I have running on a T2000 running Solaris 10. Thanks
# df -h
swap 3.5G 1.0M 3.5G 1% /etc/svc/volatile
swap 3.5G 208K 3.5G 1% /tmp
swap 3.5G 56K ... (2 Replies)
Discussion started by: jamba1
2 Replies
5. UNIX for Dummies Questions & Answers
Hi All,
Does anyone know what the best commands in the UNIX command line are for obtaining this info:
current CPU usage
memory usage
virtual memory usage
preferably with date and time parameters too?
thanks
ocelot (4 Replies)
Discussion started by: ocelot
4 Replies
6. AIX
Hi,
Would any one be so kind to explain me :
are ulimits defined for each user seperately ? When ?
Specialy what is the impact of :
max locked memory
and
virtual memory
on performance of applications for a user.
Many thanks.
PS :
this is what I can see in MAN :
ulimit ]
... (5 Replies)
Discussion started by: big123456
5 Replies
7. HP-UX
Hi!
I work with HP-UX and I have to monitorize the use of virtual memory for different processes.
(java processes for Tibco Adapter) And if these processes exceed a limit send a message to the syslog.
I donīt know how to monitorize this...
Should I do a script? or use an aplication, for example... (3 Replies)
Discussion started by: Kurohana
3 Replies
8. Programming
Hi,
First of all I appreciate this group very much for its informative discussions and posts.
Here is my question.
I have one process whose virtual memory size increases linearly from 6MB to 12MB in 20 minutes. Does that mean my process has memory leaks?
In what cases does the... (4 Replies)
Discussion started by: shriashishpatil
4 Replies
9. UNIX for Dummies Questions & Answers
Hi,
can anyone explain me what virtual memory is ( for which we use vmstat commande line ) comparing with RAM ?
many thanks before. (2 Replies)
Discussion started by: big123456
2 Replies
10. Shell Programming and Scripting
HP UNIX version 10.20
I have been using system variable names in some shell scripts in order to automate execution of some test software. I have recently found that there appears to be a restriction with the 'ls' command when listing specific files (e.g. ls *.c). If I pipe the output into wc, I... (5 Replies)
Discussion started by: degwright
5 Replies
mem(7D) Devices mem(7D)
NAME
mem, kmem, allkmem - physical or virtual memory access
SYNOPSIS
/dev/mem
/dev/kmem
/dev/allkmem
DESCRIPTION
The file /dev/mem is a special file that provides access to the physical memory of the computer.
The file /dev/kmem is a special file that provides access to the virtual address space of the operating system kernel, excluding memory
that is associated with an I/O device.
The file /dev/allkmem is a special file that provides access to the virtual address space of the operating system kernel, including memory
that is associated with an I/O device. You can use any of these devices to examine and modify the system.
Byte addresses in /dev/mem are interpreted as physical memory addresses. Byte addresses in /dev/kmem and /dev/allkmem are interpreted as
kernel virtual memory addresses. A reference to a non-existent location returns an error. See ERRORS for more information.
The file /dev/mem accesses physical memory; the size of the file is equal to the amount of physical memory in the computer. This size may
be larger than 4GB on a system running the 32-bit operating environment. In this case, you can access memory beyond 4GB using a series of
read(2) and write(2) calls, a pread64() or pwrite64() call, or a combination of llseek(2) and read(2) or write(2).
ERRORS
EFAULT Occurs when trying to write(2) a read-only location (allkmem), read(2) a write-only location (allkmem), or read(2) or
write(2) a non-existent or unimplemented location (mem, kmem, allkmem).
EIO Occurs when trying to read(2) or write(2) a memory location that is associated with an I/O device using the /dev/kmem spe-
cial file.
ENXIO Results from attempting to mmap(2) a non-existent physical (mem) or virtual (kmem, allkmem) memory address.
FILES
/dev/mem Provides access to the computer's physical memory.
/dev/kmem Provides access to the virtual address space of the operating system kernel, excluding memory that is associated with an
I/O device.
/dev/allkmem Provides access to the virtual address space of the operating system kernel, including memory that is associated with an
I/O device.
SEE ALSO
llseek(2), mmap(2), read(2), write(2)
WARNINGS
Using these devices to modify (that is, write to) the address space of a live running operating system or to modify the state of a
hardware device is extremely dangerous and may result in a system panic if kernel data structures are damaged or if device state is
changed.
SunOS 5.10 18 Feb 2002 mem(7D)
How Unix implements virtual memory?