In computing, memory refers to the state information of a computing system, as it is kept active in some physical structure.

learn more… | top users | synonyms

6
votes
1answer
2k views

Disable random memory address generation in my programs

I'm reading "The art of exploitation" and would like to try some experiments, including reading from and writing to various memory address. I've created some simple programs and trying to overwrite ...
4
votes
2answers
7k views

What is the difference between 32-bit PAE and 64-bit kernels?

I ask this only in regards to memory addressing. I know that a PAE kernel allows the OS to access more memory than a standard 32-bit kernel, however, what are the other implications? What specific ...
5
votes
1answer
954 views

Linux - why is kernel.shmall so low by default?

I run DB2 on Linux where I have to allocate the vast majority of memory on the machine to shared memory segments. This page is typical of the info that I've found about shmall/shmmax: http://www....
1
vote
1answer
140 views

How can I test the system footprint of applications?

I am about to develop a piece of software and I want to ascertain the impact it has on my system. The main things I am look for are load times, memory and CPU usage and shutdown time, although I would ...
15
votes
3answers
5k views

How to detect memory type under Linux?

Which Linux utility can tell me if I have registered or unbuffered ECC memory in my server? Lshw and dmidecode do not work for me; dmidecode provides no information about registered vs. unbuffered: ...
4
votes
3answers
745 views

Preloading the OOM Killer

I don't have any swap partition/file on my machine, and only 2GB of RAM. Sometimes it happens that the memory gets saturated by some process (Xorg+browser+compiler+...) and the system hangs ...
9
votes
3answers
829 views

Memory size for kernel mmap operation

I'm interested in the way Linux mmaps files into the main memory (in my context its for executing, but I guess the mmap process is the same for writing and reading as well) and which size it uses. So ...
0
votes
4answers
531 views

Mnemonics for Unix functions?

Does anyone have any useful mnemonics for remembering the order of function parameters or the return values of Unix system calls? I am suffering from "memory leaks".
9
votes
2answers
917 views

Memory management principle used by Linux

Is memory management in the Linux Kernel done using paging or segmentation or both?
1
vote
1answer
2k views

How to view and change kernel memory size?

How can i view the kernel's share of memory on a machine? How can I increase it? What should I consider before doing it?
7
votes
2answers
976 views

What governs the limits of shell brace expansion?

In this example I refer to the expansion of a sequence of integers, but perhaps(?) the limits would be relevant to all aspects of brace expansion.. This more general view is also of interest to me. ...
9
votes
2answers
3k views

.dtors looks writable, but attempts to write segfault

This is Ubuntu 9.04, 2.6.28-11-server, 32bit x86 $ cat test.c main() { int *dt = (int *)0x08049f18; *dt = 1; } $ readelf -S ./test ... [18] .dtors PROGBITS 08049f14 000f14 000008 ...
8
votes
2answers
2k views

Can I identify my RAM without shutting down linux?

I'd like to price some new RAM for our in-house VMware testing server. (It's a consumer box we use for testing our software on and running business VMs). I've forgotten what kind of RAM it has and I'd ...
2
votes
2answers
998 views

Questions on Linux kernel internals [closed]

I was reading "Linux device drivers, 3rd edition" and faced a few kernel items I don't quite understand. Hope gurus on this forum will help me out. Does the Linux kernel internally operate with ...
8
votes
2answers
1k views

Kernel Panic because of RAM stick?

one of my RAM sticks causes a Kernel Panic on my Ubuntu 10.10 (something like "not syncing" with a lot of memory adresses shown on screen). It's definitely this one RAM stick and not its socket ...
7
votes
3answers
781 views

How to track down memory spikes?

I have an app running on rackspace cloud (ubuntu 10.04). For some reason, over the last 3 nights, the memory has been spiking and then leveling off for about 7 hours before eventually falling off. ...
8
votes
2answers
1k views

How to find out how much memory a program taking

I use htop to watch my processes, but most of services ran are multi threaded, so they are shown on several lines with a % of memory use which in some cases is the same for all, sometimes it varies ...
5
votes
2answers
2k views

Is it possible to execute code in heap space?

I would like to know if i can execute a code piece sitting inside the heap space?
5
votes
2answers
1k views

ZONE_NORMAL and it's association with Kernel/User-pages?

Above is presented a case where I have only 512 MB of physical memory. What I have read up so far, is that ZONE_NORMAL is mapped to the kernel virtual address space as shown. Essentially I have a 512 ...
3
votes
2answers
3k views

How does cached memory work for executables?

I always understood cached memory in Linux (as in free -m) as pages of memory that can be reused if they are needed again, or quickly freed if more memory is needed by new applications (I found this ...
4
votes
3answers
309 views

Randomise or shred memory of an application

Is it possible to randomise or shred memory of a particular application just after its life ends, or better, whenever it deallocates some memory? A command-line utility like this would be perfect: ...