how to calculate (if possible) the end address of an image file in a flash memory. I'm trying to create a checksum and checkheader function and the info that I got is the file's offset, how many sector it consumes and its size. I kinda need the end address, sad thing is, I don't know how to calculate it.test.img's start address is 0, the size is 0x20000 and consumes 3 sectors.
View 6 RepliesI am trying to write a script to calculate the total amount of installed memory to use during an anaconda kickscript, so the swap file is created at 2 x the installed memory. I so far have the amount of installed RAM DIMMS but need a way to total them up and produce a varible I can use in the pre section of the install.
Code:
dmidecode -t 17 | grep Size | awk ' { print $2 }'
Output:
2048
2048
Note: on some servers there could be from 1 DIMM up to 16 DIMMS installed so the script needs to be able to handle this. I also can not use bc as it does not exist during the install stage. I am guessing I need a while loop to do this and use expr but do not know where to start for this logic.
if i attach a shared memory to my process whch part of the address space it will add(like stack, heap, data, code...).
View 3 Replies View RelatedWhen I try to access at physical address (0xD0000), we known that it is necessary to convert physical address to virtual address using function IOREMAP(0xD0000, 1024) and return me 0xC00D0000.
Now our doubt is when I have a board with I/O in address 0x150, is it necessary to convert this address to other virtual address??? or with inb(0x150) return me state of I/O in this address? How can I known where is this I/O address in my map memory?
If i have a shell script to run on a Linux unit, which has a command to Reset(or say upgrade) the unit in between the script.Is it possible to find out the memory address of the next waiting command so that i can store the address to any environment variable in flash , then after Reset will continue Run from the stored address.
View 3 Replies View RelatedSo I'll try to be brief and to the point here: I've got a couple of C / C++ apps that communicate with one another via shared memory. These worked completely fine until.. well, about twenty minutes ago when I finished making some network card changes and suddenly, I've got a weird problem going on. At one point, Parent app waits for Child app to set a boolean indicating it's finished initialization. This worked fine the last time I ran this app up (a few days ago). But right now, the shared flag never seems to get triggered (I've added a printf("Waiting..."); in Parent app until the flag is set). All the code leading up to it being set in Child app seem to be running smoothly, so I tried spitting out the addresses of the shared memory locations. The addresses mapped by Parent app and Child app are different; this seemed odd, so I went back and wrote a simple miniature app that just opened a shared structure on my own box, and I get the same thing - different addresses - but the miniature apps work just fine.
Is it normal for a shared memory space to be mapped to two different addresses across two processes?
If so, does anyone have any idea what might be the issue at hand with my Parent / Child app scenario? The Child creates the shared memory, the Parent has a wait before it opens it, and if it doesn't exist should fail (opening with PROT_READ | PROT_WRITE)... it doesn't fail so it's evidently there.
All of this worked until literally just a few hours ago and I made some changes to my network cards, and I can't even imagine how that could have changed whether or not shared memory mapping worked...
Kernel 2.6.21.5, slackware 12.0
nasm 2.03.01
ld 2.17
GNU gdb 6.6
This GDB was configured as "i486-slackware-linux".
Code:
What could the cause of the message output by gdb possibly be? Reading some tutorials, I've learn the flat memory model is used in linux. So, in particular, I needn't care about the DS segment register.
Also, line 7 in the listing above, suggests nasm is assuming 32-bit addressing and so, I think it is using the flat memory model.
I am writing a game in C with SDL. I can successfully display one image on the screen and animate it. However, I am having a lot of issues getting the background to display using the same method. I was asking for help on SDL related forums, but I determined that the issue is not SDL related, and it is actually a pointer issue. However, I can't find where I'm going wrong.
Code:
#include <SDL/SDL.h>
struct image
[code]...
I allocated a chunk of memory using kmalloc in a Device Driver. Kmalloc provides a pointer to the allocated memory. This is one of my first few drivers.
I assume that the address returned is a Virtual address. I need to find the physical address of the memory location. I am working on an Intel 64 bit Fedora machine. I used the virt_to_phys() routine present in <asm/io_64.h>. I found that this routine returns an unsigned long value (32 bit) instead of an unsigned long long value (64 bit). Moreover, it seems that it simply returns the address - OFFSET instead of extracting the value in the page tables.
So is there any function / system call in Linux which will allow me to see the actual physical address on the Intel 64 arch.
I have set swappiness to 0:
# sysctl vm.swappiness
vm.swappiness = 0
According to various sources, this should mean that applications have priority over file chaches, and swap should only be used when the applications themselves need more memory than is physically available. So I naively took the value free provides in the '-/+ buffers/cache' line as 'free' as the amount of memory to be available on the server. Unfortunately this is not even close to true: On a server with 20GB RAM, memory utilization by this measure never reached 50%, yet the system swaps.
I then figured out that I could use 'sync; echo 3 > /proc/sys/vm/drop_caches' to drop cached stuff. I was very surprised to still have 12.5 GB cached data after doing that. I am figuring that it's those 12.5 GB which force the system to start swapping. I also tried to use /proc/meminfo to figure out how that cached memory is used (by comparing its content before and after dropping caches). However, I don't see the correlation between the numbers provided there and what part of the cache can be dropped.
The closest match seems to be the 'Mapped' line, which was 10GB. I am pretty sure that being mmapped keeps the kernel from dropping cache. However, the value is 2.5 GB less than the cache which can't be dropped. So it is not the whole answer. What I am looking for is some way to determine how much memory the kernel could provide by dropping stuff if he needs to because of memory pressure. Is there maybe a way to simulate drop_caches without actually doing so?
The amount of potentially available memory does not have to be scientifically correct, but the number should at least be always in the right ballpark, which right now, it ain't... The point here is that it's a productive system. Sy doing stuff like dropping caches or filling memory until the system starts to swap is not a permanent solution to figure out the value. By the way, it turned out that postgres was the culprit in this concrete case, stopping it made dropping all caches possible, but that does not answer the general question of how to estimate available memory...
1. Is my assumption correct that I can subtract 'Mapped' from the freeable cache memory completely?
2. Where could the other 2.5 GB be used?
3. Is there a way to get a better guess of how much memory the system can free if necessary, before swap has to be used?
is there a way to calculate the total memory consumed by user ?
View 12 Replies View RelatedI want to calculate the total amount of memory used by the system, Someone please confirm if the below formula is correct.Quote:
((memUsed-mebBuffers-memCached)*100)/memUsed => totalMemoryUsed%
Code:
free -o
total used free shared buffers cached
Mem: 8167004 8115292 51712 0 87680 1444676
Swap: 8388584 3252996 5135588
((8115292-87680-1444676)*100/8115292) => 81%
As per the above calculation 81% of memory is used.Is this correct? and if so Am I running out of memory?what is the limit in % that I should maintain for a better performance?
How do I calculate broadcast adrress if the address space is 192.168.36.16/28 then what would be broadcast address.
View 7 Replies View RelatedUsing 10.04 Netbook version. I am finding on my Asus EEE 901 that sometimes file copy just seems to freeze - seems to happen usually when copying from the built-in SSD memory to the plug-in SDHC memory card. I have tried reformatting the card and using a different card. It is not just this computer since I found the same thing on my last Asus which was the 900 model.
I am told that there are issues with Nautilus. Is there anything which can be done to improve this or is there anything else which I can install besides Nautilus? I am assuming that there is some issue related to Ubuntu's handling of SDHC memory cards.
It is becoming annoying because it seems to work sometimes and then not. When it happens only option seems to be to turn the netbook off and on again. Even if the file copy is cancelled the card seems to be unaccesible until rebooted.
Also after a certain point it seems that when I try and copy new files to the card, they appear to copy ok but obviously are corrupt in some way - when you try to play videos for instance they are faulty.
I am using malloc and frees a lot in my program. It shows its allocated but when i remove it doesnt show as the memory is removed(I am using the top command to view VIRT memory usage). If this continously grows what would happen to my program (Will it go out of memory?)
View 4 Replies View RelatedI am writing an application that wants to access periphals registers outside the standard (allowed) memory area.
Doing so gets me "segmentation fault".
I know, this is natural behaviour.
One way of getting around this is writing the module which has to be loaded by linux. I will consider this some time later.
For now, I want to come to some quick result and allow linux or gcc compiler to write to those memory areas of periphals. Is there a direct way to do so?
How can I get the physical address corresponding to a virtual address in linux by using /proc file system
View 1 Replies View RelatedI have a lot of files in the server with name like checkfile.jsp and in the file has two or three lines with an ip address xxx.xxx.xxx in it. I wish to know if there any command to grep for the i p address and remove itin file but keep the " ", eg "xxx.xxx.xxx"
View 9 Replies View RelatedRAM for older machines like I use is fairly cheap these days. But flash memory is just as cheap or cheaper. So I'd like to ask about the feasibility of expanding my system's memory using flash memory. And about whether creating a partition for swap on the flash memory, or whether a swap file on the flash device, is the better way to go.
By flash memory I have in mind mainly USB sticks or what are sometimes called "pen drives." But I do also have CF and SD cards that, with the proper cheap adapter (one of which I already own for adapting CF) could be used to create extra swap space. So, what is the current consensus on the feasibility/advisability of using flash memory for swap? I've read about the limited write cycles of flash being an argument against using it for swap. But recent reading indicates to me that the limited write cycles problem applies mostly to older, smaller-capacity flash memory. Some will come out and say that, for larger-capacity flash memory, the life of the device is likely to exceed the amount of time your current computer will be useful (I think I've seen estimates in the range of 3-4 years life--minimum--for newer, higher-capacity flash memory).
A more persuasive argument I've heard against using flash memory for swap is that access times for these devices can be much slower than SATA, and maybe even IDE, hard drives. That would certainly dictate against using flash memory for swap.
So, how about some input on this issue? Anyone using flash memory for swap? If so, what kind (e.g., usb stick or SD/CF)? Are you using a swap file or a swap partition? How's system performance? Likewise, has anyone had flash-memory-used-as-swap die on them? The consequences would undoubtedly be dire. Also, has anyone measured flash memory access times to confirm or refute claims about slow access times? Are some types of flash memory better/worse than others in terms of access times?
I want to calculate length of my array, say Unix here.
Code:
[linux1@HMLINUX1 abc]$ declare -a Unix=('Debian' 'Red Hat' 'Suse' 'Fedora');
[linux1@HMLINUX1 abc]$
[linux1@HMLINUX1 abc]$ echo ${#Unix[@]}
5
This should be ideally 4, but somehow it is showing as 5. However, when I am removing the space as RedHat instead of Red Hat, it is working perfectly.
Code:
[linux1@HMLINUX1 abc]$ declare -a Unix=('Debian' 'Redhat' 'Suse' 'Fedora');
[linux1@HMLINUX1 abc]$ echo ${#names[@]}
4
i've been using a awk script to calculate my data... i have 3 files:
file a1.txt:
2
3
4
[code]....
the results were (3.5, 6 and 3) which is pretty easy.. now i want to combine all this into 1 file and each have different columns and called it avg.txt which have something like this in the end:
3.5 6 3
i have a sorted file with many repeated lines like this:
1ujw
1ujw
1ul1
1us7
[code].....
i need to calculated haw many times each line is repeated, for ex
1ujw 2
1ul1 1
1us7 5
etc.
I want to calculate log in bash script. I searched but could not find any bash command to directly do it. I am also thinking to send the variable in C program, calculate in C and get the answer back in bash script.But I think it is a long process. as I have to do this
i) gcc -o log log.c
ii) ./log > log_result.txt
iii) then read the result from log_result.txt
im trying to calculate how much time does my program run, use very simple script
clock_t end, start;
start= clock();
int i;
printf("initial %d
",(int)start);
[Code]....
but it outputs 0 all the time. cant figure out where could be the problem.
i have the example code below, i want to calculate the time taken for a sample program to run. but i keep getting undefined reference error.
#include <sys/time.h>
#include <iostream>
int main(int argc, char **argv) {
struct timeval startTime;
struct timeval endTime;
[Code]...
i'm trying to write a program with c socket programming,what i am trying to reach is a program which will calculate a computer's downloaded data from the internet,just to know how much he/she download?
View 1 Replies View RelatedE.g. 98 is represented as 1100010 (number of valid bits is 7)
What is the formula to calculate the number of valid bits in a byte ?
ı need to calculate how many nanosecond the process takes . must give the same value every time (c++) ubuntu 10.10 my system information:
*-cpu
description: CPU
product: Intel(R) Core(TM)2 Duo CPU T7300 @ 2.00GHz
vendor: Intel Corp.
physical id: 400
[code]...
I'm using pyqt3 for my app and am lost on even how to attempt this task... On a vinyl cutter to have the blade pivot it must be offset from the center of the shaft it's on so say for example a .25mm offset would leave a .25mm unwanted vinyl attachment when the cutting is done. I somehow have to average or extrapolate that .25mm xy coordinate and add it to the hpgl plot file as a PUx,y; command? I have enclosed a simple sample file that has three images in it. In the corresponding hpgl file everything between the PU commands that are starting with PD are the code for that image (star for eg the pu to move to next image and then all PD for the next image and so on, so once the formula or procedure is figured out it can be applied to as many images there are in the file. Placing the new command at the head of each image PD group. Since there are absolute and relative cutters I enclosed the same exact plot for both types as the coordinates on relative can be negative numbers. Only PU and PD commands and a ";" as a command delimiter as sometimes many commands are on one line.The offset variable will come from a spinbox but .25 is good for an example.
View 14 Replies View RelatedIm doing a sudoku-solver as a school assigment in Java. It is supposed to solve both 6x6, 9x9 and 12x12 boards.Im pretty much done with my algorithm(brute force), but I'm having a hard time figuring out how to calculate the right Box for a Square. I found this snippet:
Code:
// calculate BoardPos for index, where index is 0..80
void loadBoardPosFromIndex(BoardPos &pos, int index) {
pos.index = index;
[code]...
This works on 9x9 boards, but I really dont get the math behind this, and how I can create a generic rule for both 6x6, 9x9 and 12x12 boards.