This seems like a relatively simple question, but the answer seems to elude everyone: What is the MAXIMUM SIZE of a Linux loopback device (not counting any specific filesystem limitations)? Is it the maximum size of a linux block device?
View 4 RepliesI have extracted the WebCamStudio java application into a folder in my Fedora 13 x86_64 installation. I can run WebCamStudio with the command java -jar "WebcamStudio.jar".
I can successfully select sources and view preview etc. However, the bottom status line permanently states "no output". There is no vloopback device to select in Cheese, camstream, Skype, AMsn etc. Does anyone know how I can get the loopback device to work?
I have added my username to the group "video"
I only have /dev/video0 - should there be another module for the loopback device?
Linux 2.6.33.6-147.fc13.x86_64
WebcamStudio 0.55a
The concepts of pseudodevice and loopback device ?
View 1 Replies View RelatedI have the following scenario: I have a file that I want to edit from certain point a certain amount of bytes.
I tried using losetup but failed:
Code:
If I loop the file entirely it works, but that's not helping me. (I'm actually keeping the C option for last since shell programming is less restrictive.
I have two ethernet card on my computer, I want to make a TCP or UDP communication between these two cards, so I disable loopback: #ifconfig lo down. but with out loopback I can't even ping an eth from another one. how should I do? I want traffic to really pass eth cards.
View 2 Replies View RelatedI am trying to expand my Ubuntu partition into my Windows 7 C: drive, but the win7 partioner will not let me shrink it because of immovable files. Is there anyway for me to but an loopback device in the windows partion, and have Ubuntu boot with that as the root device?
View 1 Replies View RelatedI was wondering if it is possible to create a growing image for a loopback device. Like a file that you create that will grow with the data that is placed on it instead of a file that has to be the size of the entire file system?
View 4 Replies View RelatedWe�re experimenting with deploying SUSE 10 SP3 systems and adding them to a Windows domain and DNS. Oddly, when we register in DNS, it gets registered under two address: the real IP address, and the address 127.0.0.2. Also, an ip addr command shows that the loopback device lo has two addresses: 127.0.0.1 and 127.0.0.2.
The above behavior is just on SP3. On SUSE 10 SP2, the lo device has only the 127.0.0.1 address, and the system is able to register correctly in DNS.
Do you know what the 127.0.0.2 address signifies, or how to get rid of it?
how to mkpart with maximum size available?
mkpart primary 0 3001G
I have 3TB raid disk. I cannot install centos using GPT partition. I need to use parted and mkpart to format it.
Alternate Heading: Unable to use opensuse partitioner to fully format a Seagate 1Tb drive OK. Swapped over a motherboard to increase the number of slots available for hard drives so that I could expand my raid array (4 X 1Tb drives). Discovered I had no thermal paste so all delayed for 24 hours while I bought some, miscalculated on rebuild and had to reinstall OpenSuse but in the end system is now up and running. Unfortunately when I formatted my new 1Tb drive (Seagate) it formats to 931.50 Gb while the other 4 drives formatted to 931.51 Gb (they are WD). I'm now in the position that when I try to add this new drive I get :
mdadm: /dev/sdc1 not large enough to join array
Is there any way I can resize the existing devices down to 931.50 Gb so that I can add in the new drive without having to restore the array?
I use U-server. I set up an mail server as described in Ubuntu Documentation > Ubuntu 11.04 > Ubuntu Server Guide > Email Services.
How can I turn off maximum attachment size. On my server I don't want to limit the size of e mails that arrives.
I manage my server with webmin
When I try to delete a file, ( move to trash ) It says , The trash has reached It's maximum size! clean the trash manually. When I click on the trash icon on desktop it is empty. Where is the trash? Where can I delete these files ?
View 2 Replies View RelatedIs there any maximum limit to the heap memory allocation?My program is in PERL and i am using a solaris system. when i did "pmap pid" (pid = my process id) it is showing a number of heap memory allocated and all of them with GB sizes. This single process is eating up most of the physical memory.Is it normal and is there any way to get the heap memory size down
View 3 Replies View RelatedHow do I find out maximum I/O request size?
I'm using CentOS release 5.2
I know that the default size is 128 K, how do I find out/confirm this?
I'm kind of new to programming in Linux & c/c++. I'm currently writing a FileManager using Ubuntu Linux(10.10) for Learning Purposes. I've got started on this project by creating a loopback device to be used as my virtual hard disk. After creating the loop back hard disk and mounting it has the following configuration.
Code: $> sudo fdisk -l /dev/loop0
Disk /dev/loop0: 10 MB, 10977280 bytes
255 heads, 63 sectors/track, 1 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/loop0 doesn't contain a valid partition table Now what I want to do is develop a c++ program to read & write files to this loop back device,which I'm using to simulate an actual hard disk,at the blocks & sectors level. So far I've come up with the following code. But I'm still unable to read files from the hard disk one block at a time.
Code: #include <iostream>
#include <stdio.h>
using namespace std;
int main() {
char block[512]; int length=0;
cout<<"Implementation of the File Handler Read Method..."<<endl;
FILE *f = fopen("/dev/loop0", "r");
if(f == NULL) {
cout<<"Error In Opening the HardDisk File Retuning Error..."<<endl; return -1; }
//Read One Block of Data to Buffer length = fread(block, 1, sizeof(block), f);
/* Do something with the data */ cout<<"Length : "<<length<<endl;
return 0; }
When I run this Program All what I get is the message for NULL. "Error In Opening the HardDisk File Retuning Error...". So I could open the loopback device as a file an access it at the sectors & block level.
First off all, I'm booting from a large MEMDISK using PXE (900MB) . Due to our environment, I cannot decrease the size, nor move files to a nfs/iSCSI/... environment. Everything needs to be in that MEMDISK.
Now, when I try to run the OS, I get out of vmalloc space. How do I increase it to a number which allows such a large image to be mapped? I tried the parameter "vmalloc=1280M", but with that parameter, I don't get past the Booting the kernel screen.
Memory should not be an issue, since the machine(s) have at least 2GB RAM. (900MB MEMDISK + 256MB for other kernel stuff + 768MB for user stuff). The machine(s) have a Pentium 4 Extreme Edition processor, with hyperthreading and SSE2, but no EM64T.
How can I boot the system, and get past that message? Decreasing the MEMDISK size is not possible too. It is at the smallest we can get with our userland + kernel + modules.
How do I change the size of the available shared memory on Linux?evidently 4GB is not enough for what I am doing (I need to load a lot of data into shared memory - my machine got 8GB of RAM).
View 2 Replies View RelatedI'm using fc14 and the SG driver to test some SCSI (SAS) targets. In doing so, I'm bumping up against what appears to be a 512KB maximum transfer size per command. Transfers up to 4MB sometimes work, but often they result in ENOMEM or EINVAL returned from the write() function in the SG driver. I could not find any good documentation on how the SCSI system in Linux works so I've been studying the source for drivers in drivers/scsi.
I see that there is a scsi_device struct that contains a request_queue struct that contains a queue_limits struct that contains an element called max_sectors. The SG driver seems to use this to limit the size of the reserve buffer it is willing to create. I see that there are several constants used to initialize max_sectors to 1024 which would result in the 512KB limit I see (with targets having 512 byte sectors). At this point I have several questions:
1) When the open() function for the sg driver gets called, who initializes the scsi_device struct with the default values?
2) Can I merely change the limits struct to arbitrary values after initialization and cause the SG ioctls to set the reserve buffer to allow greater values?......
How to restrict the maximum size of an array variable in perl such that Ishould not be able to have array elements beyond the maximum size?
View 7 Replies View RelatedI'm wondering what's the maximum heap space a process can use (not necessarily by a single malloc()) in Ubuntu x86_64. Which parameter determines the size
View 7 Replies View RelatedI created a VM disk image with kvm-img, but I forget what was the max size of that disk image when I created it. Currently, its size is 6.2G, I want to install some large packages in that VM, so I want to make sure the disk image can expand to an adequate size.
View 1 Replies View RelatedI have written a script.
#/bin/bash
a=`du -sh /root/samplefolder | cut -f1`
echo $a > testfile
[code]....
The aim of this script is, when the folder reaches 20M then attributes will be set to that particular folder so that no newfiles and folders cannot be created or copied to that samplefolder. whenever i copy a file morethan 20M to that folder its getting copied fully and then the attributes were applied. But i dont want this to happen, when the folder reaches its maximum current write operation to that folder should be stopped automatically with a error.
I have set up squid server. My cache directory has been set up as per following statements.cache_dir ufs /Cache1/squid 10000 16 256cache_dir ufs /Cache2/squid 10000 16 256Now the problem is that size of /Cache1 and /Cache2 has reached to about 8GB and in near future it will reach the maximum limit of 10GB. I just want to know that whether I need to delete the contents of these directories or otherwise.
View 1 Replies View RelatedBoth gThumb and Geeqie image viewers have limited maximum size for thumbernails. Is there any way to work with bigger thumbernails (or slide photos)?
View 3 Replies View RelatedI'm setting up a loopback server for work related testing. I have a small program that needs to be executed through telnet from about 200 IP's on the same network. On the server, I have to set a static ip, enable telnet login, and place my 2 program files in the appropriate folders so it will run. I have been on this for 2-3 days and haven't got far.
My /etc/Network/interfaces file is this...
Auto lo
iface lo inet loopback
The rest of terminal is filled up with these, and it states that the file only has 32 characters. I don't know if this is a privilege issue or not. I've read several threads on telnet, and lots of arguments about ssh, but I can't run ssh, so I need to enable telnet. There is not a security issue. I run a private network where the only valuable resource would probably be the text file with my IP address on it. Its also accessed by people that have very limited networking knowledge and no linux knowledge...
So,
Set static IP
Setup telnet server...
Any takers?
I have a client's linux server where someone added a script which sends spam mails from the server's local loopback address (127.0.0.1) all my seniors worked on it and couldn't trace the script on the server this issue was going for a week, now I have an idea to bring down the loopback interface of that particular server(ya, that was not a permanent solution but just had an idea), but my support manager told that it will bring the whole server down(so far as i have learn't loopback address is used only for testing the NIC card's functionality), is that really bring the server down.?. How ever i tried this using a test machine all the connections works fine even after i bring down the loopback interface. As my client's server is a production server i can't test it there without clear knowledge, can any one help me out whether will it bring down the server or will it cause any side effects on it(i know that you guys are experts so i am asking it here)?
View 5 Replies View RelatedHow do you go about getting the raw size of a block device under Linux from within a C program? And I mean the raw size of the block device itself, not a file system that may or may not be installed on it. And I'd like to be able to get the raw size of any block device, from hard drives (e.g., /dev/sda) to LVM partitions (/dev/mapper/vg0-home) to loop devices to anything else that is a Linux block device.
View 3 Replies View RelatedAre there any maximum amount of logical volumes a LVM2 volume group can contain?
View 1 Replies View RelatedI have a 32-bit Linux server with an ext3 file system. Is there any kind of upper-limit to the number of hard links I am allowed to use? (Per inode...? Per directory...? Per filesystem...?) And (just out of curiosity) would this be any different if I had a 64-bit machine or a different file system?
View 1 Replies View Relatedtell me the maximum limit of connections FTP server
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