I am new to Linux kernel/user space programming having been an assembly programmer in my previous life. I am now using 2.6.x kernel on an embedded CPU that has a few dedicated hardware blocks (including more CPU running just C-code, i.e., no operating system). There is a single DRAM connected to this chip with one Linux CPU + multiple h/w blocks. No swapping.Question(s):
1. The Linux CPU needs to talk to hardware blocks that obviously physical DRAM addresses while Linux processes/threads use virtual addresses.
2. How do I translate these addresses back-n-forth? For example, a Linux process may want to allocate memory and then hand it off to a hardware block to write into it. Then after a while the process will read it.
3. Sometimes, the hardware block may write a physical address into the shared memory. The Linux CPU will read the shared memory and then convert the physical address to virtual memory and go read that location.
How does one achieve all of this? If this is being extremely stupid, then please let me know. Hopefully, you can give me some pointers.
I recently installed Ubuntu Server 9.10 with the intent of using it as a platform for running a couple of Windows XP virtual machines along with Linux/Ubuntu.
I had no problems getting the server installed. Had no problems getting the network up and running so that I had access to both my internal network as well as external connectivity to the internet. Had no problems getting a VM installed and putting Windows XP inside of it. Had no problems setting up a bridge between the WinXP virtual machine and the physical ethernet card (eth0).
What Im having trouble with is figuring out how to bridge from multiple VMs AND Ubuntu natively through one physical ethernet card.
When I set up the bridge, it knocks out the static IP address of the ethernet card that was set up initially with Ubuntu when first installed before the VM was created and installed. Therefore, connectivity within Ubuntu natively is lost.
Similarly, am having trouble figuring out how the second VM (also going to be running WinXP) is going to get its connectivity since it doesnt seem to like me setting up 2 bridges to the same physical ethernet interface card.
I need all 3 machines to have static IP addresses and be visible/accessible from the external network for either web/mail/dns/etc servers on the Ubuntu side and for remote PC control functionality on the VM side.
I have tried setting up alias ethernet interfaces (eth0:1, eth0:2, eth0:3) with static addresses which work fine from native Ubuntu in presenting multiple IP addressees, but it seems that Im not permitted to bridge to these alias interfaces.
This may seem like a silly question but I have many servers and sometimes we forget when we login if it physical or virtual running on a VMware system. This makes a diffrence when I try to get a console access etc. So I wanted to know before if its physical or VM.yes I know i can change motd once i get the info or make a list etc. There are many ways not OS related for me to find this info out. But I was wondering if there was a Linux command that I could use when I ssh to a system to check if its physical or logical?I have inventory information etc and vm vsphere to check but that can be time consuming if I just want to check something quick.
uname -a or something like that that would tell me would be cool. I am thinking there is no command as Linux really does not care if its running Vm or physical.
I use the command ln -s a lot to create symbolic links. The problem is that I need to run a routine that looks for a specific string in ALL of my websites and I'd do it somehting like this:
Code: cd /home grep -R "function_enhanced_mail_v100.php" * however, it's going to recurse all the "folders" and include symbolic links which I don't wish to do. Is there any way to prevent this?
I've read several write ups on how to convert a physical linux box to a virtual one, but have yet to do it. I've tried a few times just playing around with no success. Generally I use VMware ESX as my host of choice, but am open to citrix's XEN (as citrix presentation server is my day job). I run 3 websites out of the house (on junk left over desktop.. can't believe I've had such good (lucky) uptime). One of the sites was particularly difficult to set up, so I'd rather not ahve to do it over again. It's built on OScommerce (LAMP).. so it's a database server as well come to think of it. So.. what have you tried to convert with/to?
I have two old windows 95 computers. The problem is I have files and programs that have specific settings that I need. The computers are old and I want to just make a copy of the hard drive and insert it into virtual box. How can I do this?
A process is trying one access to memory, for example through an array (ex.: vect[0]=123. What happens?
Here below what I guess but I'm not sure and accept any comment (please, distinguish between "the system" and "the CPU" in case).
Let's suppose swapping to disk disbled.
We have two scenarios: without and with cache.
If no cache is present in the system: 1. The CPU must discover the phys addr of vect[0] virtual addr. To do that, has to read from 3 (or 2 depending on the system?) pages tables, stored in memory as well. 2. The CPU writes to the final address.
These mean 4 memory accesses.
If cache is present: 1. Like above but, if the pages tables are in cache, we have 3 accesses to that. 2. If the req. page is not in cache, it's reads from ram and transferred to it. Afterwards, cache is written. In the best case we have 4 cache accesses.
I have set up OpenVPN server using a bridged configuration. My networking "powers" aren't that advanced, so I did this by following the openvpn tutorial for bridged servers. I have tested this with several clients connecting to my server from different locations and it works very nicely (including broadcasts).
My server's LAN IP address is 192.168.2.4, and my LAN's mask is 24. Clients connecting to my server get assigned IP address that also fall within that subnet (i.e., the 192.168.2.x pool contains both physical machines in my home and "virtual" hosts). This is what the OpenVPN walkthrough specifies:
[Code]...
I was wondering if it would be possible for the VPN to fall within a different subnet (such as 10.0.1.x). I would also like to do that without adding another physical NIC to my server, or changing my physical IP address. I would imagine this is possible, since that's how hamachi does it.
I have a 32 bit Ubuntu installed and my Laptop has 4GB RAM, but only 3GB is considered by Linux. My question is: what is the reason for the upper limit on physical memory ?
Code: dmesg | grep Memory [0.000000] Memory: 3052428k/3112960k available (4673k kernel code, 56364k reserved, 2121k data, 656k init, 2200904k highmem) I am familiar with the virtual memory concept where linux splits upper 1GB for kernel and lower 3GB for user processes. In total, linux 32bit can address 4GB virtual addresses. Does this meant that 1GB of physical memory is already mapped to 1GB of kernel space and Linux only shows the remaining 3GB physical memory left for the user in the above command.
I did some searching on the internet and found some articles related to this, but it only confused me further since some articles suggest 4GB is the upper limit with mentioning whether it's virtual or physical memory, some bring in the concept of PAE, etc. I'm relative new to Linux's memory management, so it'd be really helpful if someone could answer this.
I am encountering some problems regarding CentOS 5 and I am going to kindly ask your help in debugging further what is happening. I will give as much information as possible about the setup. Here we go. We use on one server of our servers, GOautodial, an inbound/outbound call center application, that it's installed on a CentOS 5.5 (Final).
# cat /etc/*release* cat: /etc/lsb-release.d: Is a directory CentOS release 5.5 (Final) GoAutoDial CE 2.0 # uname -a Linux xxxxx.com 2.6.18-194.8.1.el5.goPAE #1 SMP Fri Jul 30 05:30:57 EDT 2010 i686 i686 i386 GNU/Linux
Get the list of virtual addresses being accessed by any application during its execution time. I don't want the complete memory map but just the pages which were accessed during an application's execution?
I've been experimenting with Debian coming up with a system with suits my needs. I have done this and I'm wondering, "Do I have to start from scratch on my physical machine or can I convert an existing VDI to IMG and possibly port it to the physical machine?"
I am currently using windows xp, but I have acquired another hard drive and wish to install ubuntu to it, unfortunately i do not have a working cd drive. I have loaded the newest iso in daemon tools and it asks me if i want to install it in windows, or restart my computer to do a full install. i wish to do neither. i want to install a full copy to my other drive with the virtual cd drive. I have found alot of help dealing with installing it on the same drive as windows or something that would require a floppy drive. this task seems like it would be alot simpler than installing on the same drive, buy maybe not. Did i miss a tutorial somewhere?
How to get the list of virtual addresses being accessed by any application during its execution time. I don't want the complete memory map but just the pages which were accessed during an application's execution?
How to get the list of virtual addresses being accessed by any application during its execution time. I don't want the complete memory map but just the pages which were accessed during an application's execution?
As i undertsand - out of 1GB of the virtual Address space for Kernel from 3GB to 4GB of the process address space, Kernel image (code, data, bss, stack, heap) resides staring @0x0 address. Vmalloc area starts either at the end of Physical ram size or at 896M. This 896M cap is mandated to ensure that minimum of 128MB is reserved as vmalloc_reserve for vmalloc,kmap etc.
Is the understanding correct? Now trying to map Physical Zones into this 1GB address space
Initial 16MB is mapped to ZONE_DMA 16MB - 896MB is mapped to ZONE_NORMAL 896MB - 1024MB is mapped to ZONE_HIGHMEM
Does this mean that Kernel image is residing in ZONE_DMA area? Any call to vmalloc() in kernel code will return address beyond 896M? insmod of any LKM will internally invoke vmalloc() to obtain contiguous area - where will this code physically located along with rest of kernel code in ZONE_DMA or in ZONE_HIGHMEM?
So essentially, it finds dx files, sorts them by numbers at the beginning, then performs the dx function I made (loops over all of the #-protein.dx and #-water.dx files).
It works fine when I'm running it on Ubuntu 11.04. However, when I try to run it on OSX, I get the following error:
Code: mh320m01:DA_R02 janickij$ ./MOD_Loop_Tuber_Script.sh find: illegal option -- t find: illegal option -- y
I have been learning Debian by using a virtual machine. After fine-tuning my installation procedure, I decided to copy that installation to my physical system. The hard drive already has another Linux based system installed. I plan to dual boot.After copying files I updated fstab and menu.lst.The partition scheme between the virtual and physical environments are similar, but the partitions are not mapped exactly the same.Thus the Debian system on the physical hard drive fails to boot simply because the initrd is created for the root partition location on the virtual machine. The initrd created in the virtual machine is looking for the root file system on /dev/hda1 whereas on my physical drive the new location is /dev/sda7.How can I rebuild the initrd on the physical system? I started to use the installation DVD in rescue mode, but I did not get too far.
I read once that you could use VMWare's converter to convert a physical machine into a virtual machine to run in VirtualBox. Can someone point me in the direction of a tutorial or just give me instructions on how to do this? I was very confused by the converter and how to get the image to work with virtualbox.
I have googled the net and found some information, but need more on translating. I need programs both for linux and windows xp for translating programs, documentation and etc. I found poEdit, but is there some simpler program to work with? I also need how-to (more simpler - more usefully) for the entire process from getting po or pot files, translate them and upload them. Is SVN suitable for that (need to mention that I only have general idea of what SVN is; didn't worked with it).
I need a small shell based program that prints the mac address of physical ethernet adapter from it's firmware. I need this utility for license generation and appliance activation. I have tried several example but none of them is flawless, The easiest method I have found is to parse the output of "ifconfig" command but it has also some drawbacks.
1. Firstly program should differentiate between physical and virtual adapters. Physical means installed on board(wired or wireless) or installed additionally. Virtual adapters are those created by VPN or created by virtualization apps such as VirtualBox/VMWare etc. I am not interested in virtual ones.
2. In case of more them one physical adapters(wired and wireless), it should print the mac address and description(name & vendor) of both/all adapters.
3. If media is disconnected then also it should be able to read the mac address and description(name, vendor) of card.
4. This one is bit complex. I know that 'ethtool' can show you the universal mac address but it's limited to use only 2 types of drivers and won't work in all cases.
I have been learning Debian by using a virtual machine. After fine-tuning my installation procedure, I decided to copy that installation to my physical system. The hard drive already has another Linux based system installed. I plan to dual boot.After copying files I updated fstab and menu.lst.
The partition scheme between the virtual and physical environments are similar, but the partitions are not mapped exactly the same.Thus the Debian system on the physical hard drive fails to boot. I think the initrd created in the virtual machine is looking for the root file system on /dev/hda1 whereas on my physical drive the new location is /dev/sda7.How can I rebuild the initrd on the physical system? Or how can I build an initrd in the virtual system that will function on the physical system.I started to use the installation DVD in rescue mode, but I did not get too far.
I get errors trying to virtual IPv6 Addresses i a lab environment. It works fine up to 2033 (?) adrressses, but when I try to add more i get "Cannot allocate memory" error:
I had cloned a centos 5.6 installation from virtualbox virtual machine to physical box. Everything work fine. However, the time showing in os using date command differs from bios time by roughly 4 hours. I am running ntp services which sync the time with another centos server on the network. It appears that some services are using virtual clock and some use physical clock. How do I get rid of virtual clock and only use physical clock?
apache virtual host to limit the concurrent connections of virtual hosts? Taking into account the host of each virtual user's home directory can also have more than one subdirectory, which should be restricted to a subdirectory. Is beyond the control of the operation of these sites in a subdirectory. Best local restrictions or limitations to the overall situation.
I have spent considerable hours searching forums and googling. I have yet to find out what "lm-sensors acpitz-virtual-0 Adapter: Virtual device temp1:" is actually looking at. I have an Abit IP35 motherboard with Ubuntu 9.04 installed.
Here is the output from sensors:
Virtual Device Temp 1 keeps going up to 121 degrees and the computer shuts down. None of the others overheat. Also, my bios does not show my voltages to be set like it lists above. The bios in the motherboard is the latest from Abit.
