Today I just realized in my Ubuntu Linux, I can mount and store files on my newly purchased hard drive as a raw device without a file system. (as long as I partitioned the disk correctly)
So, I am not sure if my below statement is correct, looking for expert to answer:
Looks like it's not required to create a file system on a disk in order to use it in Linux? Is it correct?
I have some very basic understanding of how a file system works. In Linux, is the concept of "inode" a file system feature or a Linux feature?
I understand that the "inode" file system works unlike NTFS or FAT32 that it tries to spread out the data across the disk so that Linux/Unix doesn't need as Windows like "defgramentation" program to keep data in consecutive chunks. My question is, if I am storing my data on a raw device without a file system, and if "inode" is a file system feature not a Linux feature, what will the actual data layout look like on the raw device then?
Thanks in advance
Related
I am wondering if it is possible to have a usb key in a raw format and still read/write files on it.
It should be cross-platform and understood by a dedicated software we ship.
I am kind of creating a non-bootable file system in a hurry, and I just need to read/write some values at some offsets on this raw storage space.
People who will use it will be shipped the software able to read those values (not the operating system who will surely see raw/free space, but we don't care about that).
Will I run into troubles with the mounting, or whatever?
Or is it green light?
Thanks
Yes, absolutely, you can read and write the "unformatted" SD card or USB memory. You can also format it to whatever filesystem you need by writing to pages of that memory. The only possible difficulty is that the OS (at least later Windows versions) might not allow writing to the disk if the user account doesn't have admin rights.
I am working on a project for set top boxes and I need to mount a HDD partition formatted with xtvfs filesystem.
I have only received the following information regarding xtvfs:
The partition formatted with xtvfs is basically a type 1 (FAT12) to be used with xtvfs
I searched the internet and found a program called Copy+ that can be used to copy xtvfs images form one HDD to another.
The set top I am working on uses linux and so I need to mount and read the partition on it.
I have the following question:
I did not find any xtvfs named filesystem supported in the kernel. Can I be able to mount it using vfat?
If not, then how do I get to work such a filesystem in Linux.
Information on XTVFS is hard to find and support is not widespread - http://wiki.ph-mb.com/wiki/XTVFS is probably the best page I found. I could not find a linux driver for it. XTVFS is based on FAT32 and mounting that on Linux will get you part of the way - basically for everything but the video files. The video files have a separate Video FAT and video data section. I wrote some code to read files from an XTVFS image and will share it once it is tidied.
I have read that RFS is the basic skeleton which is needed in a computer while booting linux.
As per my knowledge File system is a directory structure for storing files.
When RFS is already there, why do we need a other file system like EXT2 and several others.And where these file systems are mounted(EXT2 or other) .
Are these several file system co exist together with RFS when pc is running.
You mast first know what is RFS:
RFS is a Samsung file system for user space applications formatted as RFS (Robust File System). RFS is a FAT 16/32 based file system with a sort of journalling system on it. The code to build and use the RFS file system is proprietary and only used in Samsung equipment, such as TV's, BluRay players and cellphones.
So it's a different file system, and can be used in a partition and other can be used in other partition.
On unix-like file systems, it is possible to add lots of different types of devices and logical structures to a file system, as if it were a file or directory by mounting them from a file system. One of the most common things to add to a bare-bones file system is ... another file system. This allows the computer to keep only the most essential files on the root file system, keeping it cleaner so that it is easier to clean up if something goes wrong or gets corrupted. That means that most application-level programs live on an "extended" filesystem (EXT) because the computer does not need those programs in order to turn on.
Read more about the root file system here: http://www.linfo.org/root_filesystem.html
I want to create a file from kernel and this file must be accessed from user space. Other ways of communication (for example ioctl) is not suitable, because the user space application needs only files, and I don't have the source code of it.
I need to do this on MAC. If I were using Linux, I would use sysfs for it, but on MacOs they dont have sysfs, so I decided to end up with devfs
I created the sample soultion and everything works great, but the problem is that the device file (devfs file) does not have size. The user-space code checks for file size and skips this file. I know how big the size will be, but I dont know how to set it to devfs file.
I dont want to create the file in real filesystem, because it can be quite big. All I want is to redirect reads and writes to my internal functions.
FUSE (http://en.wikipedia.org/wiki/Filesystem_in_Userspace) would be ideal for be, but this involves user-space daemon.
Any suggestions?
I'm writing a patch for VFS FAT implmentation on kernel 3.0
I want to add posix attributes to FAT files that are created in linux.
to achive that, I must save a file that contains all the relevant information on the mounted drive.
I know that reading and writing files from kernel space is something normally shouldn't be done, and I'm looking for another way to read/write the data.
I saw articles on the net that suggested to use /proc or to create a userspace daemon that will do the IO for me. I wanted to know if anyone saw or know where can I look at an implmentation of a thing like that,because I didn't find any examples for that over the net.
I'm not looking for a read/write to proc example, I want to see an entire solution for this issue.
Have a look at the quota implementation; this is a mechanism (ok, presumably not available on vfat) which reads/writes files from the kernel.
Additionally, the "loop" block device is another example of a kernel facility which does file IO.