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17

The distro kernels are all compiled from the official source, with distro specific patches applied. These patches are relatively minor compared to the scope of the kernel itself. As long as you know what you are doing, you can substitute a custom kernel into any of the mainstream distros, although this is discouraged since it may cause a mismatch with ...


15

SCSI and ATA are entirely different standards. They are currently both developed under the aegis of the INCITS standards organization but by different groups. SCSI is under technical committee T10, while ATA is under T13.1 ATA was designed with hard disk drives in mind, only. SCSI is a broader standard, capable of controlling mass storage devices, tape ...


14

First of all, nobody "gets the kernel from Linus". Yes, Linus is still actively involved in the kernel's development and has final say in any disputes but he most certainly does not write it alone! The wikipedia page on the Linux kernel is quite good on the subject: The kernel changes made in year 2007 have been submitted by no less than 1900 developers ...


12

This can be do the same thing with purge: sync && echo 3 > /proc/sys/vm/drop_caches From man proc: /proc/sys/vm/drop_caches (since Linux 2.6.16) Writing to this file causes the kernel to drop clean caches, dentries and inodes from memory, causing that memory to become free. To free ...


3

A FILE structure in C is typically called the file handle and is a bit of abstraction around a file descriptor: The data type FILE is a structure that contains information about a file or specified data stream. It includes such information as a file descriptor, current position, status flags, and more. It is most often used as a pointer to a ...


3

Does this figure show segments that were retransmitted due to congestion or is it limited to lossy links? If so (and I'm thinking it might be the case) that might muddy the waters even more to the point of this not being a good metric to use. segments retransmitted in netstat -s includes all the kernel's TCP retransmissions for any reason, including ...


3

No. The kernel is specifically designed to disallow user mode code from running in ring 0. In order to do this, you will have to write a kernel module, and then talk to your module through some method (perhaps ioctl) from your user mode program. Writing a kernel module does not require patching the kernel, but the kernel module must be written very ...


3

As the kernel documentation states, /dev/nfs is not a real device but only a hint to the kernel to use NFS as rootfs. You'll also have to tell the kernel where to find this root through the nfsroot parameter or a properly set up DHCP daemon. For the latter one to work you'll also have to either configure your kernel to auto-configure its network ...


3

A 32-bit process can access only about 3GB. (It can be less, depending on the kernel compilation options.) It doesn't matter whether the kernel is a 32-bit or 64-bit one — that only affects the ability to run 64-bit applications. PAE is a way to allow more physical memory but doesn't change the size of the virtual memory seen by each process. That's pretty ...


3

I know you should use No-op for Solid Sate Drives or SSD s for sure. Not necessarily. I don't know why people keep treating SSD's as some kind of special case where you don't need the benefits of other schedulers. Having rotating disks just means it's more important to have requests merged. Merging requests is just one thing that the scheduler does. ...


3

Varnish appears to use a plain memory-mapped file for its shared memory (instead of, e.g., POSIX shm_open). From the source: loghead = mmap(NULL, heritage.vsl_size, PROT_READ|PROT_WRITE, MAP_HASSEMAPHORE | MAP_NOSYNC | MAP_SHARED, heritage.vsl_fd, 0); On BSD, MAP_NOSYNC requests that the kernel not write the shared data to disk unless forced ...


3

Linux uses RAM in a different way from what other operating systems do. Rather than sitting there with unused RAM, Linux stores data that it thinks might be used in RAM-any applications may be cached here, files, etc. As a result, Linux RAM usage is higher than what is used by running applications. This extra usage is buffered to be sued by other things. ...


2

go into the BIOS of the host and rearrange the order of the hard drives and removable drives. This will adjust the order as it appears to the Linux kernel.


2

Try this from the Ask Ubuntu section: http://askubuntu.com/questions/318583/how-can-i-solve-fixed-channel-1-mon0-is-on-channel-1-issue-when-using-airo The lastest dev version has the --ignore-negative-one option. Obtain the lastest dev version from subversion: Install Subversion: On Debian/Ubuntu: sudo apt-get install subversion Then, obtain it via svn. ...


2

I want to add these file into my kernel such way that when kernel start this hello.o file execute and run What you are trying to achieve shouldn't be made through kernel edition. Executing a program at boot time can be handled in much simpler ways, without need for kernel programming experience. You can: Execute it when your shell starts: Write ...


2

You might see some information from here. Generally, a file descriptor is an index for an entry in a kernel-resident data structure containing the details of all open files. In POSIX, this data structure is called a file descriptor table, and each process has its own file descriptor table. The user application passes the abstract key to the kernel through a ...


1

The documentation for the pam_loginuid PAM module gives a pretty good hint: The pam_loginuid module sets the loginuid process attribute for the process that was authenticated. This is necessary for applications to be correctly audited. This PAM module should only be used for entry point applications like: login, sshd, gdm, vsftpd, crond and atd. ...


1

Ok, so here's the way the boot process works: firmware > bootloader maybe > kernel ${parameters} > initramfs > userspace maybe On a redhat installation disk their dracut system of scripts is what builds and constitutes initramfs and their anaconda installation system constitutes the final userspace. It is udev that handles the device setup - as in, it ...


1

Or should I simply ignore it? Unused variables could be an indication of a coding mistake. If you are satisfied this is not the case and want to suppress the warning for a particular variable, you can use a (GCC specific) __attribute__ tag, e.g.: /* Unused parameter (in definition, not declaration): */ void somefunc (int x __attribute__ ((unused))) { ...


1

"Variable set but not used" warnings are informational. According to the official documentation, -Wunused-but-set-variable controls the behavior of: Warn[ing] whenever a local variable is assigned to, but otherwise unused (aside from its declaration). This warning is enabled by -Wall. The purpose is to catch situations where the programmer assigns a ...


1

Looking through the Wikipedia page for menuconfig I do not see a similar option. There's a bullet within that page that states the following: The help information is distributed throughout the kernel source tree in the various files called Kconfig. So one could use grep to search for whatever you wanted through these files. You can also use ? within ...


1

Concise Version: As @ninjalj pointed out, the workload application should probably be considered the authoritative source on whether any given adjustment was beneficial to workload performance. Depending on whether your requirements are latency or only overall throughput on the system, you can make the judgment call as to whether changes in behavior better ...


1

Stable does not help. The 4.7 - 4.8 inconsistency is still there. The inconsistency has existed for me since (around) version 4.4 of gcc.


1

According to the ArchWiki, you must blacklist b43 module because it conflicts with brcmsmac.



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