I have a C program that computes the page fault service time in C. For this program I have 2 large files (of less than 3GB each – almost the size of the RAM) I get the following compiler warnings: When I run it with the command I get the error What does the code do? We map both the
Tag: operating-system
Many-to-one mapping of user threads to a kernel thread
As I understand it, in many-to-one mapping, one kernel thread manages many user threads. This kernel thread helps the user threads make system calls etc. What I don’t understand is: Why do we have many-to-one mapping if a single blocking call would block all user threads managed by the kernel thread ? I…
C – Linux Kernel – Assistance with current_uid()
I have been working on part of an assignment which I am having trouble fixing. The requirement was to intercept the system call open and to replace it with a new system open call only for regular users and would print out the user id and filename in the system log. Otherwise it would just execute the standard…
Java Command Line on Different OS’s
Okay, so I am using process builder to launch an independent java process from the current java process, using the code: to test it, just as a simple questin, will the command always be “java -jar something.jar,” on all operating systems? and if not, what are the formats for mac and linux? Answer …
Coding of Admin-Guest login section in an OS
I developed an authentication algorithm for user authentication as part of my masters thesis and implemented it in PHP. I intend to know how can I implement the algorithm for operating system login, in which language (for linux)? also where the code will reside because it will not be click and run code it wil…
Who schedules threads?
I have a question about scheduling threads. on the one hand, I learned that threads are scheduled and treated as processes in Linux, meaning they get scheduled like any other process using the conventional methods. (for example, the Completely Fair Scheduler in linux) On the other hand, I also know that the C…
Understanding load average vs. cpu usage [closed]
Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers. This question does not appear to be about a specific programming problem, a software algorithm, or software tools primarily used by programmers. If you believe the question would be on-topic on another Stack …
How does the fork() know whether it is in child process and in parent process? [closed]
Closed. This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 9 years ago. Improve this question When a fork() system call gets executed , the processor turns into kernel …
how to intercept calls to the file systems
I am interested in intercepting all system calls related to the file system and instead having my own code run. For example, calls to creat, write, close, lseek, getcwd, etc. My goal is to create a function like execve that captures all file I/O from the spawned program to an in memory filesystem managed by t…
What do these strace system calls mean?
I need to profile the performance of an application for which I am using strace. However, I do not really know how to interpret the various system calls the strace emits. Examples of a few of them are below: I would be grateful if someone could briefly explain in plain English what these lines from (A) to (F)…