Questions tagged [os-kernel]

Questions about the fundamental component of an operating system, which manages the allocation of resources to applications.

Filter by
Sorted by
Tagged with
0
votes
1answer
27 views

OS: Are User-level threads and software threads (and also kernel-level threads and hardware threads) the same?

I am referencing the Book Fundamentals of Computer Algorithms" by Ellis Horowitz et al. At the part which they talk about multi-threading models, user-level and kernel-level thread are introduced....
2
votes
1answer
54 views

How were operating systems even made?

By that, I don't mean what is needed to make an operating system. I know that OSes are built on top of kernels and whatnot. But what I mean is, it wasn't like anyone could just "program" the ...
0
votes
1answer
67 views

Is vmlinux a virtual machine?

From Wikipedia, On Linux systems, vmlinux is a statically linked executable file that contains the Linux kernel Does that mean vmlinux is a virtual machine that runs Linux? I am really confused.
1
vote
1answer
48 views

Paging only for user code. What about kernel code?

Why is paging done only for user code (user space)? I know that the basic intuition behind paging is for managing larger logical address space in smaller physical main memory space. Won't the kernel ...
0
votes
0answers
27 views

Is a signal handler invocation an upcall?

I am struggling with the definition of an upcall. Presumably, an upcall is a mechanism that allows the kernel to execute a function in userspace. By this definition, an invocation of a signal handler ...
2
votes
2answers
62 views

Can User Level Thread read/write Kernel thread?

As far as I read in a OS text book (Operating Systems by Silberschatz) Kernel mode is for privileged task, so it it true to claim that "User Level Thread can read/write Kernel threads" ? ...
-1
votes
2answers
32 views

Does FreeRTOS replace linux or run ontop? [closed]

I am looking into FreeRTOS, just for personal learning and I am stuck on how the fundamentals of how it works with Linux. So for example, I am able to build FreeRTOS on my linux ubuntu machine. Now ...
0
votes
0answers
32 views

Is it possible to run more than one Turing Machine emulator using only one processor kernel?

I had this question on computer architecture exam and can't find an answer anywhere. Is it possible to run several Turing Machine emulators at once using only one processor kernel? a) Yes, by ...
2
votes
2answers
104 views

Why doesn't everyone use distributed operating systems?

As requested by a moderator, this question as been separated from my question about microkernel-based operating systems. In the 1980's, the team that developed C and Unix developed a distributed ...
3
votes
1answer
741 views

Why doesn't everyone use microkernel-based operating systems?

From what I have read on operating systems, the impression I have been receiving is that, for at least 30 years, "everybody has known" that microkernel-based operating systems are "better" than ...
1
vote
1answer
43 views

Is “capability-based security” vs “hierarchical-protection-domain based security” a false dichotomy?

The wikipedia page on capability-based security states: Capability-based security is to be contrasted with an approach that uses hierarchical protection domains. However, in order to implement ...
3
votes
1answer
50 views

A microkernel fully hardcoded in hardware?

Does there exist a (micro-)kernel of an operating system that is fully implemented in hardware? That is, a kernel that is not stored in RAM, and loaded into CPU registers after an interrupt or system ...
1
vote
0answers
22 views

Journey of a process from compilation to execution [closed]

I am reading operating system, and after reading some topics (Processes, Main Memory management) I got somewhat confused. I have knowledge about certain things but I am not able to combine and ...
1
vote
1answer
41 views

Is it possible for a syscall to pack together different places in memory?

While programming with buffers like uint8_t* in C++ I often arrive at situations on where I'm forced to do copies. For example, if I receive packets in chuncks from ...
1
vote
2answers
146 views

Why do operating systems freeze?

I am currently writing from a computer on which a VM has just frozen due to exhausted RAM. I am obviously no expert in the field of operating systems but i know that they implement certain memory ...
0
votes
2answers
34 views

How can the initial “booting” state of a computer be different at different time points? [closed]

In my experience, sometimes a computer boots normally, and in a time span of days, the computer won't boot, then again, it will boot normally again. I am not a computer science expert so I assume that ...
0
votes
1answer
157 views

How are hardware interrupts handled?

I have read that a hardware interrupt is handled asynchronously by the CPU, which means that the interrupt signal may arrive at any point of time with respect to the CPU clock cycle. Now, this means ...
1
vote
0answers
18 views

Why do we need volume as an abstraction on top of partition?

I'm curious about what do we need volume as an abstraction on top of hardware partition? What problem it tries to solve? What is the limitation of this concept?
-1
votes
1answer
106 views

Calculation of speed up of a program executed in multi-threaded system

Speed up of execution of a program is to be calculated within a multi-threading rather than a single thread system. The program's 30% instruction can be executed serially & rest can be executed ...
0
votes
1answer
24 views

need for an example of synchronous but non periodic interrupt

I know that synchronous interrupts are interrupts that occur with a clock tick (after finishing an instruction) and I think that periodic if they happen in every n ticks of the clock. To get a better ...
0
votes
1answer
68 views

Is OS mode required for accessing general purpose registers

In which of the following cases a process executing in user model is required to enter into the OS mode? (a) Decreasing the value of unsigned integer value in a register to less than 0 (b) Accessing ...
2
votes
1answer
336 views

In a kernel, what are “global constructors”?

I am a beginner developing kernels (though I have developed several Hello World programs in C and C++). I frequently see reference being made to global constructors (e.g., osdev https://wiki.osdev.org/...
1
vote
0answers
23 views

User-level threads and information available to the kernel

User-level threads are transparent to the kernel. How is htop able to show user-level threads running on my system? I know that those threads are user-level threads ...
10
votes
1answer
5k views

What is the real advantage of Google's new Fuchsia operating system kernel?

Google's new in-production OS which it desires to replace not only Android but many other devices utilizes a completely new kernel: The code differs from Android and Chrome OS due to its being ...
6
votes
2answers
652 views

Why operating system needs interrupt stack, if it has process control block?

I'm reading about an operating system but some concept confuses me. What doesn't confuse me: When an interrupt or system call or processor exception occurs, it happens when user mode tries to ...
1
vote
1answer
23 views

Are process-safe mutexes shared between OSes?

I understand you can use process wide mutexes, but does this still apply if you have an additional virtualized operating system provisioned? For example, take two OSes: ...
0
votes
0answers
14 views

Operating Systems - Why Stack Growths For a Fixed Parameter N Are Inconsistent?

I am taking an Operating Systems course and as a project, we are printing the content of the PCB of a process from task_struct of that process and its mm_struct & vm_area_struct pointers. During ...
1
vote
2answers
59 views

Are Kernel Codes (which are written in C) compiled during boot time?

I have a confusion regarding how the Kernel is loaded during the boot time. The intuition I have is like following: During installation of an OS, the compiled Code of the Kernel (depending on the ...
-1
votes
1answer
38 views

how applications send tcp data to internet?

What i know is that applications create "socket"(visualized concept for high level programmers),the socket will address the ip addresses and send to internet and forward the feedback data.What i ...
0
votes
2answers
177 views

On what abstraction is a filesystem actually built on?

Data is read in terms of a block from a storage device(magnetic, optical, flash). Size of the block depends upon the filesystem and os. The physical device may have different units of storage like ...
6
votes
3answers
2k views

Why do we try to maximize Lagrangian in SVMs?

I was learning about support vector machines from MIT OpenCourseWare. I figured it out. I understand why we try to minimize $\frac{1}{2} w^2$. I just did not get why we try to maximize Lagrange ...
1
vote
0answers
429 views

Do user level threads take advantage of multi processing?

I asked this question here on stackoverflow, but maybe because of off-topic over there, it didn't received proper response. Does user level threads take advantage of multiprocessing ? I read one such ...
-4
votes
1answer
111 views

Touchpad driver missing after windows 10 installation in acer E3-111-290X [closed]

I was asked by a friend to help installing windows 10 in an acer E3-111-290X that was previously running windows 7, but after installing windows 10 the touchpad stopped working.I've tried several ...
9
votes
2answers
1k views

What is a file?

I'm looking for a formal definition of file that does not only include storage but also abstractions like procfs or /dev/null (or any fuse-based file) that do not relate to storage. So far I know ...
4
votes
0answers
359 views

Are these modern operating systems monolithic or microkernel?

I know that (at least at its conception) Linux and Mac OS were both monolithic kernels. My question is, what kind of kernels are Linux, Mac OS, and Windows today and why?
0
votes
1answer
113 views

How many bits are needed? Advantages/disatvantages of this configuration?

So the question is: Assume we had 15 CPU instructions and, for each instruction, we were trusting one particular component of the kernel to handle it. How many modes do we need to support (including ...
2
votes
2answers
724 views

Language that system calls are implemented in

Lately, I have been reading about operating systems design. The idea that all user space programs utilize Kernel services via a "System Call Interface" have got me thinking further into this. Is ...
0
votes
1answer
129 views

If I write code in machine language, then I have access to the CPU in both modes (user and kernel), since the OS is bypassed, correct?

Codes written in machine language can have access to both CPU modes (Kernel and user), since the OS is bypassed, correct?
1
vote
0answers
36 views

local addresses in segmentation

I'm reading "Understanding Linux Kernel 3rd edition" and it starts talking about memory segments. It says that a logical address is: Included in the machine language instructions to specify the ...
2
votes
1answer
3k views

User level threads are transparent to the kernel?

Find whether given statement True or False? Explain. User level threads are transparent to the kernel? My attempt : False. Since, user level threads are managed by a user level library however, they ...
0
votes
1answer
455 views

What features should a critical section have to maximize performance?

Critical sections limit performance by constraining parallel execution and adding overhead. What features should a critical section have for improving performance?
0
votes
0answers
333 views

What are disadvantages of a Operating System that recognise file extensions ?

When Operating system recognise the file types It has several advantages like 1. avoid mistakes like trying to print a object file that produce garbage output but I can't think about disadvantages ...
3
votes
2answers
3k views

What is a student process?

According to Galvin and Silberschatz, 5 queues are maintained in multilevel queue scheduling, each for: System Process Interactive Process Interactive Editing Process Batch process Student Process ...
1
vote
2answers
3k views

Switching between user-level and kernel-level threads

After reading difference between user-level threads and kernel-level threads ,now I am in doubt of context switching.Context switching is managed by OS when switching between processes/threads but ...
1
vote
2answers
96 views

Handling TOCTTOU with system calls

What are some of the best practices when implementing system call functionality for handling/avoiding "Time of check to time of use" (TOCTTOU) security issues?
3
votes
1answer
71 views

Relation between Signals and Events

There are POSIX signals (linux man), and various event-based operating systems (such as TinyOS, most seem to be targeted at embedded systems). But the mechanisms seem very similar. Are the terms '...
1
vote
1answer
232 views

Are Time-sharing and multi-tasking operating systems same or different

My question is regarding time-sharing and multi-tasking systems. Time-sharing operating system assigns time slot to each task while multi-tasking OS runs various jobs in parallel. But as I get it, ...
10
votes
1answer
1k views

Writing a multitasking operating system for a processor without MMU

I've been thinking of writing a hobby operating system for some of the ARM processors. There are many popular single-board computers with ARM MPU, so I simply wanted to purchase one of those (choosing ...
14
votes
2answers
10k views

Performance of microkernel vs monolithic kernel

A microkernel implements all drivers as user-space programs, and implements core features like IPC in the kernel itself. A monolithic kernel, however, implements the drivers as a part of the kernel (e....
14
votes
2answers
156 views

What are potential pitfalls with having a minimal kernel that runs managed code?

Suppose I want to build an operating system based on a very small native lower kernel that acts as a managed code interpreter/runtime and a larger upper kernel compiled to a non-native machine ...