Questions tagged [operating-systems]
Questions about the principles of software that interfaces between hardware and applications.
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Work out corresponding logical address
this should be a simple question but I don't quite understand how to work out the logical address from the information given.
Question:
Suppose a program is running on a system with a simple base ...
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Execution-time address binding, logical addresses creation
In the operating systems that make use of the execution-time address binding who is responsible for the creation of logical addresses?
EDIT
I'm thinking that the logical addresses are generated by the ...
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Swapping in mobile systems
I know that swapping is avoided in mobile systems because of limited memory but I came across this question and couldn't answer if the answer is yes.
Should swapping be done in Mobile systems? If yes, ...
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Need help to find some courses about system software design and development
The question's title itself says what I want. I've already searched this term on google but I can't find any course with this theme. What terms I can use to search about this course?
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How does the kernel sends information generated by an interrupt to the right process?
Andrew S. Tanenbaum, in his book Modern Operating Systems states that,
When a hardware interrupt occurs while a user thread is running, the interrupted CPU switches into kernel mode. If the interrupt ...
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What is the advantage of a hashed inverted page table versus an ordinary hashed page table?
A hashed inverted page table has a hash table that points each page number to its frame number. This frame number can then be used as an index to the inverted page table to get the PID and page number....
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How are interrupts handled?
Andrew S. Tanenbaum, in his book Modern Operating Systems, states that
Once the CPU has decided to take the interrupt, the program counter and PSW
are typically then pushed onto the current stack and ...
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Questions regarding Translation Lookaside Buffer (TLB)
TLB is used in the paging memory scheme to reduce the time taken for memory access for a user's memory location through storing pages in this TLB cache and it depends a lot on the hit ratio (The ...
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Why windows 11 does not support old cpu?
I know CPUs execute machine language code. Also I know operating systems such as Windows and Linux are a piece of code. But I cannot understand why Windows 11 does not run on a somewhat old CPU.
Can ...
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what is the relation between operating systems and automata theory?
I want to do some research on how machine theory (automata theory) is applied in the operating system. Also thank you for introducing useful links and books.
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Virtual and physical address spaces in address binding
I just need to check my understanding regrading two points .As was stated in the textbook "Operating systems concept " :
The compile-time and load-time address-binding methods generate
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Does every thread store its context in a separate PCB?
Is a thread's context stored in the process's PCB, or is a new PCB created for the thread?
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More info about traffic controller in process management of an OS
I was going through some texts and shared PPT of my university and I found the term "traffic controller" in the Process management section under the functions of an Operating System.
The PPT ...
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Understanding the difference between API, system call and system call interface
as anticipated in the title, I can't understand the difference between API, system call and system call interface.
Most of all, I can't understand if the system call interface is actually a "...
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Boot Loaders, Boot Sectors, BIOS, and GRUB
Again, I must apologize if this is "easily googlable". I have tried.
My understanding is that the BIOS typically looks for the magic number 0x55aa at the end of a 512 byte sector (so bytes #...
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How are I/O operations handled on a computer?
What does the computer do when an I/O operation needs to be done during the process? Does the message that we need to do some I/O operation directly reaches the device controller or device driver? ...
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Tigers and elephants can't drink water from a pond simultaneously, while more than one tiger or more than one elephants can drink water simultaneously
Below is a question on synchronization mechanism which was asked in an interview in Indian Statistical Institute, M.Tech CS. I got hold of it from here.
There is a forest where there are tigers and ...
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Can spooling be used for all I/O devices?
I read in my textbook that a spooling could be used to elinmate the possibility of.having a deadlock in some cases. But does spooling work for all I/O devices? If not what are some examples of those ...
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How MAC (Mandatory Access Control) model prevents trojan horse attacks?
I've heard that the MAC Model prevents Trojans to charm files on the system.
How is it possible? Can somebody show any example that MAC model protects us against it?
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Why is C still the fastest? Critique my take
A friend and I were surprised that C still has near-best performance among languages. I thought about why this is, and I wrote up a few paragraphs. I wonder if the friendly folks on CS stack could ...
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What does it exactly mean by information management as a function of O/s
I have read that information management is a function of O/s by which it
A) Manages, stores, retrieves,modify data. It makes sure that right people have access to their information.
B) Some of the ...
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What is meant by capability-based addressing and capability-system model?
What is meant by capability-based addressing and capability-system model? For context, I'm trying to understand the paper on Capability Hardware Enhanced RISC Instructions (CHERI). I haven't been ...
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How to study in and outs ofOperaring Systems
I want to study operating systems in depth, in particular windows, linux and android OS. What is the best way to get started?
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Is there an OS with capability to freeze/unfreeze any app?
I'm looking for an operating system (commercial opensorce or any) which can freeze any currently running application (video/audio playback, a game etc.).
While the app is frozen the OS must be able to ...
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Definition of the term "access efficiency" in the context of computer systems
In a two-level virtual memory, the memory access time for main memory, $t_M=10^{−8}$ sec, and the memory access time for the secondary memory, $t_D=10^{−3}$ sec. What must be the hit ratio, $H$ such ...
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Are there any operating systems that utilize only user threads?
We're going over threading models in my freshman CS class. Are there any examples of operating systems that use exclusively user threads (N:1)? It looks like 1:1 is far and away the most common model ...
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Choice of process to swap out to reduce thrashing
Is the problem to decide which process should be swapped out in the event of thrashing, a NP problem? Are there any heuristics to decide a suitable candidate(like the largest process or one which has ...
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Question Regarding number of frames required for multilevel page tables
I have a problem and I'm not sure where I am going wrong with this, description
so as you can see it is given a 3 level paging system with 8 bit page index on every level, now I break down logical ...
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Context switching and Program Counters
This is a really short question and a straightforward one for anyone who knows the subject well. But its also super specific, so I can't find the answer online.
I know a program counter is saved when ...
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Exceeding limits of virtual address space
I still am confused whether I am asking the right question but here goes
Consider a X bit processor. It can address theoretically a main memory of 2^x bytes(assuming byte addressable). Now consider an ...
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Can Operating system allocate a page of process to any free frame in memory?
Consider I have a user program of 6 pages and 4 byte page size. Now my memory has 300 frames out of which 10 frames are free for allocation. Can the OS allocate page 1 of the given process to any of ...
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Why does python's threading library use OS level threads when it can't achieve parallelism?
I was surprised to hear that the threading module from python uses OS level threads. From what I know, OS level threads are more expensive (but can achieve parallelism) meanwhile green threads are ...
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Why is copy speed periodic? (or seems to be)
When copying ~80Gb data from one USB 3.2 stick to another, i noticed that the GUI of the transfer speed had clear periodicity. Out of curiosity, what could be the reason for this? No other active ...
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Computing number of pages in page table from given information incorrectly?
I am trying to solve the following problem:
Provided a 64-bit CPU that is byte addressable with a linear page table and 12-bits utilized for the page's offset, determine how many pages the page table ...
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How many page frames does the system have for user process?
Operating System MCQ Question:
If a system has 1 GB RAM with a page size of 8KB and operating system occupies 16 MB of RAM, how many page frames does the system have for user process?
a. 129024
b. ...
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If a 32-bit computer system is being used, what are the size of the data/address/control bus width? [duplicate]
Are they exactly 32bits for a 32-bit system ?
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Timesharing and the MMU
Imagine we are running a program on a modern operating system, such as Linux or Windows. After running for some time, the program's time slice is up. A different program (process) starts to run again. ...
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Mathematical models of computation that capture more advanced OS and CPU design features
The universal Turing machine is the standard theoretical model of a stored-program computer. While in one sense as general as possible (Turing completeness), it doesn't explicitly contain many of the ...
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Differences between reliability and availability using an example
My definitions of reliability and availability are as below respectively .
reliability := property of failure interval .
availability := property of occupancy rate .
I want to show the differences ...
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CPU utilization estimation
In the Modern Operating System by Andrew Tanenbaum, Herbert Bos the authors provide their explanation of the concept of CPU utilization in the following way:
A better model is to look at CPU usage ...
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Incorrect average turnaround time calculated for FCFS schedule?
I am trying to solve the following problem:
If all of the jobs listed below are scheduled FCFS (First Come, First Serve) with no switching overhead, the average turnaround time is going to be:
...
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Deadlocks: Why if 2 threads are waiting for a lock from each other results in a deadlock?
I am confused as to why 2 threads waiting for a lock from each other will result in a deadlock. Let's say I have a Thread 1 that needs to execute contents in Lock 1 and then Lock 2 and a Thread 2 that ...
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What is the need for Kernel threads?
I'm a bit confused about kernel-threads, I searched a lot at the Internet, SOF and here but found very diverse and conflict answers. What is the need for Kernel threads? Are they threads that are only ...
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Over the course of history, did Linux and Windows NT kernel design learn from each other?
Linux Kernel in its primitive form was first written in 1991; Windows NT kernel (differ from Win9x Kernel which was based on DOS) purportedly began development in 1990. both being a monolithic kernel, ...
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Why semaphores lead to loss of modularity?
In this article Semaphores in Operating System and other articles on the internet, they have mentioned one of the disadvantages of semaphores is that it leads to loss of modularity. They further said ...
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What happens when I open a file? Is a temporary copy of the file created?
When I open up a file two different editors, vscode and sublime, changes saved in vscode are visible directly in sublime text. Same doesn't work with nano text editor. Any help?
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How does the Linux kernel build its symbol lookup table?
I am writing a small x86-64 OS. I am trying to make sense of how Linux loads modules at runtime by linking them into the kernel.
I understand that Linux builds a symbol lookup table. Basically, a ...
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How is segmentation a solution to external fragmentation
As per Galvin's book, segmentation is the solution to external fragmentation. But in segmentation, the memory blocks are of different sizes. So, if one segment is removed that creates a hole. If we ...
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What are the minimum functions, services, or features of a software to be called as an operating system?
When can we say that a software is an operating system and not a firmware, in terms of what it can do?
I know that firmware is usually stored in ROM and OS is stored on HDD/SSD, but technically you ...
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How could a page be invalid in demand paging?
I was reflecting on what I learned about demand paging and I have a question:
In demand paging, we have entries in the page table only for frames that are present in physical memory. So I was ...
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