New answers tagged operating-systems
1
Hash functions can have collisions, and you need to resolve the collisions. If two (PID, page_number) pairs map to the same row, only one can be stored there, and you need to have a mechanism to find the other one.
You can use page tables to map multiple virtual addresses (pages) to the same physical address (frame). For instance, this may be used to ...
3
Many people confuse these two bits. I'll try to explain the concept to best of my knowledge.
Let's say we have 32 bit architecture. so process virtual address space(VAS) will have size of 2^32. VAS space of a process has kernel code and data part and user code and data part.Page table of process contains entries for both user/kernel part. kernel page table ...
1
Swapping a process means to move all of its memory onto the hard disk. Paging means to move a single page of memory onto the hard disk. So, the difference is the granularity at which data is moved between main memory and persistent storage (the hard disk). Over time, the term "swap" has been used more broadly and not everyone uses the word "...
2
One processor can only execute one process at a time. Today processors have several cores/threads in the same chip. Even if you have one core in your processor, the OS needs to swap the entire execution context (the entire process) in order to execute something else and it needs to do it efficiently to prevent latency in rendering.
What is called a swapper ...
2
The processor has a control bus which allows it to tell the motherboard it wants to write somewhere else than RAM. When the processor sets a certain line on the control bus, it can write data to a port instead of RAM.
The processor can send data to certain ports which, by convention, are used to talk to hardware. The Hard-Drives have controllers which will ...
-1
I think student process is to like help student in their work and catch up.
5
Since the OS manages scheduling, we guarantee mutual exclusion for the following steps.
But how do you guarantee mutual exclusion inside the OS?
On a single-processor machine¹, you know that only the kernel code that serves the lock system call is executing. All other threads are in a known state. However the kernel code can be interrupted at any time by a ...
answered Nov 10 at 21:15
Gilles 'SO- stop being evil'
39.3k7 gold badges103 silver badges167 bronze badges
2
OS locks require hardware support because every instruction in the ISA takes multiple clock cycles to complete. It has to go through a instruction execution cycle having fetch,decode,execute,write... stages (there are processor with >20 stages). Also most of the processor nowadays are pipe-lined processors. I.e, since hardware for each stage of the ...
0
I might be too focus on the algebra. I believe I only need to argue or proof a scenario that would give the least density of the system that will fail to meet a deadline.
As shown in the figure below, all tasks start at the same time with same period and deadline. For each of period, each task only have time slot D=D1=D2=...=Dn to execute. In other words, ...
Top 50 recent answers are included
