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The question actually is :
If I have some processor named x
I have 3 Operating Systems named a,b,c
Now how can I decide that which operating system controls the processor ?
What is the basic understanding between the processor and Operating system ?
And the above 3 operating systems are not of different versions from same company..
To be specific how Android hardware is different from iPhone hardware and why can't iOS be installed on Android hardware...??
Thanking you..
You are actually asking a question which shows your lack of understanding of OS, CPU and other technical terminologies.
Actually, You need to study the basic of Os and CPU to get a deep understanding on the topic. But, I will definitely help you out by defining both the terminologies.
Your computer's operating system has two main objectives in its management of the central processing unit, or CPU. First, the OS makes sure that as many processor cycles are used for work as possible.
Second, the OS schedules the processor's attention among the demands of different processes. Processes are actions that can be controlled and are the basic units of software with which the OS communicates. A process may be a task, such as a virus check, that runs in the background so you never even know it's working. It also may be one of several tasks that an application, such as a spreadsheet, executes at your request. In a multitasking OS, the OS has to switch the processor's attention between competing processes many times per second because the processor can only do one thing at a time.
Briefly summarizing :
A processor is the 'engine' of the computer - it runs all the software and moves data around. The best processor in general has more cores (core i7), and a higher speed.
An operating system is the 'traffic cop' of all the software on the computer - it's software that controls how all the other programs on the computer work together and share the resources of the computer.
Hope you have got an idea :)
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I am trying to understand, what is an OS image and VM image and how they are different?
An OS Image commonly refers to a collection of the programs and data files needed to make an operating system functional. That is a minimal definition; but an image needn't be minimal.
A Virtual Machine image commonly refers to all of the state: memory, device registers, etc... of a virtual machine. In contrast to an OS Image, a Virtual Machine can be restarted after halting; whereas an OS Image restarts from the beginning. A system image commonly refers to the equivalent of a virtual machine image for a real hardware machine.
Why do these terms exist? When an operating system starts, there is little to no functioning system software on the target machine; so the first level of starting (bootstrapping) is to put some lump of something into RAM, and start executing it. That lump might be an operating system, or may be a small intermediate system that will then load the actual operating system (or load yet another boot loader). An example is grub or u-boot.
An intermediary system may be more functional than to just load a lump and jump. It might understand file systems, and be able to parse device database; thus construct an appropriate OS image for the target hardware on the fly. The division of labour is a compromise chosen by the system designer.
Intel based systems add an incredibly complex intermediary into all of this with a system called ACPI which sits underneath the Extensible Firmware Interface. The A in ACPI stands for Advanced, I suppose new and improved was too transparent.
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Some media have reported that a new hardware bug in Intel processors, allowing user mode processes to access kernel mode memory, has been discovered:
It is understood the bug is present in modern Intel processors
produced in the past decade. It allows normal user programs – from
database applications to JavaScript in web browsers – to discern to
some extent the layout or contents of protected kernel memory areas.
The effects [of fixes] are still being benchmarked, however we're
looking at a ballpark figure of five to 30 per cent slow down,
depending on the task and the processor model.
After the bug is fixed, which slowdown am I to expect for multicore floating point computations?
To my understanding, only the performance of switches between kernel and user mode are affected. For example, handling a lot of I/O is a workload where this is frequent, but CPU-intensive processes should not be affected as much.
To quote from one article that analyzes performance of the Linux KPTI patch:
Most workloads that we have run show single-digit regressions. 5% is a good round number for what is typical. The worst we have seen is a roughly 30% regression on a loopback networking test that did a ton of syscalls and context switches.
...
So PostgreSQL SELECT command is about ~20% slower with KPTI workaround, and I/Os in general seem to be impacted negatively according to Phoronix benchmarks especially with fast storage, but not gaming performance, Linux kernel compilation, H.264 encoding, etc…
Source: https://www.cnx-software.com/2018/01/03/intel-hardware-security-bug-fix-to-hit-performance-on-windows-linux/
So, if your FP computations rely mostly on in-memory data shifting and not I/O, they should be mostly unaffected.
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I'm told, that Windows NT was first designed to implement the microkernel architecture, but moved away to hybrid kernel.
What caused the change? I'm having trouble trying to find any info about this.
The main reason that Windows NT became a hybrid kernel is speed. A microkernel-based system puts only the bare minimum system components in the kernel and runs the rest of them as user mode processes, known as servers. A form of inter-process communication (IPC), usually message passing, is used for communication between servers and the kernel.
Microkernel-based systems are more stable than others; if a server crashes, it can be restarted without affecting the entire system, which couldn't be done if every system component was part of the kernel. However, because of the overhead incurred by IPC and context-switching, microkernels are slower than traditional kernels. Due to the performance costs of a microkernel, Microsoft decided to keep the structure of a microkernel, but run the system components in kernel space. Starting in Windows Vista, some drivers are also run in user mode.
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I need to learn the basic knowledge of OS, kernel and CPU architectures since some jobs do require those background.
Is there a good book or online resource that I can refer to.
I don't know if you had a specific OS in mind, but one of the best books on how the Windows operating system works "under the hood" is called Windows Internals. It describes in detail how everything from the kernel, to device drivers, and the file system all work.
If your looking for a good book on how CPUs and processors work, in general, I recommend Computer Architecture: A Quantitative approach. Very good info there!
Also, some good resources on how CPUs work, with perspective to programmers, can be found from the Intel technical library. Everything is free to download there and it makes for some good reading!
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I do not understand the difference between operating system and kernel. Can someone please explain it?
The kernel is part of the operating system and closer to the hardware it provides
low level services like:
device driver
process management
memory management
system calls
An operating system also includes applications like the user interface (shell, gui, tools, and services).
The difference between an operating system and a kernel:
The kernel is a part of an operating system. The operating system is the software package that communicates directly to the hardware and our application. The kernel is the lowest level of the operating system. The kernel is the main part of the operating system and is responsible for translating the command into something that can be understood by the computer.
The main functions of the kernel are:
memory management
network management
device driver
file management
process management
Basically the Kernel is the interface between hardware (devices which are available in Computer) and Application software is like MS Office, Visual Studio, etc.
If I answer "what is an OS?" then the answer could be the same. Hence the kernel is the part & core of the OS.
The very sensitive tasks of an OS like memory management, I/O management, process management are taken care of by the kernel only.
So the ultimate difference is:
Kernel is responsible for Hardware level interactions at some specific range. But the OS is like hardware level interaction with full scope of computer.
Kernel triggers SystemCalls to tell the OS that this resource is available at this point of time. The OS is responsible to handle those system calls in order to utilize the resource.