Ucosii and Linux differences and connections

Ucosii and Linux differences and connections

Want to understand the Linux system architecture through ucosii, so refer to some information, simple collation of ucosii and Linux differences and contact, in order to better learn Linux.

The specific comparisons are as follows:

OS	Interpretation	Ucosii	Linux
OS Defined	1. Interface between the user and the computer; 2. It is also the interface of computer hardware and other software.	1. Free, source code public time-sharing multitasking multi-user operating system	1. Free, real-time multi-tasking operating system exposed by source code
Kernel	1. Is the core of an operating system; 2. is a hardware-based first layer of software expansion, providing the most basic functions of the operating system, is the basis of the operating system, it is responsible for managing the system's processes, memory, kernel architecture, device drivers, files and network systems, determine the performance and stability of the system.	1. The kernel includes system initialization, task scheduling, memory management, interrupt in and out of the leading, clock beats, event processing and other parts, but it does not provide input and output management, file system, network and other services; 2. It is a preemptive kernel that allows interrupt service programs to be interrupted, and the task is re-dispatched after the interruption, that is, the highest priority task is recalled.	1. Kernel includes process management, memory management, device management, network management, four parts; 2. It is a non-preemptive kernel with poor real-time. When the process is running in the user state, it can be preempted by a higher priority process, but when he enters the nuclear mentality, the priority level is no longer able to preempt it; 3. Differentiate between user state and nuclear mentality.
Real-time sex	1. Real-time tasks are divided into soft real-time and hard; 2. Hard to response time requirements, and time is not satisfied can lead to fatal errors, soft real-time with the response time is required, but not mandatory, will not cause fatal error to the system.	1. is a preemptive real-time kernel based on priority scheduling, not only the kernel supports preemption, but also supports the preemptive scheduling of tasks, the tasks with low priority can be preempted by high priority tasks, and can be preempted by service interruption. This ensures that the system responds to external events as quickly as possible. 2.UCOSii Real-time performance is better.	1. Mainly consider the fairness of scheduling and throughput indicators, although the system can be real-time events to high-priority methods to respond to real-time events in real time, but the effect is limited, the response time requirements of high-performance hard real-time tasks, can not meet the requirements; 2. Through some improved measures, the real-time of Linux can be compensated, for example: Increase kernel preemption, fine-grained system clock granularity, improve shielding interrupt processing, improve scheduling algorithm and so on. 3. It is non-preemptive scheduling, poor real-time
Task scheduling	1. Coordinating tasks for the use of resources within a computer system (such as memory, I/O devices, CPUs)	1. Preemptive scheduling based entirely on task priority. When a task with a higher priority is in the ready state, the task's context switches, the current task stops running, and the control of the CPU is assigned to a higher-priority task; 2. Can dispatch up to 64 tasks, each task has a different priority, the current operation is always the highest priority task; 3. Task scheduling with equal priority is not possible. The determination of the highest priority task is achieved by establishing a ready-to-use task table; 4. Each task has a separate stack space, and there is a task control block TCB, which contains all the information in the task execution.	1. Its scheduling strategy is priority scheduling and time-slice rotation scheduling; 2. Different from the ucosii, the time-slice rotation scheduling can carry on the scheduling of the same priority tasks, so that these tasks run for a period of time, so that the same priority tasks in the system have equal operational rights; 3. The scheduling algorithm is implemented according to the scheduling of each task 4 parameters related to the real-time process of the static priority, process scheduling policy, user-defined priority and the process of scheduling the remaining time slice; 4. The mechanism of task scheduling determines the obstacles to the fact of time
Memory management	1. Technology for the allocation and use of computer memory resources during software runtime	1. It adopts the fixed partition mode in the continuous storage space management mode; 2. Each memory partition has a memory partition control block.	1. It uses a page-based management mechanism in a continuous storage space management approach; 2. It uses virtual storage technology, each task from memory to obtain a certain number of pages, the current non-access to the page replacement, in order to make room for the page task, there is uncertainty, high-real-time system will not be used.
Time Management	1. Clock and timing interrupts for the operating system	1. It uses the hardware timer to produce a periodic interrupt with a period of milliseconds to achieve the system clock; 2. The task is an infinite loop, and the system is a preemptive kernel, in order to avoid the high priority of the task exclusive kernel, in the low-priority task at the right place must add a delay function to pause the current task. 3. You can also use timing to implement periodic interrupt callback functions.	The 1.Linux clock is also implemented by a timed interrupt; The 2.Linux system has two clocks, one is a real-time clock, and is only timed when the operating system shuts down and is battery powered. The other is the system clock, when the system clock is initialized according to the real-time clock, and then the system based on the frequency of periodic interrupt timing, the system clock is not present in the shutdown. Synchronize with the real-time clock at shutdown.
File system	1. Is the organization and distribution of the space of the file storage device, the system responsible for storing the files and protecting and retrieving the deposited files.	1. No file management system	1.Linux file system inherits the UNIX system's file system function characteristic, also uses the EXT2 file system, EXT2 The function is powerful, easy to expand, the performance optimizes comprehensively; 2. There is also a virtual file system that allows Linux to support multiple different file systems. The/proc file system is a pseudo-file system where users and applications can get system information and change certain parameters of the kernel.
Portability	1. Porting the operating system to a different processor; 2. Two systems can be run on a variety of platforms, consistent good.	1.UCOSii transplantation is relatively simple; 2. Only a few K bytes of RAM are required.	1.Linux transplant is more complicated; 2. Requires hundreds of K bytes ram or more.
User interface	No	1.ucos is not available, it needs to be made up by a third-party graphical interface system, such as: Uc/gui,emwin.	The 1.Linux has a good user interface, including a user interface shell, and a system invoke interface.
Application areas	No	1.UCOSii widely used in industrial control, single-chip microcomputer field, the cable digital TV field set-top box design, mobile communication terminal field.	1.linux is widely used in the server field, and has reached a certain level in desktop applications.
Other	No	1.ucos also supports some of the better mechanisms, such as semaphores, to achieve synchronization and mutual exclusion between tasks and tasks, and between task and interrupt service programs; Message Queuing for buffering communication between tasks; mailbox, a low-overhead mechanism for transmitting information; 2. Priority inheritance protocol and ceiling protocol to solve the problem of task scheduling is blocking. 3. Standard Ucos no input/output management, no network service	The 1.linux also has the independence of the device and manages all external devices uniformly as files. New devices only need to add the necessary device drivers to the kernel. This also makes Linux a better fit

The above is only a relatively simple comparison of the common, not specifically explain the advantages of Linux and its complexity. I hope you will correct the communication.

Ucosii and Linux differences and connections