operating system concepts 9th

Article title: master advanced re-compile the Linux operating system kernel. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source. An important feature of Linux is its open source code. any software engineer in the world can add cod

//Operating system and computer principles are described in memory management page management, but I and many of the first time to learn paging, will be confused page table size and the relationship between page table item size, I carefully analyzed the post wrote this blog, only when learning and communication, personal understanding of the use, if the error or analysis is not rigorous, Please correct me.A

works in this way. The concepts of centralized application objects (Blackberry/j2's Midlet or BREW's IApplet) are used by both the iPhone, Brew, and Blackberry ). In contrast, Android forces you to design small, self-sufficient mimi applications, which leads to some very interesting behavior, such as, by default, when a user rotates the screen or releases a keyboard, Android ends the current Activity and recreates it. Finally, professional mobile dev

A personal summary of the privilege level in the IA32 segmentation mechanism: In IA32 's segmented mechanism, it is divided into 4 privilege levels (RING0~RING3): Level0 High (inner layer)L e v E l 1L e v E l 2L e v E l 3 Low (outer) The difference between the privilege levels is the restriction of the instruction (mainly the limitation of the system instruction, such as Lgdt,lldt, etc.). It is very easy to understand that the higher the privilege le

not necessary to write and write data as a whole. For example, the field ing mechanism is described (Image Source: Click to open the link) Paging Mechanism The paging mechanism solves a memory usage efficiency problem in the preceding segmentation method. The core idea is that the system allocates page Y in the memory for page X in the program execution file, at the same time, page y is added to the ing table (page table) of the virtual space addre

; theProarr[i]. tatime=proarr[i].finitime-Proarr[i].arrtime;94 } the the } the 98 /* About * Main function - */101 voidMain ()102 {103System"mode con cols=100 lines=30");//Window Width Height104 intflag=1; the intN;106printf"number of \n\t processes:");107scanf"%d",n);108 while(intarrN) {109 Intputjobarr (); the }111System"CLS"); theprintf"\n\t This is the data you entered: \ n");113 Putoutalljobarr (); the the sort (); the Simulatecohort ();117 118printf"\ ___________

; Slice=1;//3. Thinking: What is the role of slice? And why is the assignment changing? for(i=1;i1)-pcb[i].priority); i++) Slice=slice*2; for(i=0; i) {(pcb[i].cputime)++; pcb[0].truetime++; if(pcb[0].truetime>=pcb[0].reqtime) Break; } if(pcb[0].truetime>=pcb[0].reqtime) {printf ("\ nthe process%s is complete. \ n", pcb[0].name); for(i=0; i) {k=i+1; Pcb[i].arrtime=Pcb[k].arrtime; strcpy (Pcb[i].name,pcb[k].name); Pcb[i].reqtime=Pcb[k].reqtime; Pcb[i].priority=pcb[k].priority;

process and write process in accordance with the FIFO method to achieve mutual communication between a shared file, called a pipeline. The transmission of information by a character stream. Need to have the following functions, mutual exclusion, synchronization, to determine whether the other party exists or notMessaging communication: Use formatted messages to encapsulate the data in the message, and pass the message between processes using a set of communication commands provided by the wrong

first ready, it enters the first-level queue.(3). (*) Consider the blocking State B (Blocked) of the process to increase the blocking queue. The time at which the process is blocked and blocked is determined by the resulting "random number" (the frequency and length of the blocking is more reasonable). Note that a process can be converted to a blocking state only if it is in a running state, and the process is only ready to be converted to a running state.2.Experimental contentAccording to the

; i) { for(r=0; r) if(Pcb[i]. arrtimePcb[r]. Arrtime) {Cunfang=Pcb[r]; PCB[R]=Pcb[i]; Pcb[i]=Cunfang; } Else if(Pcb[i]. arrtime==Pcb[r]. Arrtime)if(pcb[i].priority>pcb[r].priority) {Cunfang=Pcb[r]; PCB[R]=Pcb[i]; Pcb[i]=Cunfang; } }.....}voidShijianpian () {} Summary: Through this experiment, the process of scheduling have a certain understanding, there are many do not understand the place. This harvest is very big, this experiment for me is difficult, bu

encountered a lot of difficulties. Although the structure can be defined relatively skilled, but for the call structure in the program is not very understanding, resulting in multiple errors, and by consulting the relevant information, and then constantly modify, before the relevant experimental basis requirements to complete. In addition, writing procedures need a good habit of thinking, and to be good at transforming the computer operation and the actual situation, in order to understand the

level queue if it is not completed.When the process is first ready, it enters the first-level queue.(3). (*) Consider the blocking State B (Blocked) of the process to increase the blocking queue. The time at which the process is blocked and blocked is determined by the resulting "random number" (the frequency and length of the blocking is more reasonable). Note that a process can be converted to a blocking state only if it is in a running state, and the process is only ready to be converted to

. There are two main points in this sentence. It is best to read them together several times. 1. Concepts of logical and physical address spaces The logical address space is the address space corresponding to the logical address, also called the relative space, virtual space The physical address space is the address space corresponding to the physical address, also known as absolute space. The address generated by the CPU. The address in the instruct

In everyday English, the shell can be translated into shells, most of which means a device or structure that can protect the inner core. In computer science, the shell actually refers to a provider that can use the entire computer's resources through system calls or library calls.It is both a command parser and a programming language. As a command parser, it can interpret and execute user-entered commands, and can automatically interpret and execute a