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MIT6.828 lab2:http://pdos.csail.mit.edu/6.828/2014/labs/lab2/ LAB2 is mainly about the paging process of the system, there is a simple virtual address to the physical address of the process. About the system paging, the MIT6.828 virtual address into the physical address--level two paging: http://blog.csdn.net/fang92/article/details/47320747. The following are mainly lab2 of several exercise of the problem-solving process. 1. First Boot_alloc () function: static void * Boot_alloc (uint32_t N) {

files the file system can establish is related to the number of inode, where there is enough space but not enough inode When the system reads the file, it needs to find the inode and analyze whether the permissions recorded by the inode are consistent with the user, and if so, to begin to actually read the contents of the block. Inode to record a lot of information, but only 128bytes, and Inode record a block number to spend 4byte, if I have a file 400MB and each block is

paging mechanism sees the entire linear address space and the entire physical address space as composed of pages, and any page in the linear address space can be mapped to any page in the Physical address space (we call a page or page frame in the physical space)80386 pages that use 4K byte size. Each page has a length of 4 K bytes and is aligned on a 4K byte boundary, that is, the starting address of each

line is set to 4K, so the entire file system capacity should be 4*65536*4k so big! The 2nd line of Sectsz refers to the logical magnetic region (sector) capacity set to 512bytes so big meaning. The bsize in line 4th refers to the capacity of block, each block is 4K meaning, a total of 262,144 blocks in this file system. The Sunit and Swidth in line 5

machine uses a full size design, but the feel is not very flexible. One of the highlights of the Asus Zenbook Pro UX501 is the 15.6-inch 4K screen, yes, 3840*2160 Pixel's Super high-definition touch screen. The color of the screen is good, the touch is responsive and the perspective is very broad. Unfortunately, the 4K screen has become the biggest drag on Asus Zenbook Pro UX501 and will tell you why. Ac

both section-mapping and page-mapping, so how do you distinguish between mapping, the key in the page directory entry with the minimum 2bit, as follows:MMU according to the page catalog entry minimum 2bit to determine what to do next, all 0, invalid page directory, MMU will send the CPU to issue an exception. Page-mapping will also be subdivided into coarse page table (thick page) and fine page table (fine page tables), whether the two-level page table maps 64k/

http://blog.csdn.net/killmice/article/details/42745937 The test tool FIO is read sequentially as an example, with the following commands: fio-name IOPS-RW = Read-bs = 4k-runtime = 60-iodepth 32-filename/dev/sda6-ioengin E Libaio-direct = 1 where rw = read for random reads, BS = 4k for each read 4k, filename specifies the corresponding partition, here I am/dev/sd

OneView with AS SSD benchmarkIncludes 4 aspects of test (sequential read/write, 4K Random read/write, 64 thread 4K read/write, seek time) As SSD's main test, but also the most common on the Internet to get test results, is its main interface on the continuous, random, access time, such as 8 related tests, as well as compression and file replication test. Let's start with a brief explanation of how eac

for 2440, there are not many ways to start. Generally is the outside a NAND flash, 2440 has a NAND flash insideController, the first 4K of NAND Flash is automatically copied to 2440 in-chip SRAM. 2440 this in-chip SRAM is calledStepping Stone is also just 4 K. when you make your startup code, it's uboot. Uboot is generally divided into two parts, generally called BL1 and BL2. BL1 and BL2 both add up to the whole uboot. Each of the two sections has a d

, SandForce, Samsung and JMicron, Phison and so on. Different company's product, the characteristic is different, the performance and the price difference is many. Some inexpensive SSD, basically use a few price comparatively inexpensive of the Taiwan series product, performance is fair, still more superior than mechanical hard disk. Medium and high-end products, most of the use of Marvell/sandforce chips. Samsung can design and manufacture the main control chip and memory chip at the same time,

Level two page table Page Catalog entry 1024 Physical Address (4K page) of the page table for each of the first 20 bits size 4B Page table 1024*1024 A physical address for each page with a size of 4B first 20 bits Page frames are 4k paging, and for 32-bit logical buses, the last 12 bits are blocked off, only need the first 20 bits to find the address of this page plus 12-bit offset, you can find the specifi

Tags: retrieving enhanced not tar spatial database bytes size RmanFirst, in explaining under what circumstances need to open large pages and why need to open a large page before understanding the next page of Linux related knowledge:The following content is based on a 32-bit system, 4K of memory page size made calculation1) Table of contents, used to store the page table location, a total of 1024 directory entry, each directory entry point to a page t

request needs to allocate memory and read Response from the buffer similarly.MemoryStream is a reliable solution, it realizes automatic expansion, but the expansion process can not be separated from the byte copy, and the frequent allocation of memory will affect performance, approximate expansion example code is as follows://initByte [] buffer = new byte[4096];int32 offset = 0;//write bytesbyte[] bytepreparecopy = / /from Outsideif (bytepreparecopy > buffer. Length-offset) {byte[] Newbuffer =

SRAM from the corresponding external memory.Step two: Run the BL1 (16KB) read from Iram and execute it. BL1 is responsible for initializing the Nandflash, and then reads BL2 to Iram (the remaining 80KB) and then runsStep three: Initialize the DRAM from Iram run BL2,BL2, then read the OS into DRAM, then start the OS and the boot process ends.My confusion:I use the s3c2451 Development Board is in the Nandflash start, said Nandflash can not directly read the data, how to start?Resolution: The diff

with the latest 2-core CORTEX-A72 CPU and 2-core A53 CPU collocation architecture. A72 is the best arm performance and state-of-the-art processor, so mstar6a938 is the first in the TV industry to use the A72 core chip, and A53 is the world's smallest 64-bit processor. The highest performance arm CPU core is combined with the most efficient arm CPU core, so as to switch the kernel freely according to different computing requirements, provide computing power instantaneously, and realize the real

). The virtual address space is divided into units called pages (page), and the corresponding physical address space is partitioned, in the form of a page frame. The page and page boxes must be the same size. Next, I'll take a picture with an example of how the page and page boxes are mapped under the MMU Dispatch:In this example we have a machine that can generate a 16-bit address, its virtual address range from 0X0000~0XFFFF (64K), and this machine only 32K physical address, so he can run 64K

As_ssd_benchmark Assessment of the overall processOnly 4k aligned, ahic mode not turned on ...This 200 score instantly scares the urine. Power on 1 minutes 27s, the old machine, not so, Bo master angry, bo main lu!!! Bo mainly to change the result of this egg. So the old-age machine modification tour was opened. What is the old age machine? Blogger Pen, 10 notebook, including 10. Why? sata3.0 typically turns on large-scale builds after 10 years, typic

are usually incompatible and in one segment because of a semi-closed connection, in which case the client cannot send the data to the server after the connection is closed. However, the server can also send data to the client until the server closes the connection.3. Flow controlIf the sending side is sent at a faster rate, the receiver receives the data after the processing is slow, and the size of the receive buffer is fixed, the data is lost. TCP protocol through " " Sliding window ( Sliding

requiredIf the cookie expiration date is not set, its life cycle is saved until the browser is closedThe Expires property of the cookie object is set to MinValue means never expiresThe amount of data stored by a cookie is limited, and most browsers are 4K so don't store big dataSince not all browsers support cookies, the data is stored in clear text in the clientCode: Resopnse.Cookies[“UserID”]=”test”; String UserName= Resopnse.Cookies [“UserID”].ToS

storage space, C6 the non-boot partition inode default size of bytes. C5 is a byte5)The Inode is a string of numbers, and the Inode ( a string of numbers ) used by different files is unique in the file system .6)inode the same files, each other as hard-link files (two portals of a file)7) A file is created to occupy at least one inode and one block8)block size generally has several 1k,2k,4k . where boot partition is 1K, other normal partition is