Today let's continue to talk about the structure of the raid card. RAID card with CPU seems to be a small computer system, has its own CPU, memory, ROM, bus and IO interface, but this small computer is to serve the big computer. It is important to include the SCSI controller on the SCSI RAID card, because the physical SCSI disks are still attached to the back end. Its front end is connected to the PCI bus of the host, so there must be a PCI bus controller to maintain the PCI bus arbitration, data sending and receiving functions. Also need to have a ROM, is generally used as a Flash chip ROM, which stores the initialization of the RAID card necessary code and the implementation of the RAID function required code. The role of RAM, first of all, is as a data cache to improve performance; Secondly, it is the memory space required by the CPU on the RAID card to perform RAID operations. XOR chip is specially used to do parity data calculation of RAID3, 5, 6 and so on. Letting the CPU do the validation would require code execution, which would take many cycles. However, if a dedicated digital circuit is used directly, the result is obtained immediately as soon as it is in and out. Therefore, in order to get rid of the CPU, the circuit module specially used for XOR operation is added, which greatly increases the speed of data check calculation. The difference between RAID card and SCSI card is the RAID function, the other is not too different. A RAID card is called a multi-channel RAID card if there are multiple SCSI channels on it. At present, the SCSI RAID card has up to 4 channels, and its back end can be connected to 4 SCSI buses, so up to 64 SCSI devices (16 bit bus) can be connected. With the addition of RAID functionality, the SCSI controller becomes a puppet of the RAID program code and does whatever the RAID tells it to do. The SCSI controller is fully aware of the disks under its control and communicates with the RAID application code. Once the RAID code knows which disks are in the SCSI controller's hands, it can adjust the RAID code to use ROM options such as RAID type, strip size, and so on, instructing its dummy SCSI controller to report "virtual" logical disks to the host instead of all physical disks. Hint: RAID has a concept of striping in mind. By striping, we don't really mean dividing the disk into bars and strips as in low-level formatting. This striping is all "in the mind," that is, in the program code. Because once the position and size of the strip are set, they are fixed. An LBA address block on a virtual disk corresponds to one or more LBA blocks on the real disk, and these mappings are predefined through the configuration interface. And a certain RAID algorithm is often embodied in some complex formulas, rather than using a table to record the corresponding LBA of each virtual disk and physical disk, so the efficiency will be poor. After each 10 arrives, RAID has to query this table to obtain the LBA of the corresponding physical disk, and the query speed is very slow, let alone in the face of such a large table. If we use a functional relationship formula between logical LBA and physical LBA to do the operation, the speed is very fast. Because mapping is performed entirely by formula, no flags are ever written to the physical disk to mark the so-called strips. The concept of a strip is only logical and does not exist physically. Therefore, the concept of strip only "memory" in the RAID program code can be, to change is to change the program code can be. The only thing that needs to be written to the disk is some RAID information, so that even if the disk is removed and placed on another RAID card of the same model, the previously made RAID information can be correctly recognized. The SNIA association has defined a standard format of DDFRAID information, requiring all RAID card manufacturers to store RAID information in accordance with this standard, so that all RAID cards are common. After striding, the RAID application code directs the SCSI controller to submit a virtualized "virtual disk" or "logical disk," or simply a LUN, to the OS-level driver code. 1. Structure of a RAID card RAID card with CPU seems to be a small computer system, has its own CPU, memory, ROM, bus and IO interface, but this small computer is to serve the big computer. It is important to include the SCSI controller on the SCSI RAID card, because the physical SCSI disks are still attached to the back end. Its front end is connected to the PCI bus of the host, so there must be a PCI bus controller to maintain the PCI bus arbitration, data sending and receiving functions. Also need to have a ROM, is generally used as a Flash chip ROM, which stores the initialization of the RAID card necessary code and the implementation of the RAID function required code. The role of RAM, first of all, is as a data cache to improve performance; Secondly, it is the memory space required by the CPU on the RAID card to perform RAID operations. XOR chip is specially used to do parity data calculation of RAID3, 5, 6 and so on. Letting the CPU do the validation would require code execution, which would take many cycles. However, if a dedicated digital circuit is used directly, the result is obtained immediately as soon as it is in and out. Therefore, in order to get rid of the CPU, the circuit module specially used for XOR operation is added, which greatly increases the speed of data check calculation. The difference between RAID card and SCSI card is the RAID function, the other is not too different. A RAID card is called a multi-channel RAID card if there are multiple SCSI channels on it. At present, the SCSI RAID card has up to 4 channels, and its back end can be connected to 4 SCSI buses, so up to 64 SCSI devices (16 bit bus) can be connected. With the addition of RAID functionality, the SCSI controller becomes a puppet of the RAID program code and does whatever the RAID tells it to do. The SCSI controller is fully aware of the disks under its control and communicates with the RAID application code. Once the RAID code knows which disks are in the SCSI controller's hands, it can adjust the RAID code to use ROM options such as RAID type, strip size, and so on, instructing its dummy SCSI controller to report "virtual" logical disks to the host instead of all physical disks. Hint: RAID has a concept of striping in mind. By striping, we don't really mean dividing the disk into bars and strips as in low-level formatting. This striping is all "in the mind," that is, in the program code. Because once the position and size of the strip are set, they are fixed. An LBA address block on a virtual disk corresponds to one or more LBA blocks on the real disk, and these mappings are predefined through the configuration interface. And a certain RAID algorithm is often embodied in some complex formulas, rather than using a table to record the corresponding LBA of each virtual disk and physical disk, so the efficiency will be poor. After each 10 arrives, RAID has to query this table to obtain the LBA of the corresponding physical disk, and the query speed is very slow, let alone in the face of such a large table. If we use a functional relationship formula between logical LBA and physical LBA to do the operation, the speed is very fast. Because mapping is performed entirely by formula, no flags are ever written to the physical disk to mark the so-called strips. The concept of a strip is only logical and does not exist physically. Therefore, the concept of strip only "memory" in the RAID program code can be, to change is to change the program code can be. The only thing that needs to be written to the disk is some RAID information, so that even if the disk is removed and placed on another RAID card of the same model, the previously made RAID information can be correctly recognized. The SNIA association has defined a standard format of DDFRAID information, requiring all RAID card manufacturers to store RAID information in accordance with this standard, so that all RAID cards are common. After striding, the RAID application code directs the SCSI controller to submit a virtualized "virtual disk" or "logical disk," or simply a LUN, to the OS-level driver code. We through several articles detailed introduction of raid card, I believe you have a deeper understanding of raid card. If you have a lot of questions about server accessories, storage, then welcome to consult, it is my pleasure to answer your questions. STOR Technology Limited will also provide you with a large number of original high-performance products, such as: lsi 9480 8i8e, lsi 9361 4i, lsi 9341 8i and so on, three-year warranty and unsurpassed factory price to reduce your concerns.

Software RAID has three disadvantages: ① it takes up memory space; ② occupy CPU resources; Software RAID programs cannot make the disk partition on which the operating system is installed into RAID mode. Because the RAID program runs on top of the operating system, the RAID functionality cannot be implemented until the operating system is booted. In other words, if the operating system is corrupted, the RAID program will not run, and the data on the disk will become a bunch of useless stuff. Because the data on the RAID disk can only be recognized and read and write correctly by the program that implements the corresponding RAID algorithm. If there is no corresponding RAID program, the data on the physical disk is just a few fragments, and only the RAID program can combine these fragments. Fortunately, most of the current RAID program will store their own algorithm information on the disk, once the operating system has a problem, or the host hardware has a problem, you can connect these disks to other machines, and then install the same RAID software. After the RAID software has read the RAID information stored in a fixed area on the hard disk, it can continue to use it. Software RAID has so many shortcomings that people are constantly thinking about more methods to implement RAID. Since software has so many drawbacks, what about hardware? RAID card is a method to implement RAID function with independent hardware. To realize RAID function in hardware, we must find a physical hardware as a carrier, SCSI card or motherboard on the south bridge is undoubtedly the carrier. Extra chips have been added to SCSI cards to implement RAID functions. These chips are specially used to execute RAID algorithm, can be ASIC such as high cost and high speed computing chip, can also be general instruction CPU such as general code execution chip, code can be loaded from ROM directly to execute, can also be loaded into RAM before execution, so as to realize RAID function. A RAID card (SCSI card or IDE expansion card) is called a RAID card. Similarly, the RAID function can also be implemented on the south bridge chip of the motherboard. Because the chips in the south bridge cannot rely on the CPU to perform their functions, these chips rely entirely on the circuit logic to operate on their own, and although they are fast, they are less powerful than the plug-in RAID cards. From some motherboard advertising can be seen, such as the so-called "onboard" RAID chip is the guide bridge to realize the RAID function of the chip. In this way, the operating system does not need to make any changes, in addition to the RAID card driver does not need to install any additional software, you can directly identify the virtual disk has been generated by RAID processing. For software RAID, the operating system to the actual perception in the bottom or at least the physical disk, but for the hardware RAID, the operating system cannot perceive the underlying physical disk, only by the manufacturer to provide a RAID card management software to view your card is connected on a physical disk. Also, when configuring a RAID card, it cannot be done in the operating system, but must be done by entering the hardware (or by using the RAID card configuration tool in the operating system). General RAID card is in the boot self test, into its ROM configuration program to configure a variety of RAID functions. RAID cards overcome the shortcomings of software RAID, so that the operating system itself can be installed on top of the RAID virtual disk, which is not possible with software RAID. Later I will also discuss the relevant knowledge of raid card from multiple dimensions. If you have any questions about storage technology, welcome to consult and answer your questions wholeheartedly. With more than 10 years of professional experience, STOR Technology Limited can also let you experience the original high-performance products at the factory price, such as: megaraid 9460-16i, megaraid 9560-8i, sas 9300-16i and so on. Contact us now！

Today we are going to talk about RAID implementation and configuration in the operating system. Some people write programs directly on the host, running at the bottom of the operating system, the physical disk submitted from the host SCSI or IDE controller, using the idea of seven stars Beidou, virtual into various modes of virtual disk, and then submitted to the upper program interface, such as volume management program. These programs use a configuration tool that lets you choose which disks to combine and form which type of RAID. For example, if two IDE disks and four SCSI disks are installed on a machine, the IDE hard disk is connected directly to the IDE interface integrated with the motherboard, and the SCSI disk is connected to a PCI interface SCSI card. In the absence of RAID program to participate in the conditions, the system can identify six disks, and after the file system format, mount to a disk letter or directory, for the program to read and write. After installing the RAID program, the user through the configuration interface, the first two IDE disks made a RAID 0 system. If the original IDE disk is 80GB, then RAID 0 will become a 160GB "virtual" disk. Then the user makes a RAID5 system with 4 SCSI disks. If the original SCSI disk capacity is 73GB, the capacity of the virtual disk after making the 4 disks into RAID5 will be about 3 disks, that is, 216GB. Of course, because the RAID program needs to use part of the disk space to store some RAID information, the actual capacity will be smaller. After being processed by the RAID program, these six magnets eventually become two virtual disks. If you are on the Widows system, opening Disk Manager will only show you two hard drives, one with a capacity of 160GB (drive 1) and the other with a capacity of 219GB(drive 2). The disks can then be formatted, for example, to an NTFS filesystem. The formatter has no sense that more than one physical hard disk is writing data. For example, the formatter may at some point issue a command to write data from memory start address so and so to disk 1 (a RAID 0 virtual drive consisting of two IDE disks) at LBA start address 10000 and length 128. The RAID program will intercept this command and analyze it. Disk 1 is a RAID 0 system, so the data of 128 sectors starting from LBA10000 will be calculated by the RAID engine, and the logical LBA will be corresponding to the physical LBA of the physical disk, and the corresponding data will be written to the physical disk. Once written, the formatter receives a signal that the write was successful and moves on to the next IO. After this process, the upper layer is completely unaware of the details of the underlying physical disk. The same is true for other forms of RAID, but the algorithms are more complex. But even though the complex algorithm, after CPU operation, it is thousands of times faster than the disk read and write speed. Tips: To ensure performance, only the same type of disk can be used for the same disk group, although it can also be designed to IDE magnetic Disk and SCSI disk are combined to form a virtual disk, but it is not designed this way unless specifically required. If you have any technical questions about storage, please contact me. I will be happy to answer your questions and provide you with original and new high-performance raid cards such as megaraid 9540 8i. hba card: such as LSI 9500 16i , LSI 9500 16e. 3 years warranty with high quality factory price, provide maximum security for you.

LSI 9460-16i is a RAID controller card. Its specifications and advantages have been introduced to you before. Next, I will briefly describe its application and precautions: Application: Enterprise Storage Environment: Megaraid 9460-16i is suitable for storage solutions in medium to large enterprise environments. Because it supports multiple internal SAS/SATA ports, it can manage large-capacity internal disk arrays and provide reliable data storage and high-performance access for enterprises. Data center environment: In the data center, the 9460-16i can scale storage capacity and provide high performance data storage and access. It can support multiple storage devices, and has a powerful RAID function to ensure data integrity and availability. Virtualized environments: For virtualized environments, the megaraid sas 9460-16i provides high performance and reliable storage management. It supports the storage requirements of multiple virtual machines and enables appropriate RAID configuration as needed to ensure the stability and performance of the virtualized environment. Notes: Compatibility: When choosing an LSI 9460-16i 05-50011-00, make sure it is compatible with your server or storage device. Check the manufacturer's compatibility list to confirm that the RAID controller you choose is compatible with your system's hardware and software environment. Cold and hot backups: To ensure data security and high availability, consider configuring cold or hot backups. Cold backup is to keep a backup disk array to back up data, and hot backup is to generate backup copies in real time to provide fast recovery. These policies help mitigate the risk of hardware failure or data loss. Regular monitoring and Maintenance: It is important to regularly monitor the condition of the LSI 9460-16i controller and disk array. Checking logs, performing disk checks, and updating firmware and drivers in a timely manner are key steps to ensure controller stability and performance. Data backup: Although the RAID controller provides some level of data protection, it is still recommended to take regular data backup. Data loss can occur due to RAID controller failure, multiple disk failure, and accidental deletion. Therefore, it is very important to back up your data regularly. The above is the general application and precautions. Specific applications and considerations may vary depending on your environment and requirements. Of course, we will be happy to answer your questions, and believe that with STOR Technology Limited professional experience and strength, we can provide you with the required high-performance products.

LSI 9480-8i8e brings you an unprecedented high performance storage solution. As an advanced storage controller, megaraid 9480 8i8e combines innovative technology with excellent performance to provide users with a more efficient and reliable storage solution. Using the latest SAS technology, the LSI 9480-8i8e supports eight internal ports and eight external ports, providing more connection options for your storage devices. Whether you are in a personal office or an enterprise data center, the LSI 9480-8i8e can meet your different storage needs. Excellent performance is a highlight of the LSI 9480 8i8e. It uses an advanced RAID engine and supports multiple RAID levels such as RAID 0, RAID 1, RAID 5, and RAID 6 to provide excellent data security and reliability. Whether you're dealing with large data sets or high-speed data transfers, the LSI 9480-8i8e makes it easy. In addition, the LSI 9480-8i8e also supports hot plug and hot backup functions, allowing you to replace the hard disk or backup without downtime, improving the availability and maintainability of the storage system. What's more, its smart power management technology can reduce energy consumption, saving you money while being environmentally friendly. The LSI 9480-8i8e( 05 50031 00 ) also provides comprehensive monitoring and management capabilities that enable real-time monitoring and configuration adjustments through installed software to ensure that your storage system is always in optimal condition. Whether you are looking for a high-performance storage solution for your business or adding more storage options for your personal computer, the lsi raid card 9480-8i8e is the solution for you. It gives you more connection options, superior performance, and reliability, providing the perfect solution for your storage needs. Welcome to consult, STOR TECHNOLOGY LIMITED will give you the ultimate professional pre-sale and after-sales service, to provide you with the original high-performance products and 3 years warranty, for you to eliminate all concerns.

LSI 9361-16i is a RAID controller card produced by Broadcom, which is widely used in enterprise storage systems and servers. Let me briefly introduce some common specifications and advantages of the LSI 9361-16i ( 05-25708-00 ):   Specification: 1. Interface: PCIe 3.0x8 (backward compatible with PCIe 2.0)   2.Ports: 16 internal SAS/SATA ports   3.RAID level support: RAID 0, RAID 1, RAID 10, RAID 5, RAID 50, RAID 6, RAID 60   4. Storage capacity expansion: supports up to 256 physical devices   5. Memory: 1GB 1866 MHz DDR3 SDRAM (upgradeable to 4GB)   Advantages: 1. High performance: Megaraid sas 9361-16i has powerful processing power and data throughput, which can provide excellent performance and is suitable for high load storage environment.   2. Resilience and flexibility: Multiple RAID levels are supported to meet different data protection and performance requirements. It also supports hybrid drive types, including SAS and SATA, providing greater storage flexibility.   3. Data protection and reliability: 9361 16i has a variety of data protection functions, such as RAID level failure protection, hot backup, bad track repair and data encryption, to ensure data security and integrity.   4. Management and monitoring functions: the supporting management software (such as MegaRAID Storage Manager) provides rich monitoring and management functions, including remote management, alarm notification, configuration management, etc., to simplify management and maintenance.   5. Scalability: Support multiple LSI 9361-16i cards to expand through SAS link, providing greater storage capacity and performance.   Please note that specific specifications and benefits may vary from product version to product version and vendor changes. For the most accurate information, it is recommended to contact me directly for the latest and detailed product information, and STOR Technology Limited will provide you with the most detailed service and high-performance original products.

LSI 9440-8i is a RAID controller with the following specifications and advantages:   Specification: 1. Interface: The LSI 9440-8i is equipped with eight internal SATA/SAS ports to support the connection of multiple hard drives and mass storage devices.   2.RAID support: The controller supports multiple RAID levels, including RAID 0, RAID 1, RAID 5, RAID 6, RAID 10, and RAID 50, as well as JBOD (Independent Disk Only) mode. This provides flexible data protection and storage configuration options.   3. Data transfer rate: The megaraid 9440 8i supports SAS data transfer rates up to 12Gb/s, providing fast and stable data transfer.   4. Cache and Processor: The controller is equipped with 2GB DDRIII cache and built-in I/O processor for fast RAID computations and data operations to improve system performance.   5. Backup Battery Module (BBU) support: megaraid sas 9440 8i supports the insertion of a backup battery module to provide the protection of cached data and power failure recovery.   Advantages: 1. High performance and reliability: LSI 9440 8i provides high-speed data transmission and processing capabilities, suitable for application scenarios that require large capacity storage and high performance. The supported RAID level and cache mechanism can provide data redundancy and fault tolerance, and ensure data security and reliability.   2. Data protection and Redundancy: With different RAID levels, LSI 9440-8i allows to configure redundancy and data mirroring to provide fault tolerance and data redundancy to ensure that data is not lost.   3. Flexible storage configuration: Supports a variety of different RAID levels and JBOD modes, enabling users to flexibly configure storage according to their specific needs.   4. Management and monitoring: LSI 9440-8i（05-50008-02）provides management tools and monitoring functions for configuring controllers, monitoring disk status, troubleshoing and performance optimization to improve the efficiency of system management and maintenance.   High performance LSI 9440 8i, professional after-sales service, new original quality assurance, three-year warranty, immediately enjoy the factory price!

Experience unparalleled data storage and management with the cutting-edge MegaRAID SAS 9460-8i and 9460-16i. These innovative RAID controllers offer unrivaled performance, reliability, and flexibility for enterprises of all sizes.   The MegaRAID 9460 16i is designed for large-scale storage systems, providing an impressive 16 internal ports to handle massive amounts of data. With its advanced data protection features like RAID levels 0, 1, 5, 6, 10, 50, and 60, you can rest assured that your valuable information is safeguarded against any unforeseen circumstances.    Equally impressive is the Megaraid 9460 8i, offering 8 internal ports for efficient data management. Its versatile connectivity options ensure seamless integration into any existing infrastructure, making it the ideal choice for businesses seeking a reliable and scalable storage solution.   Both the LSI 9460-8i and LSI 9460-16i are built with high-performance PCIe 3.0 connectivity, ensuring lightning-fast data transfer speeds and reduced latency. Whether you're running complex database applications, hosting virtual machines, or handling intensive workloads, these RAID controllers deliver the exceptional performance needed to support your business operations.   Harness the power of MegaRAID technology, as the 9460-8i and 9460-16i elevate your storage capabilities to new heights. With their comprehensive management tools, intuitive user interface, and extensive compatibility with leading operating systems, managing and monitoring your storage environment has never been easier.   Designed with enterprise-grade components, the MegaRAID SAS 9460-8i and 9460-16i ensure maximum endurance and durability. These reliable controllers have undergone rigorous testing and meet the highest industry standards, guaranteeing long-term reliability and peace of mind.   Don't compromise on your storage infrastructure. Trust the MegaRAID SAS 9460-8i and 9460-16i to provide the perfect balance of performance, scalability, and data protection for your enterprise needs. Upgrade your storage capabilities and stay ahead of the competition with these cutting-edge RAID controllers.   STOR Technology Limited is a cloud storage and cloud computing hardware solution provider with many years of professional experience. We offer a wide range of original new lsi raid cards and lsi hba cards so you can experience high performance products while reducing costs. Of course, we also provide all kinds of server accessories and professional technical consultation. ODM orders are welcome and we are honored to provide you with professional solutions.

In this section, we will take a look at the chips and boards commonly used in various enterprise computer systems.   RAID cards refers to a SAS or SATA controller with RAID function, such as LSI 9560 8i. HBA cards refers to a SAS or SATA controller without RAID function, such as: sas 9300 16i,the controller can be directly welded to the mainboard and connected to the CPU through the PCIE bus. You can also make a PCIE card and insert it into a PCIE slot on the mainboard. PCIE cards come in many forms.   One is standard (full-height full-length, half-height half-length, etc. At present, they are basically half-height and half-length), and the other is non-standard or customized (these cards are in various forms, but still use the PCIE protocol, but the physical interface form changes). One type of non-standard Card, called a Mezzanine Card, is designed to save space in the computer case by having slots that are vertically oriented rather than parallel to the surface of the board, so that the card sits parallel to the motherboard.   The hard disk of an enterprise computer is plugged into a backplane and wired to the SAS HBA/RAID controller. Sometimes you need to connect more hard disks, and the number of direct connection ports of the SAS controller is not enough, so you need to use a SAS Switch (the industry is not called Switch, but SAS Expander) chip to expand the number of interfaces.   This chip can be placed on the backplane, and the hard drive signal is first connected to the SAS Expander, and then connected to the SAS controller from its uplink port. If the backplane space is relatively small, can not accommodate the SAS Expander chip location, in order to consider flexibility, Microsemi company introduced SAS Expander card, which is a PCIE card, but only use the PCIE interface to power, do not transmit signals. The SAS interface is exported from the SAS Expander to the connector.   In this way, the upstream signals of the backplane and SAS controller are connected to the SAS Expander card using cables. In this way, a SAS switching network is formed, and the SAS controller can identify all hard disks.   There is another chip often used in some enterprise computers: the PCIE Switch. As the number of PCIE channels provided by the CPU is not enough, just like SAS, a Switch chip is needed to expand the number of PCIE channels. Enterprise computer systems also contain some chips, such as BMC, sound processing chip/card, GPU/ graphics card, mechanical hard disk controller chip, solid state disk controller chip and so on.

The enterprise computer system market is a relatively open, standardized/compatible, full of competition market. In this market ecosystem, there are mainly the following roles: semiconductor manufacturing factories, semiconductor circuit designers, board design manufacturers, complete machine designers, complete machine manufacturers, complete machine manufacturing designers, software developers, system integrators, end users.   The operation process of this ecology from upstream to downstream is: the semiconductor circuit designer designs the corresponding chip, and sends it to the semiconductor manufacturing factory in the form of a layout to wait for manufacturing. After the chip leaves the factory, the design and manufacturer of the board (various HBA cards, Raid cards, motherboards, etc.) purchases the chip, sends it to the board manufacturing factory for processing and welding, and leaves the factory.   Machine design Manufacturers purchase board, chassis, power supply and other assembly into the machine factory. Large and small system integrators directly face the end users, design IT system architecture and schemes for users, purchase various products, software + hardware from corresponding manufacturers, and then provide users with pre-sale evaluation and consultation, sale process management, installation, deployment, and after-sales maintenance services.   Get the most out of your computing system with expert advice and after-sales support from our team of experts at STOR. Trust us to deliver best-in-class server components and software to meet your performance and budget requirements.   With the improvement of CPU integration, there are basically only two main chips on the motherboard: CPU(For servers) and I/O bridge.

The operating system kernel needs to provide a complete I/O control process and prepare a large number of various data structures to manage the flow of I/O between various modules.   These modules include: VFS directory layer, Page Cache layer, file system layer, network processing layer, common block layer, I/O scheduler layer, block device driver layer, external I/O channel controller driver layer. These layers together form a large and complex I/O protocol stack.   I'm sure you already have an idea of how programs use I/O devices. The most common I/O devices fall into three categories: network card devices, storage devices（st2400mm0129）， and interactive devices such as keyboards/mice. These devices can be connected to the system through PCIE or USB ports. The question is, how is the data sent to them generated and sent all the way to the device driver and to the device?   If a user mode program wants to read the contents of sector 0 of a hard disk fan, it cannot directly manipulate the hard disk, because it cannot call the functions provided by the hard disk device driver at all, it can only delegate the kernel code to do this through the read system call.   In the parameters of the read system call, the user side program must at least tell the kernel: which device to read, which bytes of the device to read from, where to put the data read back into memory, and other parameters (such as what way to read when reading, etc.). The same goes for reading files. 

The LSI 9380-8e has been introduced in previous articles. Now let me introduce the LSI 9380-4i4e 05-25190-02. This is a raid controller by Broadcom with the following specifications and benefits:   Specification: 1. Interface: The megaraid sas 9380 4i4e is equipped with four internal SATA/SAS ports and four external SATA/SAS ports, enabling it to connect to both internal and external storage devices. 2.RAID support: The controller supports multiple RAID levels, including RAID 0, RAID 1, RAID 5, RAID 6, RAID 10, and RAID 50, as well as JBOD (Independent Disk Only) mode. 3. Data transfer rate: support 12Gb/s SAS data transfer rate, high bandwidth, can provide faster data transfer speed. 4. Drive compatibility: Compatible with SATA and SAS hard drives, providing flexibility and scalability. 5. Caching: Provides caching mechanisms to improve performance and support hardware RAID computations to reduce the burden on the host processor.   Advantages: 1. High performance: LSI 9380-4i4e LSI00439 adopts advanced technology and high transmission rate, which can provide excellent storage performance and is suitable for applications requiring high-speed data transmission. 2. Data protection: Support multiple RAID levels, including redundancy and data mirroring, to provide data redundancy and fault tolerance to ensure data security and reliability. 3. Scalability: Four internal and four external ports provide high drive connectivity, making it suitable for scenarios where multiple storage devices need to be connected and flexible storage expansion. 4. Management and monitoring: LSI 9380-4i4e is equipped with management tools to simplify the configuration, monitoring and troubleshooing process and improve the efficiency of system management.   The lsi 9380-4i4e from STOR Technology Limited is an original high-performance array card with a 3-year warranty. And our team has more than 10 years of professional experience, provide perfect pre-sales and after-sales, so that you experience the most extreme service at the most affordable price.