Some programs are written directly on the host computer, running at the bottom level of the operating system. Using the concept of the Big Dipper, they virtualize the physical disks presented by the host's SCSI or IDE controller into various virtual disks, which are then presented to upper-level programming interfaces such as volume management programs. These software programs use a configuration tool to allow users to select which disks to combine and what type of RAID configuration to form.   For example, a machine might have two IDE drives and four SCSI drives installed. The IDE drives are connected directly to the motherboard's integrated IDE interface, while the SCSI drives are connected to a PCI SCSI card. Without the involvement of a RAID program, the system can recognize all six drives, format them with the file system, and mount them to a drive letter or directory for read/write access by applications.   After installing the RAID program, the user uses the configuration interface to configure the two E drives into a RAID 0 system. If each IDE drive originally had a capacity of 80GB, the RAID 0 configuration would create a single "virtual" disk with a capacity of 160GB. The user then configured a RAID 5 system with four SCSI drives. If each SCSI drive originally had a capacity of 73GB, the virtual disk capacity after the four drives were configured in RAID 5 would be approximately the capacity of three drives, or 216GB. Of course, because the RAID program uses some of the disk space to store RAID information, the actual capacity will be reduced. After processing by the RAID program, these six drives are ultimately reduced to two virtual disks. In Windows, opening Disk Manager will only show two hard drives: one with a capacity of 160GB (hard drive 1) and the other with a capacity of 219GB (hard drive 2). These two drives can then be formatted, for example, using the NTFS file system. The formatting program will be completely unaware of the data being written to multiple physical drives.   For example, at a certain moment, the formatting program issues a command to write data from memory start address X to LBA start address 10000 and length 128 on hard drive 1 (a RAID 0 virtual drive composed of two IDE drives). The RAID program intercepts this command and analyzes it. If hard drive 1 is a RAID 0 system, the RAID engine will calculate the data for the 128 sectors starting at LBA 10000, mapping the logical LBAs to the physical LBAs of the physical disks and writing the corresponding data to the physical disks. After writing, the formatter receives a successful write signal and proceeds to the next I0. This process obscures the upper-level program's knowledge of the underlying physical disk details. Other RAID configurations operate in the same way, albeit with more complex algorithms. Even these complex algorithms, when processed by the CPU, are thousands or even tens of thousands of times faster than disk read and write speeds.   STOR Technology Limited provides you with high-quality 9560-16I, 9560-8I, 9361-4I, 9540-8I，9670W-16i, etc. We provide you with higher-quality services and assured after-sales service. Welcome to visit us and discuss related products with us. Our website: https://www.cloudstorserver.com/ Contact us: alice@storservers.com / +86-755-83677183 Whatsapp : +8613824334699