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How does the hard drive receive data?
The hard drive contains a spinning platter with a thin magnetic coating. A “head” moves over the platter, writing 0’s and 1’s as tiny areas of magnetic North or South on the platter. To read the data back, the head goes to the same spot, notices the North and South spots flying by, and so deduces the stored 0’s and 1’s.
What is the role of kernel in operating system?
The kernel is the essential center of a computer operating system (OS). It is the core that provides basic services for all other parts of the OS. It is the main layer between the OS and hardware, and it helps with process and memory management, file systems, device control and networking.
Does the hard drive store information permanently?
Understanding File Systems and Hard Disks. Storage media are physical devices and items that store data permanently. Hard disks are nonvolatile storage devices that are used to store and retrieve data quickly. This means that no data is lost when the computer or device is powered off.
How is the kernel important to the I / O system?
The kernel maintains a number of important data structures pertaining to the I/O system, such as the open file table. These structures are object-oriented, and flexible to allow access to a wide variety of I/O devices through a common interface.
How does a driver handle an I / O request?
When the driver’s DPC gets control, it uses the context (passed in the ISR’s call to IoRequestDpc) to complete the I/O operation. The DPC calls a support routine to dequeue the next IRP (if any) and to pass that IRP on to the driver-supplied routine that starts I/O operations on the device (see Step 5).
How does FSD handle multiple I / O requests?
The FSD can break the original request into smaller requests (possibly for more than one device driver) by calling an I/O support routine ( IoAllocateIrp) one or more times to allocate additional IRPs. The additional IRPs are returned to the FSD with zero-filled I/O stack location (s) for lower-level driver (s).
Where does the FSD access the I / O stack?
The FSD accesses its I/O stack location in the IRP to determine what operation it should carry out. The FSD can break the original request into smaller requests (possibly for more than one device driver) by calling an I/O support routine ( IoAllocateIrp) one or more times to allocate additional IRPs.