Clusters and sectors relate to storage areas on a disk - not the operating system.
Boot sector
The volume boot sector.
A clustered system combines multiple computers into a single system to perform computational task distributed across the cluster.
Format all other drives instead of that conatain operating system
first the booting files are loaded in the RAM and these files are in the boot sector where operating system is installed . after loading these file then these files load the operating system in the RAM , some portion of RAM is Allocated by the OS. after that window is ready to perform tasks.
On a partition on your hard disk. It is launched by bootloader located in so-called boot sector.
thrashing
A cluster system consists of multiple independent computers connected together, each with its own operating system and resources, while a multiprocessor system has multiple processors sharing the same memory and operating system. In a cluster system, each node operates independently and communicates through a network, whereas in a multiprocessor system, all processors share the same memory space and can access shared resources more efficiently. Clusters are typically used for high availability and scalability, while multiprocessor systems are designed for high performance and parallel processing tasks.
Missing or corrupt boot sector
PC-DOS is the original operating system for the IBM PC. It is basically the same operating system as MS-DOS, but was distributed by IBM instead of being licensed directly from Microsoft.
The operating system is the most important part of a operating system because without an OS you will not be able to do anything with your computer and it will effectively be useless, instead of a computer you have a pile of components that does nothing
It means that there is no operating system on the selected boot device, or the boot sector has been overwritten.