Computer Memory and Storage

NUMA stands for Non-Uniform Memory Access. In this architecture, memory access time depends on the memory location relative to the processor.

This RAID level refers mirrored set without parity.

Digital storage capacity is fundamentally measured in bytes, which represent the amount of data a storage medium can hold.

Floppy disks and hard disks are considered external or secondary storage devices because they are not the primary volatile memory (RAM) of the computer.

RAM performance is primarily defined by how quickly the processor can retrieve data from it, which is known as access time or latency.

RAM stands for Random Access Memory, a form of computer memory that can be read and changed in any order. The other options are incorrect.

 Direct memory access

To improve efficiency, operating systems group disk sectors into larger units called clusters for file allocation.

Clusters are defined as a fixed number of contiguous disk sectors, which serve as the basic unit of space allocation for files.

Interleaving is a technique used to improve disk performance by placing logical blocks in non-contiguous physical sectors to account for controller latency.

In UNIX systems, the kernel is responsible for managing the buffer cache, which stores disk blocks in memory to improve I/O performance. The file system uses these cached blocks, but the management itself is a kernel-level function.

Defective sectors on a storage medium, such as a hard disk, are commonly referred to as bad blocks or bad sectors. These areas are marked by the operating system so that they are not used for data storage.

In UNIX, the kernel maintains a portion of memory to cache disk blocks to reduce disk access frequency; this mechanism is specifically called the buffer cache.

Blocking is the process of grouping records into blocks for storage. Deblocking is the inverse process, where records are extracted from these blocks after being read from storage.

The virtual address space size is determined by the number of bits in the address bus of the processor. For example, a 32-bit address bus supports 2^32 bytes of virtual memory.