Chapter 3 & 4 Flashcards
central processing unit (CPU)
Part of the computer that consists:
- arithmetic/logic unit
- control unit
- register areas
arithmetic/logic unit (ALU)
The part of the CPU that performs mathematical calculations and makes logical comparisons
control unit
The part of the CPU that sequentially accesses program instructions, decodes them, and coordinates the flow of data in and out of the ALU, the registers, the primary/secondary storage and various output devices.
Register
A high-speed storage area in the CPU used to temporarily hold small units of program instructions and data immediately before, during, and after execution by the CPU
Primary storage (main memory; memory)
The part of the computer that holds program instructions and data
Instruction time (I-time)
The time it takes to perform the fetch instruction and decode instruction steps of the instruction phase
Execution time (E-time)
The time it takes to execute an instruction and store the results
Machine cycle
The instruction phase followed by the execution phase
Pipelining
A form of CPU operation in which multiple execution phases are performed in a single machine cycle
MIPS
Millions of instructions per second, a measure of machine cycle time
Clock speed
A series of electronic pulses produced at a predetermined rate that affects machine cycle time
Megahertz (MHz)
Millions of cycles per second, a measure of clock speed
Gigahertz (GHz)
Billions of cycles per second, a measure of clock speed
Moore’s law
A hypothesis stating that transistor densities on a single chip will double every two years
Byte (B)
Eight bits that together represent a single character of data
Random access memory (RAM)
A form of memory in which instructions or data can be temporarily stored
Read-only memory (ROM)
A nonvolatile form of memory
Cache memory
A type of memory speed that a processor can access more rapidly than main memory
Multiprocessing
The simultaneous execution of two or more instructions at the same time
Coprocessor
The part of the computer that speeds processing by executing specific types of instructions while the CPU works on another processing activity
Multicore microprocessor
A microprocessor that combines two or more independent processors into a single computer so that they share the workload and improve processing capacity
Parallel computing
The simultaneous execution of the same task on multiple processors to obtain the results faster
Massively parallel processing systems
A form of multiprocessing that speeds processing by linking hundreds or thousands of processors to operate at the same time or in parallel with each processor having its own bus, memory, disks, copy of the operating system, and applications
grid computing
The use of a collection of computers often owned by multiple individuals or organizations to work in a coordinated manner to solve a common problem
Secondary storage
Devices that store large amounts of data, instructions, and information more permanently than allowed with main memory
Sequential access
A retrieval method in which data must be accessed in the order in which it is stored
Direct access
A retrieval method in which data can be retrieved without the need to read and discard their data
Sequential access storage device (SASD)
A device used to sequentially access secondary storage data
Direct access storage device (DASD)
A device used for direct access of secondary storage data
Magnetic tape
A type of sequential secondary storage medium
Magnetic disk
A direct access storage device with bits represented by magnetized areas
Redundant array of independent/ inexpensive disks (RAID)
A method of storing data that generates extra bits of data from existing data, allowing the system to create a “reconstruction map” so that if a hard drive fails, this is send can rebuild lost data
disk mirroring
A process of storing data that provides an exact copy that protects users fully in the event of data loss
virtual tape
A storage device for less frequently needed data so that it appears to be stored entirely on tape cartridges
optical storage device
A form of data storage that uses lasers to read and write data
compact disc read-only (CD-ROM)
A common form of optical disc on which data cannot be modified once it has been recorded
digital video disc (DVD)
A storage medium used to store software, video games, and movies
network-attached storage (NAS)
Hard disk storage that is set up with its own network address rather than being attached to a computer
storage area network (SAN)
A special-purpose, high-speed network that provides high-speed connections among data storage devices and computers over a network
policy-based storage management
Automation of storage using previously defined policies