Architecture and Fetch exectue cycle definitions Flashcards
Hardware
The electronical/ physical components of the computer system e.g. microprocessor, hard drive (BCS)
Software
Programs, routines and procedures that can be run on a computer system/ hardware (BCS)
Stored program concept
A program must be resident in main memory to be executed.
It is processed by fetching machine code instructions in sequence from main memory and executing them one at a time in the processor.
Von Neuman Architecture
Programs/ instructions and data are stored in one single store (MAIN memory)
RAM/ main memory
Used for programs which are currently being run and data which is being processed and is directly addressable by the processor - volatile
ROM
Data and instructions are fixed during manufacture onto the ROM chip. It is permanent and cannot be deleted or amended. Example of data in ROM would be the boot strap loader, Non-volatile.
EEPROM
(Electronically Erasable Programmable Read-Only Memory).
A type of non-volatile memory whose contents can be erased and reprogrammed using a pulsed voltage.
Peripheral
A piece of equipment that can be attached to the central processing nit e.g. hard disk, keyboard.
Addressable memory
Memory directly accessible by the CPU.
Secondary memory
Memory that is not directly accessible to the processor but uses the I/O channels.
Cache
Stores recently used data and instruction so that it can be quickly accessed at a later time.
On-chip cache
Area of microprocessor that contains cache memory.
Disc cache
Area of very fast memory between a hard drive and RAM.
RAM cache
Area of very fast memory between RAM and the microprocessor.
Web cache
File containing recently accessed web pages.
External storage
See secondary memory.
Clock speed
The frequency at which a clock pulse occurs (AQA)
Register
A small but very fast storage unit on the processor where data/ control information is temporarily stored (AQA).
Binary word
A group of bits that can be addressed, transferred and manipulated as a single unit (BCS).
General purpose register
A register not assigned a specific role by the processor designer. Programmers may use some but not all dedicated registers.
Dedicated register
A register assigned a specific role by the processor designer. Programmers may use some but not all dedicated registers.
Bus
Set of parallel wires connecting independent components of a computer system (AQA).
(Dedicated register) Program Counter
Stores the address of the next instruction to be executed.
Memory Address Register
The CPU register that either stores the memory address from which data will be fetched to the CPU or the address to which data will be sent and stored.
Memory Buffer Register
Stores the data or instructions being transferred and from the immediate access store
Current Instruction register
Register that is a part of the CPU’s control unit and stores the instructions currently being executed or decoded.
Accumulator
Stores results of arithmetic and logical operations.
