# A-level Computing/CIE/Advanced Theory/Hardware

 Specification link Logic Gates and Circuit Design produce truth tables for common logic circuits including half adders and full adders derive a truth table for a given logic circuit Boolean algebra show understanding of Boolean algebra show understanding of De Morgan’s Laws perform Boolean algebra using De Morgan’s Laws simplify a logic circuit/expression using Boolean algebra Karnaugh maps show understanding of Karnaugh maps show understanding of the benefits of using a Karnaugh map solve binary logic problems using Karnaugh maps Flip-flops show understanding of how to construct a flip-flop (SR and JK) describe the role of flip-flops as data storage elements Reduced instruction set computing processors (RISC) show understanding of the differences between reduced instruction set computing processors (RISC) and complex instruction set computing processors (CISC) show understanding of the importance/use of pipelining and registers in RISC processors show understanding of interrupt handling on CISC and RISC processors Parallel processing show awareness of the four basic computer architectures: single instruction, single data (SISD), single instruction, multiple data (SIMD), multiple instruction, single data (MISD), multiple instruction, multiple data (MIMD) show awareness of the characteristics of massively parallel computers

## Flip-flops

Flip flops are an application of logic gates with the aim of creating memory.

SR Flip-flops

They can be formed using NAND or NOR gates.

JK Flip-flops

Modified SR type where the J & K inputs are the same as the S & R inputs. The values of Q and Q' are returned to inputs K & J respectively.

## RISC Processors

### CISC Processors

•Complex Instruction Set Computing

•Emphasis on hardware

•Transistors store complex instructions

•Executing a set of instructions may take more than one cycle

•Aim is to complete a task in as few lines as possible

•Processor is able to understand and execute a series of operations

•Has pre-defined instructions that allow processes to be more efficient e.g. using a MULTIPLY command that knows how to take 2 numbers and multiply them together

•Short code= less RAM required

### RISC Processors

•Reduced Instruction Set Computing

•Emphasis on software

•Executing a set of instructions only takes one cycle

•Aim is to complete cycles as fast as possible

•Simplified instructions e.g. using the MULTIPLY example, it would have to load the values to be multiplied, multiply them and then store the answer

•Longer sequences = more RAM required

•Can take advantage of pipelining

•Cheaper to produce due to needing fewer transistors

•RISC compliers are more complex as they generate extra instructions

## Parallel Processing

### Massively Parallel Computers

• This refers to a large number of processors.
• They all work together to process a program simultaneously.
• They all communicate with one another using a messaging interface.