Lecture 2
Input-Process-Output Model ：Input data --> Process -->Output data
1. Thiswas an essential scheme of the von Neumann model.
2. Three componentsrequired for this model: Hardware, Software, Data that is being manipulated.
Hardware:
Central Processing Unit (CPU) 中央处理器：an active part which performscalculations and other operations.
Main memory (primary storage), or RAM (random access memory)随机存取存储器holds data and programs for access by CPU.
Secondarystorage二级存储器: --Long-term storage –Holds programsand data –Hard disk硬盘, CD, DVD
Input devices: keyboard键盘, mouse鼠标,scanner扫描仪…
Output devices: monitor显示屏, speaker扬声器,printer打印机…
Software:
Difference: --Hardware (e.g.CPU): can carry out only very simple operations操作 likeadding number, but it run very quickly.
--Software: can performuseful tasks, which are combined in the form of programs.
Machineinstructions机器指令: are executedin the CPU. Every CPU has its ownfixed instruction set (100-200 instructions). In different CPUs, sets aresimilar, but there is no standard set.
High Level Programming Languages (HLLs)高级程序设计语言: 1. Are more suitable for programming 2. The programsin HLL still have to be translated to the machine codes.
The von Neumann Model冯·诺依曼模型:
Idea:The computer is a general-purpose machine通用机器 controlled by an executableprogram可执行程序
Context: 1. A program is a list of instructions used to direct指挥 a task.
2.Both program and dataare held in computer’s memory and both represented by binary codes
3.Model’s main point: memory isre-writeable.
4. A processor处理器is an active part of the machine thatexecutes the program instructions.