CS 87A Module 1

What does the CPU do? what are its basic functions? Where is it located?

Runs programs; Fetch, decode, execute. It’s located on micropresors.

What is the RAM

Random Access Memory/ Main Memory; where the computer stores programs and the data used.

What does a Secondary Storage device do? What are some examples of them?

They hold data for long periods of time. Disk drive/ hard drive (magnetically encode data on spinning circular disk), Solid state drive (faster than disk/hard drive, no moving parts, stores data on solid state memory), Flash memory (portable, no physical disk), Optical devices (data encoded optically).

What is application software? What are some examples?

Programs that make computers useful for everyday tasks. Word processing, email, games, and web browser.

What is system software? What are some examples?

Programs that control and manage basic computer operations. Operating system, utility program (preforms specific tasks to enhance computer operation/ safeguard data), software development tools (create, modify and test software programs)

What is a bit? What is a byte?

A bit is on/off and can be 0 or 1. A byte is 8 bits and its value can be 0-256.

What is a formal v. natural language? Examples? Which is Python?

Natural- spoken (Spanish, English), evolved naturally. Formal- designed by people for specific applications (Math). Programming languages are formal languages that have been designed to express computations.

What are Syntax and Syntax rules? Tokens and Structure

Syntax- a set of rules for putting keyword and operators to write program. Tokens are basic elements (words, numbers, chemical elements), only legal tokens can be used in code; 3+3=$6 is illegal because $ isn’t an arithmetic function. Structure is the way tokens are combined; 3+/3 is illegal even though + and / are legal tokens because they can’t be used next to each other.

What does an assembler do? What are low-level and high-level languages, ex.?

Assembler- translates assembly language to machine language for CPU. Low-level language- similar to machine language (assembly language). High-level language- allows simple creation of powerful and complex programs (no need to know how CPU works/ write lots of instructions, more intuitive to understand).

What is a program made up of?

Program: Keyword+Operator=Syntax

Define Keyword

A predefined word used to write program in high-level language (each has a specific meaning).

Define Operator

Preform operations on data (math to do arithmetic).

Define Statement

Individual instructions used in a high-level language.

Define Complier

Translates high level language program to machine language program, which can be executed at any time by the CPU.

Define Interpreter

Translates and executes instructions in high-level language program. Used by Python one instruction at a time, no separate machine language program. High level language program —> Interpreter (becomes machine language instruction) —> CPU

Define Source Code and Syntax error

Source code- statements written by programmer. Syntax error- prevents code from being translated

What is a value? Ex. value and types?

Value- letter/number belonging to different types. 2= integer, 42.0= floating-point number, ‘Hello, world!’= string, ‘2’ and ‘42.0’ = string.