Software

Low-Level Language Expanded

Machine Language ● Binary code Assembly Language ● Uses abbreviations called opcode Assembler ● Translates assembly code into machine code (binary)

Compilers

Software that translates high-level programming languages (such as c++, java, etc..) into the lowlevel machine language that is understood by a computer processor.

Compilers

high level programming language must be automatically translatable to lowlevel code this puts constraints on the expressiveness of computer programming languages ● Natural Language is Vague Computers don't do well with non-precise instructions programming languages have to be very precise

What is Software

2 Basic Categories of Software: Applications software ● This is what we usually think of... ● Programs for end-users ● Examples: MS office, database programs, word processors, games, instant messaging, email, browsers... and etc.. Systems software ● The bridge between applications software and computer hardware ● Interact with the hardware at a low-level (very basic level) ● Provides a high-level environment in which we can run applications on ● Examples: operating systems, compilers, assemblers... etc

Difference between a compiler and a interpreter?

A compiler is a systems software that translates high-level programming languages into the low-level machine language that is understood by a computer processor. Interpreter translates one sentecne at a time(HTML) . Source programs is interpreted every time. No object code is produced.

What category do computer games fall into?

Applications Software

Translating Code

Compilers ● Converts entire program (source code) into machine language code (object code) ● Both the source code and object code are stored on the disk ● We execute (or run) the object code ◘Object code is loaded into memory (RAM) ● Machine language is processor specific Interpreter ● Translates one sentence at a time (HTML) ● Source program is interpreted every time! ● No object code is produced

Two examples of a low level language?

Machine Code or Assembly language

What do Operating Systems do?

Manages the system and applications ● Organizing files (folders etc) ● Manage downloading ● Scheduling programs on the processor ● Interfacing with the internet ● Managing communication with peripherals ● Providing security ● ...and lots more (GUI, windows, ...)

After going through the compiler the source code becomes?

Object code or executable file that is then loaded into ram by the operating system and the cpu executes.

What cateogry does OS fall into?

Systems Software

What is source code?

The source code is the high level language version of a program written in a text editor. Once a piece of code is compiled and the object code is created it is hard for humans to read or modify the code without the source code. -We run or execute the object code.

What we Will be Using

We us an editor to type in commands ● We will use eclipse Source code ● a C++ program Compiler ● Translates the source code to binary (provided there are no errors - it will check for errors) Object code ● A C++ program in binary code Linker ● Links your code with libraries turns your object code into executable code (we see this as a .exe file) Libraries ● Predefined code that we include in a header file

Putting it All Together

an application is written in a high-level programming language (e.g. c++) 2. the code is translated to machine language by a compiler 3. when you want to run the application, the operating system loads the code into RAM (random access memory) 4. the fetch/decode/execute cycle is performed

Eniac 1946

•ENIAC 1946 (Electronic Numerical Integrator and Computer) "The procedure for instructing the ENIAC in its routine, then, consists of setting program switches on the units so that, when stimulated by a program input pulse, the program controls will cause the units to carry out a set of specific operations." - Adele Goldstine, 1946