Page 54 - DCAP507_SYSTEM_SOFTWARE

System Software Avinash Bhagat, Lovely Professional University

Notes Unit 3: Machine Structure and Assembler Basic Functions

CONTENTS

Objectives
Introduction
3.1 Machine Structure
3.1.1 Software Architecture
3.2 New Approach to New Machine
3.3 Machine Level Language (1940-1950)
3.4 Assembly Language (1950-1958)
3.5 Summary
3.6 Keywords

3.7 Review Questions
3.8 Further Readings

Objectives

After studying this unit, you will be able to:

 Explain Machine structure
 Demonstrate Approach to new machine
 Discuss Machine language
 Scan Assembly language

Introduction

The Assembler translates symbolic source language instructions into an object program. The
object program may be either relocatable or absolute. The Loader of the Basic Control System
loads and links relocatable programs. The Basic Binary Loader loads programs in absolute form.

The Assembler accepts as input a paper tape containing a control statement and a source language
program. The output produced by the Assembler may include a punched paper tape containing
the object program and/or an object program listing.
Assembler is a program that converts computer instructions into bits that can be processed by
processor in computer to perform certain operation. We have discussed machine structure in
unit 1 also.

3.1 Machine Structure

The field of computer science has come across problems linked with complexity since its
formation. Earlier problems of complexity were solved by developers by choosing the right
data structures, developing algorithms, and by applying the idea of separation of concerns.
Although the term "software architecture" is relatively new to the industry, the basic principles
of the field have been applied sporadically by software engineering pioneers since the mid
1980s. Early attempts to capture and explain software architecture of a system were vague and

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