What is a Systems Analyst? & What Does A System Analyst Do?

• Systems analysts are people who understand both business and computing.
• Systems analysts study business problems and opportunities and then transform business and information requirements of the business into the computer-based information systems and computer applications that are implemented by various technical specialists including computer programmers.

A formal definition:

• A systems analyst facilitates the study of the problems and needs of a business to determine how the business system and information technology can best solve the problem and accomplish improvements for the business. The product of this activity may be improved business processes, improved information systems, or new or improved computer applications frequently all three
• When information technology is used, the systems analyst is responsible for:
• the efficient capture of data from its business source
• the flow of that data to the computer
• the processing and storage of that data by the computer
• the flow of useful and timely information back to the business and its people
• Information technology is a contemporary term that describes the combination of computer technology (hardware and software) with telecommunications technology (data, image, and voice networks).

What Does A System Analyst Do?

• A system analyst is a system-oriented problem solver.
• System problem solving is the act of studying a problem environment in order to implement corrective solutions that take the form of new or improved systems.
• Most systems analysts use some variation of a system problem solving approach called a system development life cycle.
• A systems development life cycle (SDLC) is a systematic and orderly approach to solving system problems.

The SDLC usually incorporates the following general-purpose problem solving steps:

• Planning - identify the scope and boundary of the problem, and plan the development strategy and goals.
• Analysis - study and analyze the problems, causes, and effects. Then, identify and analyze the requirements that must be fulfilled by any successful solution.
• Design - if necessary, design the solution not all solutions require design.
• Implementation - implement the solution.
• Support - analyze the implemented solution, refine the design, and implement improvements to the solution. Different support situations can thread back into the previous steps.

What is a user?

• A user is a person, or group of persons, for whom the systems analyst builds and maintains business information systems and computer applications. A common system is client.
• There are at least two specific user/customer groups: system users and system owners.
• System users are those individuals who either have direct contact with an information system or application or they use information generated by a system.
• System owners provide sponsorship of information systems and computer applications. In other words, they pay to have the systems and applications developed and maintained. 

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Defining a System

A collection of components that work together to realize some objectives forms a system.

            In other words, a system is a set of interacting elements, interacting with each other to achieve a predetermined objective or goal.

            In a system the different components are connected with each other and they are interdependent. For example, human body represents a complete natural system. We are also bound by many national systems such as political system, economic system, educational system and so forth. The objective of the system demands that some output is produced as a result of processing the suitable inputs. A well-designed system also includes an additional element referred to as ‘control’ that provides a feedback to achieve desired objectives of the system.

            Basically there are three major components in every system, namely input, processing and output.

i) Input:–  It includes, Capturing/accepting and assembling components that enter the system to be      processed. Example: raw data, raw material etc.

ii) Processing:– Process is the series of changes to be done on information, to convert input into output.

iii) Output:– Output is produced by the transformation process to their ultimate destination. Example: reports, finished products etc.

Characteristics of a system:

·     Every system has a certain objectives and goals.

·         Main system has a several subsystems or models.
·         The lifecycle of the system is expression of the phases in the alive usage life of the system.
·         System operates in the terms of goals and predetermined scope.
·         Systems in real life do not operate in isolation.

Types of systems are:

a)    Physical Systems, such as man, weapons etc.
b)    Abstract Systems, such as god, nature etc.
c)    Open Systems, such as man
d)    Closed Systems, such as chemical process.
e)    Probabilistic Systems, such as arrival pattern, class etc.
f)     Man-Machine Systems, such as aero plane.

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Implementation of Data structure

There are three levels of implementation of data structures which are:

1. The Abstract Level:– The abstract(or logical) level is the specification of the data structure-the "what" but not "how". At this level, the user or data structure designer is free to think outside the bounds of anyone programming language.
2.  Application Level:– At the application of user level, the user is modeling real-life data in a specific context.
3.  Implementation Level:– The implementation level is where the model becomes compatible, executable code.

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What is data structure?

A data structure is the organization of data in computers memory or in a file.

Some examples of data structures are: array, stack, queue, link list, binary tree, hash table, heap and graph. Data structures are often used to build databases. Typically, data structures are manipulated using various algorithms.

Based on the concept of Abstract Data Types (ADT), we define data structure by the following three components

1. Operations: Specifications of external appearance of data structure
2. Storage structures: Organizations of data implemented in lower-level data structures.
3. Algorithms: Description on how to manipulate information in the storage structures to obtain the  results defined for operations.

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Basic Components of operating Systems.

The basic components of operating systems are.
a) Process Management:  

The operating System is responsible for the following activities in connection with process management.

· Process creation and deletion 

· Process suspension and resumption 

· Provision mechanisms for process synchronization and process communication

b) Main-Memory management  

The operating system is responsible for the following activities in connection with memory management. 

· Keep track of which parts of memory and currently being used by whom 

· Decide which process to load when memory space becomes available. 

· Allocate and De-allocate memory space as needed.

c) Secondary-Storage management  

The operating system is responsible for the following activities in connection with disk management. 

· Free space management 

· Storage allocation 

· Disk scheduling

d) I/O system Management 

The I/O system management consists of 

· A buffer-caching system 

· A general device-driver interface 

· Drivers for specific hardware devices

e) File Management 

The operating system is responsible for the following activities in connection with file management. 

· File creation and deletion 

· Directory creation & deletion 

· Support of primitives for manipulating files and directories 

· Mapping files onto secondary storage 

· File backup on stable (non volatile) storage media.

f) Protection system 

Protection refers to a mechanism for controlling access by programs, processes or users to both system and user resources. 

The protection mechanism must. 

· Distinguish between authorized and unauthorized usage. 

· Specify the controls to be imposed. 

· Provide a means of enforcement

g) Networking (Distributed System)

A distributed system is collection of processors that do not share memory or a clock. Each processor has its own local memory. The processors in the system are connected through a communication network. A distributed system provides user access to various system resources. Access to a shared resource allows. 

· Computation speed-up 

· Increased data availability 

· Enhanced reliability

h) Command-Interpreter system 

Many commands are given to the operating system by control statements which deal with. 

· Process creation and management 

· I/O handling 

· Secondary-storage management 

· Main-memory management 

· File system access 

· Protection 

· Networking 

The program that reads and interprets control statements called variously 

· Control-card interpreter 

· Command-line interpreter 

· Shell(in UNIX)

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Functions of operating system

The main functions of operating system are listed below

• Implementing the user interface. 
• Sharing hardware among users. 
• Allowing users to share data among themselves. 
• Preventing users from interfering with one another. 
• Scheduling resources among users. 
• Facilitating input/output. 
• Recovering from errors. 
• Accounting for resource usage. 
• Facilitating parallel operations. 
• Organizing data for secure and rapid access. 
• Handling network communications. 
• Interpretation of commands and instructions. 
• Establishment and enforcement of priority system. 
• Automatic transition from job to job as directed by special control statements. 
• Assignment of processor to different tasks being performed by computer system. 
• Allocation of main memory and other storage areas to the system programs.

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Development stages in operating Systems

Operating systems have developed through a number of distinct phases or generations, which corresponds roughly to the decades. Which are described below.

i. The 1940’s first generations

The earliest electronic digital computers had no operating systems. Machines of the time were so primitive that programs were often entered one bit at time on rows of mechanical switches. Programming languages were unknown (not even assembly languages). Operating systems were unheard of.

ii. The 1950’s second generations

By the early 1950’s, the routine had improved somewhat with the introduction of punch cards. The general motors’ research laboratories implemented the first operating system in early 1950’s for their IBM701. The system of 50’s generally ran one job at a time. These were called single-stream batch processing systems because programs and data were submitted in groups or batches.

iii. The 1960's Third Generation.

The Systems of the 1960's were batch processing system but they were able to take better advantage of the computer resources by running several jobs at once. So operating system designers developed the concept of multiprogramming in which several jobs are in main memory at once, a processor is switched from job to job as needed to keep several jobs advancing while keeping the peripheral devices in used.

For example, on the system with no multiprogramming, when the current job paused to wait for other I/O operation to complete, the CPU simply sat idle until the I/O finished. The solution for this problem that evolved was to partition memory into several pieces, with a different job in each partition. While one job was waiting for I/O to complete, another job could be using the CPU.

Another major feature in third generation operating system was the technique called spooling. In spooling, a high-speed device like a disk interposed between a running program and low-speed device involved with the program in Input/output. Instead of writing directly to a printer, for example outputs are written to the disk. Programs can run to completion faster, and other programs can be initiated sooner when the printer becomes available, the outputs may be printed.

Another feature present in this generation was time-sharing technique, in which each user has an on-line terminal. Because the user is present and interacting with the computer, the computer system must respond quickly to the user requests, otherwise user productivity could suffer. Time searing systems were developed to multiprogramming large number of simultaneous interactive users.

iv. Fourth Generation

With the development of LSI (Large Scale Integration) circuit, chips, operating system entered in the personal computer and the workstation age. Microprocessor technology evolved to the point that it became possible to build desktop computers as powerful as the mainframes of the 1970's. Two operating systems have dominated the personal computer scene Ms-Dos written by Microsoft Inc. for the IBM PC and other machines using the Intel 8080 CPU and its successors and UNIX. Which is dominant on the large personal computers using the Motorola 6899 CPU family.

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