Multi-User Operating System

INTRODUCTION

Let’s first understand what an operating system is. An operating system is a big piece of software that acts as an interface between the user and the computer hardware, which does multiple functions such as 

• Memory Management
• File Management
• Processor Management

In General, The Operating System that we use on our computers at home, our laptops, tablets, phones would often be identified as a single-user operating system since only one user can interact with the computer at any given point in time. 

Now what is a Multi-User Operating System: 

A multi-user operating system is an operating system that allows multiple users to connect and operate a single operating system. The users interact with it through terminals or computers that gave them access to the system through a network or machines such as printers. The operating system should have to meet the requirements of all its users in a balanced way so that if any problem would arise with one user, it does not affect any other user in the chain.

EXAMPLES OF MULTI-USER OPERATING SYSTEM:

Multiple Virtual Storage – An operating system from IBM that runs on the Mainframe. It is widely used in Enterprise computing which involves high-intensity I/O. Example: Banking, Insurance, and Aviation business. 

Unix – An open system Architecture that is highly reliable for small and medium scale business computing solutions. Since it’s based on Open system Architecture, Tech giants have their version of Unix such as Solaris, AIX, even Mac OS. Example: Hospitality industry, Healthcare, 

TYPES OF MULTI-USER OPERATING SYSTEM

• Distributed System
• Time – sliced System
• Multi-processor system

Distributed Operating System:

• Distributed Operating system also known as distributed computing is a collection of multiple components located on different computers that interact, co-ordinates, and emulates as a single coherent system to the end-user. End-user will communicate or operate them with the help of the Network. 
• This system divides resources in a way that multiple requests can be handled and in turn each, individual request can be satisfied eventually.
•  Example of the distributed system:
• Electronic banking, and Mobile Apps can be sited as the best example of Applications that can be hosted on Distributed OS. Users can conduct numerous transactions using a single network from the comfort of their place. 

Time sliced system:

• It is the system where each user task is allocated to a short span of CPU time. In other words, each task is assigned to a short period. These time slices appear too small to the eyes of the user. The decision to run the next piece of job is decided by an internal component called the ‘Scheduler’. This scheduler identifies and executes the run instruction or task that needs to be executed depending on the priority cycle.
• The users can take turns and thus the Operating System will handle user’s requests among the users who are connected. This feature is not available in the Single User Operating System, where the user and the machine come in contact directly. 
• Example of Time sliced system:
• Mainframe, a practical exam of the time-sliced system, where a user will be allocated a specific time slice to perform a complex task.

Multiprocessor system:

• Multiprocessor system is the one, where the system uses more than one processor at the same time. Since all the processors would be working side by side, the work would be completed at a pace that would be much faster than the single-user operating system.
• Example of Multi-processor system:
•  We can take Windows Operating System as a practical example of a multi-processing system where word processor, spreadsheets, music player etc., everything can be opened at the same time without affecting the efficiency of any application that is being opened.

FEATURES OF MULTI-USER OPERATING SYSTEM

 The Multi-user operating system can be documented with 4 features:

Multiple processing: 

• As described earlier, we can execute multiple programs at the same time. 
• For instance, students can edit a word document by surfing the internet (maybe google), and also attach an excel file in the document instantaneously. 

Sharing of resources:

• It is the feature that can be mapped to time slicing. Multiple peripherals such as printers, hard drives, etc. can be shared or we can even share different files or data. 
• One such example which can be quoted here is the webmail system. In this, thousands of users log on at a time to check their emails, and send messages etc., which proves that the OS supports even millions of users at the same time. Thus, a webmail application requires thousands of computers which can in turn serve thousands of people at a time. 

Processing of data at the back end:

• This feature allows data to be processed at the back end when they are not allowed to be processed at the front end.
• This allows other programs to interact with the processor in the front end simultaneously. 

Invisibility:

• Many functions of the multi-user operating system is invisible to the users. This is because of the aspects such as the OS is instinctive or it happens at the lower end such as formatting of the disk and so on.

WORKING MODE OF MULTI-USER OPERATING SYSTEM

Ideally, the multi-operating system consists of the Master system.

This Master system can be used by all users at any place and at any time, the users can also open their own working view of the system. This view is called the “Local view”. This is the working model of the multi-user operating system.

The users can add, delete, update records based on their requirements. This working model will not be visible to the other users of the system unless a user shares it or saves it to the Master system.

COMPONENTS OF MULTI USER OPERATING SYSTEM:

 The multi user operating system has Three Components,

Processer:

• The core of the computer called CPU (Central Processing Unit) is otherwise called the brain of the computer. In large machines, CPU would require more ICS. Whereas on smaller machines, CPU is mapped in a single chip popularly called as Microprocessor.

Memory:

• The physical memory that is present inside the computer is where storage happens. It is otherwise called Random Access Memory (RAM). The system can correct data that is present in the main memory, therefore every program that is executed must be copied from a physical storage such as hard disk. Main memory is always marked important because, it determines how many programs can be executed at one time and the amount of data that would be available.
• The types of physical storage can be segregated as:
• Hard Disks:
  •  It can hold large amount of data and how also determines how many programs can be run at a single time.
• Floppy Disks:
  • It is inexpensive but can hold only less data when compared to hard drives. It is also portable.
• Optical Disks:
  • They use Lasers to read and write data. They can hold large data like hard disks but they are not portable like hard drives. CD (Compact Disk) is used to write and read files.
• Tapes:
  • They are inexpensive as well. They hold large memory but data access in random cannot be done.

Terminals:

• Dumb Terminal:
  • It is featured with its computer and keyboard.
  • It does not have the processing power. 
  • They are used to do remote work on mainframe systems.
• Smart Terminals:
  • Simple editing and processing can be done using a smart terminal. They are inexpensive but do not have any physical storage devices such as hard drives. 

Input/ Output devices:

• They are used to transfer and receive data. Input devices can be mouse and keyboard. 
• Output devices can be printers and monitors. 

It has four software components namely,

Kernel:

• Kernel is called the low-level component of the computer system. Kernel is written in the low-level programming language and is present in the main component of the computer, that is processor and it can interact with the hardware of the system.

Device handler:

• The concept that is behind the device handler is “Queue “where we follow “first in, first out “strategy. It functions on each input and output device. It works continuously and it also discards any blocks on the input/ output device.

Spooler:

• Spooler executes all the processes that are running on the computer and it also provides appropriate output. 
• Spooler is mainly used in output devices such as printer.

User Interface:

• UI is the point of communication between users and the software/hardware. 
•  It creates an easy work platform for all users and thus serves to be an inexplicable component in the multi-user operating system.
• Let’s see one example in detail which is being used across the world in a major way. 
• The Mainframe is one of the systems which works on the concept of a multi-user operating system. It is widely used in banks, to store bank accounts and transaction details. 

MAINFRAME

Most of today’s business workloads rely on Mainframe. Web transactions would easily be made possible with the help of mainframe systems, because it’s hardware and software components are ideal for accommodating a large number of users and they allow to access data rapidly and simultaneously, without any interference. 

Why Mainframe?

Security:

• The Mainframe is unique as most of the data gets encrypted at the hardware level which makes it nearly impossible to breakthrough. Enterprises handling critical banking transactions, Government data etc., rely on Mainframe for its robust security system. 

Scalability:

• By scalability, what we mean today is the system should be able to function normally with a change in the amount of data it handles. The performance should be constant even when processors, memory, etc. would be added or deleted. The ability of an organization to carry on with its work without any hindrance, be it with large or small networks and any degree of complexity would define scalability of the network with which it is operating. The Mainframe satisfies one such requirement among users, thus making it a perfect example for a multi-user operating system.

Reliability:

• The system’s hardware s equipped so well that it can detect and recover its problems on its own. Health checker can be quoted as an example here as it can identify any problem before it could cause any impact.

Serviceability:

• Mainframe’s serviceability is a trademark feature that it owns. It can detect any failure and on point, it can determine the reason for that particular failure. 

• If we say that a system is serviceable, it means that if any error has occurred that has caused operations to stop, the system should be able to fix it in a relatively short period of time. In that way, we could say that the mainframe is one of the most serviceable multi-user systems.

Compatibility:

• Some applications in the mainframe were developed years back and some applications might have been developed recently. Mainframe works on all kinds of system and that determines the ability of mainframe. Records over 100 years are still present on the mainframe system, untouched in the same format.

Now let’s talk about how businesses rely on mainframe systems:

• They perform transactions on a large basis (millions of transactions per second).
• They support a large number of users and applications and they are allowed to operate simultaneously. 
• Large bandwidth communication is possible with the help of mainframe systems.

ADVANTAGES OF MULTI USER OPERATING SYSTEM

• Avoids Disruption:
  • We have already seen that multiple computers operate on the same network. So, if one computer gets disturbed it doesn’t affect any other computer present on that network, making it as the primary advantage of the Operating System.
• Distribution of Resources:
  • Users can share their work with the other users, thus marking the exemplary boon of multi user operating system.
  • Say for example, if a user wants to view a pdf version of file which the other user is working on, the user who is working on the file can simply share it so that the required user can access the file.
• Library:
  • It is used in library to record the name and author of books, which is in turn connected to the other computers on the network, so that any librarian can open the system and view the details of a book.
• Used in Airlines:
  • It is used in Airlines, tickets reservation system, where in one user can login and book a ticket, whereas the other can use it to cancel a ticket, it can also be used to check the availability and status of tickets.
• Economy improvement:
  • Most of the companies are marching towards multi operating system to reduce their expenditure.
  • For large companies, where expenditure plays a major role, investment is required in hardware and software components. In that case, companies would naturally look up to avoid that expenditure by deploying minimum machines for maximum number of users.
• Backing up of Data:
  • With the use of multi user operating system, backing up of data can be done on the machine which the user is using. Therefore, it would be a kind of surprise if data would get lost, thereby saving time and expenses for the company.
• Speed efficiency:
  • The speed at which data is exchanged is increased by using electronic mailing system. Lakhs of mails can be sent and received at the same time thus making work easier.
• Stability of servers:
  • Servers are very systematic and stable. The technologies which are emerging go hand in hand with the up- gradation of hardware and software. Access to serves is possible remotely from different countries at different timeframes.
• Real time Scenario:
  • Time taken for shifting of tasks is comparatively less in real time systems. The occurrence of errors is less when compared to other systems. The size of programs written is smaller thus avoiding hanging up of applications.
  • The allocation of memory is well organized in real time systems.
  • The major boon of multi user operating system is that with the use of it, jobs won’t get interlaced and the resulting output would not be baffling.
  • Each user’ s logs is maintained as to when and what job they did which is the most efficient feature of multi user operating system.

DISADVANTAGES OF MULTI-USER OPERATING SYSTEM

• Virus:
  • In the multi-user operating system, since many computers are used on a single network, if the virus affects one computer, the computers on the network would be affected as well, paving the way for viruses attacking all systems.
• Visibility of data:
  • Information on the computer is shared with the public, so privacy becomes a concern here. 
• Multiple Accounts:
  • Creating multiple accounts on a single computer might be dangerous at times. So, it’s better to have an individual machine for each user. 

 SUMMARY OF MULTI-USER OPERATING SYSTEM

•  Thus, multiple users can operate at the same time using one network.
•   It is cost-effective and speedy.
•  Though it has several pros it is quite complex.
•  No wait time is required for accessing the system.
•  It uses “Task Switching “to encourage real-time environment. 
•  It is used in mainframe computers mostly.
•  Standalone systems are not supported by a multi-user Operating system.
• Equilibrium between users has to be taken care of in the case of MUOS. 

CONCLUSION

Thus Multi-User Operating System (MUOS) is the best construction and combination of all hardware and software. The server and client are connected on a single PC thereby making it very reliable for users. Thus, you should be able to satisfy numerous requirements with MUOS. Please feel free to reach me to tell your suggestions and comments, so as to discuss more!!

REFERENCES

1. http://ecomputernotes.com/fundamental/disk-operating-system/
2. https://www.ibm.com/support/knowledgecenter/zosbasics/com