Question

1. Each of the Mobile Operating Systems discussed in class—Android, IOS, Windows 8 – use a layered architecture. Create a graphic to compare their architectures and discuss any significant differences.
2. What makes a Mobile Operating System special? That is why is it different than other Operating systems?
3. What is the purpose of synchronizing processes?
4. What method of Inter-Process Communication must be used in distributed systems?
5. Given the following code for processes A and B. If process A is scheduled then process B is scheduled what are the possible values inside the shared memory locations Interest, Payment, and Balance if the location Interest holds 10%, the location payment holds $100, and the location Balance holds $1000? explain
   
   Process A                    Process B
   

R1 = Interest              R3 = Payment
R2 = Balance             R4 = Balance
R2 = R2*(1 + R1)     R4 = R4 – R3
Balance = R2             Balance = R4

6. What requirements must be met to ensure the Critical Section is maintained?

Answer 1

Various mobile operating systems:-

Android

September 20th, 2008 was the date when Google released the first Android OS by the name of ‘Astro’. After sometime next upgraded versions ‘Bender’ and ‘Cupcake’ were also released. Google then adopted the trend of naming Android versions after any dessert or a sweet in alphabetical order. The other releases are Donut, Éclair, Froyo, Gingerbread, Honeycomb, Ice Cream Sandwich and Jelly Bean. Marshmallow (Android 6.0) is so far the latest Android version from Google. Since the platform is not closed like iOS, there are too many great Android apps built by developers.

Just after stepping into the smartphone and tablets market Android gained immense popularity due to its beautiful appearance and efficient working. Many new features were introduced which played a significant role in Android’s success. Google Play is an official app market that contains millions of different apps for Android devices. Samsung, HTC, Motorola and many other top manufacturers are using Android in their devices. Currently, Android is one of the top operating systems and is considered a serious threat for iPhone.

Some of the smartphones operating on Android are HTC Desire, Samsung Galaxy Gio, Motorola Droid Razr, Samsung Galaxy S3 and HTC Wildfire.

Symbian

Symbian OS is officially the property of Nokia. It means that any other company will have to take permission from Nokia before using this operating system. Nokia has remained a giant in the low-end mobile market, so after Java Symbian was the most used in mobile phones until a couple of years ago. Still, Symbian is widely used in low-end phones but the demand rate has been continuously decreasing. By upgrading Symbian mobile OS, Nokia has made it capable to run smartphones efficiently. Symbian ANNA and BELLE are the two latest updates that are currently used in Nokia’s smartphones. Overall, the Symbian OS is excellently designed and is very user-friendly.

Unfortunately, the Symbian OS graph is going downwards nowadays due to the immense popularity of Android and iOS.

Some of the phones currently running on Symbian OS are Nokia C6-01, Nokia 603, Nokia 700, Nokia 808 Pure View, Nokia E6 (ANNA) and Nokia 701 (BELLE). Symbian is a popular choice among Nokia dual sim mobile phones as well.

Apple iOS

iOS was introduced on 29th June 2007 when the first iPhone was developed. Since then iOS has been under gone many upgrades and currently the latest one is the iOS 9.

Apple has still not allowed any other manufacturer to lay hands on its operating system. Unlike Android, Apple has more concentrated on the performance along with appearance. This is the reason that the basic appearance of iOS is almost the same as it was in 2007. Overall it is very user-friendly and is one of the mobile best-operating systems in the world.

Blackberry OS

Blackberry OS is the property of RIM (Research In Motion) and was first released in 1999. RIM has developed this operating system for its Blackberry line of smartphones. Blackberry is much different from other operating systems. The interface style, as well as the Smartphone design, is also different having a trackball for moving on the menu and a qwerty keyboard.

Like Apple, Blackberry OS is a close source OS and is not available for any other manufacturer. Currently, the latest release of this operating system is Blackberry OS 7.1 which was introduced in May 2011 and is used in Blackberry Bold 9930. It is a very reliable OS and is immune to almost all the viruses.

Windows OS

All of you will be familiar with Windows OS because it is used in computers all over the world. Windows OS has also been used in mobile phones, but normal mobile phone users find it a bit difficult to operate it but at the same time it was very popular among people who were used to it.

This was the case until Nokia and Microsoft joined hands to work together. The latest Windows release by Microsoft is known as Windows 7 which has gained immense popularity among all kinds of users. With its colorful and user-friendly interface, it has given Windows OS a new life and is currently in demand all over the world. Another reason behind its success is that this latest OS is used in very powerful devices made by Nokia. The computer like look has totally vanished from the windows phones with the release of Windows 7. Samsung and HTC also released some Windows-based phones, but they could not many places in the market.

What makes a Mobile Operating System special? That is why is it different than other Operating systems?

Ans:- A mobile operating system, also called a mobile OS, is an operating system that is specifically designed to run on mobile devices such as mobile phones, smartphones, PDAs, tablet computers and other handheld devices.

Things that make the mobile operating system special are:-

User Friendly:- The mobile operating system is a user friendly system that can handled by it's users. this is properly in understandable mode. The operating system is responsible for determining the functions and features available on your device.

Fast Working Speed:-

File explorer:-

Smooth working mood:-

Things that makes the mobile operating system (OS) different than others/computer OS

The difference between a mobile operating system (OS) and a computer OS has to do with how individual tech companies have rolled out various versions of the operating systems that supply the fundamental environments for traditional software applications as well as new mobile apps.

Mobile and computer operating systems have been developed in different ways and for different uses. Computer OS products are older and more familiar to larger groups of users. Through the last 20 or 30 years, the simple idea of a computer operating system has been continually built on and improved. Through this time, Microsoft Windows and Apple's Mac OS have emerged as the two dominant operating system designs. There have also been some open-source operating systems designed for traditional computers as alternatives to Microsoft or Apple licensed operating systems. These include Linux, FreeBSD, OpenBSD, and GNU.

There are a lot of details involved in computer OS design, but one prominent fact is that computer operating systems were not really designed for mobile use over wireless networks. Instead, they evolved and were understood, as part of a wired system, most commonly, as parts of a single physical machine. As such, developers and engineers focused on a lot of technical specifics related to items like boot protocols, program threads, multiple process handling, CPU operation, and other elements of the traditional OS.

The purpose of processes synchronization originates when processes need to execute concurrently. The main purpose of synchronization is the sharing of resources without interference using mutual exclusion. The other purpose is the coordination of the process interactions in an operating system.

Methods used in inter-process communication in a distributed system:-

Interprocess Communication is a process of exchanging the data between two or more independent processes in a distributed environment is called Interprocess communication. Interprocess communication on the internet provides both Datagram and stream communication.

Characteristics Of Inter-process Communication:
There are mainly five characteristics of inter-process communication in a distributed environment/system.

Synchronous System Calls:
In the synchronous system calls both sender and receiver use blocking system calls to transmit the data which means the sender will wait until the acknowledgment is received from the receiver and receiver waits until the message arrives.
Asynchronous System Calls:
In the asynchronous system calls, both sender and receiver use non-blocking system calls to transmit the data which means the sender doesn’t wait from the receiver acknowledgment.
Message Destination:
A local port is a message destination within a computer, specified as an integer. Aport has exactly one receiver but many senders. Processes may use multiple ports from which to receive messages. Any process that knows the number of a port can send the message to it.
Reliability:
It is defined as validity and integrity.
Integrity:
Messages must arrive without corruption and duplication to the destination.
Validity:
Point to point message services are defined as reliable, If the messages are guaranteed to be delivered without being lost is called validity.
Ordering:
It is the process of delivering messages to the receiver in a particular order. Some applications require messages to be delivered in the sender order i.e the order in which they were transmitted by the sender.

After Execution of process A and B, values will be:-

Balance equals $900 and R4 equals $1000.

Requirements must be met to ensure the critical section is maintained in these processes like every statement execute after each other and no one executes in parallel mode.