Saturday, 30 November 2013
New Site : Gamelanits.com
We've created a new site called Gamelantis. We sell videogames for Nintendo, Playstation and Xbox 360 and also will keep you up to date on the newest releases, cheats and what's going on in the game world.
Sunday, 10 November 2013
What you need to know about Amazon.com
Brief History
- Amazon was incorporated in Canada in July 1994.
- It went online in 1995 as a virtual bookstore that became one of the internet's biggest success stories.
- Investors included Tom Alburg and Nick Hananuer.
- In 1999 Amazon raked in 1 billion dollars in sales.
- In 2001 it made a fiscal loss of 1.4 billion dollars and had to lay off 200 workers.
Who founded Amazon?
Jeffery Bezos is the creator of Amazon.Born on January 12th 1964 Albuquerque, New Mexico. He started his company in his garage where he sold his first book. The company was named after the Amazon River because the name Amazon was a place exotic and different. Within the first two months of business Amazon sold to all 50 states and over 45 countries. In 2013,Bezos made headlines when he purchased The Washington Posting a $250 million deal.
What are the services offered by Amazon?
Some of the services offered by Amazon are:
- Compute - Amazon Elastic Compute Cloud delivers scalable, pay-as-you-go compute capacity in the cloud. Amazon Elastic MapReduce is a web service that enables businesses, researchers, data analysts, and developers to easily and cost-effectively process vast amounts of data.
- Content Deliver - Amazon CloudFront is a web service that makes it easy to distribute content with low latency via a global network of edge locations.
- Database - Amazon Relational Database Service is a web service that makes it easy to set up, operate, and scale a relational database in the cloud.
- Deployment & Management - IAM enables you to securely control access to AWS services and resources for your users. IAM enables you to create and manage users in AWS, and enables you to grant access to AWS resources for users managed outside of AWS in your corporate director.
- Support - AWS Support is a one-on-one, fast-response support channel to help you build and run applications on AWS Infrastructure Services.
Amazon network is worth 90 billion as of 2013. The company makes money by essentially leasing space to retailer like Nordstrom, Land's End and Target, who use Amazon.com as a supplemental outlet for their online
sales. Amazon handles the entire sales transaction from start to finish and gets a cut of each sale (usually about 10 percent to 15 percent) and sometimes charges additional listing or subscription fees
What is life like working at Amazon?
Amazon currently employs more than 88,400 people around the world. Centered in Seattle Washington and requires long hours between 8-10 working hours per day. Day shifts are $10 per hour and night shifts are $11 per hour. Work fields include: fulfillment centers, customer service centers, data centers, and software development centers. Amazon offer employees health care benefits for them and their families, saving plans and opportunities to work in new areas.
What inventions is Amazon working on right now?
What inventions is Amazon working on right now?
New inventions by Amazon include: as kindle fire, ebooks, ebook reader and kindle fire tablet computer• Launch vine.com for buying green products such as groceries, and household items.
Sunday, 3 November 2013
Multithreading
Before we get into the main topic of this post allow me to define a few things.
What is a thread? - A thread is a flow of execution through a process code. Sometimes called a light weight process it has its own stack, program counter and system registers. In other words it is a seperate flow of control which belongs to a sole process and is not able to exist outside of one.
Types of threads
1. User Level Threads - The application is in charge of thread management. The kernel does not know of the thread's existence. A single thread is started by the application and that application initially runs on that thread.
2. Kernel Level Threads - These threads are managed by the kernel and are supported directly by the operating system.
And now the main event...............
Multithreading is the ability of a program to manage multiple request from a user or multple requests from multiple users. Each thread can operate independently even while all of them may be using the same resources. Operating systems work faster using threads than creating multiple processes.
Two applications of multithreading are:
1. In Server applications
2. In situation where large amounts of mathematical operations are needed.
The figure below shows a comparison between a single threaded and multithreaded process
Types of Multithreading
Temporal
a)Block multithreading - In this process one thread may be running until it stalled due to an event that might take some time to occur. In this case the threading processor allows the next thread in the read-to-run list to be executed until the previous thread had received its data and can resume its function. This multithreading type is also know as Coarse-grained multithreading.
b)Interleaved multithreading - Also know as Fine-grained mulitithreading, this type of process removes all stalls from data dependencies from the execution pipeline. A data dependency is a program statement which refers to a previous statement. A pipeline is a set of data processing elements that are connected in series. The output of one element is the input of another. Notice by defining these two statements the first sentence is easier to grasp. Since one statement is dependent on another statement and its result, time will be needed to get the required data. The question is: How much time will it take?
Simultaneous multithreading - Instructions from more than one thread can be executed in any pipeline stage at a time. A super-scalar processor is used. This processor, during every CPU cycle, usually issues a number of instructions from a single thread but in simultaneous multiprocessing issues instructions from multiple threads.
Types of Multithreading Models
1. Many to One relationship - Many user threads are mapped to one kernel thread. Only one thread can access the kernel at a time therefore multiple threads cannot run in parallel.
2. One to One relationship - As the name suggests only one user thread is mapped to one kernel thread. This relationship allows threads to be more in sync than the many to one. 0S/2, Windows NT and Windows 2000 use this type of relationship.
3. Many to Many relationship - A number of user threads are mapped to more than one kernel thread. The number of kernel threads to user threads could be the same or less.
If you're still not quite getting it, the figure below shows the different multithreading relationships.
Advantages and Disadvantages of Multithreading
Advantages:
1. Memory locations and resources can be shared which means that less resources are used.
2. Application responsiveness is improved. If an application can be launched on its own thread then it will not freeze up.
3. Simplification of the program structure. Simple routines can be created for each activity which makes intricate programs much more easier to design and code. This will in turn make the application suitable for a variety of user commands.
Disadvantages
1. Changes in application programs as well as the operating system are required hardware support for multithreading is more visible to software.
2. Even though shared resources are seen as a plus, threads may interfere with each other while this is happening.
3. Difficulty debugging. Replication of an error is harder to do than in a single threaded application so identifying and verifying the root of the cause will be more troublesome.
Before we get into the main topic of this post allow me to define a few things.
What is a thread? - A thread is a flow of execution through a process code. Sometimes called a light weight process it has its own stack, program counter and system registers. In other words it is a seperate flow of control which belongs to a sole process and is not able to exist outside of one.
Types of threads
1. User Level Threads - The application is in charge of thread management. The kernel does not know of the thread's existence. A single thread is started by the application and that application initially runs on that thread.
2. Kernel Level Threads - These threads are managed by the kernel and are supported directly by the operating system.
And now the main event...............
Multithreading is the ability of a program to manage multiple request from a user or multple requests from multiple users. Each thread can operate independently even while all of them may be using the same resources. Operating systems work faster using threads than creating multiple processes.
Two applications of multithreading are:
1. In Server applications
2. In situation where large amounts of mathematical operations are needed.
The figure below shows a comparison between a single threaded and multithreaded process
Types of Multithreading
Temporal
a)Block multithreading - In this process one thread may be running until it stalled due to an event that might take some time to occur. In this case the threading processor allows the next thread in the read-to-run list to be executed until the previous thread had received its data and can resume its function. This multithreading type is also know as Coarse-grained multithreading.
b)Interleaved multithreading - Also know as Fine-grained mulitithreading, this type of process removes all stalls from data dependencies from the execution pipeline. A data dependency is a program statement which refers to a previous statement. A pipeline is a set of data processing elements that are connected in series. The output of one element is the input of another. Notice by defining these two statements the first sentence is easier to grasp. Since one statement is dependent on another statement and its result, time will be needed to get the required data. The question is: How much time will it take?
Simultaneous multithreading - Instructions from more than one thread can be executed in any pipeline stage at a time. A super-scalar processor is used. This processor, during every CPU cycle, usually issues a number of instructions from a single thread but in simultaneous multiprocessing issues instructions from multiple threads.
Types of Multithreading Models
1. Many to One relationship - Many user threads are mapped to one kernel thread. Only one thread can access the kernel at a time therefore multiple threads cannot run in parallel.
2. One to One relationship - As the name suggests only one user thread is mapped to one kernel thread. This relationship allows threads to be more in sync than the many to one. 0S/2, Windows NT and Windows 2000 use this type of relationship.
3. Many to Many relationship - A number of user threads are mapped to more than one kernel thread. The number of kernel threads to user threads could be the same or less.
If you're still not quite getting it, the figure below shows the different multithreading relationships.
Advantages and Disadvantages of Multithreading
Advantages:
1. Memory locations and resources can be shared which means that less resources are used.
2. Application responsiveness is improved. If an application can be launched on its own thread then it will not freeze up.
3. Simplification of the program structure. Simple routines can be created for each activity which makes intricate programs much more easier to design and code. This will in turn make the application suitable for a variety of user commands.
Disadvantages
1. Changes in application programs as well as the operating system are required hardware support for multithreading is more visible to software.
2. Even though shared resources are seen as a plus, threads may interfere with each other while this is happening.
3. Difficulty debugging. Replication of an error is harder to do than in a single threaded application so identifying and verifying the root of the cause will be more troublesome.
Thursday, 24 October 2013
Welcome to our first bolg
Onekha Elvin and Doniello Raynes are happy to have created our first blog. We are both students of ABIIT perusing our degree in Computer Science. Stay tuned for hot issues and topics from us.
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