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Hard Disk buying guide for data center environments

Buying a hard disk for data center applications is not that easy, as one has to keep in mind latency, typical seek times, rotational latency/rotational speed, data transfer rates, error correction codes and buffer/cache size. So, here are few guidelines, which can make the task of an IT manager easy on this note.

Latency and data seek- Hard disk latency and data seek time are very much important in storage environments. How quickly the disk can find and read a sector is what is called access time, which takes place in two steps. At first, the head must be moved to the correct track and then the head must wait for the platter to spin and read the related sector. Seek time is the time required for the head to position itself over the track and latency time is the time taken for the desired sector to position itself under the head. It is a fact to be notified that moving a head to the desired sector takes a bit longer time, than position the sector beneath the head. So, low seek times are critical to good disk performance.

Getting deep into the theory of seek time and latency period, the seek time is usually longer the wait. Earlier, Seek time was measured in milliseconds and varies to how many tracks the heads must traverse. Usually, the seek time from one track to the next track is usually quick and is in just milliseconds. Since, nowadays low the seek time is better, it is being measured in nanoseconds. In general, an average seek time is nothing but the system requiring to travel one-third of the way across the disk. Earlier, hard disk drive vendors use to offer hard drives with seek times almost equal to 100ms. But now things have changed and now average seek time on a new drive is between 5ms and 10ms.

Rotational latency/speed- For all you folks, who have an opinion that once a head positions itself over a track, its job is done-here’s an update. The head has to wait for the correct sector to rotate to a position beneath it. This can happen in half spin or it has to wait for another full revolution of the disk to complete. This is called rotational latency period. When average latency period is taken into account, you can go with a simple assumption that on average, the disk must make a half revolution to get to your sector. The latency period is calculated by the manufacturers from spindle speed and is normally in milliseconds.

Rotational latency is influenced by rotational speed. Nowadays, hard disk manufactures are coming up with drives which are rotating with 5000rpm to 15,000rpm speeds. It must be remembered that the higher the spindle speed, the lower the average latency. Thus, you can calculate the average latency based on half of the platter rotation and in worst case latency on a full rotation of the disk.

Data transfer rate- How fast a disk can transfer data found on its platter, constitutes data transfer rate. In actuality, the transfer rate is a measure of the amount of data that the system can access over a specific period of time, say one second. Here again, external data transfer rates and internal data transfer rates come into existence. External data transfer rate is the speed of communication between the cache and system memory. The internal data transfer rate is the speed at which the hard disk can physically write or read data from the platter. So, data transfer rates are influenced by these two factors and vary depending on the density of the data on the disk and how fast the disk can spin to locate the data.

Error correction code- It is a fact that no electronic data transmission or storage is 100% free from errors and each has its own error rate. However, modern hard drives have default error detection & correction techniques. Disk systems are great as storage media, but they do have their own issues. As soon as the first byte is placed on the disk, it starts to dissolve. This is due to the presence of magnetic domains on the disk that define the data slowly and randomly make it unrecognizable. Though the disk will be fine, data images will fade after few years.

For this reason, hard drive manufactures are coming up with systems that detect and correct minor data loss on an automated note. They are coming up with controllers which make a note of the information while being written to the disk and then try to detect whether errors gave occurred in the data, while reading it back.

Size of buffer/cache does matters- If a computer uses RAM which responds to requests in 1/10th of a nanosecond, the disk drive responds to requests in 1/10th of millisecond. So, when a data is being moved to a faster to slower medium, a cache acting as an intermediate will be useful in holding recently used or anticipated data in improving performance. The cache helps in reducing the amount of data that needs to travel through the bottleneck area. So, that is why hard disk drive performance can improve by caching.

Therefore a disk cache seeks to use the speed of memory to bolster the effective speed of disk. The cache is held in memory chips and is Megabytes in size. Thus, the OS can access data which was previously placed in the disk cache on as-per-need basis. By using this disk cache, a cut down on the number of physical seeks and transfers from the hard drive can be observed. Smart cache algorithms mean that there is no need to change the size of the disk cache. This cache buffer acts as a resting area for one or more tracks, and sometimes to the entire cylinder worth of information. Therefore the cache buffer can be effective in speeding up both throughput and access time in a hard disk.

So, if an IT manager is buying a hard drive for his/her data center environments, they can make a note of the above said points before going for a selection, in order to make their decision remarkably appreciable.

AT&T GigaPower Fiber to compete with Google Fiber

Google Fiber, launched in United States in September 2012 will soon be getting a competitor in this business. AT&T one of the top telecommunication services providers in United States has decided to launch its GigaPower Fiber in almost 100 possible municipalities across the country.


AT&T will offer Ultra Fast fiber network in all these municipalities at competitive rates and probably a bit less than what Google Fiber is currently offering. Just like Google, AT&T has also chosen Kansas City as its launch pad and will extend its GigaPower Fiber to Chicago, Houstan, Los Angeles, Miami, Oakland, Orlando, San Antonio, San Diego by this year end. By March 2015, the company wants to extend its services to all the 42 major States of America.


Now for those who want to know, what you can do with 1GigaByte per second speed, here’s an update. 1GBPS can offer 30 songs download in just 1.3 seconds. It can download your favorite 50 minute TV show in just 3 seconds and can download a HD movie in just 36 seconds.


Currently, AT&T is silent on the cost of such high scale bandwidth. But reliable sources from the company say that the price of such service may range in-between $60 to $80/month.

IDC reveals that major cloud service providers in Asia have slashed their prices

International Data Corporation (IDC) has announced that all major service providers in Asia have slashed their prices for core services dramatically in the current year due to stiff competition. The research firm also suggested that this move has now become a serious threat to many small cloud service providers who are trying their best to establish themselves in this business.


“If smaller CSPs are strong enough to smartly live up to the competition, then they can survive in business. But if they are not strong enough, then their existence is surely in jeopardy in said region”, said Chris Morris, Lead Analyst, of Cloud services and technologies, IDC.


Thus, Chris predicts that small Cloud service providers will face tough time in Asia from now on, as dropped prices from big players, will automatically force them to drop the prices of their current services. If this trend proceeds, then IDC clearly predicts that this may drive the small cloud service providers into major pitfalls.


In case, if IDC predictions turn into reality, then this will drive consolidation amongst the cloud vendors for sure and will automatically eliminate small cloud businesses on a permanent note.

Apple announces recycling services on occasion of Earth Day

Apple, Inc. on the occasion of Earth Day has launched recycling services on a worldwide note . As a part of this program, Apple will accept all those old and worn out mobiles phones, PCs and other e-waste which are related to its company and third parties. This program will remain active through out this year in all parts of world along with United States.


Apple has taken this initiative in order to redesign its responsibilities towards environment and has officially formulated certain guidelines to all its stores located in different parts of the world.


As a part of this program, Apple has come up with an idea of paying back to those entire users in the form of gift cards, who are participating in its recycling program. For those who are giving away their old mobile phones and PCs, Apple will offer them gift cards, if in case, their donated product is reusable. With the gift card, users can purchase any Apple product at a discounted rate. If the product is not in a position to be reused, then Apple will recycle the product at no cost to the user.


Apple has made an official announcement that it has set up its recycling program in 95% of countries where its businesses are active and has diverted over 421 million pounds of equipment from landfills since 1994.


Those user’s who are disposing off their mobile phones and PCs related to other companies, will not get a gift card, but their names will be published in an upcoming website dedicated by Apple to green environment.


Now, reviewing this step under business perspective, it is a known fact that many companies are into this business of recycling e-waste. But Apple’s Vice president of Environmental Initiatives, Ms. Lisa Jackson justifies her company’s move as truly productive. She says that company brand do matters in such businesses and when people are being rewarded for showing their concern towards environment, then it becomes completely rational from business perspective.

Approach DNF Consulting Services for all your IT needs!

With the kind of technological developments taking place in software and ecommerce fields, the need to hire skilled professionals is increasing day by day. Here’s where DNF Consulting Services can help in advising enterprises on how best Information Technology can help to meet in their business objectives. Additionally, DNF Consulting can also help in offering the best of its services to leverage aspects such as estimation, management, implementation, deployment and administration of IT system in your business environments.

As new technological paradigms such as Internet of things, Big Data, Cloud Computing hitting the deck, CIOs are being forced to grapple with the current technologies and deployment models in order to get the best of ROI from the technology investments.

Here’s where DNF Consulting helps in walking out of this clutter with ease. This is an IT and Business consulting firm, which will help to leverage a deep understanding of technology, domain and business processes to address key business requirements.

  • If you are new in business and need help in hiring professionals for your IT department, DNF will help you out on this issue.
  • If you are struggling to find out a way of your present IT crisis, then just approach DNF Consulting Services and relax, as it looks after anything and everything then after, giving you peace of mind and time to look into your other business perspectives.
  • In order to make your IT environment future proof in a cost effective, you can approach DNF Consulting, as it helps in maximizing ROI on IT spend.

So, for those who are interested in knowing more about DNF Consulting expertise, here’s an update. DNF Consulting Services offers a full spectrum of the Software Development lifecycle which includes reengineering, application development and maintenance of all sorts of IT applications. You can treat this company as a one-stop shop for all your IT needs.

From a company’s point of view, you get everything related to IT from DNF consulting. And from a candidate’s point of view, you can approach DNF for all your needs related to your first job or a job change in IT field

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Google Glass may also turn into a TV screen!

For all Google Glass lovers, here’s an update which will amuse you a lot. Google engineers who are coming up with Google Glass have plans to turn this gadget into TV screen in near future. The company has already pressed a team of experts into a secret project on this issue and results are expected to be out by early next year.


As per the latest reports from reliable sources, Google Glass users may soon watch movies and related internet content direct on their eye wear. As per sources, the engineers have already succeeded in embedding related technology into the eye gear which turns the spectacle lenses into a TV screen with the press of a button. But their biggest challenge on a present note is to make the whole gear light as a feather and they are working on it.


A reliable source, who is a part of this research project, has also informed that by early next year, Google might introduce this specially made eye gear to the world, but probably as a new innovative gadget and not as a ‘Google Glass’ eye gear. The source added that the concept of recording will be similar to that of a Google glass. But more specs will be added into this gadget in order to give the user a TV viewing experiencing with the help of Wi-Fi concept.


So, whether this will turn into a reality or not, let’s wait and watch till next year.

Amazon users will get 10GB free cloud storage capacity

Amazon has followed the footsteps of Google cloud and has decided to merge its Cloud Drive with Kindle storage. From now on, Amazon cloud storage users will get a 10GB free storage space which can be used to store videos, photos and various other files.


Amazon’s storage consolidation of its cloud means, its users can easily manage, move, copy or delete their files in an easy way. So, from now on ‘Send to Kindle’ features will be available in a sub folder of Amazon Cloud Drive.


From user’s point of view, this news can excite those who are already on Amazon Cloud platform. But consolidation of storage may not excite those who are in a hunt for a new cloud storage platform, as 10GB of storage space will exhaust within few months time to many.


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