How Does the CPU Cache Work?

The cache on your CPU has become a very important part of today’s computing. The cache is a very high speed and very expensive piece of memory, which is used to speed up the memory retrieval process. Due to its expensive CPU’s come with a relatively small amount of cache compared with the main system memory. Budget CPU’s have even less cache, this is the main way that the top processor manufacturers take the cost out of their budget CPU’s.

How does the CPU Cache work?

Without the cache memory every time the CPU requested data it would send a request to the main memory which would then be sent back across the memory bus to the CPU. This is a slow process in computing terms. The idea of the cache is that this extremely fast memory would store and data that is frequently accessed and also if possible the data that is around it. This is to achieve the quickest possible response time to the CPU. Its based on playing the percentages. If a certain piece of data has been requested 5 times before, its likely that this specific piece of data will be required again and so is stored in the cache memory.

Lets take a library as an example o how caching works. Imagine a large library but with only one librarian (the standard one CPU setup). The first person comes into the library and asks for Lord of the Rings. The librarian goes off follows the path to the bookshelves (Memory Bus) retrieves the book and gives it to the person. The book is returned to the library once its finished with. Now without cache the book would be returned to the shelf. When the next person arrives and asks for Lord of the Rings, the same process happens and takes the same amount of time.

If this library had a cache system then once the book was returned it would have been put on a shelf at the librarians desk. This way once the second person comes in and asks for Lord of the Rings, the librarian only has to reach down to the shelf and retrieve the book. This significantly reduces the time it takes to retrieve the book. Back to computing this is the same idea, the data in the cache is retrieved much quicker. The computer uses its logic to determine which data is the most frequently accessed and keeps them books on the shelf so to speak.

That is a one level cache system which is used in most hard drives and other components. CPU’s however use a 2 level cache system. The principles are the same. The level 1 cache is the fastest and smallest memory, level 2 cache is larger and slightly slower but still smaller and faster than the main memory. Going back to the library, when Lord of the Rings is returned this time it will be stored on the shelf. This time the library gets busy and lots of other books are returned and the shelf soon fills up. Lord of the Rings hasn’t been taken out for a while and so gets taken off the shelf and put into a bookcase behind the desk. The bookcase is still closer than the rest of the library and still quick to get to. Now when the next person come in asking for Lord of the Rings, the librarian will firstly look on the shelf and see that the book isn’t there. They will then proceed to the bookcase to see if the book is in there. This is the same for CPU’s. They check the L1 cache first and then check the L2 cache for the data they require.

Is more Cache always better?

The answer is mostly yes but certainly not always. The main problem with having too much cache memory is that the CPU will always check the cache memory before the main system memory. Looking at our library again as an example. If 20 different people come into the library all after different books that haven’t been taken out in quite a while but the library has been busy before and so the shelf and the bookcase are both full we have a problem. Each time a person asks for a book the librarian will check the shelf and then check the bookcase before realising that the book has to be in the main library. The librarian each time then trots off to get the book from the library. If this library had a non cache system it would actually be quicker in this instance because the librarian would go straight to the book in the main library instead of checking the shelf and the bookcase.

As the fact that non cache systems only work in certain circumstances and so in certain applications CPU’s are definitely better with a decent amount of cache. Applications such as MPEG encoders are not good cache users because they have a constant stream of completely different data.

Does cache only store frequently accessed data?

If the cache memory has space it will store data that is close to that of the frequently accessed data. Looking back again to our library. If the first person of the day comes into the library and takes out Lord of the Rings, the intelligent librarian may well place Lord of the Rings part II on the shelf. In this case when the person brings back the book, there is a good chance that they will ask for Lord of the Rings part II. As this will happen more times than not. It was well worth the Librarian going to fetch the second part of the book in case it was required.

Cache Hit and Cache Miss

Cache hit and cache miss are just simple terms for the accuracy of what goes into the CPU’s cache. If the CPU accesses its cache looking for data it will either find it or it wont. If the CPU finds what’s its after that’s called a cache hit. If it has to go to main memory to find it then that is called a cache miss. The percentage of hits from the overall cache requests is called the hit rate. You will be wanting to get this as high as possible for best performance.

Small Business SEO Checklist

In 2005 there were 11.5 billion web pages that could be publicly index able by the web. There is an over abundance of information and your browser gives you access to all this information, and to the say the least there is going to be a multitude of so-called experts on any subject and SEO is no different.

There are some SEO best practices that stand the test of time, and regardless of the ongoing debate there are some basics that you need to check off before you start going any further with higher level SEO strategies. You may hear terms like, personalized search, or link building, but before you start getting lost down the rabbit hole please have these items checked off on your list and have these best practices on your tool belt.

Everything Starts with the Key Word

You could know everything there is about SEO, you could have a greatest web designers in the world and have an entire multi-million dollar infrastructure built around your business but in the SEO world if you don’t have the key words that you want associated with your business and eventually ranking for your website it’s similar to having a Ferrari without ever filling the tank with gas and taking it out of the garage to take it for a spin.

You are going to need key words, and you are going to have to find good ones. Good key words, in the SEO world, can be described as key words that are searched for allot but don’t have allot of competition. Eg., the keyword “real estate” is searched for quite a bit but is it realistic to go after such a key word that is very competitive? No.

So do some due diligence and use some free tools on the web to find the keywords that you think will be a good fit. As a general rule of thumb the more niche the better. Yeah, “Red Widgets” may be a great key word with good search volume, but “Red Widgets San Diego” would be allot easier to rank and it is geographically specific to your area so there is a higher chance you will close the deal if it’s a local customer versus somebody who’s calling your from Whistler, BC.

Search Engine Spiders Eat Text

This may seem like Chinese to you but this phrase will make sense if you know how a search engine works. The only way a search engine is going to find your site is with their search engine spider which crawls the web and sends back all the text it’s crawled and it caches it on their servers.

To make sure that your site is cached for the right key word you must tag your HTML appropriately with the level of importance as follows.

  1. Title
  2. h1
  3. h2
  4. first key words of your paragraph
  5. meta description
  6. meta keywords
  7. alt tags for images
  8. actual text on web page

New Content

One very important aspect of a web site that search engines weigh in heavily with their rankings is the updating of content and the indexing of new content. That’s why it’s always recommended that you have a blog on your website that is updated daily with new posts.

If it looks like your site is being outfitted with fresh content on a daily basis that offers more information on your service, brand or product to searchers so Google, or Yahoo! will consider that when ranking their search results for certain keywords.

Submit Your Sitemap

It’s important to have content on your website that is useful to the visitors to your site, but it’s also important for the content to be easily to navigate through. So build a sitemap, make it easy, readable and submit it to Google Webmasters.

Get in the Habit of Linking

Links are basically the scaffolding of the world wide web, they hold all the information together organically with out having a central nervous system, or data center. The web just IS, it’s a force of nature, and an ever expanding organism and the more links your have linking to your website the more scaffolding you have holding up your site, the more relevant you become for certain subjects.

Importance of Archiving Solutions For Business

One important thing about archiving solutions is that you can now manage your mails at a more convenient manner and you can prioritize those that need urgent applications. The purpose of this process is to help email users to enjoy a more spacious and organized system for handling electronic mails. This system gives way for new incoming mails to be readily found and accessible.

This archiving solutions process is vital to small and medium sized businesses which do not have the sophisticated database. There are documents that are of monumental value but are not yet very much needed at the moment. These are the types of information that must be kept for future reference. With archiving solutions you inbox will be supported with a process that can help you put aside those documents that are not yet in use.

All it needs is a storage system for the emails form the inbox that need to be placed in the archive. The storage or depositary must also be secured with passwords to ensure the preservation of these important documents that in placed in the archives. The process is very easy and convenient to use.

As a standard part of implementing program control flow, clear the session state of unneeded values using clear-cache page processes or clear cache directives in the. This is important if they are found in the URLs which are used to navigate to pages. Use password-page item types that do not save state. This prevents the entered passwords from being saved in the session state tables.

When there is a need for sensitive data tot persist in a session, save it in archiving solutions session state tables in encrypted form. Most documents or emails that are to be stored in the archives are considered very valuable and sensitive. When you are trying to access this sensitive data you must try to protect them after using.

You can check online for email support service that provides this type of process for your business. In any form of business, the email is already an important factor that must be given due importance. There is a great need to keep vital documents in a storage that needs the proper archiving solutions.