Basic information about i386, i686 and x86_64 architectures

32 bit vs 64 bitI was going through mails and in one mail a person asked me, what is this 32 bit and 64 bit things and how do I know if my system is 32 bit or 64 bit. Which application my system would support and so on…
So, I thought better to document one small article which will answer those questions with minimal essential explanation of the terms involved using simpler way. I googled and collected few important paragraphs from various tech sites and posting it at one place.

i386 and i686 are both part of the x86 family of processors. They just refer to the specific age of the processor platform. i386 is an older platform (early 90s?) used back when 386 processors were used in machines. Then this was upgraded to 486 processors, which was the same basic instruction set as 386 just faster and newer. 586 was another upgraded and were when the term Pentium started floating around. Eventually all of these got encapsulated into the x86 architecture name. i686 just refers to the 6th generation of x86 architecture.

For all intents and purposes i386 and i686 is the same thing, just that i686 is a lot newer. They will have some additional instruction sets, but will be backwards compatible with i386. I would venture a guess that all of the processes you find today that use x86 would be classified as i686 processors.

x86 refers to a processor family. x86_64 is different than x86 (it is the 64 bit brother of x86). There are also Alpha processors, Sparc, ARM, PPC. These all refer to different processor families.

If you are installing an OS and a CPU is from the x86_64 processor family, then you cannot install an ARM based OS on that hardware.

Intel released the following processors on the dates shown

  • June 8, 1978 – 8086
  • February 1982 – 80286
  • October 17, 1985 – Intel386™ DX Processor <- this was the first i386
  • June 16, 1988 – Intel386™ SX Processor
  • April 10, 1989 – Intel486™ DX Processor
  • March 22, 1993 – Intel® Pentium® Processor <- sometimes referred to as i586
  • November 1, 1995 – Intel® Pentium® Pro Processor
  • May 7, 1997 – Intel® Pentium® II Processor <- I think this was the first of the i686
  • February 26, 1999 – Intel® Pentium® III Processor
 
[vim]
$ /usr/bin/isainfo -kv
64-bit sparcv9 kernel modules

$ uname -m
sun4u

$ uname -m
x86_64
 
$ uname -m
i686
[/vim]
 
32-bit systems were once desired because they could address (point to) 4 Gigabytes (GB) of memory in one go. Some modern applications require more than 4 GB of memory to complete their tasks so 64-bit systems are now becoming more attractive because they can potentially address up to 4 billion times that many locations.
Since 1995, when Windows 95 was introduced with support for 32-bit applications, most of the software and operating system code has been 32-bit compatible.
Here is the problem, while most of the software available today is 32-bit, the processors we buy are almost all 64-bit.

So how long will the transition from 32-bit to 64-bit systems take?
The main issue is that your computer works from the hardware such as the processor (or CPU, as it is called), through the operating system (OS), to the highest level which is your applications. So the computer hardware is designed first, the matching operating systems are developed, and finally the applications appear.

We can look back at the transition from 16-bit to 32-bit Windows on 32-bit processors. It took 10 years (from 1985 to 1995) to get a 32-bit operating system and even now, more than 15 years later, there are many people still using 16-bit Windows applications on older versions of Windows.
The hardware and software vendors learnt from the previous transition, so the new operating systems have been released at the same time as the new processors. The problem this time is that there haven't been enough 64-bit applications. Ten years after the PC's first 64-bit processors, installs of 64-bit Windows are only now exceeding those of 32-bit Windows. Further evidence of this inertia is that you are probably reading this tutorial because you are looking to install your first 64-bit software.

Your computer system in three parts
Now we'll look at those three components of your system. In simple terms they are three layers with the processor or CPU as the central or lowest layer and the application as the outermost or highest layer as shown below:

To run a 64-bit operating system you need support from the lower level: the 64-bit CPU.
To run a 64-bit application you need support from all lower levels: the 64-bit OS and the 64-bit CPU.
This simplification will be enough for us to look what happens when we mix the 32-bit and 64-bit parts. But if you want to understand the issue more deeply then you will also need to consider the hardware that supports the CPU and the device drivers that allow the OS and the applications to interface with the system hardware.

What 32-bit and 64-bit combinations are compatible and will work together?
This is where we get to the practicalities and can start answering common questions.
The general rule is that 32-bit will run on a lower level 64-bit component but 64-bit does not run on a lower level 32-bit component:

  • A 32-bit OS will run on a 32-bit or 64-bit processor without any problem.
  • A 32-bit application will run on a 32-bit or 64-bit OS without any problem.
  • But a 64-bit application will only run on a 64-bit OS and a 64-bit OS will only run on a 64-bit processor.
These two tables illustrate the same rule:
Table 1 — What is compatible if I have a 32-bit CPU?
Processor (CPU) 32-bit 32-bit 32-bit 32-bit
Operating System (OS) 32-bit 32-bit 64-bit 64-bit
Application Program 32-bit 64-bit 32-bit 64-bit
  Yes No No No
 
Table 2 — What is compatible if I have a 64-bit CPU?
Processor (CPU) 64-bit 64-bit 64-bit 64-bit
Operating System (OS) 64-bit 64-bit 32-bit 32-bit
Application Program 64-bit 32-bit 32-bit 64-bit
  Yes Yes Yes No
The main reason that 32-bit will always run on 64-bit is that the 64-bit components have been designed to work that way. So the newer 64-bit systems are backward-compatible with the 32-bit systems (which is the main reason most of us haven't moved to 64-bit software).

An example of backward compatibility is Windows 64-bit. It has software called WOW64 that provides compatibility by emulating a 32-bit system. See the article How Windows 7 / Vista 64 Support 32-bit Applications if you want to know more. One important point that is made in that article is that it is not possible to install a 32-bit device driver on a 64-bit operating system. This is because device drivers run in parallel to the operating system. The emulation is done at the operating system level so it is available to the higher layer, the application, but it is not available to the device driver which runs on the same level.

Hardware virtualization is the exception to the rule
Another question many people have is whether a 32-bit system can run 64-bit software. As more people are looking to use 64-bit Windows they are wanting to try it out on their existing systems. So we are getting more questions about whether they can run it on their 32-bit processor or under their 32-bit OS.

Following the general rule, we would expect that you cannot run 64-bit software on a 32-bit system. Except that there is one exception called virtualization.

Virtualization creates a virtual system within the actual system. Virtualization can be achieved in hardware or software but it works best if the virtual machine is created in the system hardware. The guest operating system is not aware that there is a host operating system already running. This is the way that a 64-bit operating system can think that it is running on 64-bit hardware without being aware that there is a 32-bit operating system in the mix.

Tables 3 and 4 illustrate the result. Provided that the virtual machine can actually be created and isolated by the virtualizing software then the host OS is effectively removed from the equation, so I've grayed it out. We can now apply the general rules for a non-virtualized system to the three remaining layers.

Table 3 — What is compatible if I have a 32-bit CPU and software virtualization?
Processor (CPU) 32-bit 32-bit 32-bit 32-bit
Host Operating System 32-bit 32-bit 32-bit 32-bit
Guest Operating System 32-bit 32-bit 64-bit 64-bit
Application Program 32-bit 64-bit 32-bit 64-bit
  Yes No No No
 
Table 4 — What is compatible if I have a 64-bit CPU and software virtualization?
 
Processor (CPU) 64-bit 64-bit 64-bit 64-bit
Host Operating System 32/64-bit 32/64-bit 32/64-bit 32/64-bit
Guest Operating System 64-bit 64-bit 32-bit 32-bit
Application Program 64-bit 32-bit 32-bit 64-bit
  Yes Yes Yes No
Before you hurry away to try running 64-bit in a virtual machine, you must check that your computer BIOS supports hardware virtualization. If it does not then hardware virtualization will not work even if the CPU does support it.

Emulation of the 64-bit CPU is not an option
All the feasible configurations that we have looked at so far have the processors (CPUs) running software that use the instruction set that is native to that processor. Running 64-bit software on a 32-bit processor doesn't work because the 64-bit instructions are not native to a 32-bit processor.

But what if I could emulate a 64-bit processor using 32-bit software?

It is theoretically possible but practically impossible to emulate a 64-bit processor while running software on a 32-bit processor. Even if you can get non-native 64-bit emulation to work, the virtual machine that duplicates a 64-bit CPU would run very slowly because every 64-bit instruction has to be trapped and handled by the emulator. 64-bit memory pointers also have to be converted to work within the 32-bit address space.

Furthermore, my understanding is that the x86 (32-bit) processors used in PCs and Apple Macs are not able to completely emulate the x64 (64-bit) instruction set. Some 64-bit instructions cannot be trapped by the emulator. This causes the system to crash when the x86 processor tried to run those x64 instructions.
 

Read more

Interesting facts related to computer that you would like

Here are some interesting points related to computer that you would love to hear:
 
1. It took the radio 38 years and the television only 13, but the internet reached 50 million users in only 4 years.
 2. The computer mouse was invented by Doug Engelbart in 1963. It was made out of wood (weird, huh).
 3. In 2009 the average number of Internet transactions per second was 2,000.
 4. Early hard disks in personal computers held only 20 MB of data and cost around $800. In 2010 you could get a 2 GB flash drive for around $8. This implies that there is a 100-fold reduction in the price and a 100-fold increase in storage capacity.

 5. Rear Admiral Grace Hopper, the first female admiral in the US Navy is also known in the computer world for creating the popular programming language COBOL. She also came up with the term ‘debugging’ after removing a moth from a computer.

 6. The computing power in today’s cell phones is much higher than the processing power of all the computers in the Apollo 11 Lunar Lander that put 2 men on the moon.
 7. The two main components in IT (Information Technology) are hardware and software. But there is also a lesser known ‘grey’ component. This is the software that is stored in hardware and cannot be modified easily. It is known as ‘firmware’.
 8. There are over 20 billion web pages on the internet, and that number is rapidly growing every day. Also, there are over 2 billion internet users worldwide at present.
 9. RIM (the BlackBerry operating system company) co-CEO and cofounder Mike Lazaridis dropped out of college to start his own company. He did so after reading Microsoft’s founder, Bill Gates’, book.
 10. The first hard disk drive was created in 1979 by Seagate. Its capacity was a whopping (not) 5 MB.
 11. HP, Google, Microsoft, and Apple have one thing in common – apart from the obvious that they are IT companies. They were all started in garages.
 12. The 12 engineers at IBM that developed the IBM PC had a code name – “The Dirty Dozen”.
 13. The first and still the oldest domain name to be registered is Symbolics.com, it was created on March 15th, 1985.
 14. Most Central Processing Units (CPU’s) are sold as a bit slower than they actually run. By over-clocking them you can get them to run faster – for free.
 

Read more

How Grinch Penetrates Defenses

Tech Grinches have been quite busy this year round with their evil activities – snatching away happiness from people by stealing their confidential data. There have been high statistics recorded for data breach in year 2012. The most unfortunate have been the retail business, where company data have been targeted most often and with ease. The Grinch and his companions have used specific tools to attack people this year – keyloggers and spyware being the most useful modes of attack.
Read more

Increasing Social Shares – Complete Guide

Any website owner or blogger would want to increase social shares in order to get more traffic. The mainstay of any blog lies in the traffic it can attract, hence devising ways and means to increase social shares and in turn diverting traffic is the ultimate goal of a blog. Social sharing is critical not only for the existence of a site but for its healthy growth and sustenance. Here are a few points to guide you to make your content the most sharable.

Read more

Comparing Microsoft Surface: it’s not apples to Apple

With the public release of both Windows 8 and the Surface tablet around the corner, more and more articles come out either praising or loving the strategy.Unfortunately a key component of the Surface functionality is overlooked when comparing it against rivals from Apple and Google – Windows 8 supports multiple profiles.
This is a big difference between the tablet OS platforms.While iOS and Android have been built to operate smartphones and tablets Microsoft has taken a different approach by making their desktop operating system work on a tablet. This allows users to get the best of both worlds instead of having to live on either device – or worse: carry both.
Read more

Brief Analysis on Google Search Engine

There are lots of Search Engines are there in the market. But Google was and is the best Search Engine over the internet till date. It has more than 80% of market share in US over other search engines.
Microsoft launched Bing, but it is still at bottom 5 list of top search engines. I personally never liked Bing too. Once upon a time Lycos was very famous but Google just killed it!
Yahoo Search Engine also plays an important role to make our search easier by serving better results. But then also it just covers 6% approx. of total queries search over the internet amongst all search engines. Baidu from China is now becoming popular too, because it's widely used in China.

Read more

Good analysis on Microsoft vs Apple strategies

In pursuing your MBA, some of the most important lessons you’ll learn come from looking at the example set by big businesses gone before you. From the good to the mediocre to the downright ugly, there are plenty of businesses to base your own decisions on, whether you’re trying to determine what to do or what not to do in a business situation.

Today’s infographic examines a prime instance of a company that has seen great success, and yet doesn’t seem to be going anywhere in the modern industry: This company is the well-known titan Microsoft. Under the watchful, savvy eye of Bill Gates, Microsoft grew and flourished quickly, enjoying a great deal of success in its early years. But since its boom in the first wave of the tech era, Microsoft has slowly but surely stagnated and fallen into the shadow of successful innovators, specifically, Apple, for example.

Read more

Tips To Improve LapTop Battery BackUp

Laptop Battery Consumption1. Reduce brightness by changing power plan
             On most of the laptops and netbooks, you can choose power plan and adjust brightness of the display. You power plan should be such that, if you are not using your laptop for 3 – 5 minutes, display screen should turn off. Display should dim in first 2 minutes of stand by time. Generally these values are set to 10 minutes but you will have to change it to 2 – 3 minutes to get more backup from current battery.

 
2. Turn OFF Signal Check for Bluetooth and Wi-Fi 
                    If you are not using Bluetooth on your laptop, you should turn that off. When your laptop keep searching for bluetooth devices, it consumes so much battery power. Same is the condition with Wi-Fi as well. If you are not using Wi-Fi on your laptop, turn off that option.
 
3. Use Hibernate rather than Sleep
            Windows is having option to hibernate your system rather than keeping that running in sleep mode. If you have opened lot many important applications, and you don’t want to close them, you keep your laptop in sleep mode so that when you come back, you can get you laptop in same situation.
But even in sleep mode, laptop or netbook keep consuming power. You can use Hibernate option to shutdown your laptop. In case of Hibernate, your laptop saves the current session (list of opened programs) on hard disk and when you will start your laptop next time, it will open all your last time running programs as well.
 
4. Keep control on Background Applications
         There are few programs which start running when your laptop or computer starts. Whether you want them or not, they keep running in the background and consumes battery life and power. You should keep and eye on them and if you don’t need them , turn them off.
To see which applications are running in the background, you can go to “Task manager” in windows by right-clicking on the Taskbar and choosing “Start Task Manager”. In task manager, under Processes, you can all the programs running on your laptop. You can turn them off from task manager or you can control them by using MSCONFIG command on Run window.
 
5.Use classic themes , to cut down usage of graphics .
 
6.Prefer head phones than external speakers.
 
7.Use flash drives instead of CD/DVD.
 
8.Do not over charge the battery as it reduces the battery life, charge only when the battery is indicated low by the computer.
 
9.Use the right adapter
           Ensure that the adapter you use to charge the laptop battery is an original one or one with the correct     specifications. A mismatch in the wattage could cause an overload thus damaging the laptop and the battery.
 

Source: http://vittechnocentre.blogspot.in/2012/06/tips-to-improve-laptop-battery-backup.html

Read more