Dual core Processing [ Dual Core Vs Core 2 Duo ]

Welcome to the horrible naming convention by Intel having duo , dual and the numeral 2 confusing geeks and nerds and would definitely confuse many of us , however I have kept it straight explained the dual core processing before we differentiate Intel's processors . Hope this helps !!!

DUAL CORE PROCESSING

Dual-core refers to a CPU that includes two complete execution cores per physical processor. It combines two processors and their caches and cache controllers onto a single integrated circuit (silicon chip). It is basically two processors, in most cases, residing side-by-side on the same die.

Dual-processor (DP) systems are those that contains two separate physical computer processors in the same chassis. In dual-processor systems, the two processors can either be located on the same motherboard or on separate boards. In a dual-core configuration, an integrated circuit (IC) contains two complete computer processors. Usually, the two identical processors are manufactured so they reside side-by-side on the same die, each with its own path to the system front-side bus. Multi-core is somewhat of an expansion to dual-core technology and allows for more than two separate processors.

Taking Advantage of Dual-core Technology
A dual-core processor has many advantages especially for those looking to boost their system's multitasking computing power. Dual-core processors provide two complete execution cores instead of one, each with an independent interface to the frontside bus. Since each core has its own cache, the operating system has sufficient resources to handle intensive tasks in parallel, which provides a noticeable improvement to multitasking.

Complete optimization for the dual-core processor requires both the operating system and applications running on the computer to support a technology called thread-level parallelism, or TLP. Thread-level parallelism is the part of the OS or application that runs multiple threads simultaneously, where threads refer to the part of a program that can execute independently of other parts.

Key Terms To Understand Dual-core
Dual-core :
Dual-core refers to a CPU that includes two complete execution cores per physical processor.
CPU
The CPU is the brains of the computer. Sometimes referred to simply as the processor or central processor, the CPU is where most calculations take place.
Processor
Short for microprocessor or CPU.
Ic
Another name for a chip, an integrated circuit (IC) is a small electronic device made out of a semiconductor material.

Even without a multithread-enabled application, you will still see benefits of dual-core processors if you are running an OS that supports TLP. For example, if you have Microsoft Windows XP (which supports multithreading), you could have your Internet browser open along with a virus scanner running in the background, while using Windows Media Player to stream your favorite radio station and the dual-core processor will handle the multiple threads of these programs running simultaneously with an increase in performance and efficiency.

Today Windows XP and hundreds of applications already support multithread technology, especially applications that are used for editing and creating music files, videos and graphics because types of programs need to perform operations in parallel. As dual-core technology becomes more common in homes and the workplace, you can expect to see more applications support thread-level parallelism.

Core 2 Duo

Core 2 Duo microprocessor family, was introduced on July 27, 2006. The Core 2 Duo processors include two cores, each core having 32 KB L1 data and 32 KB L1 code caches, and both cores having shared 2 or 4 MB L2 cache. The Core 2 Duo CPUs run at lower frequency than Pentium 4 processors, but they offer excellent performance due to more efficient architecture:

Each processor's core can execute up to 4 instructions per cycle.
Shared L2 cache allows the same copy of data to be used by both cores. Another advantage of shared L2 cache is that more heavily loaded core can use bigger portion of L2 cache - up to the full size of the cache.
Core 2 Duo architecture includes other performance enhancing features. One of these features is a "macrofusion". This feature allows the processor to load and execute common instruction pairs as one instruction.

Overall, despite of lower processor frequency, the performance of Core 2 Duo family is much higher than the performance of Pentium 4

Final Say Made simpler

Core 2 Duo , Dual Core , Pentium D explained :

Dual core is simply a generic term referring to any processor package with two physical CPUs in one.

Core 2 Duo refers to a CPU that includes two complete execution cores per physical processor. It combines two processors and their caches and cache controllers onto a single integrated circuit (silicon chip).

The Pentium D, Dual Core, Core 2 Duo and Athlon X2 are all current CPUs that have dual cores in one package.

Pentium D : The Pentium D is simply two Pentium 4 Prescott cpus inefficiently paired together and ran as dual core.
Dual Core ( aKa Core Duo ) :
> Dual Core is the Intel's first generation dual core processor based upon the Pentium M made mostly for laptops (though a few motherboard manufacturers have released desktop boards supporting the Core Duo CPU), and is much more efficient than Pentium D .
Core 2 Duo :
> Core 2 Duo is the Intel's second generation (hence Core 2) processor made for desktops and laptops designed from the ground up to be fast while not consuming nearly as much power as previous CPUs.

What's the difference ???????

Dual Core : Each core has its own cache

Core 2 Duo : Both cores having shared 2 or 4 MB L2 cache

Prefetching Myths ( Funny, It Worked Last Time - odd mutterings of a performance junkie )

One more time: do not clean out your Prefetch folder!

Yet another Web site posted yet another “tip” today recommending that you clean out your Prefetch folder to improve performance of Windows . Researchers are repeatedly writing about it that clearing the prefetch is no way to improve the performance of the machine but it seems that this bogus advise doesnt seem to end !!!

Ryan Myers, a developer on Microsoft’s Windows Client Performance Team says that 

“Misinformation and the Prefetch Flag”

" XP systems have a Prefetch directory underneath the windows root directory, full of .pf files — these are lists of pages to load. The file names are generated from hashing the EXE to load — whenever you load the EXE, we hash, see if there’s a matching (exename)-(hash).pffile in the prefetch directory, and if so we load those pages. (If it doesn’t exist, we track what pages it loads, create that file, and pick a handful of them to save to it.) So, first off, it is a bad idea to periodically clean out that folder as some tech sites suggest. For one thing, XP will just re-create that data anyways; secondly, it trims the files anyways if there’s ever more than 128 of them so that it doesn’t needlessly consume space. So not only is deleting the directory totally unnecessary, but you’re also putting a temporary dent in your PC’s performance. "

Bottom line: You will not improve Windows performance by cleaning out the Prefetch folder. You will, in fact, degrade Windows performance by cleaning out the Prefetch folder. 

WHATS THE MYTH ( ITS NOT WHAT IT LOOKS LIKE AND WHAT YOU THINK LIKE !!!! )

Scenario 1 :

As you boot your notebook or access programs on your notebook/desktop, XP’s prefetcher copies portions of those files to the Prefetch area of your hard drive --- THIS IS WHAT YOU THINK !!!!! That’s completely wrong.

What happens : 

The files in the Prefetch folder contain lists of pages that that should be loaded when a program starts. Each file is essentially an index. Windows XP doesn’t copy portions of any files to the Prefetch folder. 

Scenario 2 :

When your desktop/notebook boots, XP prefetches portions of the files you use most frequently and has any application you’ve recently run waiting and ready to go ---THIS IS WHAT YOU THINK !!!!! This is equally absurd.

What happens :

 If this were true, it would mean that Windows was actually loading into memory every program you’ve ever used, every time you start Windows. That’s not the way it works at all. When your PC starts up, Windows looks in the Prefetch folder to determine how best to load Windows. It doesn’t do a thing with the .pf files for applications (unless, of course, you’ve configured one of those apps to start up with Windows).

The .pf files don’t get used at all until you run a program. What actually happens when you click an icon is that Windows uses the information in the Prefetch folder to decide which program segments to load and in what order to load those pages.

Scenario 3:

The drawback to prefetching is that XP will prefetch a program even if you use it only once or twice. XP will retain a copy of a portion of it in the Prefetch folder. From there, it will prefetch the program, taking resources from your workstation even though you may have no intention of ever using the program again---THIS IS WHAT YOU THINK !!!!! Think ALIKE

What happens :

When you run a program, Windows creates a .pf file for it in the Prefetch folder. When you run the program again, Windows looks for this .pf file and uses it to determine how to load the program. The hash doesn’t contain any portion of the original program code. If you never run the program again, that .pf file never gets used, and in fact it gets deleted eventually.

Cold boot disk encryption attack ( aKa RAM HACK )

** This information is certainly not to teach how a cold boot hack could be done , however letting ourselves know how hacking technology is rapidly spreading from a device to device is not harmful .

** Source : Princeton University ( NewJersey , United States ) 

Cold boot disk encryption attack is shockingly simple and effective

It's an old adage that no security measure is worth anything if an attacker has physical access to the machine, but things like heavy-duty disk encryption are supposed to at least slow things down. 

Sadly, that may not actually be the case, as a group of Princeton researchers has just published a paper detailing an exploit that requires little more than a spray duster and a screwdriver. Since the encryption key for systems like BitLocker and FileVault lives in RAM, all an attacker has to do to get it is cool the RAM modules with the air duster held upside down, yank the DIMM, and insert it into another machine, where it can then be read to access the key. Of course, this assumes that you've already typed in your password, but check the video after the break to see how long bits in RAM stay written -- even if you've turned off your computer, there's a chance the key can still be read. Looks like there's an actual benefit to MacBook Air's soldered-in RAM after all, eh?

Watch it Here :) 

Abstract :

Contrary to popular assumption, DRAMs used in most modern computers retain their contents for seconds to minutes after power is lost, even at operating temperatures and even if removed from a motherboard. Although DRAMs become less reliable when they are not refreshed, they are not immediately erased, and their contents persist sufficiently for malicious (or forensic) acquisition of usable full-system memory images.

This phenomenon limits the ability of an operating system to protect cryptographic key material from an attacker with physical access. We could use cold reboots to mount attacks on popular disk encryption systems — BitLocker, FileVault, dm-crypt, and TrueCrypt — using no special devices or materials.

The extent and predictability of memory remanence and report that remanence times can be increased dramatically with simple techniques.