hardware articles computer hardware

An Introduction To Raid – Greater Reliability ,faster, Less Costly Hard Drive Units

Posted by Arthur Fellon

What is a raid setup on a computer system?

Like anything else it depends who you talk to.

Raid hard drive systems had their acronym explained as “Redundant Array of Individual Drives “and “Redundant Array of Inexpensive Drives”. The acronym for this is the shortened
term “RAID”. What is a raid setup on a computer system?
Like anything else it depends who you talk to.

Raid hard drive systems had their acronym explained as “Redundant Array of Individual Drives “and “Redundant Array of Inexpensive Drives”. The acronym for this is the shortened term “RAID”.

Capacity, reliability and performance are all important for file servers or other computer systems when you are storing large or very important files.

It is often said that “It is not if you hard drive will fail. It is at what point in time your hard drive will fail”.

Of course if your hard drives fail even if you have backup the last bit of data which was being written onto the hard drive when the failure occurred will be lost.

You can get much greater capacities, avoid losing data from disk failure, and do all this with the RAID (the acronym for the system).

RAID can now be done with standard commercially available hard drives so the cost is now within your price range for all the benefits and peace of mind RAID will give you.

RAID can be simply explained as putting the hard drives in parallel sequence.

The host adapter (usually called the RAID system controller) sits between one higher stream (on the computer side) and several lower rate data streams (on the hard drive side). When the computer writes to the disks , the host adapter takes high stream data and breaks it into many synchronized streams , one for each of the disks in process called “Striping “. Upon reading the data the host adapter takes the data stream from each disk multiplexes the sets of data streams and coordinates sending the resulting combined set of data onto the computer.

It is all a matter of redundancy which makes RAID such a good thing in most cases.

There are six different levels of RAID functionality depending on your requirements. – the level of data security and integrity you want as well as the size of hard drive space you want.

First of RAID Level 0 which spreads the data across multiple disks. You can get a similar effect to the RAID Level 0 by having multiple disks and using the features in Windows 2000 or its successor Windows XP.

Since the data volume and rate to any specific disk is a fraction of the aggregate you will receive larger capacity and better performance from a RAID 0 setup than from any one conventional disk.

As well data can be sourced from multiple drives as once. This can be most useful in shared situations which may benefit from enhancements in speed, two examples which come to mind are game servers and peer to peer (P2P) file or music file sharing servers.

However since there is no allocation for error correction or redundancy RAID 0 is not a safe system for vital data. Data will be lost on disk failure. Only use RAID 0 in situations where you need the extended disk capacity or performance gain but not enhanced data reliability.

Secondly in sequence there is RAID Level 1.

In the same way that RAID 0 focuses solely on storage capacity and performance with no concern whatsoever on reliable data storage RAID 1, which us also called “Disk Mirroring” uses disks in pairs to save the files in a redundant manner.

Several points.

One performance may be slower as it takes time for the host adapter to send the data and for the drives to write it to disk,

Secondly a user may delete or damage files which of course will be stored in that way on both drives.

Raid 1 hence offers better reliability than RAID 0 or the conventional drive setups but does not give full security for your data or enhanced performance.

Next in sequence we have RAID Levels 2, 3 and 4.

Raid 2 adds one or more disks to hold error correction codes with which lost data can be reconstructed.

Raid Level 3 is the same as RAID Level 2 but uses a simpler code the maximum storage capacity with Raid 3 may be somewhat less.

Raid Level 4 is nearly the same as RAID LEVEL 3 but instead of “Striping “ across disks is operates at a sector level, You now have the better situation of both a simpler , less intensive demanding system and as well as good data reliability . In addition performance may be enhanced as large data blocks can be written faster due to more coordinated writing to the drives in smaller “sector” areas.

Lastly is RAID Level 5.

Raid level 5 is the same as the excellent RAID Level 4 except that instead of dedicating a single disk to storing the data the data stream is striped across all the disks. You have greater performance with greater reliability for your computer systems.
A RAID setup may take some effort and training on your part.
Base your planning for your new RAID system on a careful analysis of your needs.
What is important in your situation currently? Disk size capacities, data reliability and integrity, performance or a combination or all.

The History Of Microcomputers

Posted by William Piker

The history of microcomputers does not compare with the history of ancient Mesopotamia (Iraq). Microcomputers (now commonly held as PCs) have been around for only 25 – 30 years.
It is good to have some knowledge of this history both to give some perspective of where we are today and to know where a number of our basic computer standards that we take for granted – as if they came from heaven, originated.

The very first microcomputer machines were as exciting as a do-it yourself set – a thrill if you were the type who forever liked to tinker with things to make them work. .

Early personal computers (or micococomputers as they were first called lacked a clear standard. The computer chip makers – Intel, Motorola and Zilog - all competed in the microprocessor (CPU) in a rash of different computers from different manufactures. None were compatible with any others.

IBM’s introduction of the real IBM PC in August 1981 opened the eyes of many. IBM had scores of sales representatives with credibility who were well entrenched in corporations and businesses around the world.

The IBM sales staff – used to selling big ticker items and invoicing hundreds of thousands of dollars – well dressed in “IBM Blue “ three piece suits , were well accustomed to corporate life and power structures with the “movers and shakers” who counted .

IBM opened their own stores selling all IBM hardware as well as their own brand of software. The software had been written by third parties and adapted for the PC- DOS (IBM‘s proprietary version of the Microsoft Operating System DOS sold under license). IBM insisted that all the software be packaged in the very same standard plain white boxes with identical blue labeling.

A number of companies began to produce machines that used the MS-DOS (Microsoft DOS) operating system .In the beginning, they were similar to PC-DOS machines, but were not fully compatible – software for PC-OS would seldom run on an MS-DOS machine and vice –versa. Somewhere along the way however the 2 merged so that in the end there was little distinction between the two operating systems – IBM PC-DOS and Microsoft MS-DOS. Hence both the IBM compatible computes (clones) and genuine IBM computers would both run the same software properly.

IBM kept the pressure on with its next system release, the 6 MHz PC/AT, the first machine to use Intel’s next generation chip the 80286 CPU. .

However, these first generation ATs were plagued by frequent hard disk failures. Without any warning, a user’s disk would fail and important and essential data would be lost. The problem was so widespread that IBM clones manufacturers started to erode IBM’s market dominance.

This went on as the clone competition continually improved their products. As well PC clones were substantially cheaper than IBM’s machines, with larger hard disks (from 40 megabytes to even the unbelievable 100). Greater memory became standard, and options such as built in serial and parallel ports were added to system boards. As well clones often included displays, display adapters and software in attractively priced bundles.

The PC/AT continued to sell well, but IBM’s market share began to erode, even though it was selling more machines than ever before. Other clone manufacturers (Compaq and Advanced Logic Research for example) moved quickly on Intel’s next big microprocessor introductions.

The die was set. The IBM PC set the standards but the clone manufacturers forever dominated the market which IBM had developed and lost.

About The Author:
Bill Piker Vintage Computer Enthusiast mailto:vintagecomputermanuals@yahoo.com Blog http:www.vintageomputers.com http://www.vintagecomputermanuals.com

Why Choose A Core 2 Duo For Your CPU In Your New High End Computer ?

Posted by Art Fellon

It must have been difficult for Intel to watch AMD’s Athlon 64 and then the Athlon 64 X2 and FX pretty much take over the performance PC market, putting the once-untouchable chip giant into a position where its only competitive response was to cut prices. Those were dark days indeed. But now, with the release of the long-awaited codename “Conroe” — the Core 2 Duo and Core 2 Extreme processors — Intel looks set to start a new age of desktop domination.
Most onlookers expected Intel to take back the performance crown from AMD, but few anticipated the sheer magnitude of this victory, or the nearly flawless style with which Intel performed it. And the Core 2 Duo is just the first strike in this battle, as Intel is also planning preemptive Pentium D price drops and has revamped its single-core Pentium 4 and Celeron D lines as well.

The Conroe excels in three areas, which add up to the very definition of what a current buyer expects from a top-end desktop CPU. These factors are price, performance, and power requirements, and the 65-nanometer-process Core 2 Duo and Extreme have surpassed their AMD counterparts in each, completing the same type of triple play that AMD had turned on the Pentium 4 and Pentium D.

The question of who’s got the best performance is not even up for debate: The 2.93GHz Core 2 Extreme X6800 is the fastest desktop processor on the planet, and the 2.66GHz Core 2 Duo E6700 is not far behind. Even the next-step-down 2.4GHz Core 2 Duo E6600 is an outstanding desktop performer that can outpace AMD’s flagship Athlon 64 FX-62 in most tests.

Power and cooling requirements are also extremely low — the Core 2 Duo line offers the lowest power draw of any dual-core processor, with the Core 2 Duo Extreme not far off. Prices are also extremely competitive. In fact, it’s amazing that for such a competitive price , the Core 2 Duo E6600 can outrun AMD’s entire desktop lineup. The lower-end Core 2 Duo E6300 and E6400 models are even more affordable, although their 2MB instead of 4MB of Level 2 cache mean their relative performance isn’t as high.

Intel has accomplished this via a drastic shift away from the Pentium’s NetBurst technology. Conroe’s next-generation core performs more instructions per clock cycle (IPC), rather than having a longer and potentially less efficient pipeline that can be clocked into the stratosphere. Core 2 processors’ 2MB or 4MB of 256-bit L2 cache feature what Intel calls Advanced Smart Cache, dynamically shared between the two cores for maximum efficiency rather than chaining half the cache to each core.

With IPC levels exceeding those of AMD plus clock speeds up to 2.93GHz and a 1066MHz front-side bus, Intel has moved well ahead in the performance game despite sticking with traditional CPU and chipset architecture rather than AMD’s on-chip-memory-controller approach.

The Conroe design also reflects a need to keep power requirements and heat production down via various power-saving technologies. Since the basic architecture will be shared through all of Intel’s processor lines (except the Itanium), including upcoming mobile CPUs, this translates into very power-efficient processing.

The Core 2 Duo and Extreme processors may offer industry-leading performance, but Intel’s SpeedStep technology ensures that the chips can ramp down the multiplier and reduce clock speed to conserve battery power and/or lower core heat levels.

Moreover, new Intelligent Power Capability can go beyond slowing the CPU as a whole to turning various core functions on and off as required. These power-saving techniques don’t get in the way of outright performance, as the Conroe instantly jumps back to top speed when required.

Through the use of technical expertise obtained through advanced CPU server technology and exprertise Intel has leapfrogged once again to a combination of power , low energy use and heat production and reliability especially since with advances in CPU speed can disabling and damaging hear.

The Core 2 Duo CPUs should be a major consideration in your next high end computer purchase.

About The Author:
Mr. Arthur Fellon IT Dept Head Ace Employment Services http://www.aceemploymentservices.net Interest in Vintage Computer Technology http://www.vintageomputersystems.net http://www.vintagecomputermanuals.com

How To Properly Install A New Video Card

Posted by Otis Cooper

Your video card is one of those components in your computer you want to both learn as much about it as possible and to learn how to remove the old one and install a new card quickly.Playing those awesome games will be that much more enjoyable with one of those muscle bound video cards boosting video performance to the max.

Having the most up to date video quality is without a doubt the number three upgrade consideration. Upgrading the Hard Drive and RAM Memory are in front of all others.

Learning to remove your system unit cover,locate your video card,removing the old card so you can install a faster one can be educational and make it fun in the process.

After choosing the video card that you know is compatible with your monitor,open the system unit after the system is turned off,unplugged, and all peripherals are disconnected.

You want to stop and remove any electrical static charge your yourself by touching a metal object.This reduces the chance of damaging any chips in the computer.

You may want to lay the system unit on its side for easier access to the empty expansion bays. Locate the empty AGP Slot to insert the video card and remove the cover plate at the rear of the case with a screwdriver.

Save the screw to secure the card later.Newer motherboards are now equipped with the PCI Express slot.Check your motherboard manual if you are in doubt as to which type of slot you have

Before removing the new card from its protective wrap,ground yourself to remove any and all electrical static charge from your body.Now you can carefully and firmly inserted the card into the Accelerated Graphics Port.

Aligned the card in the port and slowly but firmly pushed the card in the AGP Port.You may use a slight rocking back and forth motion to seat the card in the port.

Check to be sure it has been pushed all the way in the slot for a solid connection.Secure the card to the case with the screw you saved from the cover plate earlier.

Check and double check your installation process before replacing the cover onto the system unit case.With the cover replaced,reconnect peripherals and turn on the computer.

The operating system should detect the new video card and install the device driver software that will allow the card to talk to the computer.A cdrom should have come with the new card with the device drivers and other useful software.

And you should now be able to experience the ultimate in crisp,clear quality graphics on your monitor.Its that easy to install and setup your video card.

The new PCI Express technology comes with some other benefits as well. For one, the amount of trace routes on motherboards are reduced by the circuitry of motherboards. When using 4 routes instead of 32 for a basic connection, the motherboard manufacturerswill no doubt favor this technology.This greatly reduces the costs of producing motherboards in the long term.

PCI Express connectors are similar in appearance and connection method to 32-bit PCI slots. PCI Express 1X slots are about the size of current modem riser,close to 1″ long.The X16 interface has 164-pins for graphics is very similar in appearance to the standard AGP port. The flexibility to adapt to PCI express devices of different bandwidths is built into the midrange X4 and X8 slots that we have seen.

The biggest impact that PCI Express has made on the desktop market is with the PCIe,the x16 graphics slot. Found in the latest Intel and AMD-based chipsets, This new technology has replaced AGP 8x as the platform of choice for graphics cards.You will want to understand the new PCI Express card as much as possible since it is the most recent video display technology.

When you purchase your next computer,forget the Advanced Graphics Port or the AGP card,be certain your new computer comes with the new PCI Express video card install.You will be glad you did especially if you love those new high resolution games they keep coming out with.

Copyright 2006 Otis Cooper

Otis F. Cooper is solely dedicated to boosting the knowledge and confidence of every computer user. Use his informative articles and videos to understand all about the PC. Read more in depth articles for pc training and repair at http://www.repairarticles.com

Keeping Your Computer Happy

Posted by Mae Paulino

Does your computer last for only a year or so, hangs every so often, and gets struck by virus most of the time? Are you giving it enough hours of rest? Is it cool enough most of the times? Can its memory handle all the applications that you use?

If you still don’t know it by now, computers are like people too! Yep, you read it right, computers may not feel like we do but it also suffers from stress that is brought by overworking and can break down if without proper care - computers, like people, also needs to be looked after to get the right productivity that you expect from it. This article aims to shed some light on how to make your computer happy and efficient that will last for a long time.

Invest on quality hardware, repairs or upgrades as well as up-to-date and original software programs.
One of the mistakes that people make is that whenever they encounter a problem with their computer like hanging and viruses is that they would usually leave it and would not perform any diagnostic tests at all. If you are one of these people, stop the habit for remember, prevention is always better than cure. We have to remember to treat our computers like we would to ourselves whenever we’re sick. We would not just let ourselves be consumed by stress… right?
Investing does not mean keeping up with what’s “the latest”, the “hippest” and the most expensive gadget the market has to offer. It’s basically just giving your computer what it needs for it to function as fast as you want it to be. One thing though, you have to make sure it’s one of the best (but still budget-friendly) so you’re not putting money down the drain.
Same goes with software programs, pirated software programs may be cheap when you bought it some where, however, the end result will make you wish you had just settled with the real thing. One of the downsides of having pirated programs is that because it’s pirated you are not given the opportunity for support as well as the freebies that is available to legal users. Another downside of using illegal programs is that because you are not given the right support, more viruses and other harmful scripts may be left unfiltered by your computer thus, causing more harm and making you shed more money for the cost of the repairs. So for me, it is better to put money out on one go rather than having to shed it one at a time due to screw ups.
Don’t forget to run tests every week.
If your computer seems as if it takes years to boot and respond even to your simplest queries, then maybe you’re not doing diagnostic tests frequently enough. Files need to be sorted accordingly to make some space for new files that you are about to create and to be able to increase the access speed; that is what Disk Defragmenter is for. It is usually bundled with several operating systems like Microsoft, utility systems like Norton Antivirus and several standalone defragmenter programs. It had to be run as often as once a week to achieve an optimum speed for your computer.
Running utility tests every week will be of big help to keep your computer virus and worm-free. Remember to keep your anti-virus programs updated to ensure that they will be able to protect your computer from the latest virus program on the web. In addition, sometimes, anti-virus programs are just not enough, and that means you have to have other software that will shield your computer from any malicious scripts and programs. Adding some pop-up blocker and spyware products won’t hurt your budget since there are several applications in the web that are free for download.

Cool it.
If you go from one task to the next without the luxury of rest, the end result would be you would be overly strain and then just breakdown. Computers are not different; you have to let it rest for a couple of hours before resuming work especially if you do not have air conditioners within your workplace. In addition to this, you must also make sure that your computer has the necessary cooling solutions to keep your computer from overheating when you have to work overtime.
Do not collect dusts.
Make sure that you clean your computer at least once in three months so that it is not only free from those pesky viruses and worms but also dust-free. The keyboard is got to be the dirtiest in all the set so I suggest that you take special notice of it. I found a very helpful article on how to clean your keyboard thoroughly and you can see it by clicking here.
Your computer is not the only thing that must be cleaned; you also have to be sure to clean your workspace everyday and your environment free from pests since they will also be responsible in destroying your computer hardware.
These are but simple tips, but if followed correctly, will provide you with a harmonious and long relationship with your computer.
Mae Paulino is a web designer for 2 years. She is currently working for Wicked Innovations - Your Quality Offshore Web Development Partner. Get the internet presence you have been dreaming for with Wicked Innovations.

Selecting a New Motherboard: A Beginner’s Guide

Posted by Michael Quarles

Are you looking for a new motherboard? With so many models available, deciding which to buy can be difficult. However, if you use this checklist, considering each motherboard feature, you should be able to find one that’s right for you.
1. Socket type: What socket type does your CPU require? A 775 for Intel Pentiums? Perhaps a 939 AMD. Start to narrow your selection with this most basic criteria, matching motherboard socket to CPU.

2. Form factor: The board has to fit your case. The size of the board is its “form factor”. An ATX form factor case will accept 12×9.6 inch boards. But a microATX requires boards no larger than 9.6×9.6. Please note that any of the smaller boards can be mounted in an ATX case.

3. RAM: You’ll probably buy a board that uses PC3200 RAM. But be aware that some older boards still on the market call themselves “PC3200 capable” but can only use it in up to two banks. Also, some boards only have two slots, rather than the more common number of three. If you need to run 3 GB of RAM, for extreme game play, you’ll need a three-slot board.

4. Front Speed Bus: It’s an oversimplification to say this number is the speed information passes through your motherboard, but it’s a good enough definition for our purposes. Faster is better, but keep in mind that speed is money, if you’re on a budget. The tops on AMD based systems is a whopping 2000MHz.

5. Video and sound on the motherboard: Do you want these two items built into the board, or would you rather buy cards and plug them in? Video on the motherboard is usually adequate, unless you’re a gamer. In that case you’ll want to forgo it in favor of the next feature.

6. AGP port: Gamers, video editors, 3-D animators, all want the best graphics card they can get, so they require an Accelerated Graphics Port. Most all boards have them, but make sure they will handle 8X or better speed, if you’ve got your heart set on a really fast card.

7. PCI slots: How many slots will you need for things like modems, capture cards, and the like? Some of the microATX boards come with only two, which may be inadequate. I favor boards with 4 or more slots, giving plenty of expansion capability.

8. Firewire: If you shoot and edit video, 1394 IEEE, otherwise known as firewire, is a necessity. If a board you’re considering doesn’t have it, figure on using one of your PCI slots for a card.

After you’ve gone through these eight items, you should be well on the way to making your selection.

Michael Quarles is the author of Building a PC for Beginners .

Graphic Cards: How To Choose The Best

Do you remember the old computing days when there were no sounds except for maybe a beep occasionally and printers making more noise than a cat on a scratching post or how about monitors that offered nothing more than a green or orange glow?

Well, I do! Thank goodness those days are nothing more than history and now we can enjoy the glow of our high resolution monitors that offers us life-like images on a daily basis. We no longer have to squint at some fuzzy displays but can enjoy almost picture perfect animation on the majority of websites.

Now, these images are nothing more than a mass of barely visible dots, known as pixels, and monitors today can display more than a million pixels but it’s up to the computer to interpret how to allocate these pixels in order to create an actual image.

This interpretation process happens on the graphics card and these cards can be upgraded. In fact, many users are tempted to look for the latest and greatest (or should I say expensive) card out there, but there is a better way for choosing just the right graphics card for the job? Here are a few helpful solutions that will help you to determine which the best graphics card for your computer is.

First, before you go out and buy the latest graphic card because you think you need it consider what you will be doing with your computer. If you don’t expect to do much more than some internet surfing, some word processing, maybe using your email or doing some chat room or forum activities. Then you most likely won’t need any additional graphics support than what will most likely be found on the motherboard with integrated graphic capabilities.

But, if you do plan to work with graphic arts or plan to play a lot of games on your computer you will definitely need to get a graphics card that has a lot of memory as well as a high-speed processor.

A tool you may wish to use is the frame rate measurement which is often a major advertising component for the different graphic cards that are available. Basically this rate refers to the measurement of frames per second or FPS which is nothing more than the rate of complete images a graphic card will display in one second. Now, High end cards will display more than 60 FPS (which by the way is more than twice the amount the human eye can process per second) and therefore provides the illusion of animation and animated scrolling.

If you are going to be doing a lot of graphic work then you will not be contented with the FPS rating. As anyone that does any 3-D imaging on the computer will tell you, FPS will actually do very little to measure the worth of a graphics card for them. In actuality 3-D images are nothing more than triangles, and graphic cards catering to the graphic artist demographic offer a rating that calculates how quickly the card can calculate the triangles and build the frame image.

One thing that really is a concern of everyone is speed. All graphic cards speed is directly influenced by their hardware. If the clock speed and bit rate are low on your computer, then the card will operate much slower than if it were high. In addition the pre-existing hardware also plays a critical role. A high- end graphics card cannot make up for an otherwise outmoded computer system, and a low end computer processor or motherboard will counteract the speed of even the fastest graphics card.

It is apparent that upgrading a graphics card is not so simple a task, and remember bigger is not always better. If you have a somewhat out of date system, it may be a useless attempt to only upgrade your graphics card, since your system most likely will work against any speed increase your card may be able to offer you. In the same way if your needs are very simple (in computing terms) then it might not be worthwhile to spend a lot of money on a graphics card that you will not use to its fullest potential. Hence it is always wise to know what you will require prior to buying, and to be fully aware of your systems hardware and software configurations prior to adding a new component to the mix.

Garry Allen is a successful Webmaster and publisher of Best-Rated-Laptops-and-Computers.info. Providing you with more information on computer technology and answering the question what’s the best rated laptop that you can research in your bathrobe on his website.

What Is Random Access Memory

Posted by Park Oskar

RAM is considered volatile storage because as soon as the power supply is stopped, the contents of RAM are lost. Hence, the data in RAM stays as long as the computer is running. RAM is much faster to read from and write to, when compared to other storage devices like hard disk, CDROM, Floppy disk etc. RAM can be both read and written; therefore, it is sometimes also called read-write memory.

There are two fundamental types of RAM:

(a) Dynamic RAM (DRAM)

(b) Static RAM (SRAM)
(a) Dynamic RAM (DRAM): Dynamic random access memory is the most common kind of RAM, which stores each bit of a data in a separate capacitor and a transistor. Capacitors tend to leak electrons, thus the need for recharging arises. Hence, DRAM, unlike SRAM needs to have its storage cells refreshed or given an electric charge every few milliseconds. This refresh requirement operation is from where dynamic RAM gets its name. DRAM is a volatile memory because it loses data when the power supply is stopped.

DRAM’s structural simplicity gives it an advantage over SRAM. It consists of only one transistor and a capacitor per bit, due to which it has very high density. SRAM, on the other hand, requires six transistors.

There are three basic types of DRAM:

(i) Synchronous DRAM (SDRAM): While all the other types of DRAM work asynchronously to the system clock, Synchronous dynamic random access memory is a type of DRAM that synchronizes itself with the microprocessor clock speed. It is a type of RAM that is twice as fast as EDO DRAM. The speed of SDRAM is rated in MHz than in nanoseconds. SDRAM chips are mounted on DIMM memory modules. These memory modules are classified according to the CPU speed that they are designed to support.

(ii) RAMBus DRAM ( RDRAM): Rambus dynamic random access memory is a type of synchronous dynamic RAM, developed by Rambus Corporation. It is a high speed memory technology, which transfers data up to 800 MHz. Since, RDRAM narrows the memory bus to 16-bit, systems get more speed by running channels in parallel. RDRAM has heatsinks to dissipate heat, which is a major issue with RDRAM. Manufacturing of RDRAM is expensive as compared to other RAMs

RDRAM memory modules (RIMM) can only be used on the motherboards specifically designed for them. A 16-bit and 32-bit RDRAM RIMMS have 184 and 232 pins respectively.

(iii) DDR-SDRAM: stands for double-data-rate synchronous dynamic random access memory. It is a type of Memory integrated circuits that are used in computers. DDR transfers data over the bus over both (rising and falling) edges of the clock cycle, doubling the data throughput over that of standard SDRAM. DDR memory runs at bus speeds up to 400 MHz. DDR memory chips are mounted on 184-pin DIMM modules. DDR SDRAM consumes less power, hence is best suited for laptops.

(b) Static RAM (SRAM): Static random access memory is the kind of RAM that holds its data without external refresh, as long the power remains applied, unlike DRAM that needs to be periodically refreshed. It is a type of memory that is faster and more reliable than DRAM (Dynamic RAM). Since, Static RAM operates on the principle of moving current, it is a volatile memory.

There are three basic types of Static RAM (SRAM):

• Async SRAM: Short for asynchronous Static Random Access Memory. It is an older type of SRAM, which works independently of the system clock, that is, asynchronous.

• Sync SRAM: Short for synchronous Static Random Access Memory. This type of memory is synchronous with the system clock. This SRAM is more expensive.

• Pipeline Burst SRAM: This is the commonly used memory. Pipeline means larger packets of data are re sent to the memory at once and is acted on very quickly. This type of SRAM can operate at bus speed higher than 66 MHz.

Park Oskar a freelancer writer for http://www.stellarinfo.com, a leading provider of data recovery software & service provider. Download recovery software Demo to recover lost, deleted or corrupted digital data.

All About Dye-Sublimation Printers

Posted by John Sollars

Dedicated photo printers differ from all-purpose printers as they are designed to print photos only, as opposed to text or graphics documents in addition to photos. They are generally compact in size and lightweight, and some models even feature batteries that allow you to print without the need for an outlet. Most photo printers, including dye-sublimation (or dye-sub) printers, are built around a thermal dye engine, though there are a few that feature inkjet technology.

For many years, dye-sublimation printers were specialist devices used in demanding graphic arts and photographic applications. The advent of digital photography led to the entry of this technology into the mainstream, forming the basis of many of the standalone, portable photo printers that surfaced in the second half of the 1990s.

The term “dye” in the name refers to the solid dyes that were used in the process instead of inks or toner. “Sublimation” is the scientific term for a process where solids (in this case, dyes) are converted into their gaseous form without going through an intervening liquid phase.

The printing process employed by true dye-sublimation printers differs from that of inkjets. Instead of spraying tiny jets of ink onto a page as inkjet printers do, dye-sublimation printers apply a dye from a plastic film. A three-pass system (featuring solid dyes in tape form on either a ribbon or a roll) layers cyan, magenta, yellow, and black dyes on top of one another. The print head on a dye-sub printer uses tiny heaters to vapourise the dye, which permeates the glossy surface of the paper. A clear coat is added to protect the print against ultraviolet light. Although this method is capable of producing excellent results, it is far from economical. Even if a particular image does not need any one of the pigments, that ribbon segment is still consumed. This is the reason it is common for dye-sub printer compatible paper packs to contain a transfer film capable of producing the same number of prints. In addition, dye sublimation inks need a paper that allows the ink to remain on the surface of the paper.

Nowadays, a number of inkjet printers on the market are capable of deploying dye-sublimation techniques. The cartridges in such printers spray the ink, covering the page one strip at a time. The print head heats the inks to form a gas, controlled by a heating element that reaches temperatures of up to 500° C (higher than the average dye sublimation printer). A big difference in the results with dye-sublimation technique is that because the dyes are applied to the paper in gas form, they do not form distinct dots with a hard edge like inkjet printers. Instead, the edges are softer and blend into each other easily. Additionally, the infusion of the gaseous dye into the paper yields a more colour-fast picture.

Comparing Dye-Sublimation Printers and Inkjet Printers
Although it is difficult to point out every possible advantage and disadvantage when comparing inkjet and dye-sub printers, the following list mentions the major points that apply to most people printing photos at home.
Advantages of Inkjet Printers over Dye-Sub Printers:
· Prints are very precise with sharp edges
· Latest models offer incredible detail that exceeds most dye-sub printers
· Variety of papers/surfaces available—including matte, luster, glossy.
· Not locked in to one manufacturer’s paper
· Some archival inkjets can produce prints that long-lasting
· Most inkjets can print on many different surfaces that are designed to accept ink, including CDs, CD inserts, envelopes, etc.
· Inkjets have a considerably larger colour gamut and usually produce more vivid photos than dye-subs
· Easier to obtain large format inkjets that can print 11×14, 13×20 sizes, or larger
· Inkjet printing is often cheaper than dye-sub printing
Inkjet Printer Disadvantages:
· Often much slower than dye-sub printers
· Most non-archival inkjets produce prints that fade a little (sometimes a lot) faster than dye-sub prints
· Print heads sometimes clog and require cleaning, or even replacement

Advantages of Dye-Sub Printers over Inkjet Printers:
· Very fast
· Relatively maintenance-free
· Smooth with no dot patterns visible, even under magnification
· Produce excellent shadow detail in dark areas where some inkjets may be “blotchy”
· Prints are usually more durable and more waterproof than inkjet prints
· For many viewers, dye-sub printers produce photos that look and feel more like real photographs due to the smoothness of the prints and the absence of visible dot patterns
Dye-Sub Printer Disadvantages:
· Consumer level models often smear high contrast edges (like a black square on a white background) to some degree, making charts, graphs, and line art look a little less “precise”
· Dye-sub prints typically only last as long or slightly longer than a good non-archival inkjet printer and are generally not considered “archival”
· Paper type selection is very limited and while dye-sub printers produce excellent glossy photos, most fall behind or do not even offer the option of matte prints
· Dye-sub printers use an entire page and an entire page worth of ribbon even to print one small wallet size photo
· Pages cannot be normally fed through the printer twice to fill more of the page as they can in inkjets
· Dust can sometimes get inside and cause vertical scratches on prints
· Dye sub printing and the cost of paper and toner (ribbon) is often higher than inkjet printing

Few Popular Models of Dye-Sublimation Printers

Canon Selphy CP710
Dye-sub printer for 150×100mm photographs

Samsung SPP-2040 photo printer
Dye-sub printer with 300×300dpi resolution

Samsung SPP-2020
Digital photo printer that produces 100×150mm snapshots

HiTi Photo Printer 641PS
Dye-sub printer for 152×102mm photographs

Sony PictureStation DPP-FP30
A user-friendly dye-sub photo printer

Kodak EasyShare Printer Dock 6000
A dye-sublimation printer for compatible Kodak cameras

Kodak EasyShare Printer Dock 6000
A dye-sublimation printer for compatible Kodak cameras

Olympus P-10 Digital Photo Printer
A dye-sublimation printer that prints straight from your Olympus digital camera

Polaroid PP46d photo printer
A dye-sub photo printer

Olympus P-440
Dye-sub printer capable of printing A4 photographs

Sony DPP-EX50
Dye-sublimation photo printer

John Sollars is the managing director of Solar Electronics, which are both ink and fax toner suppliers based in Shropshire, UK. To access a comprehensive online shop of original and re-manufactured printer ink cartridges including products by Canon please visit http://www.stinkyinkshop.co.uk/acatalog/Canon_Inkjets.html

What Is Optical Disk?

Posted by Park Oskar

Optical Disk
Optical disk is an electronic data storage medium from which data is read and written to by using a low-powered laser beam. It is flat, circular, plastic or glass disk on which data is stored in the form of light and dark pits. The laser beam reads the pits and the data can be accessed. There are three basic types of optical disks:

• Read-only optical disks: The optical disks, which are recorded at the time of manufacture and cannot be erased. CD, CD-ROM, DVD-ROM, and DVD-Video are the read-only disks.

• WORM: WORM stands for write-once, read many. The optical disks that can be recorded by the user only once but cannot be erased. After they have been recorded once, they behave like a read-only optical disk CD-R, DVD-R, and WORM disks are write-once.

• Rewritable/Magneto-optic disks: The optical disks that can be erased and written to with the new information. CR-RW, DVD-RAM, DVD-RW, and magneto-optic disks and Data play are rewritable. Rewritable disks use magneto-optic or phase change technology.

An optical disk offers many advantages over magnetic storage media.

• Highest storage capacity
• Low cost per Megabyte of storage
• Environmental condition tolerance
• High data stability
• Long media life

An optical disk has much more storage capacity on the order of gigabytes, than a magnetic disk. It can hold up to 6GB of data in comparison to 1.44 MB of a diskette. Optical disks are inexpensive to manufacture. Data stored on optical disks is resistant to power surges or magnetic disturbances, such as head crashes or corruption form stray magnetic fields. Hence, they provide high data stability. Optical disks are less vulnerable to extremes of hot and cold as compared to the magnetic disks. Optical disks have long media life than magnetic disks.

OPTICAL STORAGE DEVICES
CD-ROM

CD-ROM: is an abbreviation of Compact Disc Read-Only Memory. A CD-ROM is a CD that contains computer data, which cannot be read or rewritten. In computers, CDROM is the most commonly used optical storage technology. CD-ROM is a compact disc that contains information, which is accessible by a computer. It is composed of polycarbonate plastic, thin reflective metal layers, made of aluminium and a lacquer coating. Data is stored on the disc as a series of light and dark pits; the light portion refers to the spaces between the pits. A laser beam reads the pits and the data can be accessed.

CD-ROM is an adaptation/EXTENSION of the compact disc that is designed for music storage and playback. The format of CD-ROM is very similar to an audio CD; the only difference being the standards used to store data. A standard 120 mm CD-ROM holds up to 700 MB of data, or about 70 minutes of audio. This may mean that One CD can contain over one thousand novels; an average novel being composed of 60, 000 words. Once the data is written to a standard CD-ROM disc, it cannot be altered or rewritten.

A CD-ROM can be read using a CD-ROM drive, which is almost common on the personal computers. A CD-ROM drive may be connected to the computer in several different ways depending on the type of interface, such as:

• IDE (ATA)
• SCSI
• SATA
• Firewire
• USB

Almost all modern CD-ROM drives can play audio as well as video CDs.

CD-ROM STANDARDS

CD-ROM format provides an outstanding solution to the problem of storing large digital files. Several formats are used for data stored on CD-ROMs. These include Red book standards for audio-CD, White Book and Yellow Book for CD-ROM. An ISO 9960, which defines the standard file system of a CD-ROM is due to be replaced by ISO 13490.

CD-ROM FORMAT

One CD-ROM sector contains 2352 bytes, which is further divided into 98 24-byte frames. A CD-ROM contains a third layer of Reed-Solomon error correction in order to achieve improved error correction and detection.

Mode-1 CD-ROM: It has full three layers of error correction data, which contains 2048 bytes of the available 2352 per sector. Mode-2 CD-ROM: It is mostly used for video files, which contains 2336 user-available bytes per sector.

CD-ROM SPEEDS AND USES

+ Early CD-ROM drives were known as single-speed and could read the data at the speed of 150 KBps.

+ CD-ROM drives can transfer data up to the speed of 7800 KBps

+ CD-ROM can store audio, video, text and program instructions. It is used to store software programs.

DVD-ROM

DVD-ROM: is an abbreviation of Digital Versatile Disc- read only memory. DVD-ROM is an optical disc storage media format that can be used for data storage, which includes movies with high video and sound quality. DVD-ROM is a non-volatile optical storage medium similar to CD-ROM, which contains computer data that cannot be erased or rewritten. These DVDs are read-only disks that have storage capacity for 133 minutes of high quality video, in format, and audio full- length feature film. The discs are pressed in a similar fashion as the CDs. The reflective surface is gold or silver colored.

DVD-ROM can be accessed using a DVD-ROM drive attached to the personal computer. DVD-ROM drives are backward compatible, i.e. they are also capable of reading CD-ROMs and audio CDs as well. The DVD-ROM supports disks with capacities of 4.7 GB to 17 GB and access rates of 600 KBps to 1.3 MBps. A standard DVD disc store up to 9.4 GB of data. DVD-ROMs are of same size as a compact disc, but holds data about 7 times more. DVD can store that much of data because both the sides of a disc are used, with sophisticated data compression technologies.

DVD-ROM is a variation of CD-ROM that is being used in place of CD-ROMs in many personal computers. All DVD-ROMs contain a file system, UDF, which is an extension of the ISO 9660 Standard used for data CDs.

CD-RW

CD-RW is an abbreviation of compact disc-rewritable. It is a recordable CD format that can be erased and rerecorded multiple times, just like a floppy disk or a hard disk. It is a rewritable version of CD-ROM. CD-RW disc is round plastic, about 5 inches in diameter. CD-RW disks can be played or recorded in the CD-RW drive only. These disks behave unusable when put in a regular CD-drive or a CD-R drive cannot be played. A CD-RW drive can read everything except a DVD.

A CD-RW can hold 650 Megabytes of data (unlimited number of times) written by a CD-RW drive. CD-RW cannot be selectively overwritten but can be extended. CD-RWs must be closed before they can be read in a normal CD-ROM drive. CD-RW disks cannot be read using a CD-ROM drive built before 1997. CD-RWs can be randomly read and written because of the variation of UDF format. CD-RW disks and drives are more expensive than a regular CD-ROM drive or media. A CD-RW disc can be read optically by laser light.

DVD-RW

DVD-RW: stands for Digital Versatile Disk-Rewritable. It is a re-recordable optical disc, which can record up to 4.7 GB per side in a similar fashion to a CD-RW. DVD-RW supports sequential read/write access i.e. the device may need to wait for the correct location in a constantly revolving medium. The information stored on DVD-RW can be erased and rerecorded over multiple times without damaging the medium.

DVD-RW is a phase-change erasable format based on DVD-R, using similar mark length, track pitch and rotation control. The format is supported by the DVD Forum. DVD-RW is also called “DVD Dash RW” and “DVD Minus RW”.

DVD-RW can be played in many DVD drives and players. Depending on quality, recording time varies from 1 hour to 6 hours.

If these optical disk gets damaged then the stored data becomes in accessible, these lost or damaged data can be recovered by usinig Stellar Phoenix CD Data Recovery Software

About Authur
Park Oskar a free lancer writer for http://www.stellarinfo.com, a leading provider of data recovery software & Services provider. Download recovery software Demo to recover lost, deleted or corrupted digital data.