COMPUTER SCIENCE ONLINE: October 2008

Monday, October 27, 2008

Disable or Enable Auto run CD in Windows XP Tips

In windows XP you can enjoy a good feature to run CD or DVD automatically when you loaded it into you CD drives on your computer. This is a defaults feature in windows XP but you can disable and enable it according to your nature of work. In user interface mode there is no option to disable or enable this feature, you must edit the registry of windows and be careful to work registry.

Click Start button then type regedit in Run option then press Enter for next.

Here locate the location to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Cdrom

Here you can disable or enable automatically running your CD. Change the value of Autorun to 0 for disable and change the value to 1 for enable. At the end restart your computer for this change.

USB

USB 2.0 - Hi-Speed USB - FAQ

What is USB 2.0?
USB 2.0 is a complete overhaul to the Universal Serial Bus input/output bus protocol which allows much higher speeds than the older USB 1.1 standard did.

USB 1.1 allowed a maximum transfer rate of 12Mbits/second. That rate is now called 'USB.' Though some manufacturers label their products Full-Speed USB. Note that this seems a bit deceptive. Its easy to mistake Full-Speed for Hi-Speed.

As an aside, USB mice and keyboards need only 1.5Mbits/s to function. That performance level is also named 'USB' by the USB Promoter Group.

To sum it up, USB 2.0 specification incorporates three speeds: Hi-Speed, Full-Speed and Low-Speed. You as a consumer don't need to figure out all the jargons. Just keep in mind that only 'Hi-Speed USB' and 'USB' host and devices exist.

How do I know if my PC has USB 2.0?
You can identify whether your PC has Hi-Speed or not relatively easy. Open Device Manager and expand the Universal Serial Bus section. There should be an "Enhanced" USB host controller present.

Windows 98 systems may use a different name, because Hi-Speed USB drivers in these operating systems are not provided directly from Microsoft (Windows ME, 2000 and XP get their drivers through Windows Update).

These drivers are provided by the manufacturer, and may carry the maker's name (i.e. ADS, Belkin, IOGear, Siig, etc.). There should also be two standard version USB host controllers present as well. They are embedded in the USB chip which routes the differing USB speeds accordingly without user intervention.

There are currently 6 manufacturers of the Hi-Speed USB host silicon themselves:

ALi (Acer Labs)

Intel

nVidia (shows as "Standard" controller

Any other brand name that appears in Device Manager would likely be an add-in Hi-Speed USB PCI card. The makers above do not make add-in cards, but they do make the chips that are used in them.

How do troubleshoot "unknown device" error listed in Device Manager?

The USB device or the USB adapter requires its own power source. If your USB device or adapter came with an AC power "brick", try connecting it.

Here's a likely one - the front USB ports on your PC case may be misconnected. I've seen them that way from the factory. It's a good idea to check the connections against specifications. The standard order of connection is Red, White, Green, and Black. No more than 4 wires per USB bank are needed.

Defective device. Do not assume that all PC components work correctly out of the box. I've seen many new USB devices that do not work. If you can, try the device on another PC.

All drivers are not installed. Some devices will require installing the driver package before plugging in the device. Some devices will also require basic USB files from the Windows CD before the unit will function. The general rule is to always follow installation directions precisely and to have the Windows CD ready.

How fast is USB 2.0?
USB 2.0 has a raw data rate at 480Mbps, and it is rated 40 times faster than its predecessor interface, USB 1.1, which tops at 12Mbps. Originally, USB 2.0 was intended to go only as fast as 240Mbps.

How will consumers benefit from USB 2.0?
With speed 40 times more than that of USB 1.1, USB 2.0 broaden the range of external peripherals that can be used on a computer. Even with multiple high-speed peripherals connected to a USB 2.0 bus, the system will less likely to hit the bandwidth bottleneck. The new specification also inherits the current USB's Plug and Play and hot-swapping capability as well as providing backward compatibility for USB 1.1 hardware, allowing existing user base to upgrade seamlessly.

Do USB 2.0 & USB 1.1 hardware work interchangeably?
You may have heard that USB 2.0 is "backward-compatible" with USB 1.0/1.1 (Full-Speed USB). While that's true, USB 1.1 is also forward-compatible with USB 2.0. Whenever a system has USB 2.0 ports, you'll find the "Enhanced" USB controller in Device Manager, but you will also find two other USB controllers. These two to maintain backward compatibility to USB 1.1 devices. Each USB 2.0 host actually has 3 chips onboard. The USB controller routes signals to the correct controller chip depending on how a device is recognized. Where a device is physically plugged in has no bearing on how it is routed. All ports on a USB 2.0 motherboard can host any USB devices at all as long as the system and devices are healthy.

The vast majority of USB 2.0 devices will work on older PCs and Macs. None should flat-out fail unless there are other issues with the system. Hi-Speed USB devices will revert to Full-Speed operation when connected this way. Understand that Hi-Speed is at least ten times faster than Full-Speed in actual operation, so the speed difference is quite noticeable - unless you have never experienced Hi-Speed, of course.

When it comes to USB hub compatibility between USB 2.0 and USB 1.1, here some facts:

A powered hub is always preferable to unpowered.

USB hub ports are not as capable or flexible as real PC ports so it's best not to expect the world of them.

USB 1.1 (obsolete) hubs will work fine on USB 2.0 ports, but they cannot utilize USB 2.0 capabilities. They will default to slower speeds.

Hi-Speed and Full/Low-Speed USB devices can coexist nicely on USB 2.0 hubs. Connecting such a hub to a USB 2.0 port is recommended.

USB 2.0 hubs can be used on older USB 1.1 computers.

Although it is said that you can "cascade" up to 4 hubs, problems may start to arise after two hubs, it's best to minimize hub usage if possible.

Many USB devices don't work well on hubs. Cameras, scanners and especially USB drives are known to have problems with hub connectivity.

Remember that "active USB extensions" are really just one-port hubs.

Will USB 2.0 replace USB 1.1?
Not entirely, because many products such as generic keyboards, mice, joysticks and audio speakers do not require the faster speed of the new USB 2.0 technologies. Only bandwidth-hungry devices, such as web cams and high-capacity storage systems, will need all the speed. However, next-generation systems will come with USB 2 ports rather than USB 1.1.

How do I distinguish between a USB 2.0 and a USB 1.1 devices? New logos designed by the USB Promoter Group allow consumers to easily identify the new USB 2.0 products. The new colorful logo for USB 2.0 is labeled USB Hi-Speed, and the new logo for USB 1.1 is labeled with USB Basic Speed. However, most people won't miss it as manufacturers often label USB 2.0 READY Or 40 times faster than USB 1.1, on the boxes.

Will USB 1.1 devices run any faster on a USB 2.0 bus?
No. However, the new USB 2.0 archiclecture allows more high-speed USB 1.1 devices, such as web cams, audio devices, to share the bandwidth. Developers need to follow USB 2.0 spec in order to design higher speed peripherals that can take advantage of the extra bandwidth. USB 1.1 devices still operate at 12Mbps at full-speed and 1.5Mbps at low-speed on a USB 2.0 bus. Even though USB 1.1 devices won't run any faster, they can work alongside of USB 2.0 devices on the same bus.

What are USB Hi-Speed and USB Basic Speed logos?
These logos are part of USB Promoter Group's branding program that ensures the quality of USB products. The USB 2.0 certified products would display a blue, white and red logo, bearing the words Certified and Hi-Speed. The classic USB 1.1 certified products would display a black and white logo with the words USB and Certified.

Under a license from USB-IF, products must pass the compliance tests before manufacturers can use one of the two trademarked logos. The Promoter Group will take legal actions on manufacturers that label either logo on their products, which have not passed the tests.

What happen if a USB 2.0 devices are plugged into a USB 1.1 systems?
The entire bus under the USB 1.1 root hub will slow to 12Mbps. The operating system will probably notify the user about the sub-optimal configuration and recommend for a better course of action.

If several USB 1.1 hubs are connected to a USB 2.0 bus, then each of the USB 1.1 hubs will get a full 12Mbps bandwidth.

What is the max? Length of a USB 2.0 cable?
5m. however, if you cascade 5 hubs with 5m USB cables, this will allow you to connect a device 30m away.

What do I need to use a USB 2.0 device?
The requirement is similar to that of USB 1.1, but all components will have to be USB 2.0 compliant. A successful USB 2.0 connection requires a USB 2.0 host controller card, a USB 2.0 driver and a USB 2.0 peripheral.

How much will it cost to upgrade to USB 2.0?
Around $80 to $150. Currently, Orange Micro., Adaptec and IO Gear are shipping USB 2.0 PCI cards, some of which even have FireWire ports. Interestingly, almost all USB 2.0 PCI cards include an internal port, which is probably for connecting internal USB 2.0 IDE enclosure or USB 2.0 front panel.

Will USB 2.0 arrive on mobile computers?
Yes, but not in integrated solution on laptops. You will need a USB 2.0 Card Bus card. Orange Micro. is shipping USB 2.0 compliant 4-port Card Bus card. Eventually, notebook vendors will adapt to USB 2.0 technology, and we will see USB 2.0 ports on laptops. This transition won't happen until 2002 at the earliest.

Which operating systems support USB 2.0?
Microsoft has released the official USB 2.0 driver for Windows XP and Windows 2000. The version is 5.1.2600. The software is available on-line at Windows Update website. (If you don't have a USB 2.0 card installed in your system, Windows Update won't list the USB 2.0 driver as an update.)

The software company is still considering USB 2.0 support for Windows ME, but it already has decided not to bring USB 2.0 to Windows 98 and Windows 98 SE. If you have Windows 98, you will have to rely on 3rd party USB 2.0 support from USB card manufacturer.

Do USB 1.1 cables work with USB 2.0 devices?
Ideally, yes. USB 2.0 architecture uses the same cables and connectors as USB 1.1 compliant products. Unfortunately, only 3 out of 11 cables on the market are certified as USB 1.1 compliant. You may run into the cables that cause problems connecting high-speed peripherals. To avoid negative user experience, most vendors include USB 2.0 compliant cables with their USB 2 PCI cards and peripherals.

Speed up the Start Menu Tips

If you are still working with old or slow computer but don't worry, you can give surprise to your friends with some changing in windows registry. Edit your computer registry keys to speed up your computer start menu, because the default speed of start menu is slow. After these changes your computer start menu will response like latest computer.

Follow the given steps to change the speed of Start Menu.

First click on Start button then type Regedit in Run option.

In Registry Editor panel go to the path:

HKEY_CURRENT_USER \ Control Panel \ Desktop \ MenuShowDelay

By default the value "MenuShowDelay=400", but you can set value between 0 to 400. Now put the value "MenuShowDelay"=0 to speed up.

Now close the registry editor and restart your computer after any changes to go into effect.

Safer Registry Editing Tips

Make sure before modifying your system Registry about its backup and you need to know how to organized the registry, how to perform the basic editing, because Registry contains all information how your system runs. This backup will help you to restore Registry in case any problem occurs after modifying. Learn how you can Export and Import Registry File before Editing?

You can backup the whole Registry and only Registry subkeys also.

Click Start Button then type regedit in Run dialog box and click Ok button. Here you can backup the whole Registry or you can locate the required subkeys that contain the information that you want to edit.

Go to File menu option then click on Export option for backup and save it with on any your system drive with .reg extension and you can restore this backup going File menu using import option.

Disable drives in My Computer from unknown user Tips

If you want to prevent any users to access your computer or network shared drives using My Computer then you can hide the all drives for example C:/, D:/ and save your data from any unknown user. But next time you can turn on the display of these drives using registry editor. Now edit the computer registry to turn off the display of drives, but be careful to work with computer registry.

Follow the given steps to hide computer drives:

First click on Start button then type Regedit in Run option.

Here locate the location to:

HKey_Current_User \ Software \ Microsoft \ Windows

\ Current Version \ Policies \ Explorer

Here right click on right side of Registry editor panel and add new DWORD then put its value 3FFFFFF.

Now close the registry editor and restart your computer after any changes to go into effect.

Control all open windows using windows shortcut keys Tips

nA cool tip to minimize and maximize all your active windows programs. You can do all using your mouse, but if you want to do this with keyboard then simply press Windows key+M to minimize all active programs and later maximize it using Windows key+Shift+M.

If you want to minimize the all active windows programs one by one then use the shortcut by pressing Alt+Space+N keys and sequentially maximize the active windows programs using shortcut Alt+Space+X keys.

Change The Recycle Bin's Name Tips

You can change the name of Recycle Bin of your system if you wish. It is very easy and interesting but it require some changes in windows registry,

First click on Start button > click on Run option.

Type here regedit.exe and press enter then you will find there regedit editor.

In regedit editor you will open HKEY_CLASSES_ROOT folder, In this folder open the CLSID folder then open the {645FF040-5081-101B-9F08-00AA002F954E} folder >ShellFolder folder at last.

Here simply change the data value from "40 01 00 20" to "70 01 00 20".

After performing all above steps restart your computer then you will find option to rename Recycle name after right clicking on Recycle Bin Icon. Now you can change new name as you wish.

Database Tips

What is database?

A database is a collection of related data stored in an efficient and compact manner. The word “efficient” means that stored data can be accessed very easily and quickly.

Similarly, the word “compact” means that stored data takes up as little space as possible. In the above definition of database, the phrase “related data’ is used. It means that a database contains data or information about a particular topic such as:

Database of employees that contains data of employees of an organization or department.

Database of students that contains data of students of college or university.

A database holds related data as well as description of that data. For this reason, a database is also defined as a self describing collection of integrated records. The description of data is known as the system catalog or data dictionary or metadata. For example when a table of a database is designed, the data type, size, format and other descriptions of fields are specified. This is an example of metadata, which describes the properties of data to be stored into fields of table.

The data of any organization is its integral part. The data is very important for developing new products and their marketing. The data must be accurate and available when needed. This is the reason that all organization must organize and manage their data into database. The databases are used for variety of purposes in as organization. For example, when you purchase goods from your local supermarket, the checkout assistant will pass the purchased product through a scanner device known as bar code reader. This device will read the bar code printed on the product and gives the accurate price of the item. Actually, the bar code reader is accessing the database, which contains the information about the products. The bar code reader is linked to a database application program, which uses the bar code to access price of item. The database program automatically updates the database. The assistant can also check whether a required item is in stock by running the database application program. Similarly, you can purchase goods using your credit card. Your credit is checked by a card reader linked to a computer system. In this case, there is a database somewhere that contains information about your credit. Almost all organizations and government departments of every country in world use database to maintain their records. Some examples of large databases that have been developed around the world are:

When you draw amount from bank through ATM card, you are accessing the database; your account is accessed and checked through auto teller machine. When you draw some amount from your account, your record in the database is automatically updated immediately.

When you visit your local library, there may be a computerized database containing details of the books in the library. There will be a computerized index, which allows you to find a book based on its title, its author’s name etc.

The meteorological organization contains databases having information about current and previous meteorological data. The meteorological department is totally dependent on the meteorological data.

A database may be generated and maintained manually or it may be computerized. The library card catalog is an example of a database that is created and maintained manually. On the other hand, a computerized database may be created and maintained either by using application program, which is developed specifically for that purpose or by a database management systems.

Browsing Your Computer via the Address Toolbar Tips

Here is a very cool tip to open your system drive and web page quickly. You can open any web page without opening browser, windows will automatically open your windows browser and open your web page. you can do this if you put an Address Bar on your Taskbar.

Right click on your system taskbar > go to Toolbars and then click no Address option, here you will see a mark on Address option. After this a Address Bar will appear on your system Taskbar, you can open any web page by typing URL name here and press Enter, Windows will automatically open your web page in be default set browser.

You can also browse files and folders on your computer by using the Address Bar. simply type drive letter like C:\ , D:\ in Address Bar and Press Enter.

C:\

WiMAX

WiMAX Wireless Broadband Info

WiMAX stands for World Interoperability for Microwave Access that enables the actual broadband wireless network with high speed. WiMAX operate same like WiFi but WiFi operate with some limitation like it is base band technology and cover only 100 feet radius with slow speed. WiMAX covers a radius of 50 Km and work with the speed of 70 Mbps. WiMAX is the replacement of the wired broadband. In wired broadband connection, we can transmit data with 512 Kbps to 10 Mbps speed and more, for example DSL broadband and cable broadband. In future all new desktop and notebook computers will be incorporated with WiMAX technology. With this technology you will be connected to the internet even you are driving your car with the speed of 120 Km.

Objective of WiMAX

Superior Performance

Flexibility

Advanced IP-Based Architecture

Attractive Economics

IEEE 802.16 Specifications

Range 30 mile radius from the base station for LOS (line-of-sight).

Range 4-6 miles radius from the base station for NLOS (Non-line-of-sight)

Maximum data speed supported as 70 Mbps.

Licensed frequency band: 2- 11 GHz

Un-licensed frequency band: 10- 66 GHz

Line of sight is not needed between user and the base station unless very high date rates are required at the user premises.

Friday, October 24, 2008

Download the youtube videos on harddisk Tips

Using this tip, you can easily download the youtube.com movies and save on your computer hard disk. Actually all videos are saved on youtube in flash video format, so you can simply play these videos on the website and can't save directly to your computer. But there are many tools are available in the market to download these videos on the hard disk, but here you can do this using a website. You can convert also the downloaded videos from youtube into any common video format, for example, windows media video file (wmv), windows video file (avi) and movie file (mpeg).

Follow the given steps to download videos from youtube on your computer:

First open www.youtube.com then plays any your favorite video.

For example, you search a video and the URL of that youtube video is http://www.youtube.com/watch?v=pVkUG6XLItc The ID if this search is pVkUG6XLItc after equal sign.

Now open a website http://youtube.navi-gate.org, now copy and paste above video ID in the search box, and press button ID search.

The result may be displayed in any different language, but don't worry, just click on download button and save this video on your computer hard disk. Now use any video converter to convert it in any other common format.

Fake Windows Update Email

Well Microsoft believes that the grace period is over and wants everyone to jump on board and get Service Pack 2 (SP2) installed. I know everyone has an opinion on the Service, some good some not so good, but it really is only a matter of time. Do you know anyone without SP1 on his or her XP machine? I hope not.

As you may also know, Microsoft has picked the second Tuesday of the month to run their new security patches. These two issues have really set the stage for a new attack on windows users. Hackers have decided to try and slip one by your defenses with a Phishing/Trojan scam. You may get a spoof emails that link to a bogus Microsoft site where the hackers get you. If successful in their efforts, the ambushed PC will be infected with the TrojDSNX-05, a back door Trojan that attempts to gain control over your system. With control of your system the hacker will more than likely use you (of course unknowingly) as a spam server to mail out huge amounts of spam in your name. If a network PC happens to get infected, then a denial of Service, exploitation of network shares, and further infection are something you may look forward to.

The TrojDSNX-05 is not the newest virus on the block and can be controlled if you have decent anti-virus software that is up-to-date.

Microsoft will never send you an email reminding you to update.

Very similar to the fact that companies will never send you an email asking you to reply with your credit card and account info in order to fix some discrepancy with your account. In fact, if you ever receive any emails that seem "Phishy" to you, try going directly to the company web site (not the link in the email) and see for yourself what's going on.

As far as SP2 goes, if you haven't installed it yet I suggest doing it on your own terms, backup all your important data (pictures of the family, documents, whatever is important) set a system restore point. Go out to the manufacturer's site of your favorite programs and see if there are any known issues, FAQ's, or patches. If so, follow the instructions to properly install any necessary components and follow any necessary procedures in the exact manner in which the instructions describe. After this you should have all your bases covered, and feel comfortable installing SP2.

XP SysKey Trick

If you have Windows XP then I really think you're going to like this week's security tip. Are you in a situation where you really don't want anybody accessing the family PC while you're not around? Maybe you don't want anybody to use your computer at all. Maybe you just want a little tighter control over when and by whom your PC gets used. If any of these situations sounds like yours then read on.

This week's security tip is on the syskey command. The syskey is a command line tool to help you enable your Startup Key. Without getting too techy on you, the Startup key is a complex algorithm that if configured can stop anyone from logging on to your system who doesn't poses the key. No startup screen or user accounts will be available until you present the key, you're basically looking at a black screen with one small lonely window asking for the Startup Key to gain access. The Startup Key, which is a floppy disk with the appropriate key code, simply needs to be inserted into the floppy drive, and activated. This will satisfy the security request and allow you to proceed to the login screen. If you don't have a floppy drive then I'm afraid you might as well stop reading now.

The Startup Key is created when you enable the Startup Key process as described later in this article. One thing you must keep in mind, and is of the utmost importance, you should make at least one copy of this floppy, test it to insure that it works, and put it in a safe place. If you lose this Key you will not be able to log into you Operating System. You may even want to make a third copy to keep off-site. If you do lose your Startup key then your only option is to use a Restore Disk (If you have one) to restore your registry to a state it was prior to the enabling of Startup Key.

OK, if this sounds like a security measure you would like to put into action then follow the directions below. Again, please make at least one copy of this disk so you don't lock yourself out of your system and send me a bunch of hate e-mail. Well, with that said twice I guess it's show time. The directions below will help you get things set up, and below that I have attached a link out to Microsoft's information on this so you can look it over.

CONFIGURING STARTUP KEY:

Go to Start/Run and in the blank field type "syskey" press enter, or OK.

You should see a small window titled "Securing the Windows XP Account Database". From this Window select the "Update" button to move to the next window.

The "Startup Key" is the next window. You'll see a couple of options there, but the one we are looking for says "Startup Key on floppy disk", along with some warning about how your system is going to startup now.

After selecting this click OK, and a pop-up will alert you that the key has been changed. Another message follows asking you to insert a disk in drive A: (Floppy drive).

Insert the floppy, click OK, and one more window will come up telling you that the Key has been changed and you need to have this floppy disk in order to log into Windows. That's exactly what we want.

When you're all done go ahead and eject the floppy (you might want to slide the little lock up on the floppy to insure you don't format it on accident), and restart the PC. Windows will appear to come up normally, but after it loads the kernel the "Windows XP Startup Key Disk" window pops-up. Grab your Startup Key floppy put it in the floppy drive, and select OK. You'll see Windows load up and bring you to your user logon screen.

I told you this is a cool trick and really helps lock down you PC. I hope you get some use out of this, but please be careful.

Apply password and compressed feature in windows XP Tips

In windows XP, you can store your data on harddisk using less space than normal size. There is no need to install any third party software to compress or decompress your data, you can use windows built-in data compression or decompression feature to manage disk space issue.

I think many users are worried about the security of their file and folder also, so another benefit of this feature, you can protect your compressed file and folders with password.

Follow the given steps to implement the compression and password feature to mange data:

First double click on "My Computer" and locate the disk where you want to create compressed (zipped) folder. For example, if you want to create this compressed (zipped) folder on C drive, then open C drive.

Here open the "File" menu, go to "New" then click on "Compressed (zipped) Folder" option.

Rename this folder according to data information and press "Enter" button.

Now you can move (drag and drop or copy and paste) your files and folders to this compressed (zipped) folder then compression feature will implement automatically on that data.

When you want to open these compressed files, simple right click on compressed folder and click on Extract All. This extract wizard will automatically extract all these files to location you choose.

Now if you want to protect this compressed folder with password, simply open the compressed folder and go to "File" menu then here click on "Add a Password" option.

A small dialog box will appear with title "Add Password", type password in "Password" box and confirm password also then press Ok button.

Now when you will try to open your compressed files, system will prompt you a dialog box to enter password to open this file.

Email Security Scan Tips

The problem with all the security holes that arise from day to day is that it's hard to keep up. "Am I protected?" you wonder, "I update constantly, I scrutinize all my email messages, especially attachments, and read all of Chad's awesome security articles, but how do I know for sure?"

Well, since such a large number of security holes center around email I'm glad to announce today a service that can check your system for potential exploits. The service is a web based email scanner that you can tailor to send out over 20 different emails, each attempting to defile your system with dummy exploits. It's like hiring a security agent to go over your system and tell you what aspects of your security is in good shape, and what areas could use some improvement. When set in motion, the scanner fires off the dummy virus and exploits to the specified email address. Don't be surprised if your virus software starts popping up with security messages, as a matter of fact, this is exactly what you want to happen it means your system is seeing the threats coming in.

The emails themselves have message bodies describing what their particular test was for and how to make sure you're protected from this sort of attack. Some of the emails have attachments and some attempt to create text documents on your desktop, the emails tell you exactly what to do to ensure the tests ran correctly, thus providing an accurate assessment of your system's defenses.

In addition to the testing your system for security holes this is also a good way to educate yourself on some email-born security issues by getting a chance to see them in action without putting yourself in any danger.

Secure your password from hackers attacks Tips

Today tip will help you to secure your computer from the access of professional hackers. There are some hacker’s breaks into your computer without using any impressive programming skills but trying to find words to guess as your password. Normally people use their name, house number, mobile number and word “password” as a password. If you have very simple password then a hacker can hack your computer very easily. To safe your computer from hackers there is a best way to create a tricky password. Here I will tell you some different type of tricks to make your password that can’t guess easily by any body.

Use the maximum characters in your password.

Always set the password using maximum characters length, because it is simple method, if your password is longer then it is very difficult to guess.

Use the combination of lower-case and upper case letters in your password.

Normally computer users use the lower case in password selection but it is best practice to use the combination of both (lower-case and upper case). So using different cases in your password makes it much more difficult to crack.

Use the combination of letters and numbers in your password.

When you mix both letters and numbers just like one letter and one number then your password is more incomprehensible.

Avoid using the name of your family members as password.

Always try to avoid the name of your child, spouse, city and country name as password, because if any body knows about your personal life’s details then they try to use these detail to guess your password.

Use any tools to create random password.

Google Security

Google is always adding new products and features. One of these is the Personalized Google Homepage. You can customize it with news, movies, weather, stock market reports and more. How convenient. But there is a dark side.

Google saves your search history. Every person, place, thing, or word you look up is stored in your history (BTW-same goes for the Google Toolbar). This can be cleared or paused on your end, but it will still be saved on the Google server. It's in their Privacy Policy:

"You can delete information from My Search History, and it will be removed from the service and no longer available to you. However, as is common practice in the industry, and as outlined in the Google Privacy Policy, Google maintains a separate logs system for auditing purposes and to help us improve the quality of our services for users."

So, if you have a Personalized Google Homepage, here's how to at least manage history items on your end...

Click the "My Search History" link then "Remove Items". Put a check next to the items on the list you want removed, or select "All". Finally, hit the "Remove" button.

If you don't want Search History activated, just click the "Pause" link. Again, the search info still goes to Google, but it doesn't show up in your search history display. To turn S.H. back on just hit "Resume".

As I mentioned, the Google Toolbar also keeps your history, but it doesn't track you like the Personalized Homepage. To turn off...

Go to the "Options" button and select the "Search" tab.

Uncheck "drop down search history", "Save the search history...", and "Automatically search..."

Hit OK.

Now your toolbar searches are known only to you. As for the personal homepage searches... at least no one outside of Google or the government can see what you looked up.

Scanner Cleaning Tips

Digital scanner is a very popular input device. Its main purpose to translate images and text printed on the paper into electronic form that can be processed and stored by the computer.

To clean the scanner first unplugs your system power from the electrical outlet.

Always clean the glass of your scanner with any optical surface cleaning fluid.

This process should be done after every three months if you want to save your scanner life.

LCD Cleaning Tips

Flat panel monitors are commonly used in mobile devices such as laptop and table PCs. Similarly, smart phones, PDA calculators have LCD screens. LCD screens are much softer than old CRT screens, so they required extra care as compare to the CRT Monitors.

First read the LCD manufacturer manual about your LCD model on how to safe and clean it.

To clean LCD monitor first unplugs your LCD power from the electrical outlet.

Never use dirty cloth, spray any cleaning fluids on the LCD screen and paper towel to dry it.

Always use dry cotton cloth to clean the fingerprints and dust on the LCD screen. You can use lightly dampened soft cloth if you feel any difficulty to clean the screen.

Mouse Cleaning Tips

The mouse is the most commonly used pointing device in windows environment on the personal computers. That is why mouse required extra care as compare to the other parts of the computer. You should clean your mouse when you feel the mouse is slow to move in different directions or making some strange movements.

First disconnect your mouse from the back side of the computer.

Now read the mouse manufacturer manual about your mouse model on how to safe and clean it.

Open the ball cover from the back side of the mouse and wash the ball then dry it with cloth.

Now clean dust in the inner side of the mouse specially removes the dust on the rollers with lightly dampened cotton bud. You can use the compressed air for this purpose.

At the end dry it and Re-assemble your mouse then connect with computer.

Motherboard Cleaning Tips

Motherboard is the main part of your computer that contains all hardware components. Your computer motherboard could fry, if you do not keep it clean on periodically basis. Dust is the main cause to heat up your system and heat link to hardware failure. You can save your computer maintenance cost if you clean your computer on the regular basis. This will improve the cooling and performance of the motherboard components.

To clean your motherboard first unplugs your system power from the electrical outlet.

Using the screwdriver remove the side covers of your computer case and put them to one side.

Check all data and power cables connections. Inspect all motherboard PCI and AGP slots.

Remove all add-on card of your motherboard for example RAM, modem, VGA, sound card and LAN card.

Now blow the air around all the motherboard sides and keeping away your blower nozzle 4 to 5 inches away from main board components. You can use vacuum cleaner also for this purpose but compressed air is the better solution to clean a system.

At the end assemble back all cards, cables and side covers of your system.

I recommend you doing this after every three months if you want to save your system life.

Changing the Title on Windows Media Player Tips

You can change the title bar for the Windows Media Player

Start Regedit
Go to HKEY_USERS \ .DEFAULT \ Software \ Policies \ Microsoft \ Windows Media Player
Create a string value of Title Bar
Give it a value of whatever you want to appear in the title bar

Automatic Screen Refresh Tips

When you are working on your local computer and want to refresh any changes in your system automatically. For example some times you are watching sports results, online Stock Exchange rates and any changes to your hard drive but these changes are not usually refreshed until you press the F5 key on your keyboard.

To refresh your screen automatically you should edit your system Registry. But the best technique to edit the windows registry keys, always export or backup the whole windows registry keys on backup drive before editing. Because any mistake in Registry can cause serious problem in your computer to run properly.

Follow the given steps to change the updates automatically.

First click on Start button then type Regedit in Run option.

In Registry Editor panel go to the path:

HKEY_LOCAL_MACHINE / System / CurrentControlSet /Control / UpdateMode

Here in right hand side panel edit the DWORD value to be between 1 and 5.

Now restart your computer after any changes to go into effect.

Graphic Card Tips

The graphic card is one of the most important pieces of hardware in your PC. Without it, your super monitor with all the bells and whistles is just a junk box.

Make Directional Input

Most video cards come with simple frame capture programs, but you'll have to do some programming if you plan to integrate video capture with other operations on your computer, such as adding text data as an overlay or changing video-in channels on the fly. In this case you'll need good programming libraries in a language with which you are familiar for the video card. Some companies include libraries with their cards, but most charge extra. Most often libraries, when available, are for C or BASIC, and sometimes Pascal.

Choose Between 24 bit and 32 bit

For True Color mode, some graphic cards offer 24 bit while some offer 32 bit. Which is the best? When True Color mode was first suggested, it utilizes 32 bit which was very pleasing to the eye, they realize that 24 (with less coolers) won't look much different since the human eye can only take about a certain amount of colors. On the other hand, 24 bit will run faster compared to 32 bit because it uses less colors. So if your card utilizes 24 bit, don't worry, it isn't bad.

Always Use The Latest Drivers

Yes, it is important to make sure you always have the latest drivers. The latest drivers will offer you better performance, more utilities and more compatibility (usually for Direct X or Direct3D). Take the effort to check you card manufacturer's site to look for the latest driver updates.

Clean computer Casing Tips

When you noticed your computer case is looking yellowish then you can understand about inner side of your computer case as dirty as outside. Because Dust is the main cause to heat up your system and heat link to hardware failure. You can save your computer maintenance cost if you clean your computer on the regular basis.

Never place your computer on the ground, always use computer table or shelf for this purpose.

To clean computer case first unplugs your system power from the electrical outlet. Remove all cables and connectors from the back side of your computer.

Now use the compressed air and start clean from back to front of your computer case, specially casing and power supply fan.

At the end using lightly dampened cloth or spray any cleaning fluids on the computer case and use paper towel to dry it.

This process should be done after every three months if you want to save your system life.

CD-ROM Cleaning Tips

If your CD drive creating problem to read CD disc, taking time to read and showing message there is no disc in the drive. These are the symptoms of dirty or weak CD-drive lens, because dirty lens can create errors in reading or writing and soon will not work at all.

Follow the given steps to care and clean a CD-Drive.

First make sure your discs are clean, unscratched and you’re loaded it properly.

Always use laser lens cleaner to clean drive lens.

Insert the laser lens cleaner disc and play it for 2 to 3 min.

Using CD drive cleaner properly clean the CD-ROM laser from dust. If your drive still creating problem then open it and clean the lens with a cotton swab.

General Cleaning Tips

You can save your computer maintenance cost if you clean your computer on the regular basis. This will improve the cooling and performance of the computer components. Your computer components could damage, if you do not keep it clean on periodically basis, because dust is the main cause to heat up your system and heat link to hardware failure.

Never place your computer on the ground, always use computer table or shelf for this purpose.

To clean computer case first unplugs your system power from the electrical outlet. Remove all cables and connectors from the back side of your computer.

Now blow the air around all the hardware components and keeping away your blower nozzle 4 to 5 inches away from main board components. You can use vacuum cleaner also for this purpose but compressed air is the better solution to clean a system.

At the end using lightly dampened cloth or spray any cleaning fluids on the computer case and use paper towel to dry it.

Never clean inside computer components or other circuit board with damp or wet cloth.

Always be careful to eat or drink around the computer.

SCSI Disk

Disk SCSI (Small Computer System Interface) IDE with similar organizations in addressing.
Differences in the tool interface capable of transferring data in high speed.
High-speed transit, is a standard for computers.
UNIX from Sun Micro systems, HP, SGI, Machintos, Intel, especially computer-server computer network, and vendor-other vendor.
SCSI is actually more than just a tool interface hard disk.
Each device has a unique ID as a media introduction by the SCSI.
SCSI is a bus as capable as a checker to 7 equipment such as:

Hard
CD-ROM
CD-Recorder
Scanner music, n traveling.

SCSI Disk Version

RAID

RAID level 0

Actually not use RAID redundancy does not improve in performance.
Data distributed on the entire disk array, is the advantage of using a large capacity disk.
RAID - 0 become a model of the data strip on the disk with a data management system specific to the data stored on considered a logical disk.
Mechanism for the transfer of data in one sector at a time so that only good for handling large data transfers.

RAID level 1

Redundancy obtained by duplicate all the data on the disk mirror.
As with RAID - 0, RAID - 1 stripping also use the technology.
The difference is in level 1 each strip mapped to the logic of the two disks that are logically separate so that each disk arrays will have a mirror disk that contains the same data.
RAID - 1 expensive.
RAID - 1 increase in performance approximately doubled compared to RAID - 0 in the operation read, but not to write operations significantly increased.
Matches are used to handle data that is often experienced failure in the process of reading.
RAID - 1 still working on sector-sector.
Benefits of RAID - 1:

Request reading can be served by one of the disk because there are two disks contain the same data, depending on access to the fastest time.
Demand for storage or writing is done on 2 disks in pararel.
There are beack-up data, namely the disk in the mirror.

RAID level 2

RAID - 2 using the technique pararel access to all the disk. - All participating disk and executing every request so that there are mechanisms for synchronization and disk rotation head.
Technology used in the stripping this level, only strip small size, often in word or byte size.
Use a system error correction bits parity with the Hamming code.

RAID level 3

Organized similar with RAID - 2.
The difference in RAID - 3 requires only a single disk redudant, does not depend on the number of arrays disk.
Computing parity bit for each word and write data on disk pritas special.
When the drive failure occurs, the data re-arranged the rest of the data is still good and from information paritasnya.
Using pararel access to the data distributed in the form of small strip-strip.
Performing high-yield transfer, but can only executing a request.
I / O, so only if used in high data transaction environment decline in performance.

RAID level 4

Using techniques that independent access to every request so that disknya read or write served in pararel.
RAID is suitable to deal with the culture system data transfer rates.
No need synchronization because each disk operate independently.
Stripping the data in a large size.
Strip parity bits-per-bit is calculated to strip all the related data on each disk.
Parity stored on disk for parity.
When the writing operation, array management software not only to update the data but also related to parity.
Benefits of parity with the disk that has made special security data more secure, but with a separate disk parity will slow performance.

RAID level 5

Having a similarity with RAID - 4 in the organization.
The difference is strip-strip parity distributed across the entire disk.
For security reasons, the strip parity disk is stored on a disk other.
RAID - 5 improvement from the RAID - 4 in terms of improving performance.
Disk is usually used in the network server.

RAID level 6

It is the latest RAID technology.
Using the method of calculating parity for two reasons to anticipate the accuracy and error correction.
As with RAID - 5, parity stored on the disk other.
Have a high transfer speeds.

RAID Images

Tape Magnetic Emissions

System using the technique of magnetic tape reading and writing, which is identical with the magnetic disk system.

Medium magnetic tape, a track pararel, the old tape system bears fruit 9 tracks that allows storage one byte at a store one bit of parity on the remaining tracks.

The system uses a new tape, 18 or 36 tracks as an adjustment to the width of word in a digital format.

As the disk, magnetic tape, read and written in the form of blocks connected (continue), which is called physical records.

Block-block is separated by gaps called inter-record gaps.

Head magnetic tape is a sequential access device.

Head must adjust the location of records that will be read or written.

When the head is in place more of the desired records from the tape need rewind first, the new reading is done with the forward direction.

Very different technology on the disk using the techniques of direct access.

Lap speed magnetic tape is low so that the transfer of data to be slow.

Pita begin magnetic abandoned replaced by the type of CD products.

Thursday, October 23, 2008

Mechanism head

Head touch the disk (contact) as the floppy disk, the head of the north still have a slit or not depends on Fixed magnet field.

Gap, or the distance that the head near the head of the risk factors, namely the occurrence of an error reading.

Technology Winchester from IBM to anticipate problems rift over the head with a model head aerodynamic.

Head formed tin plate on a different disk, the disk will head.

The term on Winchester model introductions of IBM's disk 3340.

Model is a removable disk pack with a head wrapped in packs.

Now, the term used by the cleanup Winchester disk drives that are wrapped packs and the aerodynamic design of a headhunter.

Mechanism Read & Write Magnetic Disk

- The process of reading and writing through Conductive coil (head).
- Head can consist of one to head out; is / read, but there are also separate.
- During the write / read, head quiet place, the move is the HD disc.
- Write
* Head moving in the magnetic disk.
* "Vibration" was sent to the head.
* A pattern (of data) written on the surface of the disk.
- Read (traditional)
* Disk rotating magnetic, adjust the "desire" head.
* The read / write head by the same.
- Read (Contemporary)
* Head divided into 2 parts to read and write.
* Operates at high speed.
> Block data more closely and more quickly.

Magnetic Disk

Disk is a circular disc made of certain materials (metal or plastic) surface coated with a material that can be magnetic.

Mechanisms read / write head using read or write head is called a spindle conduction oil.

Design physical, head are stationer disc while the disk rotates in accordance control.

Two methods of data on the layout of diak, the constant angular velocity and multiple zoned recording.

Disk organized in the form of ring-ring concentration called tracks.

Each track on the disk separated by a gap (gap: prevent or reduce the reading and writing errors caused melesetnya head because of interference or magnetic fields).

A number of bits that will occupy the same track that is available.

As to the disk, then the density (dens Ty) disk will be large.

Data sent to the memory of this in the form of a block, block generally smaller capacity of the track.

Block-block data stored in the disk-sized blocks, called the sector.

Track usually filled some sectors, generally 10 to 100 each tracknya sector.

IDE Disk (hard drive)

IDE disk (hard drive)

IBM PC XT develop, use a Seagate 10 MB hard disk for storing programs and data.
This hard drive has 4 head, 306 cylinders and 17 sectors per track, controlled by Xebec disk checker on a plug-in card.
Technology is developing rapidly to make the disk checker that previously separated into one integrated package.
Did the IDE drive technology (Integrated Drive Electronics) in the middle of 1980.
Technology IDE disk can only handle a maximum capacity of 528 MB of disk and control 2.
IDE developed into EIDE (Extended Integrated Drive Electronics).
Capable of handling the hard drive more than 528 MB and supports address LBA (Logical block addressing), the only method that gives the number in sectors ranging from 0 to a maximum of 224-1.
This method requires checker able to convert addresses into the address LBA head, sector and cylinder.
Improving the performance of other transfer speed is higher, able to control the 4 disk, able to control the CD-ROM drive.

Intel cache Evolutions

Problem
1. External memory slower than the system bus.

Solution : Add external cache using faster memory technology.

Processor on which feature first appears : 386

2. Increased processor speed results in external bus becoming a bottleneck for cache access.

Solution : Move external cache on-chip, operating at the same speed as the processor.

Processor on which feature first appears : 486

3. Internal cache is rather small, due to limited space on chip.

Solution : Add external L2 cache using faster technology than main memory.

Processor on which feature first appears : 486

4. Contention occurs when both the Instruction Prefetcher and the Execution Unit simultaneously require access to the cache. In that case, the Prefetcher is stalled while the Execution Unit’s data access takes place.

Solution : Create separate data and instruction caches.

Processor on which feature first appears : Pentium

5. Increased processor speed results in external bus becoming a bottleneck for L2 cache access.

Solution : - Create separate back-side bus that runs at higher speed than the main (front-side) external bus. The BSB is dedicated to the L2 cache.

Processor on which feature first appears : Pentium Pro

-Move L2 cache on to the processor chip.

Processor on which feature first appears : Pentium II

6. Some applications deal with massive databases and must have rapid access to large amounts
of data. The on-chip caches are too small.

Solution : - Add external L3 cache.

Processor on which feature first appears : Pentium III

- Move L3 cache on-chip.

Processor on which feature first appears : Pentium 4

Database Tips

Database of employees that contains data of employees of an organization or department.
Database of students that contains data of students of college or university.

When you draw amount from bank through ATM card, you are accessing the database; your account is accessed and checked through auto teller machine. When you draw some amount from your account, your record in the database is automatically updated immediately.
When you visit your local library, there may be a computerized database containing details of the books in the library. There will be a computerized index, which allows you to find a book based on its title, its author’s name etc.
The meteorological organization contains databases having information about current and previous meteorological data. The meteorological department is totally dependent on the meteorological data.

Wednesday, October 22, 2008

Detect viruses in a computer using multiple antivirus engines Tips

Detect viruses in a computer using multiple antivirus engines

Virus detection and its removal are made through an antivirus program which finds out viruses in a computer and then possibly removes or repairs the virus problem. But today an interesting tip, how to scan your system without any installed antivirus program. You can scan any specific file for viruses, malware, worms and trojans on your system without any preloaded antivirus protection.

VirusTotal is a free service that facilitates you for quick scan to detect viruses, malware, worms and Trojans. Virus Total will analyze your system files using multiple antivirus engines. Virus Total is not a proper substitute of installed antivirus program, because this service works only when you will be connected to internet.

Now open the VirusTotal site to start scan process.

Now under the "Upload the file" section, click on browse button to select the virus affected file and press "Send File" button.

Here Virus Total will takes some time to upload file (depends upon the file size and internet speed).

Wireless Security Tips

10 Tips for Wireless Security

Category: Computer Network, Application Server

Wireless network, or often called with the wireless network is easy to set up, and also feels very comfortable, especially if we want to walk the road circumnavigator home or office with a portable computer but can still access the Internet network. However, because using the wireless wave, it will be easier to hack than in-use cable connections. There are a few tips here to secure the wireless network.

The step-step as follows:

Use encryption. Encryption is a measure of security first, but many wireless access points (WAPs) do not use encryption as a default. Although many WAP have wired equivalent privacy (WEP) protocol, but not enabled by default. WEP indeed have some holes in the security, and an experienced hacker would be able to open it, but it is still better than no encryption at all. Make sure to set method WEP authentication with the "shared key" rather than "open system". To "open system", he is not to Encrypt data, but only Authentication client. Change the WEP key as often as possible, and use 128-bit WEP compared with the 40-bit.
Use Strong encryption. Because of the weakness of the existing weaknesses in WEP, it is recommended to use Wi-Fi Protected Access (WPA) also. To use WPA, WAP should be downloading supporting. The client side must also be downloading a page support WPA.
Change Default Administrator Password. Most factories use the same password for the administration of all WAP their products. The default password is generally known by the hackers, who can later use to alter the settings in your WAP. The first thing that must be done in the WAP configuration is the default password change page. Use at least 8 characters, a combination of letters and numbers, and do not use the word in the dictionary.
Turn off SSID Broadcasting. Service Set Identifier (SSID) is the name of our wireless network. By default SSID of the WAP will be broadcast. This will create a user to easily find the network page, as the SSID will appear in the list of available networks in the wireless client. If the SSID is turned off, users must first know the SSID it can be quite connected with the network page.When the WAP.
Matikan are not. How this one seems very simple, but some company or individual to do so. If we have users who are connected only at a certain time only, there is no reason to run a wireless network at any time and provide the opportunity for the intruder to implement the intenet. We can shut off access point when not in use.
Change the default SSID. Factory provides a default SSID. Usefulness of off SSID broadcast is to prevent other people know the name of our network, but if you still use the default SSID, will not be difficult to guess from the network's SSID.
Use MAC filtering. Most of the WAP (not cheap cheap, of course) will allow us to filter the media access control (MAC). This means we can create a "white list" of the computer that a computer can access the wireless network we, based on the MAC or physical address of the network card in each PC. Connections from the MAC is not in the list will be rejected. This method is not necessarily safe, because it is still possible for a hacker to do packet sniffing which transmits it via the wireless network and get the MAC address is valid from one user, and then use it to make a spoof. But the MAC filtering will make an intruder difficulties that still has not been master's champion.
Isolate Wireless Network from LAN. To protect their internal network cable from the threats that come from the wireless network, should probably be made wireless DMZ or perimeter network that isolate from the LAN. That means installing a firewall between the network and wireless LAN. And to wireless client that requires access to the internal network, he must first perform Authentication with RAS server or use a VPN. This provides extra layer for protection.
Control Signal Wireless. 802.11b WAP radiating waves up to about about 300 feet. But this distance can be added by changing the antenna with the better. With the high gain antenna, we can get more distance. Directional antenna will emit signals to a certain direction, and the jet not a circle, as happened in the omnidirectional antenna is usually found in the package WAP standard. In addition, by selecting the appropriate antenna, we can control the distance signals and directions to protect themselves from the intruder. In addition, some of the WAP settings that can signal strength and direction through the WAP con fig page.
Emit wave in the frequency Different. One way to shrink from hackers who are using technology 802.11b / g, which is more popular with 802.11a. Because 802.11a working on a different frequency (the frequency at 5 GHz), the NIC in the design to work on the popular technology that will not be able to catch the signal page.

CPU Functions

CPU functions

Running programs - programs that are stored in the main way to take instruction - instruction, testing and instruction exsecution one by one according to the groove.
The view most simple program execution process is to take the processing instruction that consists of `two steps, namely:

* Operation reading the instructions (Fetch)
* Operation of instruction (execute)

Instruction cycle

Consists of Fetch cycle and the cycle execution

Fetch cycle - execution

At each cycle instruction, the CPU will initially read instructions from memory.
There are registers in the CPU, which functions control and calculate the next instruction, called the Program Counter (PC)
PC will add one calculation each time the CPU to read the instructions.
Instructions - read the instructions that will be made in the Instruction Register (IR).
Instructions - in the form of this instruction code - the code binner the interpretation can be done by the CPU and the action required.

The CPU Action

CPU - Memory, the movement of data from the CPU to memory and vice versa.
CPU and I / O, the movement of data from the CPU to the module I / O and vice versa.
Data processing, the CPU establish a number of arithmetic and logic operations of the data.
Control, is the instruction to control functions or work. For instance affairs conversion instruction execution.

Details cycle execution

Instruction Address Calculation (IAC), namely Calculation or determine the address of the next instruction that will be executed.

Involving the number of permanent additions to address previous instructions.

>> For example, if the length of each 16 bit instructions have
a long memory when 8 bits, then add 2 to address previously.

Cycle execution

Cycle for an instruction execution can involve more than a reference to the memory.
In addition, an instruction can determine an operation I / O.
Instruction Fetch (IF), read the instructions from the authorities or the location of memory to the CPU.
Instruction Operation Decoding (IOD), which analyzes the instructions to determine the type of operations that will be formed and operand that will be used.
Operand Address Calculation (OAC), which determine the address operand, this is done when the reference operand involved in memory.
Operand Fetch (OF), is taking operand from memory or from the module I / O.
Data Operation (DO), which is formed in which the operating instructions.
Operand store (OS), the results of execution to save the memory.

Figure cycle instructions

Function Interruptions

Mechanism termination or transfer of the processing instructions in the CPU to the routine interruptions.
Almost all modules (memory and I / O) have a mechanism that can work to interrupt CPU.

Goals Interrupts

In general, for management execution routine instructions to effective and efficient inter-module and the CPU - the module I / O and memory.
Each component of the computer can run tasks simultaneously, but the control is located on the CPU in addition to the speed of execution - each module is different.
Can work as the synchronization between the modules

Kind of class signal interruptions

Program, the interruptions are raised with several conditions that occur on the results of program execution.

* Example: aromatic overflow, the division of zero, operation illegal.

Timer, is the interruption of the timing raised in the processor.

* Signals allows operating systems to run certain functions regularly.

Kind of class signal interruptions

I / O, signal interruptions that are raised by the module I / O notification in respect of conditions of error and a resolution of the operation.
Hardware failure, is raised by the interruption of power failure or memory parity errors.

The process Interrupt

With the mechanism interruptions, the processor can be used for executing other instructions.
When a module is finished and ready to run the duty to receive the next assignment, the module will send a request interruptions to the processor.

The process Interrupt

Then, the processor will stop the execution of run to manhandle routine interruptions.
Once the program is completed, the interruption processor will continue the program execution again.
When interruptions received signal processor there are two possible actions, namely interruptions accepted or rejected suspended and interruptions.

Interruptions Suspended
What do processors?

Processors suspend the execution of programs that run and save the context. This is the address of store instructions that will be exercised and other relevant data.
Processors set the program counter (PC) to address early routine Interrupt handlers.

Cycle execution by the processor with the function of interruptions

Operating system complex

Interruption double (multiple Interrupt).

* For example, a computer will receive the request interruptions
during the printing process is completed with
the printer, in addition to the possible channels
of communication will submit a request
each time the interruption of data arrived.

Can be taken two approaches to handle this double interruption.

Interrupts dual approach
There are 2 approaches:

This approach is called sequential processing interruptions / sequential.

* Reject or other interruptions do not allow the interruption of a processor handled.
* Once completed processor handles the interruption of a new handled other
interruptions.

Interrupts dual approach

Processing interruption nest that is defining priorities for the interruption.

* Interrupt Handler: allow interruptions priorities higher handled first.

Multiple Interrupts - Sequential

Multiple Interrupts - Nested

Case

A system has three devices I / O: printers, disk, and communication channels, each - their priorities 2, 4 and 5. How will the process interruptions?
At the beginning of the printing system with a printer, when there is data on the delivery channel of communication so that communication module to request interruptions.
The transfer of the execution of interruption of communication modules, the printer interruptions while suspended.
When execution communication module, the interruption disk, but a lower priority because of the interruption suspended disk.
After the interruption of communication modules will be completed by interruptions that have higher priority, namely the disk.
When the disk is finished interruption, the execution interruptions printer. `Then the execution of the main program.

CPU (Central Processing Unit)

CPU

Central Processing Unit.

It is the most important components of the computer system.

Components of data processing based on the instructions given to him.

In creating the functions and tasks, the CPU composed of several components.

Main components of the CPU

Arithmetic and Logic Unit (pestle)

Control Unit

Registers

CPU Interconnections

CPU Chart

Arithmetic and Logic Unit (pestle)

The task of shaping functions - data processing functions of the computer.

Pestle is often called the machine language because the instructions do this - the machine language instructions given to them.

Pestle consists of two parts, namely the unit and the unit arithmetic Boolean logic, that each - each have the task specification work.

Control Unit

Duty to control the operation of the CPU and the overall control the computer so that the synchronization of work between the components in the run function - a function of operations.

Included in the responsibilities of the unit is to take control instructions - instructions from main memory and determine the type of instruction.

Registers

Media storage internal CPU that is used when processing data.

Memory is temporary, usually in use to store data when the data is processed or for further processing.

CPU Interconnections

System connection and a bus connecting the internal components and a bus - the bus external CPU.

CPU internal components, namely pestle, the control unit and the register - the register.

Component external CPU: other system, such as main memory, a tool inputs / outputs.

CPU internal components

Detail the structure of the internal CPU

Tuesday, October 21, 2008

Computer Evolution and Performance Part 15

Intel Core2Duo
- Further development of the Core Duo.

Building processor between the first and second.

- Technology denganL2 dual processor cache up to 2MB.
- Do not focus on speed but on the ability of computing resolution two times faster.

History of the Intel Processor

Intel's series 4004 and 8008

Intel's 8080 series, 80286

Intel's 80386 series, 486 and 586

PowerPC
- Project RISC system beginning in 1975 by IBM in the computer mini-series 801.
- Series is the first prototype, a series of commercial PC RT is the introductions in 1986.
- IBM's Year 1990 issue is the next generation of IBM RISC System/6000 which is the engine superskalar RISC workstations.
- After this architecture known as the IBM POWER architecture.
Det: RISC (Reduced Instruction Set Computers)

PowerPC
- IBM formed a partnership with Motorola produced a series microprocessor 6800.
- Apple use Motorola chips in Macintosh. Currently there are 4 groups PowerPC.

PowerPC 6800 series

Group Power PC
- 601, is a 32 bit machine is a massive production for the PowerPC architecture known community.
- 603, is a computer desktop and portable computers. This same group with a 601 series, but cheaper for the purpose of efficient.
- 604 series PowerPC machines for use lowend computer servers and desktop computers.
- 620, intended for the use of high-end servers. Machine with 64 bit architecture.
- 740/750, with a series of L2 cache.
- G4, such as the 750 series but is faster and uses 8 parallel instructions.

PowerPC 601 and 603 series

PowerPC 604 series

PowerPC 740 and 750 series

Computer Evolution and Performance Part 14

History of the Intel Processor
- 8080 (1972)

Intel's first microprocessor.

8 bit machines and data to the memory bus, 8 bits.

66 with the number of instructions ability 16KB.

- 8086 (1974)

16 bit microprocessor technology with the instruction cache.

The number of instructions reached 111 and the ability to pengalamatan memory 64KB.

- 80,286 (1982)

Development from 8086.

Pengalamatan ability to reach 133 with 1MB instructions.

- 80,386 (1985)

32 bit machine.

The system supports multitasking.

Best at that time.

- 80,486 (1989)

Progress in the cache memory technology and instruction pipelining.

It is equipped with a math co-processor.

- Pentium (1993)

Use technology that allows superscalar execution of instructions in parallel.

- Pentium Pro (1995)

Increase superscalar organization parallel to the process,

Found the system branch prediction, data flow analysis and cache memory system that increasingly sophisticated.

- Pentium II (1997)

MMX technology, capable of handling multimedia needs.

Commercial Pentium II has been using RISC technology.

- Pentium III

Floating point instructions ability to handle 3D graphics.

- Pentium IV

Floating point capabilities and increasingly sophisticated multimedia.

- Itanium

2 units have the ability to floating point, integer 4 units, 3 units furcation, Internet streaming, 128 interger register.