make a screen saver in XP & Turn off CD Auto Play

It used to be darn near impossible to create a personal screen saver using your own photo collection. To do this, you had to track down a third-party application and sloppily piece together your pictures to create a screen saver.

Well, the engineers at Microsoft must have realized they hated third-party applications and decided enough was enough. XP can take any pictures stored in your "My Pictures" folder and display them in random order as a screen saver.

To make a personal screen saver in XP, follow these directions:

Right-click an empty spot on your desktop and choose Properties.

Click the Screen Saver tab inside the Display Properties dialog box.

In the Screen Saver pull-down menu, choose "My Pictures Slideshow."

Underneath the Screen Saver pull-down menu, adjust the time of inactivity before Windows will initiate your screen saver.

Click Settings to make additional adjustments.

You'll be able to adjust transition effects between pictures, how frequently they change, what size the pictures should be, and more.

Click OK when you're done tweaking the settings adjustments. Press the Preview button to see what your screen saver looks like.

If everything is to your liking, click Apply.

Turn off CD Auto Play

Open My Computer Right click on your CD ROM and choose Properties Click on the Auto Play tab In the drop down box you can choose the Action for each choice shown in the drop down box
Or
Go to Start->Run->gpedit.msc Computer Config -> Administrative Template -> System Double click Turn off Autoplay Enable it.

Set up and Use Internet Connection Sharing & Saving Web Pages with Internet Explorer 6

Set up and Use Internet Connection Sharing

With Internet Connection Sharing (ICS) in Windows XP, you can connect one computer to the Internet, then share the Internet service with several computers on your home or small office network. The Network Setup Wizard in Windows XP Professional will automatically provide all of the network settings you need to share one Internet connection with all the computers in your network. Each computer can use programs such as Internet Explorer and Outlook Express as if they were directly connected to the Internet.

You should not use this feature in an existing network with Windows 2000 Server domain controllers, DNS servers, gateways, DHCP servers, or systems configured for static IP addresses.


Enabling ICS

The ICS host computer needs two network connections. The local area network connection, automatically created by installing a network adapter, connects to the computers on your home or small office network. The other connection, using a 56k modem, ISDN, DSL, or cable modem, connects the home or small office network to the Internet. You need to ensure that ICS is enabled on the connection that has the Internet connection. By doing this, the shared connection can connect your home or small office network to the Internet, and users outside your network are not at risk of receiving inappropriate addresses from your network.

When you enable ICS, the local area network connection to the home or small office network is given a new static IP address and configuration. Consequently, TCP/IP connections established between any home or small office computer and the ICS host computer at the time of enabling ICS are lost and need to be reestablished. For example, if Internet Explorer is connecting to a Web site when Internet Connection Sharing is enabled, refresh the browser to reestablish the connection. You must configure client machines on your home or small office network so TCP/IP on the local area connection obtains an IP address automatically. Home or small office network users must also configure Internet options for Internet Connection Sharing. To enable Internet Connection Sharing (ICS) Discovery and Control on Windows 98, Windows 98 Second Edition, and Windows Millennium Edition computers, run the Network Setup Wizard from the CD or floppy disk on these computers. For ICS Discovery and Control to work on Windows 98, Windows 98 Second Edition, and Windows Millennium Edition computers, Internet Explorer version 5.0 or later must be installed.



To enable Internet Connection Sharing on a network connection

You must be logged on to your computer with an owner account in order to complete this procedure. Open Network Connections. (Click Start, click Control Panel, and then double–click Network Connections.)

Click the dial–up, local area network, PPPoE, or VPN connection you want to share, and then, under Network Tasks, click Change settings of this connection.

On the Advanced tab, select the Allow other network users to connect through this computer's Internet connection check box.

If you want this connection to dial automatically when another computer on your home or small office network attempts to access external resources, select the Establish a dial–up connection whenever a computer on my network attempts to access the Internet check box.

If you want other network users to enable or disable the shared Internet connection, select the Allow other network users to control or disable the shared Internet connection check box.

Under Internet Connection Sharing, in Home networking connection, select any adapter that connects the computer sharing its Internet connection to the other computers on your network.

The Home networking connection is only present when two or more network adapters are installed on the computer.


To configure Internet options on your client computers for Internet Connection Sharing

Open Internet Explorer. Click Start, point to All Programs, and then click Internet Explorer.
On the Tools menu, click Internet Options.

On the Connections tab, click Never dial a connection, and then click LAN Settings.

In Automatic configuration, clear the Automatically detect settings and Use automatic configuration script check boxes.

In Proxy Server, clear the Use a proxy server check box.




Saving Web Pages with Internet Explorer 6

Occasionally, you may want to save an entire Web page on your computer (text, hyperlinks, graphics, and all). To save the Web page that currently appears in Internet Explorer, choose File-->Save As to open the Save Web Page dialog box shown in the following figure. Select the folder in which you want the page saved and then click the Save button.

After saving a Web page on your hard drive, you can open it in Internet Explorer and view the contents even when you're not connected to the Internet. If your motive for saving the Web page, however, is to be able to view the content when you're not connected to the Internet, you're better off saving the page as a Favorite marked for offline viewing. That way, you can decide whether you want to view other pages linked to the one you're saving and you can have Internet Explorer check the site for updated content.

You can also e-mail a Web page or a link to the page to a colleague or friend. To send the current Web page in a new e-mail message, click File-->Send-->Page by E-mail on the Explorer menu bar and then fill out the new e-mail. To send a link to the page instead, click File-->Send-->Link by E-Mail. To create a desktop shortcut to the Web page, click File-->Send-->Shortcut to Desktop.

Internet Connection Sharing & Increase BROADBAND

Internet Connection Sharing

To enable Internet Connection Sharing on a network connection

1. Open Network Connections.
2. Click the dial-up, local area network, PPPoE, or VPN connection you want to share, and then, under Network Tasks, click Change settings of this connection.
3. On the Advanced tab, select the Allow other network users to connect through this computer's Internet connection check box.
4. If you want this connection to dial automatically when another computer on your home or small office network attempts to access external resources, select the Establish a dial-up connection whenever a computer on my network attempts to access the Internet check box.
5. If you want other network users to enable or disable the shared Internet connection, select the Allow other network users to control or disable the shared Internet connection check box.
6. Under Internet Connection Sharing, in Home networking connection, select any adapter that connects the computer sharing its Internet connection to the other computers on your network.

Increase BROADBAND

This is for broad band connections. I didn’t try it on dial up but might work for dial up.

1. make sure your logged on as actually "Administrator". do not log on with any account that just has administrator privileges.
2. start - run - type gpedit.msc
3. expand the "local computer policy" branch
4. expand the "administrative templates" branch
5. expand the "network branch"
6. Highlight the "QoS Packet Scheduler" in left window
7. in right window double click the "limit reservable bandwidth" setting
8. on setting tab check the "enabled" item
9. where it says "Bandwidth limit %" change it to read 0

Effect is immediate on some systems, some need to re-boot. This is more of a "counter what XP does" thing. In other words, programs can request up to 20% of the bandwidth be reserved for them, even with QoS disabled, this is no big deal and most programs do not request it. So, although QOS has caused a big stink because people think it reserves 20% of their bandwidth, you can still disable it, just to be sure.

components of a pc

A pc comprises of hardware and software. Everything that you can see and touh in the pc is called the hardware. the computer has a large number of components. Each of these parts is essential to the functioning of the pc. The input devices, output devices, storage devices, processing devices, communication devices and infrastructure are the different parts of the pc.

Input Devices:
Keyboard, Mouse, Scanner

Output Devices:

Display card -

Display card used to support visual effects on a pc. The Display card takes the data from different parts of the computer and takes it to the monitor in a format that the monitor can use.
Modern display cards are very advanced and can store images as well this reduces the burden on the CPU.

Sound card -

Used to generate sound effects in a computer.

Monitor and Printer also output devices

Storage Devices:
Storage Devices are used to store data in the computers. There are several types of storage devices for computer.
Floppy Disk, Hard Disk, CD, DVD, Pendrive etc.. these are all storage Devices.

Processing Devices:
main function of a computer is to process data. Central Processing Unit ( CPU ) is the processing device of the computer. Data that the user inputs is processed by the CPU.
Various types of processing devices are as follows.

Microprocessors - Controls the flow of data in the system. The most important electronics component on the Mother Board is the microprocessor. The power of a computer how fast it can accomplish a given job, Such as resizing a digital photo depends on the model of microprocessor in the computer as well as how fast the microprocessor operates.

Chipset -
Provides vital support functions to its microprocessor. The chipset creates signals such as clocks or oscillator that sets the pace of logic operations of the microprocessor. In addition, it links the microprocessor to the rest of the computer, both the memory and external functions, through I/O ports.

BIOS -
Instructs the computer what to do before loadig any software. This program is called the Basic Input Output System ( BIOS ). It is mounted in the ROM of the comjputer.

Communication Devices:

Serial port - Connects to devices such as modems, mice, and digital cameras. Serial ports are the oldest kinds of ports in use. They transmit data in a serial fashion. Serial ports enable data flow in both directions.

Parallel port -
Connects to scanners, CD burners, hard drives and printers, parallel ports are much faster than serial ports. These ports transmit data in a parallel mammer. parallel ports are wide in size to enable parallel transmission of data.

USB ( Universal Serial Bus ) -
Connects to a wide range of devices like mouse, keyboard, modems and speakers. USB is a becoming a popular replacement for serial and parallel ports. This is because USB is highly adanced, fast and simple to use.

LAN card -

LAN card connects the pc to a network. The LAN card enables connections to other computers. We exchange data and resources across a network. The LAN card is crucial to this objective. Companies can share devices like printers across a network and access data in an intranet.

Microprocessor

Introduction:

computer is a machine that is capable of accepting data, processing it and displaying the appropriate output. It can also store data and perform a set of complex calculations to accomplish complicated tasks. These calculations are performed by Central processing Unit (CPU) of the system. CPU is also known as the microprocessor which is the heart of the system. Microprocessor accepts input from input devices such as keyboard or mouse in the form of data and instructions. It processes the data using instructions and sends the processed information to the output device such as the monitor or printer.
Microprocessors process the data using instructions. It retrives the data and instructions from the RAM. RAM is a temporary storage area that the system uses to store data and instructions.

Microprocessor sockets:
The socket on the motherboard connects the microprocessor to the motherboard. The micro processor has pins that enter the motherboard using witch the microprocessor communicates with the system.
these motherboards use the Zero Insertion Force ( ZIF ) or the Low Insertion Force ( LIF ) to install processor on the motherboard. The ZIF uses a lever to install or remove the microprocessor. The microprocessor must be installed and removed using a little force.

Socket 1 -
Socket 1 supportts microprocessors that have 169 pins. In this socket, the pins are arranged in three rows. Socket 1 supplies maximum 5 volts to the microprocessor. This socket supports the 80486SX, 80486DX, 80486DX2, 80486DX4 OverDrive microprocessor.

Socket 2 -
Socket 2 supports microprocessors that have 238 pines. In this socket, the pins are arranged in four rows. Socket 2 supplies maximum 5 volts to the microprocessor. This socket supports the 80486DX, 80486SX, 80486DX2, 80486DX4 OverDrive, Pentium OverDrive 63, and Pentium OverDrive 83 microprocessors.

Socket 3 -
socket 3 supports microprocessors that have 237 pines. In this socket, the pins are arranged in four rows. Socket 3 supplies 3.3 to 5 volts to the microprocessor. The voltage can be adjusted using jumpers on the motherboard. This socket supports the 80486DX, 80486SX, 80486DX2, 80486DX4, AMD 5x86, Pentium OverDrive 63 and Pentium OverDrive83 microprocessors

Socket 4 - Socket 4 supports microprocessors that have 273 pins. In this socket, the pins are arranged in four rows. Socket 4 supplies maximum 5 volts to the microprocessor. This socket supports the Pentum 60-66, Pentium OverDrive 120 and Pentium Overdrive 133 microprossors

Socket 5 - Socket 5 supports microprocessors that have 320 pins. In this socket, the pins are arranged in five rows. Socket 5 supplies maximum 3.3 volts to the microprocessor. This socket supports the Pentum 75-133MHz, Pentium OverDrive 125-166 and Pentium with MMX Overdrive 125-166 microprossors

Socket 6 - Socket 6 supports microprocessors that have 235 pins. In this socket, the pins are arranged in four rows. Socket 6 supplies maximum 3.3 volts to the microprocessor. The Pentium microprocessor was used on an increased scale. As a result, no processors supported this socket

Socket 7 - Socket supports microprocessors that have 321 pins. In this pins are arranged in five rows. Socket 7 supplies 2.5 to 3.3 volts to the microprocessor uses 3.3 volts. This socket supports the Pentium 75-200MHz, Pentium OverDrive, Pentium with MMX, Pentium with MMX OverDrive, K5, K6, 6x86, and 6x86MX microprocessors.

Socket 8 -
Socket 8 supports microprocessors that have 387 pins. In this socket, the pins are arranged in five rows. socket 8 supplies 3.1 to 3.3 volts to the microprocessor. The socket supports the Pentium Pro microprocessors. The socket 8 is more rectangular in shap then the other sockets.

socket 370 - Socket 370 supports microprocessors that have 370 pins. In this socket, the pins are arranged in six rows.The microprocessorss for this socket are similar to those used on slot 1. The microprocessors for this socket have the L2 cache built into the microprocessor. This socket supports Celeron 2 and Pentium III microprocessors.

Socket 462 - Socket 462 is also known as Socet A. The socket has 462 pins, of which 9 pines are blocked to prevent accidental insertion of Socket 370 CPUs. Total 453 pins are available. The microprocessors for this socket hae the L2 cache built into the microprocessor. These microprocessors can be installed only in their respective sockets. This socket supports the Athlon and Duron microprocessors.

Socket 478 - Socket 478 supports microprocessors that have 478 pines. The microprocessors for this socket have the L2 cache built into the microprocessor. These microprocessors are similar to socket 423 microprocessors. The socket 423 microprocessors are larger in size than socket 478 microprocessors. socket 478 is currently used with Intel Pentium 4 microprocessor

Socket 754 - Socket 754 is developed by AMD. It supports 64 bit computing processors. It is mainly used with the AMD Athlon 64 or Semperon processors. The socket consists of 754 pins and is of PGA - ZIF type. The voltage range for this type of sockets is 0.8 to 1.55 volts. It supports 800MHz bi-directional hyper transport technology support.

Socket 775 - Socket LGA 775 is developed by Intel. It is used with the latest processors such as the Intel Pentium 4 Extreme Edition processors, Intel Pentium D processors, Intel Pentium processors,and the Intel Pentium 4 processors with Hyper Threading technology, This sovket also supports the 64 bit computing technology.

Socket 939 - Socket 939 is developed by AMD. It supports 64 bit computing. It is used with AMD Athlon 64, AMD Athlon 64 FX and AMD Athlon 64 X2 processors. It is also used with some AMD Opteron processors. It contains 939 pins and is of PGA - ZIF type. It has an operating voltage range of 0.8 to 1.55 volts. It supports 64KB L1 cache as well as 64KB data cache and a L2 cache up to 1 MB. These types of sockets support 3D technology for better graphic resolution.

Microprocessor Slots:

Microprocessor such as Intel Pentium II, III, Xeon, Celeron and AMD Athlon are installed on cards. The card with the microprocessor on it is installed on the motherboard. The microprocessor and the card from a complete processor unit. The card is built in with the L2 cache. Frequently accessed data is stored in this cache which increase the speed of data processing.

Slot 1 -
Slot 1 supports microprocessors that have 242 pines. The microprocessor is mounted on a card that uses Socket 8. Slot 1 supplies 2.8 to 3.3 volts to the microprocessor. This slot supports the Pentium II, III and Celeron microprocessors.

Slot 2 -

Slot 2 supports microprocessors that have 330 pins. This slot supports the pentium Xeon microprocessors. This slot is found on server motherboards.

Slot A -
Intel patented the slot 1. This allowed only Intel to manufacture microprocessors that used this slot. AMD created Slot A to support the Athlon microprocessors. This slot is similar to Slot 1. Slot A usese the EV6 protocol. EV6 enables the microprocessor and RAM to communicate at an increased speed.

Memory

Types of Memory:
RAM - Stands for Random Access Memory. It is a semiconductor-based memory where the CPU or the other hardware devices can read and write data. It temporarily stores the data and it is a volatile memory. Once the system turns off, it loses the data. As a result, RAM is used as a temporary data storage area.

ROM - Stands for Read Only Memory. It stores the data permanently and it is a non-volatile memory. It does not losr the data even after the system turns off. As a result, ROM is a permanent data storage area.

Types of ROM:

PROM - Stands for Programmable Read - Only Memory. It stores programs permanently and is a non-volatile memory. Programming the ROM is sonetimes referred to as burning and it requires a special machine called a device programmer or ROM burner. Each binary 1 bit can be thought of as a fuse; when a prom is programmed, a higher voltage blows or burns the fuses at the de sired locations thus turning any given 1 into a 0. Due to this, PROM chips are often referred to as One Time Programmable ( OTP ) chips.

EPROM - Stands for the Erasable Programmable Read-Only Memory. Ultra-Violet ( U-V ) rays can remove the programs from this memory. It can be easily recognized by the clear quartz crystal window set on the top of chip. An EPROM eraser is a device that contains a UV light source that erases the chip by causing a chemical reaction, which essentially melts the fuses back together.

EEPROM/Flash ROM - Stands for the Electrically Erasable Programmable Read-Only Memory. Electrical signal removes the programs from this memory. EEPROM can be erased by an electric field, rather than exposed to UV. Also, the data can be erased bit by bit allowing only selected portions of the code to be replaced. But in case of Flash ROM, data is rewritten in blocks of 512 bytes where as EEPROM erases individual bytes.

Types of RAM:
RAM is the main memory of the computer. It holds the data until the system is turned off. Once the system is switched off, the data is lost. As a result, it is known as the temporary data storage area. There are two types of RAM, Static RAM ( SRAM ) and Dynamic RAM ( DRAM ).

SRAM ( Static Random Access Memory ) - SRAM is a type of semiconductor memory. It is a temporary data storage area. SRAM is faster in accessing data. The data accessing of SRAM makes it behave like a cache memory.

Cache RAM -
cache RAM is a type of SRAM which enables the CPU to send data at a very high speed. It is placed between the main memory and the CPU and used for a temporary storage. It is the buffer between CPU and DRAM which provides the information without the use of DRAM. Cache RAM is very fast and expensive compared to RAM. Date can be processed easily without waiting for it to be retrived from the DRAM if it is stored in cache RAM. The fastest cache RAM is known as L! and is placed inside the CPU.

DRAM ( Dynamic Random Access Memory ) - The lifetime of the data in DRAM is very short. It is approximately for fifteen milliseconds.

Types of DRAM -
SDRAM ( Synchronous Dynamic Random Access Memory ) - SDRAM synchronizes the memory speed with the CPU clock speed.The data transfer speed of SDRAM is measured in nanoseconds and megahertz units. It runs with an average speed of 133 MHz.
There are two modules of SDRAMs:
2-clock SDRAM - In a 2-clock SDRAM, each clock signal controls two different DRAM chips.
4-clock SDRAM - In a 4-clock SDRAM, each clock signal controls four different DRAM chips. The recent computers use 4-clock SDRAM.

DDR-SDRAM ( Double Data Rate Synchronous DRAM ) - It is the latest version of SDRAM. DDR is synchronous with the system clock. This memory chip consumes less power. DDR memory supports Error Correction CAoad ( ECE ) and non-parity.
There are three types of DDR-SDRAMs.
DDR - These are avelable 128MB to 1GB
DDR2 - These are avelable 256mb to 4GB
DDR3 - These are avelable 2GB to 4GB

What is Virtual Memory ?
virtual memory is a part of the hard disk which is used as a memory. It has a set of memory addresses and stores the instrctions or the data. When the processor executes the instructions, it converts the vertual memory addresses into read memory address. The main use of the virtual memory is to increase the address space.
Operating system such as windows supports virtual memory area. DOS operating system does not support the concept of the virtual memory area.

Motherboard

Introduction:
Motherboard is the most important component of a system. It is a Printed Circuit Board ( PCB ) where all the components of a system are connected. The Central Processing Unit ( CPU ), hard drives, memory and every other part of a system is connected to the motherboard by means of slots, connectors and sockets. The motherboard chipset is a series os chips that are a part of the motherboard. The chipset is very important to the operation of the system.

Types of Motherboards:

1. Desktop Motherboards -

Desktop motherboard is used in personal computers and desktops. As it is used for applications at home and in office, this type of motherboard is the most basic type.

2. Server Motherboard -

Server motherboards are more advanced than desktop motherboards and are designed to offer high-end services. These motherboards support expansion and future upgrades and can handle major applications. Server motherboards also offer improved graphics and can support different types of memory technology.

3. Laptop Motherboards -

Laptop motherboard is connected to different parts of a laptop system. It is most important part of a laptop. These motherboards generally have very advanced features as compared to the desktop motherboards.

components of Motherboard:

power supply

The power supply unit of system mostly found in the top corner of the system case accepts the AC ( Alternating current ) from the power socket in the wall. It then converts the AC to DC ( Direct current ) for the system. Now a days power supplies are available in the range of 250W to 400W.

Types of power supply:
A power supply is a system which provides power to the circuit or the devices connected to it. Power supply converts the AC to DC voltage. Maney units of the computerrequir DC power. The two types of power supplies are Linear power supply and switch mode power supply.

Linear Power Supply-
Transforms incoming voltage to a lower voltage using transformers. A diode circuit is used to rectify the AC voltage to pulsating DC. the
capacitor filter is then used to provide DC voltage with low ripples. Finally,linear regulator is used to reduce the voltage to a desired level. Linear power supply is bulky but has very low noise.
Switch Mode Power Supply -
Uses high switching frequency. It is compact and can deliver very high power. It is used as DC to DC converter in which power switches, power connectors and power supply fan.

Power Connectors:
The power supply unit provides current to the motherboard, hard disk drive, floppy disk drive and various other components of a system using the power connectors carrying small amount of power are called signal connectors. There are 5 types of connectors.

1. AT power connectors
2. ATX power connectors
3. Standard peripheral power connectors ( Molex )
4. Floppy Drive power connectors ( Mini/Berg )
5. 2/3 Pin Mini plug type connectors

AT Power connectors -

There are two 6 wire connectors named P8 and P9 which are to be connected to the motherboard with black wires inside. The PC/XT, AT, Baby AT and LPX form factors of the power supply use a pair of 6 wire connectors, called as AT style connectors to connect the power supply to the motherboard.

ATX Power Connector -

This is a 20 pin connector with 6 types of voltage coming out of it. The ATX Style power connectors for the ATX/NLX from factors use the ATX Style power connectors. This style has a single 20-pin connector.

Standard peripheral power connectors ( Molex ) -

The disk drive power connectors use 4 wire connectors. The 4 wire connectors are available in large and small size connectors. The hard disk drive, CD/DVD drives use larger size connectors, commonly called as Molex.

Floppy Drive Power Connectors ( Mini/Berg ) -
The 3.5-inch floppy disk drive use smaller size connectors, called as mini-plug.

Hard Disk Drives

Hard Disk:
A Hard disk is a secondary and permanent data storage device that is placed in the system. Now a days 2TB (2000GB) Hard disk also avalable.
A Hard disk consists of several circular platters. Each platter has read/write heads on both the sides. The platters are divided into concentric circles called as tracks, and each track is divided into smaller units called sectors. The read/write head examines and records data in these sectors. the identically aligend tracks on each side of every platter together make up cylinder.

TYPES OF HARD DISKS:
1. Standard Drives ( IDE/PATA )
2. Serial ATA ( SATA )
3. SCSI Hard Disk Drive
4. External Hard Disk Drives ( USB 2.0/Firewire )
5. Wireless Hard Disk Dirves

IDE ( Integrated Drive Electronics ):
The ATA transfers data between the hard disk and system using 16 bits with speeds of up to 100MB/133MB per second. you can connect two Hard Disks to a single controller on the system. You must set the Hard Disk to master or slave using the jumpers on the hard dis, so that the system can identify the required hard disk. This hard disk uses a 40-pin connector to connect to the system.
Also know as IDE,EIDE,PATA. ATA interface that transferred data at speeds 25MB per sec used programmed input output (PIO) technology to transfer data. ATA interfaces transferred data at 25MB per sec or higher used the ultra Direct Memory Acces (UDMA) method to transfer data. In the PIO method, the CPU controls the transfer of data from the hard disk whereas the chipset controls the transfer of data in the UDMA method

SATA ( Serial AT Attachment ):
Serial ATA transfers data using 1 bit with the speed of upto 600MB per sec but External SATA is capable of 1.5 Gbps. SATA hard disk uses a smaller 7-wire cable to connect to the system. this cable can have a maximum length of 1 meter. The power cable of a SATA hard disk is smaller tham the MOLEX connector used in ATA hard disks.
You can connect only one Serial ATA hard disk as a master or slave. You can connect more than one hard disk by connecting them to different SATA controllers on the motherboard using separate cables.

SCSI ( Small Computer Systems Interface ):
SCSI HDD is typically used in network server which includes lot of processing. SCSI is a high speed interface that enables you to connect up to 15 devices on a single port. SCSI is used with RAID (Redundant Array of Inexpensive Disk), whare two or more disks are combined together to form a single hard disk. RAID allows to access data quickly and prevents loss of data in case of a hard disk crash.

External Hard Disk Drives ( USB, Firewire )
External HDD can be connected using USB2 and Firewire interfaces. External HDD also supports high-speed data transfer. External Hard disks that uses interfaces consumes the required power from the port through which they are connected like USB or Firewire.

Wireless HDD:
Wireless Hard Disk Drives are small and light in Weight. They use 802.11g standard for communication. WL HDD requires external power supply.It is a Wi-Fi hard disk. Data transfer rate is 54 mbps.