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Types of Laptop Memory

An SO-DIMM, or small outline dual in-line memory module, is a type of computer memory built using integrated circuits.SO-DIMMs (also written SODIMMs) are a smaller alternative to a DIMM, being roughly half the size of regular DIMMs. SO-DIMMs are often used in systems that have limited space, such as notebooks, small footprint PCs (such as those with a Mini-ITX motherboard), high-end upgradable office printers, and networking hardware like routers.

There are four types of SO-DIMM memory, which build on each other's capacities.SDRAM stands for synchronous dynamic random access memory. This type of memory syncs itself up with your computer's processor, allowing smooth access. With the advances of technology, most newer laptops no longer use SDRAM.DDR SDRAM is SDRAM with a double data rate. This means it's twice as fast as standard SDRAM, and it's one of the two most common types of memory found in modern laptops as of August 2009. 200 pinsDDR2 SDRAM is yet another upgrade to the original SDRAM concept. A big advantage of this type of memory is that it draws less power than its predecessors, thus creating less drain on your laptop. 204 pinsSO-DIMMs with 204 pins are a type of double data-rate three (DDR3) memory. They range in capacity from 1 to 4 GB per module. Most of these modules have eight memory chips each, four per side, with each chip's capacity ranging from 128 to 512 MB.

Most types of SO-DIMMs can be recognized at a glance by the distinctive notches that key them for different applications:100-pin SO-DIMMs have two notches144-pin SO-DIMMs have a single notch near the center200-pin SO-DIMMs have a single notch nearer to one side. The exact location of this notch varies (read below.)204-pin SO-DIMMs (DDR3) have a single notch closer to the center than on 200-pin SO-DIMMs.256-pin SO-DIMMs (DDR4).

Variants of 200-pin SO-DIMMsThe 200-pin SO-DIMM notch is in one of three locations:If the notch is located away from the center, it indicates the DDR class of memory.When the notch is located slightly closer to the center of the board, it generally (but not always) indicates that the RAM is of the DDR2 type.These two types of memory are not interchangeable. The different notch locations are designed to prevent cross-installation. Keep this in mind when attempting to visually identify 200-pin SO-DIMM modules.This variance is designed to prevent coupling of memory and controllers of different DDR generations due to electrical incompatibility. DDR1 SO-DIMMs operate at 2.6 Volts while DDR2 SO-DIMMs operate at 1.8 Volts.General characteristics200- and 204-pin SO-DIMMs measure at 6.76cm in length and a width of 3.175cm with a maximum total depth of 0.38cm.SO-DIMMs are more or less equal in power and voltage rating to DIMMs, and as memory technology moves forward and despite their smaller size, SO-DIMM technology allows for performance speeds as high as the those of the larger DIMMs (clock speeds such as 400MHz PC-3200, for example, and CAS latency such as 2.0, 2.5, and 3.0) and capacity (512MB, 1GB, etc.).DDR2 SO-DIMM memory modules commonly have clock speeds from 200MHz up to 800MHz PC2-6400.The latest 204-pin SO-DIMMs can contain DDR3 SDRAM, with specifications such as PC3-6400, PC3-8500, PC3-10600, and PC3-12800.

PC6400 DDR2 SO-DIMM (200 pins)

PC3-10600 DDR3 SO-DIMM (204 pins)

Types of Personal ComputerMemory

Random Access Memory, or RAM, chips are where the computer stores programs and other information when it is running. It is important to have sufficient RAM installed on a computer. By 2010 standards, a computer should have at least 2 gigabytes of RAM storage capacity. Less RAM will force the computer to store part of the software in use on the hard disk and move information in and out of RAM as needed. This process is called swapping. This often cause the computer to lag. Swapping is a relatively slow process because hard disk access is much slower than RAM access. Having a lot of RAM installed will ensure that this problem will not be encountered. Over time, RAM chips have undergone improvements, with each new generation being faster than the previous type.

FPM RAMFast Page Mode RAM was one of the earlier RAM models. This chip was introduced in 1990.FPM RAM operated at a clock speed of 25 megahertz, or MHz. The FPM RAM came in 30-pin and 72-pin models. It was able to achieve speed by using only the column address when the data was located in the same row as the previously accessed data.

Extended Data Out RAM was introduced in 1994. This chip operated at a clock speed of 50 MHz. EDO RAM was used with the earlier models of Intel Pentiums prior to Pentium 4. EDO RAM had 72 Pins. This RAM was able to achieve faster speeds than FPM RAM by overlapping access cycles using the output buffer.Synchronous Dynamic Random Access Memory had 168 pins. First shipped models operated at 66 MHz and later models had a speed of 100 MHz and then 133 MHz. SDRAM was introduced in 1996. This was the first RAM chip to synchronize with the microprocessor's clock speed.

DDRDouble Data Rate RAM had 184 pins. Compatible with AMD and Intel microprocessors faster than 1 GHz, it improved on SDRAM and operated at clock speeds as fast as 266 MHz. It was twice as fast as SDRAM because it triggered off both the rising and falling edge of the clock signal. SDRAM on the other hand, used only the rising edge of the clock signal.DDR2 RAM had 240 pins. It was a newer version of DDR RAM that was introduced in 2003 and ran at clock speeds up to 533 MHz.DDR3 RAM was introduced in 2007. This is the current RAM chip used by the latest computers and video graphics cards. It has 240 pins and runs at clock speeds up to 800 MHz.

Power Supply Unit

Thepowersupplyunit (PSU) in a PC regulates and delivers the power to the components in the case.Standard power supplies turn the incoming 110Vor220V AC (Alternating Current) into various DC (Direct Current) voltages suitable for powering the computer's components.

Power supplies are quoted as having a certain power output specified in Watts, a standard power supply would typically be able to deliver around 350 Watts.The more components (hard drives, CD/DVD drives, tape drives, ventilation fans, etc) you have in your PC the greater the power required from the power supply.

By using a PSU that delivers more power than required means it won't be running at full capacity, which can prolong life by reducing heat damage to the PSU's internal components during long periods of use.

Always replace a power supply with an equivalent or superior power output (Wattage).

There are 3 types of power supply in common use:AT Power Supply- still in use in older PCs.ATX Power Supply- commonly in use today.ATX-2 Power Supply- recently new standard.

AT Power Supply

ATX Power Supply

ATX-2 Power Supply

4 Pin Berg ConnectorUsed to connect the PSU to small form factor devices, such as 3.5" floppy drives.available in:AT, ATX & ATX-24 Pin Molex ConnectorThis is used to power various components, including hard drives and optical drives.available in:AT, ATX & ATX-220 Pin Molex ATX Power ConnectorThis is used to power the motherboard in ATX systems.available in:ATX( ATX-2 have four extra pins)4 Pin Molex P4 12V Power ConnectorUsed specifically for Pentium 4 Processor Motherboards.available in:ATX(integrated into the power connector in ATX-2)6 Pin AUX ConnectorProvides +5V DC, and two connections of +3.3V.available in:ATX/ATX-2

ATX Power Supply Pinouts Below are pinout diagrams of the common connectors in ATX power supplies.

note:The pinouts above relate to the connectors not the sockets.note:To power up an ATX or ATX-2 PSU for testing, short pin 14 (PS_ON) with one of the grounds.

IP Address and IP Classes

Every host on a TCP/IP network needs to have a unique address, similar to you needing a unique address for your house. With this unique address, it is possible to send data from host to host.

Every packet contains addressing information in the header, and the IP address in the header is used to route packets.

If several people on your street had the same address, the post office would have a difficult time sorting mail. For a similar reason, IP addresses are unique on each network.What is IP addressing?

IP addressingis simply configuring each TCP/IP host with a validIP address.

For access to the Internet, a host must have an IP address that identifies not only the host address (like a house number) but also identifies the network address (like a street number). An administrator needs to be aware of proper addressing techniques so that the hosts on the network will function correctly. TCP/IP addresses are based on 32-bit addresses.IP Address classes

IP addressesare divided into five IP classes:IP address class AIP address class BIP address class CIP address class DIP address class EAll IP addresses are placed in a particular class based on the decimal values of their first octets. In the first octet, an IP address can start with a decimal value between 1 and 255.

IP class A addresseshave first octets with a decimal number from 1 to 127. Example:27.x.y.z127.x.y.z

IP class B addresseshave first octets with a decimal number from 128 to 191.Example:128.x.y.z191.x.y.z

IP class C addresseshave first octets with a decimal number from 192 to 223.Example:192.x.y.z223.x.y.z

IP class D addresseshave decimal values from 224 to 239 in the first octet, and the 4 leftmost bits are 1110.Example:224.x.y.z239.x.y.z

The last IP address class of addresses isIP class E. IP class E addresses range from 240 to 255 in the first octet, and the 4 leftmost bits are 1111. Example:240.x.y.z255.x.y.z

ClassAddress RangeSupportsClass A1.0.0.1 to 127.255.255.254Supports 16 million hosts on each of 127 networks.Class B128.1.0.1 to 191.255.255.254Supports 65,000 hosts on each of 16,000 networksClass C192.0.1.1 to 223.255.254.254Supports 254 hosts on each of 2 million networks.Class D224.0.0.0 to 239.255.255.255Reserved for multicast groups.Class E240.0.0.0 to 255.255.255.254Reserved for future use, or Research and Development Purposes.Short for Internet Protocol, IP is an address of a computer or other network device on a network using IP or TCP/IP. For example, the number "166.70.10.23" is an example of such an address. These addresses are similar to an addresses used on a house and is what allows data to reach the appropriate destination on a network and the Internet.There are five classes of available IP ranges: Class A, Class B, Class C, Class D and Class E, while only A, B, and C are commonly used. Each class allows for a range of valid IP addresses. Below is a listing of these addresses.

Types of Processor Sockets

Computer processors and motherboards are differentiated primarily by their CPU socket number. The CPU socket number is used to define the compatibility between different types of processing architectures, even within the same family of processor motherboard, for computer building purposes. Moreover, in many cases, the CPU socket number denotes cooling considerations that must be taken into account, and sometimes the physical characteristics of the CPU and socket itself

What is the difference, regarding the form factor, between the pga sockets and lga sockets?AnswerThe difference between PGA sockets and LGA sockets regarding form is that PGA sockets have a grid pin system (male connectors), which connects into holes in the mother board and in the LGA sockets system (female), the socket has holes and the mother board has the pins.

PGA: Pin Grid Array. An architecture of socket where the pins on the socket fit into holes on the motherboard. This generally refers to the method by which a component (generally a CPU) makes contact with a motherboard. Specifically, a PGA system utilizes a number of pins on the bottom of the component, which fit into holes in a socket on the motherboard, facilitating electrical contact.

LGA: Land Grid Array, and for Intel CPUs, is usually followed by a number that indicates how many pins are in the socket. When a CPU is inserted into the socket, the pins on the bottom of the socket line up with the holes that cover electrical contacts on the CPU and an electrical (and data bus) connection is made.