Hello friends, Are you planning to upgrade the RAM of your computer. If yes then let me tell something about it. You can go to MemoryUpgrade.com. This site is an online store where you can buy memory upgrade for your computer. They have the memory upgrade for any kinds of computer manufacturers such as Apple, Toshiba, Acer, Dell, IBM and many others. I was told that Dell Memory Upgrades would work for a Dell computer only. However recently, there have been some memory modules which have no problems integrating with original brands. These computer ram can become compatible with the system with just a few drivers needed for it to work perfectly. Same goes for laptop memory as there actually lots of new brands of memory modules that are compatible with the original brand computers.

Dell PowerEdge Memory module expansions PRO Memory Upgrade delivers are made by DRAM manufacturers. Delivering the same, brands and part numbers of highly reliable RAM that Dell buys when installing memory modules in new machines to our PowerEdge computer users, not third party memory. These memory prices speak for themselves, affordable and competitive to start plus, they offer the ability to make an offer on any PowerEdge RAM expansion kit we sell. All combined with serving our customers with same day shipping, tech support and loads of other helpful computer tips and information. Similarly Dell Dimension Memory are required for great performances overall.

After a long time, a post on laptops has come. One of my close friend has finally decided to buy a laptop. He used to visit cyber cafes often and spend a lot of money for surfing websites. There he wasted both his time and money because the computers were slow, net speed was low and since the computer was not his own, he cannot save any private data on it. Due to this he always had to carry blank CD’s and pen drives etc borrowed from friends. To put an end to all this, I took him to computer store where his eyes twinkled seeing flashy laptops. Hearing the price he said lets go home back and he’s fine with cyber café’s only. To make him calm down, I first asked the computer dealer to get us a glass of cold water and then I asked him what type of work he does on a computer. He said the usual things like browsing websites, sending emails, listening music, typing something on word processor, sometimes watching movie etc. At this point I asked him a simple question, “Suppose you own two vehicles, one is a V8 engine SUV and other is a nice small hatchback car with all the luxury features and if you have to go to buy an ice cream from market which is very near to your home then which vehicle would you use?” Answer is a no-brainer and its obvious one would take the small hatchback car because its fuel efficient, it’s easy to park and does the job well without any problem. Then I said why would you buy an expensive laptop with fastest processor when you are not going to use it at its full potential ever?

I asked the dealer to show us Samsung Notebook NC 20 which is VIA Nano™ ULV Processor U2250 based laptop and it’s priced much lower than other laptops. VIA Nano™ ULV Processor U2250 is a decent processor for mobile computing, it consumes less power and it can do all the daily work a normal laptop user does. The best part about NC 20 is that it gives as much as 10 hours of battery backup while others will just shut down after 2 or 3 hours or usage. Adding to the good battery backup, NC 20 is very portable with its 12.1 inches screen. Though this screen may look small but it can display at quite decent resolution of 1280 x 800-pixel. Hard disk size is 160GB which is enough for most laptop users. I had a documentary movie with me in my pen drive and upon playing I found that sound output is quite impressive, no doubt the built 2.1 channel speakers with SRS are doing their job well here. This is something we don’t find in many premium laptops as well. NC 20 built quality is excellent and you can get the feel of it from its keyboard which is very nice to use and its very typing friendly. Review at cnet says that it has the best keyboard in netbook category. With a low price, it may be a bit higher from other VIA Nano based laptops available in market but the quality it offers justifies its slightly higher price. For more information just have a look at the review over this product. So my dear friends, what are you waiting for, go and grab your notebook from the nearest Samsung outlet. All positive comments are appreciated, and please do share your personal experiences with us.

The ARPANET (Advanced Research Projects Agency Network) created by ARPA of the United States Department of Defense during the Cold War, was the world’s first operational packet switching network, and the predecessor of the global Internet. Packet switching, now the dominant basis for both data and voice communication worldwide, was a new and important concept in data communications. Previously, data communication was based on the idea of circuit switching, as in the old typical telephone circuit, where a dedicated circuit is tied up for the duration of the call and communication is only possible with the single party on the other end of the circuit. With packet switching, a system could use one communication link to communicate with more than one machine by disassembling data into datagrams, then gather these as packets. Not only could the link be shared (much as a single post box can be used to post letters to different destinations), but each packet could be routed independently of other packets. A form of packet switching designed by Lincoln Laboratory scientist Lawrence Roberts underlay the design of ARPANET.

By mid-1968, a complete plan had been prepared, and after approval at ARPA, a Request For Quotation (RFQ) was sent to 140 potential bidders. Most regarded the proposal as outlandish, and only 12 companies submitted bids, of which only four were regarded as in the top rank. By the end of the year, the field had been narrowed to two, and after negotiations, a final choice was made, and the contract was awarded to BBN Technologies on 7 April 1969.

BBN’s proposal followed Taylor’s plan closely; it called for the network to be composed of small computers known as Interface Message Processors, what are now called routers. The IMPs at each site performed store-and-forward packet switching functions, and were connected to each other using modems connected to leased lines (initially running at 50 kbit/second). Host computers connected to the IMPs via custom serial interfaces to connect to ARPANET.

BBN initially chose a ruggedized version of Honeywell’s DDP-516 computer to build the first-generation IMP. The 516 was originally configured with 24 kB of core memory (expandable) and a 16 channel Direct Multiplex Control (DMC) direct memory access control unit. Custom interfaces were used to connect, via the DMC, to each of the hosts and modems. In addition to the lamps on the front panel of the 516 there was also a special set of 24 indicator lights to show the status of the IMP communication channels. Each IMP could support up to four local hosts and could communicate with up to six remote IMPs over leased lines. The BBN team of initially only seven people were considerably helped by the detail into which they had gone to produce their response to the RFQ and quickly produced the first working units. The entire system, including both hardware and the world’s first packet switching software, was designed and installed in nine months.

In computer networking, the Address Resolution Protocol is the method for finding a host’s link layer (hardware) address when only its Internet Layer (IP) or some other Network Layer address is known. ARP is defined in RFC 826. It is Internet Standard STD 37. ARP has been implemented in many types of networks; it is not an IP-only or Ethernet-only protocol. It can be used to resolve many different network layer protocol addresses to interface hardware addresses, although, due to the overwhelming prevalence of IPv4 and Ethernet, ARP is primarily used to translate IP addresses to Ethernet MAC addresses. It is also used for IP over other LAN technologies, such as Token Ring, FDDI, or IEEE 802.11, and for IP over ATM. In the next generation Internet Protocol, IPv6, ARP’s functionality is provided by the Neighbor Discovery Protocol (NDP).

ARP is a Link Layer protocol because it only operates on the local area network or point-to-point link that a host is connected to. ARP is also very often discussed in terms of the Open Systems Interconnect (OSI) networking model, because that model addresses hardware-to-software interfaces more explicitly and is preferred by some equipment manufacturers. However, ARP was not developed based on the design principles and strict encapsulation hierarchy of this model and, therefore, such discussions create a number of conflicts as to the exact operating layer within this model. Most often ARP is placed into the Data Link Layer (Layer 2), but it also requires the definitions of network addresses of the Network Layer.

An ARP announcement (also known as Gratuitous ARP) is a packet containing valid sender hardware and protocol addresses (SHA and SPA) for the host that sent it, with identical destination and source addresses (TPA = SPA). Such a request is not intended to solicit a reply, but merely updates the ARP caches of other hosts that receive the packet. Gratuitous ARP is usually an ARP request, but it may also be an ARP reply. Many operating systems perform this during startup. It helps to resolve problems which would otherwise occur if, for example, a network card was recently changed (changing the IP-address-to-MAC-address mapping) and other hosts still have the old mapping in their ARP caches. Gratuitous ARP is also used by some drivers to ensure load balancing on incoming traffic. In a team of network cards, it is used to announce a different MAC address in the team to receive incoming packets.

Simple Mail Transfer Protocol (SMTP) is an Internet standard for electronic mail transmission across Internet Protocol (IP) networks. SMTP was first defined in RFC 821 and last updated by RFC 5321 which includes the extended SMTP (ESMTP) additions, and is the protocol in widespread use today. While electronic mail servers and other mail transfer agents use SMTP to send and receive mail messages, user-level client mail applications typically only use SMTP for sending messages to a mail server for relaying. For receiving messages, client applications usually use either the Post Office Protocol (POP) or the Internet Message Access Protocol (IMAP) to access their mail box accounts on a mail server.

Various forms of one-to-one electronic messaging were used in the 1960s. People communicated with one another using systems developed for specific mainframe computers. As more computers were interconnected, especially in the US Government’s ARPANET, standards were developed to allow users using different systems to be able to e-mail one another. SMTP grew out of these standards developed during the 1970s.

SMTP can trace its roots to two implementations described in 1971, the Mail Box Protocol, which has been disputed to actually have been implemented, but is discussed in RFC 196 and other RFCs, and the SNDMSG program, which according to RFC 2235 by Ray Tomlinson of BBN “invents” for TENEX computers the sending of mail across the ARPANET. Fewer than 50 hosts were connected to the ARPANET at this time.

Further implementations include FTP Mail and Mail Protocol, both from 1973. The work continued throughout the 1970s, until the ARPANET converted into the modern Internet around 1980. Jon Postel then proposed a Mail Transfer Protocol in 1980 that began to remove the mail’s reliance on FTP. SMTP was published as RFC 821 in August 1982, also by Postel.

The SMTP standard was developed around the same time as Usenet, a one-to-many communication network with some similarities. SMTP became widely used in the early 1980s. At the time, it was a complement to Unix to Unix Copy Program (UUCP) mail, which was better suited to handle e-mail transfers between machines that were intermittently connected. SMTP, on the other hand, works best when both the sending and receiving machines are connected to the network all the time. Both use a store and forward mechanism and are examples of push technology. Though Usenet’s newsgroups are still propagated with UUCP between servers, UUCP mail has virtually disappeared along with the “bang paths” it used as message routing headers.

Sendmail was one of the first (if not the first) mail transfer agents to implement SMTP. Some other popular SMTP server programs include Postfix, qmail, Novell GroupWise, Exim, Novell NetMail, Microsoft Exchange Server, Sun Java System Messaging Server.