Mashed Articles

Writen by Ken Marlborough

The cheapest type of RAM is dynamic RAM because it uses traditional technology as opposed to static RAM, which is expensive and uses advanced methods to store and retrieve temporary information. Dynamic RAM has capacitors that act like vessels that store temporary information for the CPU to use as and when required. This makes them cheaper as compared to static RAM that is expensive because it does not use the same technology as a dynamic RAM.

RAM chips are available in the market within a price range of $4 to $400, depending on its make, brand, upgrade, and type. The modern computer usually uses dynamic RAM that is at least 128 MB in size. This RAM race started in the 1990s when 2MB of RAM were used. However, technology has improved in leaps and bounds since then, and today using less than 128 RAM would be not advisable, as the speed and efficiency of the computer will be dramatically affected.

SIMM RAM is the oldest and cheapest of them all but can only be used with old machines and is not compatible with newer ones. It is available for less as $5 and can be bought on the Internet. A memory upgrade is the most cost effective method of improving a PC’s performance, and memory upgrades are very simple to install and require no configuring at all.

A 4 MB 30pin 60ns 3-chip SIMM RAM with a tin lead and a 2-piece 2 MB x 8 chip and logic parity is priced at $7 to $8, whereas a Cisco 16 MB Catalyst 8000 Flash SIMM can cost up to $89. The price of a RAM chip depends upon the number of nanoseconds, the brand, type, megabytes, and other such factors. The price of RAM also depends upon the type of computer that a person uses. This is because an older computer will usually use a 2 to 8 MB RAM, but a newly bought computer will need a 128 MB RAM in order to function efficiently.

Writen by Ken Marlborough

RAM is the acronym for ‘random access memory’ and is usually calculated in megabytes. A RAM chip is a module that holds freshly accessed information so that the central processing unit can have access to it. It is faster than reading from the hard drive and allows for easy access of recently stored data, information, and files. This means that all programs must be run through the RAM before they are usable.

There are two basic types of RAM, namely dynamic RAM and static RAM. A dynamic RAM is called so because it has to be constantly refreshed by the memory controller. The reason for refreshing is that the capacitors that hold the information or data have a built-in leak that can only be stopped by refreshing the information thousands of times in a second. This makes dynamic RAM slower and cumbersome compared to static RAM.

Static RAM is a type of random access memory that has a greater capacity for storage because it uses on-off switches instead of capacitors. However, static RAM is more expensive compared to dynamic RAM because it is faster and can hold more information.

Usually, advanced versions of the dynamic RAM are used instead of using static RAM because of its high price. These versions include FPM (fast page mode), ECC (error correcting code), EDO (extended data output), and SDRAM (synchronous dynamic RAM). ECC RAM is a special error-correcting RAM that is usually used in servers.

EDO RAM, or extended data output RAM, is an improvement of the traditional FPM RAM. Data can be read faster and the length of time that the output data is valid is extended, which improves time coordination between the central processing unit and RAM, thus improving the performance.

The speed of a RAM is measured in nanoseconds, and the fewer the nanoseconds (ns), the faster the computer. Today we use 50 ns computers as opposed to the 180 and 150 ns that we used in the last decade.

All existing messaging solutions (WebSphereMQ, JMS, …) use proprietary protocols. This is not a problem within a single organization. But between organizations, standard protocols are needed. Therefore, the B2B world uses protocols such as AS2, RNIF (RosettaNet) or good old (S)FTP(S).

AMQP is an initiative to bring a standard binary wire protocol to the messaging world. Just like POP3+SMTP allows you to retrieve and send emails using whatever email server, AMQP will allow any AMQP client to receive and send messages via any AMQP compliant server.

But when I read the spec, AMQP is focusing on the client-server protocol, contrary to SMTP that is (also) used for communication between mail servers. The AMQP spec states that a bridge should be used for server-2-server communication, but doesn’t provide any details. As such, AMQP is focusing on messaging within the corporate firewall.

AMQP can be used for unbalanced B2B scenario’s, where one side runs the AMQP broker. This is a setup similar to one big company or intermediary running an (S)FTP(S) server and smaller organizations putting and retrieving files from it. But for good decoupling, server-to-server communication is preferred. The server at the sending side will take care of delivering the message to the server at the opposite side. Like e.g. AS2 does: once an organization has an AS2 server in place, it becomes equal to all its AS2 counterparts.

With all this in mind, I was a bit puzzled by Paul Fremantle’s enthusiasm about AMQP. In particular because he is the WS-RM spec lead.

WS-ReliableMessaging should have brought reliable async messaging to the WS-world. But it didn’t. The WS-RM spec doesn’t mention message persistence and so (most) vendors have an in-memory implementation, which is not reliable.

I still remember going through the book “Programming Indigo” and learning about the ReliableSessionEnabled binding property. What a disappointment to learn that for real reliability, one had to use the MsmqIntegration Binding and thus the proprietary MSMQ transport layer.