Scalable System

A system is scalable with respect to either its number of components, geographical size, or number and size of administrative domains, if it can grow in one or more of these dimensions without an unacceptable loss of performance.

Some of Scalable system functions :

1. Ability to adapt to the needs of rapid growth or when a new service to be provided by the data center without making significant changes to the data center (data center) as a whole.
2. In an IP infrastructure work, also requires a system that is scalable. This service is provided on layer 2 and layer 3. Issues that must be considered related to the layer 2 is the relationship between farm servers and service devices, enabling access to the media, supporting the centralization of reliable, loop-free, predictable, and scalable

Scalability can be measured in three dimensions:

1. Load Scalability: A distributed system should be easily expanded to accommodate the load increase.
2. Scalability Geography: A system capable of managing the functionality and ability, no matter how far the user and the resource is located.
3. Administrative scalability: Any number of different managing a distributed system, distributed system is still easy to manage and use.

Scalable system can increase capacity (service) system, use new hardware and software are added easily and inexpensively via the following path:

1. Adaptation of the system to accommodate more users and respond more quickly.
2. Usually, by adding more processors or faster one.
3. existing components do not need to be replaced if it would be enlarged.
4. Need to design components that can be enlarged in a flexible capacity.

Examples of some hardware that is scalable system:

• Server: is a computer system that provides certain services in a computer network. Server is supported with processors that are scalable and large RAM, also equipped with a special operating system, called the network operating system or network operating system. Server is also running administrative software that controls access to networks and resources contained in it, like a file or display devices (printers), and provide access to a workstation network members.

Examples of some software that is scalable system:

• OpenSolaris 2009.06: It is a complete operating system for users, developers and deployers, known as a system of secure, stable, and is scalable.

Differences Computer Networks with Distributed System

Computer Networks	Distributed System
Computer connected to a compound consisting of several workstations or also combined server and client computers	Computer connected consists of the host (main computer) and the terminals (computers connected to the host computer)
Some of the computers connected to share, but each job handled by the computer that requested and asked for service. Server only serves requests according to the set queuing system.	Some host computers connected in order to do a great job or a few together. Host serving several terminals and make the process based on input from terminals
Quality of data communication transmission is influenced by the media used. The duration of a process influenced by the hardware specifications of each service station beseeching. Users can find an ongoing process (on the computer station or on the server).	Quality of data communication is influenced by the system. The duration of a process depends on which operating system the computer processor will choose which one to use. Users can not know the processes going on in the host.
Each node or workstation (the method of peer to peer) does not require special servers to handle the whole job. Between nodes can exchange files or resource owned, according to the desire or set permissions on the computer owner.	Each terminal requires the host (main computer) to be actively doing the work and communicate with other terminals. Between each terminal can not share files or resources without the intervention of the host (host supervisor).