Classic version,Superserver o Superclassic


Firebird comes in two flavors, called architectures: Classic Server and SuperServer.

Which one should I install?
Well, that depends on your situation. The following is a summary of the major differences.

Classic Server vs SuperServer 

STATE AND RELIABILITY
Classic Server:
Linux fully mature, still 'experimental' in a way, in Windows.

Superserver:
Fully mature in both Windows and Linux.

SuperClassic:
Mode and implemantada recently released in version 2.5 of Firebird.
(We have no data of its fialibidad even hybrid design that gives it a solidity
for all situations, as well as very good scalability.)


CONTROL AND ACCESS
Classic Server:

Create a process for each client connection, each with its own cache. Uses less resources if the number of connections is low.

Superserver:
Unique process with a thread (thread) separately for each connection. Shared cache space. Grows more efficient if the number of simultaneous connections.

SuperClassic:
Each customer has a dedicated thread within a single process.
No loss of scalability and reduced operational costs.
The timing of the cache is done directametne in memory, performing all
thread processes a lot faster.


CONNECTION
Classic Server:

Allows E / S directly, quickly, a database file for local connections (Linux only).

Superserver:
Local connections must be made in the form of remote access, connecting to localhost. On Windows, you can make local connections, but not as fast as version "Classic" in Linux, and are also less secure.

SuperClassic:
As Superserver local connections should be made in the form of remote access, connecting to localhost. On Windows, you can make local connections, but not as fast as version "Classic" in Linux, and are also less secure.

SERVICES IN THE SYSTEM
Classic Server:

Windows: partially implemented Services Manager (Service Manager), supporting tasks like backup / restore, database shutdown (line out the database) and so on. through the network. Other service tasks have to be performed locally using the client tools (small separate executables) that come with Firebird. Linux: Full Service Manager.

Superserver:
Full Service Manager (in Windows and Linux) that lets you perform administrative tasks (backup / restore, database shutdown, user management, statistics, etc.). Programmatically. You can connect to Manager Services through the network and therefore perform these tasks remotely.

SuperClassic:
As Superserver.


PERFORMANCE
Classic Server:

Support for SMP (multi-processor). Better performance in case of a small number of simultaneous connections that do not influence each other.

Superserver:
No support for SMP. On multiprocessor Windows machines, performance can drop dramatically even when the OS switches the process between CPUs. To prevent this, set the parameter CpuAffinityMask in the configuration file firebird.conf.

SuperClassic:
Supports SMP (multi-processor). Good performance in any situation.
Even that special.
As you can see, none of the architecture is better in all respects. This is not a surprise: not remain several architectures if one of them was losing on all fronts.

If you are still unsure what to choose (you may find all this tech talk a little excessive), use this rule of thumb:

In Windows, choose Superserver.

In Linux, choose either. In most cases you will not notice a performance difference.

Now you can choose SuperClassic performance on any platform will be similar on both Linux
in Windows so if this technology is better desenpeño in multiprocessor environments.



Note that you can change at any time from one architecture to another, its applications and databases will still work (unless your applications call functions are not supported or uncompleted Services Manager in Classic).

For Linux, the packages start with FirebirdSS SuperServer, Classic FirebirdCS packages. For Windows, there is a combined installation package; architecture is selected during the installation process.
Note

NOTE:
Firebird has a third alternative: Embedded Server (embedded server), but this is an entirely different beast and not oriented to their typical client-server installations.
This version is aimed at applications that will work in local mode and do not require client-server technology for its operation.

See the release notes for details.


Source: http://www.firebirdsql.org


A picture is worth a thousand words.

 

Firebird super server architecture diagram

 

Firebird classic server architecture diagram

 

Firebird superclassic architecture diagram

 

Source:
http://www.sinatica.com/