Know Your Computer Network Part II

Posted on February 17, 2012 by admin

Figure 3. Coaxial cable RG-58, BNC Connector, Terminator, T-BNC
RJ 45
Computer network with UTP cables maximum cable length of 100 meters per point computer. Twisted Pair cable (UTP / STP) has the following characteristics:

· Is a pair of cable-twist on each other to reduce the frequency of illegal interference.
· Can be made up of two, four, or more cable pairs.
· Two types of twisted pair cable, the STP and UTP.
· The connection uses an RJ-11 or RJ-45.

Special STP, can be more resistant to interference than UTP, and can operate at higher speeds (up to 100 Mbps)

Figure 4. UTP cable and RJ-45 Connector
UTP cableFigure 4 shows the UTP cable and RJ-45 Connector. UTP cable splicing can be done in two ways, ie straight or cross or straight and crossover. Straight connection allows you to:

The connection of the router to the hub / switch.
The connection from the server to the hub / switch.
The connection of the workstation to the hub / switch.

Crossover connection is useful for:

Uplink connections between switches.
Connection hub to the switch.
Connection hub to another hub.
PC to PC connection, between two computers (no hub / switch).
Router connection to the router interface to another interface.

In addition to the equipment already described, other equipment that is often used to build a computer network is a hub / switch to the network with star topology, Wireless Access Point to a computer with a wireless network, and the Repeater is used to overcome the distance of a point beyond the reach of computers.

Figure 5. Hub / Switch and Wireless Access Points
HUB-Switch
Steps in Computer Networking
The first step in building a computer network is setting up a transmission medium, the following set of activities will be conducted by wired UTP transmission media:
A. Tools and Materials
Computer Networking hardware needs to be prepared as follows:

A number of computers at least 2 pieces
UTP cable (assumed to be building a local computer network with a cable transmission media), each computer point the maximum cable length of 100 meters.
RJ-45 connector should be installed at each end of the cable.
Hub / switch if more than two computers.
LAN PCI Card if the computer does not have an onboard NIC.
Tang (Crimp Plugs) for connecting the cable (Figure 8).
Chasing a screwdriver to open the computer.
Bolts to lock the LAN card is installed in the mainboard.
Cutter to strip the cable shield

Figure 6. Tang / RJ-45 Crimp Plugs
Tang2. Step Work
The initial step should be done is setting up a network cable with RJ-45 connector pair at each end of the cable.
Peel the protective ends of each cable so cables that are in the open protector (cable shield only, not to peel the cables to look for copper). Figure 9. The cable ends Shelled

Insert the tip of the cables to the RJ-45 connector. With the rule if the computer is more than two and a hub / switch then connecting the cable is straight as follows:

Figure 10. Straight Cable Splicing pathways in the RJ-45 connector

Figure 11. RJ-45 connector Rear

If the cable connection will only be used between two computers or two hub / switch, then a crossover cable connection is done as follows:

Figure 12. Crossover Cable Splicing pathways on the RJ-45 connector

Use Crimp Plugs RJ-45 for locking the end of the cable in the connector

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Know Your Computer Network Part I

Posted on February 17, 2012 by admin

Computer network is a group of interconnected computers to each other so that they can share their life together the resources possessed by each computer. These resources include:
· Data and Information
· Program and Application
· The hardware such as drives, printers and modems.

Necessary to build a computer network hardware (hardware) network. Hardware is required to connect the computer with other computers to communicate and exchange resources.
To establish a network of computers, required at least 2 pieces of the computer. Two or more computers on the network can be established if:

· Connect the hardware
· Connect the software

To establish a network of hardware, each computer has the required interface (interface) is used as an intermediary between the computers and transmission media, so the computer can pass the data from the transmission medium that serves to pass data, and vice versa so that data transmissions can be received from the media back by the computer.

In the local computer network, the transmission medium is often used cables. But basically the type of cable is manifold. Types of cables include:
UTP (Unshielded Twisted Pair) / STP (Shielded Twisted Pair)
Coaxial
Fiber Optic

Especially for the network on a small scale, small office or room a lot of UTP and Coaxial cable. In the latest development is a local computer network can be built using radio wave transmission media (wireless LAN).

Figure 1. Global Connections Computer Hardware
fiber optic
Figure 1 shows the hardware requirements are used to build computer networks, namely:
The computer itself is at least two
Interface
Transmission medium.

Basically every computer can be connected to other computers to form networks, with a note that it has a computer interface devices or interfaces. To form a Local Computer Network / LAN (Local Area Network) using cable transmission media, the interface that is used is often called a LAN card or NIC (Network Interface Card). NIC can be a separate card to be installed in a computer or NIC mainboard is already integrated with mainbord (on board).

Type of LAN Card is a card and must be paired in a computer mainboard has some kind of other types of PCI (Peripheral components of Interconnect) or ISA (Industry Standard Architecture). LAN Card on the latest developments which are widely used and readily available is the type of PCI LAN Card, LAN Card in addition to easy to get this type of data transfer speeds higher than the LAN Card ISA type.
Meanwhile, to build a local computer network with a radio wave transmission media (wireless), LAN Card must be used with this type of Wireless LAN Card. Figure 2 through Figure 2 shows the various types of LAN Card.
PCI
Figure 2. PCI and USB Wireless LAN
Local computer network with a cable transmission media, can use some type of cable is the cable Coaxial cable, Twisted Pair and Fiber Optic cable. Coaxial cable has many types, but is often used with this type of Coaxial cable RG-58 A / U. Other equipment to build a computer network with a cable RG-58 A / U is a BNC-Connector (British Naval Connector or Bayonet Nut Connector or Bayonet Neill Concelman), Terminator and T-BNC as shown in Figure 5. The computer network using 10Base2 Ethernet network card and cable lengths up to 185 meters between computers

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Eliminate Idle Redundancy in Your Data Center

Posted on January 14, 2012 by admin

Oracle Active Data Guard, with Oracle Database 11g Enterprise Edition, enhances quality of service by offloading resource-intensive activities from a production database to one or more synchronized standby databases. Oracle Active Data Guard enables read-only access to a physical standby database for queries, sorting, reporting, Web-based access, and so on, while continuously applying changes received from the production database. Oracle Active Data Guard also enables the use of fast incremental backups when offloading backups to a standby database and can provide additional benefits of high availability and disaster protection against planned or unplanned outages at the production site.

BENEFITS
Increase performance—Offload unpredictable workloads to an up-to-date replica of the production database
Simplify operations—Eliminate management complexity that accompanies traditional replication solutions
Eliminate compromise—The reporting replica is up to date and online at all times, which is not possible with traditional storage mirroring technology
Reduce cost—An Oracle Active Data Guard physical standby database can also provide disaster recovery and/or serve as a test database—no additional storage or servers required

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Viewing Who’s Using Transaction Undo / Rollback Segment

Posted on October 3, 2011 by admin

Here is a script to identify the active transaction are currently using rollback segments or undo segments. Conditions, log into the database as user SYS or SYSTEM or a user who has been in the grant DBA.

col o format a10 col u format a10 select osuser o, username u, sid, segment_name s, substr(sa.sql_text,1,200) txt from v$session s, v$transaction t, dba_rollback_segs r, v$sqlarea sa where s.taddr=t.addr and t.xidusn=r.segment_id(+) and s.sql_address=sa.address(+) And substr(sa.sql_text,1,200) is not null order by 3;

col name format a8 col username format a8 col osuser format a8 col start_time format a17 col status format a12 tti ‘Active transactions’ select username, osuser, t.start_time, r.name, t.used_ublk “ROLLB BLKS”, decode(t.space, ‘YES’, ‘SPACE TX’, decode(t.recursive, ‘YES’, ‘RECURSIVE TX’, decode(t.noundo, ‘YES’, ‘NO UNDO TX’, t.status) )) status from sys.v_$transaction t, sys.v_$rollname r, sys.v_$session s where t.xidusn = r.usn and t.ses_addr = s.saddrSubmit Article :- BlinkList + Blogmarks + Digg + Del.icio.us + Ekstreme Socializer + Feedmarker +Furl + Google Bookmarks + ma.gnolia + Netvouz + RawSugar + Reddit + Scuttle + Shadows +Simpy + Spurl + Technorati + Unalog + Wink

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Know Your Grid Technology

Posted on September 23, 2011 by admin

Oracle 10g, g stands for grid. The following discussion of the Grid which I quoted from Wikipedia. Grid computing (grid computing) is the use of resources involves many separate computers that are geographically distributed and to solve problems in large-scale computing.


Background grid

The development speed of the processor developed in accordance with Moore’s Law, however bandwidth computer networks expand far more rapidly. The more quickly the lines of communication are opened up opportunities to combine the computing power of computing resources separate. This development enables large-scale distributed computing enhanced even further geographically, across the boundaries of existing administrative domains.

The rapid development of computer technology in advanced countries, making its researchers increasingly thirsty for computing power that can meet the challenges and problems they face. Although it already has a supercomputer with a very high capacity, what is out there felt this was still less, because they are trying to solve bigger problems. After all the computer that has a ” power -hungry computing researchers ” used an all-out to solve the problem, after a variety of ways to solve problems attempted, and selected the most efficient, but still the problem can not be solved as well, what should he do? Grid computing is one answer to this question.

definition of grid

According to the brief article [1 ] by Ian Foster no check -list that can be used to identify that a system of grid computing, namely:

The coordinate system of the computing resources that are not under a centralized control. If the resources used in the same administrative domain coverage, then it can not be said computing grid computing.
The system uses standards and protocols that are open ( not adrift in an implementation or a specific product ). Grid computing is composed of the agreements on fundamental issues, needed to bring together in a large-scale computing. Agreements and standards are needed in the areas of authentication, authorization, resource searches, and access to resources.
The system is trying to achieve a sophisticated quality of service, ( nontrivial quality of service ) which is well above the quality of service the individual components of the computing grid.

opportunities grid

In the book The Grid: Blue Print for a new computing infrastructure explained that what is meant by grid computing is the infrastructure hardware and software that can provide access to reliable, consistent, durable and inexpensive to sophisticated computing capabilities that are available.

” A computational grid is a hardware and software infrastructure That provides dependable, consistent, pervasive, and inexpensive access to high-end computational capabilities. ”

If someday in the future the technology needed to realize the vision of grid computing paradigm has been established, opportunities will be more open to cooperation across organizations, across continents and across the nation. Will open opportunities for researchers in Indonesia who want to do very complex computation, using the fastest supercomputer in the world, without having to make massive investments in information technology.

Products from Oracle Grid

Oracle has built a grid computing software infrastructure capable of dividing and balancing all of the load ( workload ) among different servers, and manage different servers as a single unit system.

The ability of grid computing is the equivalent of a mainframe because all components ( grids ) in – cluster. But unlike mainframes and servers SMP (symmetric multiprocessing ) are large, the grid is open ( open system technologies ) which could include small systems with Intel processors and Linux OS that costs so much cheaper.

The grid of Oracle’s products are:

Storage Grid: Automatic Storage Management ( ASM )
Grid Database: Real Application Server ( RAC )
Application Grid: Oracle Streams
Grid Control: Enterprise Manager Grid Control

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Knowing the configuration database

Posted on September 23, 2011 by admin

Here’s how to find information about the configuration of the Oracle database that we maintain. This information is very important to know, especially for DBAs who di-install/create/configure by the database ( DBA ) another.

Information about the environment Operating System ( OS )
One of the most important information is the ORACLE_HOME, the directory where the Oracle installation is placed. See the OS environment here:

In Windows, look in the registry My Computer – > HKEY_LOCAL_MACHINE – > SOFTWARE – > ORACLE
In Unix, see the user profile from the database owner. For the shell sh / ksh / bash, user profile is in the file. Profile. To shell csh / tcsh, user profile is in the file. Login

Information Instance parameters ( init file )
Its location is in $ ORACLE_HOME / dbs for OS Unix

Parameters instance, if not in – specify the init file, then Oracle will give the default value. When the instance is up, we can see the parameters of the instance through the view v $ parameter. example:

SQL > SELECT NAME, VALUE, ISDEFAULT from v $ parameter order by name;

NAME column is the name of the parameter. VALUE column is the value of the parameter. ISDEFAULT column, means the value YES if the value is still the default value or not in – specify.

Feature (option ) is used by the database
When we create the database, not all the features of Oracle database ( which we have installed ) we need. To see features that are used by the database, query the view dba_registry

SQL > select COMP_NAME, VERSION, STATUS from dba_registry;

So, it should be understood very well the difference between the information on the VIEW v $ option and in dba_registry. Feature (option ) that are installed ( there is in v $ option) is not necessarily used by the database (there are at dba_registry ). Conversely, a feature that used the database (there are at dba_registry ) is definitely a feature that already exists in the Oracle database software installation ( on view v $ option).

Information about database properties
Examples of the database is the default tablespace properties (permanent and temporary ), timezone, character set, language, etc.. Such information can be viewed by querying the view database_properties.

SQL > select PROPERTY_NAME, PROPERTY_VALUE
from database_properties order by PROPERTY_NAME;

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