martes, 8 de noviembre de 2011
lunes, 7 de noviembre de 2011
STEPS TO THE ASSEMBLY AND DISASSEMBLY OF A DESKTOP PC
STEPS TO THE ASSEMBLY AND DISASSEMBLY OF A DESKTOP PC
1) Prepare the workplace it is, well lit, at a suitable height, screwdrivers (striae), a small box for events screws, clean, dry hands, next to the guide for mounting the computer. You can also NEED pliers to remove the coils covers the front of your computer and change some bridge.
2) Connections and settings for the motherboard: this is removed and can be placed on a surface. you look at the manual and start to configure the first jumpers if any mo mount the micro, the most fan dicipador and memory as no longer have access to another during assembly. 
4) Set the plate: to fix the plate to its structure taking into account system or security use poles, place the necessary screws that are 4 or 5 so that the plate is motionless.5) Assemble the processor: insert the micro plate. if they are a pentium/MMX/K5/K6/K6-2/6X68/MII/WINCHIP and others of this style, used the ZIF (zero insertion force). is inserted at socal.
-SDR-RAM DIMM 168-pin DDR-RAM or 184-pin
DIMM, RAMBUS, we find in some places pentium IV, physically very similar to the above.
SIMM MEMORY MODULES have 2 connection possibilities: 1-for vertical insertion. 2-for diagonal insertion.
7) expancion cards: before inserting them, we must etire plate is in front of the slot where we will insert them. not all slots have the same size. in the AGP slot or PCI graphic card rage in the ICP can also go 3D accelerator card to the SCSI controller and the ISA can go to the modem and sound card.
To insert the card first trente place it in the slot. located once begins to press, but try not to do too much.
8) Storage Units: to mount the CD-ROM or DVD recording of the holes look a 5.25 "We will make match the screw holes on each side and screw it. Just to do with the drive, but this goes in the 3.5 ". hard disk must be put in a hole the size of the drive, with the exception that the gap must be blind, ie that is not accessible from the front of the box.9) power cables, are connected in 2 ways, depending on whether the plate and the box is baby AT or ATX. If there will be 2 BABY AT power connectors. these connectors are black wires, which would have to be those of a connector with the other. when inserted into the connector of the motherboard has only one position. If there will be a single ATX connector with a range that is hooked to the connector socket to allow latched
10) LED Connections: The speaker and the power button is usually a series of pins located at the bottom right of the box. (See the manual). cables LEDs (POWER IDE) and speaker (SPEAKER) usually have a black colored wire and a white wire. the colored wire is the most and white the least. colored wires always looking to one side and white on the other. the colored wire faces the PIN1 of these pins.
Power button just plug into the motherboard ATX if this is because if a cable BABY AT proviniente will come out of the power supply.
11) close the box or cabinet, connect the devices.
WHAT IS A DATA BASE:
WHAT IS A DATA BASE:
One of the databases is a "warehouse" that allows us to store information in an organized way that we can then easily find and use.
Databases The term was first heard in 1963 at a symposium in California, USA. A database can be defined as a set of related information that is grouped or structured.
At present, due to technological development in fields such as computer and electronics, most databases are in digital format (e), which offers a wide range of solutions to the problem of storing data.
FEATURES B.D
Allows to view only the records of the database when the user entered a number of records in it.
One of the databases is a "warehouse" that allows us to store information in an organized way that we can then easily find and use.
Databases The term was first heard in 1963 at a symposium in California, USA. A database can be defined as a set of related information that is grouped or structured.
At present, due to technological development in fields such as computer and electronics, most databases are in digital format (e), which offers a wide range of solutions to the problem of storing data.
FEATURES B.D
Allows to view only the records of the database when the user entered a number of records in it.
Sets the editing rights. You can add entries teachers and students, if allowed in the database. This
does not restrict the display of your tickets for all.
You can limit the maximum number of tickets for each participant.
We let you add comments to the entries in the database.
Concurrent access by multiple users.
Access security and audit.
Data Independence. This means that the data does not depend on the program and therefore any application can make use of the data.
Redundancy Reduction. We call the existence of redundant duplication of data, reducing it to get a higher maximum use of space and also prevents any inconsistencies exist between the data. Inconsistencies occur when we find conflicting data.
Security. A SBD should allow us to have a control over the security of the data.
Usually displayed as a table in a spreadsheet, in which the records are the rows and columns are fields, or as a form.
Let’s make a list of the database.
Programming to allow advanced users.
USES OF DATA ARE MULTIPLE BAES AS:
• Make list of data for certain companies or offices as needed.
• Allows different users consider the information as a corporate resource that has no specific owners.
• Data Independence. The data independence implies a separation between programs and data, ie you can make changes to the information contained in the database or access database in different ways, without making changes to applications or programs .
• Elimination of redundant information. Duplicate
• Elimination of inconsistent information. If the system is developed through conventional files, such cancellation shall be operated in both bills file Collection Control System as the file system Commissions bills.
• Allows sharing of information. Several systems or users can use the same entity.
• Maintains the integrity of the information. Only the right information is stored.
Data Independence. This means that the data does not depend on the program and therefore any application can make use of the data.
Redundancy Reduction. We call the existence of redundant duplication of data, reducing it to get a higher maximum use of space and also prevents any inconsistencies exist between the data. Inconsistencies occur when we find conflicting data.
Security. A SBD should allow us to have a control over the security of the data.
Usually displayed as a table in a spreadsheet, in which the records are the rows and columns are fields, or as a form.
Let’s make a list of the database.
Programming to allow advanced users.
USES OF DATA ARE MULTIPLE BAES AS:
• Make list of data for certain companies or offices as needed.
• Allows different users consider the information as a corporate resource that has no specific owners.
• Data Independence. The data independence implies a separation between programs and data, ie you can make changes to the information contained in the database or access database in different ways, without making changes to applications or programs .
• Elimination of redundant information. Duplicate
• Elimination of inconsistent information. If the system is developed through conventional files, such cancellation shall be operated in both bills file Collection Control System as the file system Commissions bills.
• Allows sharing of information. Several systems or users can use the same entity.
• Maintains the integrity of the information. Only the right information is stored.
BASE MANAGEMENT SYSTEM (DBMS)
Management Systems Databases, are applications that allow users to: Define, create and maintain the database and provides controlled access to it.
The DBMS is the software that interacts with users of the application programs and database.
Some of the most popular DBMS are: SQL, DB2, SLQ / DS, Oracle, Ingres, Informix, Sybase, Paradox, dBase, Access, FoxPro, R, RM / T and RM/V2.
OBJECTIVES OF A DBMS
Define the database using the Data Definition Language, which allows the structure, data type and restrictions on the data, storing it all in the database.
Separate the description and manipulation of data, allowing a greater understanding of the objects, and flexibility of querying and updating data.
Allow insert, delete, update, query the data using the Data Management Language, which allows to solve the problem presented by the file systems where you have to work with a fixed set of questions or the need for many programs of applications.There are two types of Data Management programs, which differ in the way they access data.
Procedural languages: manipulate the database record by record and must specify the operations to be performed to obtain the data results.
No procedural languages: manipulate database recordsets and specifies which data should be obtained as a result without asking the way to go. The language used is no more procedural SQL (Structure Query Language) that has become a standard and the default language of relational DBMS.
Provide controlled access to the database.
Security: unauthorized users can not access the database.
Integrity: maintaining the integrity and consistency of the database.
Recurrence Control: allows shared access to the database.
Control of Recovery: restore the database after a failure of software or hardware.
Data dictionary or catalog: contains the description of the data from the database and is accessible by the user.
Manage the physical structure of data and storage, providing operational efficiency of the database and access to the storage medium.
Provide a view mechanism that allows each user to have his own view or vision of the database. The language definition allows us to define views as subsets of the database, allowing:
Provide a safe level excluding data from being viewed by certain users.
Allow users to view data in the desired format.
A view represents a consistent and permanent database, even when the database is to make changes in its structure.
Eliminate data redundancy, provide minimal data duplication and minimize disk space used.
Provide procedural and procedural interfaces, allowing manipulation by interactive users and programmers.
Independence between the structure of the logical organization of data (physical independence).
Independence between the logical description of the database and specific descriptions of the different points of view of users.
Allow for easy data management.
Entity-Relationship Model
It is a tool for modeling data from an information system. These models express the relevant entities for an information system and their interrelationships and properties.
Management Systems Databases, are applications that allow users to: Define, create and maintain the database and provides controlled access to it.
The DBMS is the software that interacts with users of the application programs and database.
Some of the most popular DBMS are: SQL, DB2, SLQ / DS, Oracle, Ingres, Informix, Sybase, Paradox, dBase, Access, FoxPro, R, RM / T and RM/V2.
OBJECTIVES OF A DBMS
Define the database using the Data Definition Language, which allows the structure, data type and restrictions on the data, storing it all in the database.
Separate the description and manipulation of data, allowing a greater understanding of the objects, and flexibility of querying and updating data.
Allow insert, delete, update, query the data using the Data Management Language, which allows to solve the problem presented by the file systems where you have to work with a fixed set of questions or the need for many programs of applications.There are two types of Data Management programs, which differ in the way they access data.
Procedural languages: manipulate the database record by record and must specify the operations to be performed to obtain the data results.
No procedural languages: manipulate database recordsets and specifies which data should be obtained as a result without asking the way to go. The language used is no more procedural SQL (Structure Query Language) that has become a standard and the default language of relational DBMS.
Provide controlled access to the database.
Security: unauthorized users can not access the database.
Integrity: maintaining the integrity and consistency of the database.
Recurrence Control: allows shared access to the database.
Control of Recovery: restore the database after a failure of software or hardware.
Data dictionary or catalog: contains the description of the data from the database and is accessible by the user.
Manage the physical structure of data and storage, providing operational efficiency of the database and access to the storage medium.
Provide a view mechanism that allows each user to have his own view or vision of the database. The language definition allows us to define views as subsets of the database, allowing:
Provide a safe level excluding data from being viewed by certain users.
Allow users to view data in the desired format.
A view represents a consistent and permanent database, even when the database is to make changes in its structure.
Eliminate data redundancy, provide minimal data duplication and minimize disk space used.
Provide procedural and procedural interfaces, allowing manipulation by interactive users and programmers.
Independence between the structure of the logical organization of data (physical independence).
Independence between the logical description of the database and specific descriptions of the different points of view of users.
Allow for easy data management.
Entity-Relationship Model
It is a tool for modeling data from an information system. These models express the relevant entities for an information system and their interrelationships and properties.
1. It produces the diagram (or diagrams), Entity-relationship.
2. Model is completed with lists of attributes and a description of other restrictions that may not be reflected in the diagram.
Given the rudimentary nature of this technique requires some training and experience to achieve good data models.
Data modeling is not just using this technique. Other techniques are needed to achieve an implementable model directly into a database. Briefly:
§ Processing of multiple binary relationships.
§ Standardization of database relationships (some relationships can become attributes and vice versa).
§ Conversion tables (in case of using a relational database).
Relational Database
Is a database that conforms to the relational model, which is themodel currently used to implement database already planned.Allow to establish interconnections (relationships) between the data (which are stored in tables), and through those connectionsrelate the data from both tables, hence its name: "Relational Model".
Features
§ A relational database consists of multiple tables or relations.
§ There can be two tables with the same name and registration.
§ Each table is itself a set of records (rows and columns).
§ The relationship between a parent and a child table is carriedout through primary and foreign keys (or foreign).
§ Primary keys are the primary key of a record within a table andthey must meet the data integrity.
§ Foreign keys are placed in the child table contain the same value as the primary key of the parent record, by means of theserelations are made.
Is a database that conforms to the relational model, which is themodel currently used to implement database already planned.Allow to establish interconnections (relationships) between the data (which are stored in tables), and through those connectionsrelate the data from both tables, hence its name: "Relational Model".
Features
§ A relational database consists of multiple tables or relations.
§ There can be two tables with the same name and registration.
§ Each table is itself a set of records (rows and columns).
§ The relationship between a parent and a child table is carriedout through primary and foreign keys (or foreign).
§ Primary keys are the primary key of a record within a table andthey must meet the data integrity.
§ Foreign keys are placed in the child table contain the same value as the primary key of the parent record, by means of theserelations are made.
viernes, 4 de noviembre de 2011
SAFETY EQUIPMEN
• Have a fire extinguisher: in a work area should always keep a fire extinguisherhandy because whenever working with electrical equipment and electrical fires are not exempted.
• A suitable area of work: we must always have a large, clean and well lit.
• An emergency exit: should always be an emergency exit in case of fire exit.
• A first aid kit: This is a must because it is the main thing in an emergency.
• Have the appropriate attire
• Take anti-static handle
• The necessary tool
• A workbench
• A well-lit
• Do not eat on the team
• To have him proper management
• An excellent hygiene
• Disconnect power from any source
• Care and Precautions for safety in our homes we have in mind:
1. Know the hazards and characteristics of each product you purchase.
2. Really evaluate the need to purchase the products.
3. Do not mix products, follow the manufacturer's instructions.
4. Keep cleaning products, pesticides, and drugs away from children
And animals.
5. Avoid using very aggressive, highly polluting or not
Have information.
6. Separate flammable products away from heat.
7. Separate pesticides, especially of food.
8. Separate the acidic products containing ammonia or
Caustic soda or potash as.
9. Only use cleaning products in well ventilated and use air
Elements of protection.
10. Wash hands and face before eating or drink anything for
Avoid ingestion of chemicals.
11. Use only the necessary amounts, not to waste water nor
Products.
12. Leave the containers tightly capped after use.
Isopropyl Alcohol Foam: It is mainly used to remove fat and circuit boards
Clean equipment heads and video tape players.
Electronic cleaner: Cleaning of electrical contacts and electronic equipment
Navigation.
Easily removes dust, lint, light oil and grime.
Contact cleaner: Cleaner precision electrical and electronic contacts.
Avoid contact failures, improving the functioning of
Team
Compressed air dust remover: remover powder with great force and precision.
Ultra-filtered dry gas harder than others, ideal for use
On almost any surface, it is not abrasive.
Perfect choice for keyboards foam: With the perfect foam could clean any surface
Plastic very easily, providing greater durability
And look at their computing equipment.
Cleansing Gel anti unmarked striped screens: This specially formulated to leave no residue on your screen.
Precautions:
Do not apply directly on the screen.
Neat air express: express air Prolicom gas is a cleaner high-quality packaging
Pressure. Its use eliminates dust and debris buildup
The electronic components. Air - Express can be used in computer
Computing, telephone, control, medical and scientific purposes.
Plasma clean: to clean LCD and PLASMA 100% natural.
The cleaner features plasma and LCD screens boat
120ml special cleaner for plasma.
Foam monitors: computer cleaning foam pair
pcdominio.com foaming cleanser 454ml gr pcdominio plastics.
Pcd cleansing lotion: 250ml is for general cleaning of plastic components
Plastic Computer cleanser, ideal for use in the
Plastic PC, such as keyboard, mouse, monitor, speakers, etc..
Anti static wipes, to clean the practical 30-piece PC
Boat with 30 wipes ideal for cleaning the PC monitor
Since no residue. It can also be used to clean the
Keyboard, mouse and plastic items.
Preserve cleaner / degreaser: fix problems quickly
Cleaning more difficult. Particularly suitable for cleaning
Components and equipment.
Varzol: This pure product is applied to clean frames, spatulas
And tools can generally be used to remove ink residues
The hands, clothes, to mix with soap karpol for better
Degreasing
CLOROX: a chemical composition of caustic soda, sodium hypochlorite, sodium chloride, water, fragrance.
4. USE OF CLEANING EQUIPMENT
Blower: used for cleaning equipment since the equipment or boot with great force air dusting of objects.
Brush: This product is used to remove dust from the components
Draft cream: this is used to remove corrosion from contacts in the equipment.
Cleaner-mail: This chemical is used to clean electrical contacts on the components.
Foam Cleaner Keyboard: As the name says it serves to clean the keyboard.
Liquid to clean screens: it is liquid you used to clean the screens.
Frotex Cream: it is to clean the chassis.
Degreaser Cleaner E-Cards: This product is used for degreasing electrical contacts.
5. EFFECTS OF EROSION AND ACCUMULATION OF SOLID WASTE ELECTRICAL CONTACT SURFACES.
After long periods, the excessive level of moisture cause corrosion on metal surfaces. It is very rare to find contacts corroded wires in the computers, as this usually happens only in places where there are lots of moisture.
Corrosion error causes symptoms that are very difficult to diagnose. Usually these symptoms will be intermittent (sometimes the computer will work and sometimes not).
Occasionally, check the cable connections of the system to check for any corrosion.
Corrosion is a factor that affects all materials, not only metals and causing great loss of money and sometimes lives, and that corrosion can consume so much material to lose its physical properties which can force change in one or more parties in a given structure or in extreme cases the collapse of this. To avoid this, various techniques have been developed to prevent corrosion, or prevent it, but as there different types of corrosion, must also be different types of techniques to avoid it.
viruses and computer crime
Viruses and computer crime
Types of cybercrime
unauthorized access: Unlawful use of passwords and the entry of a computer system without authorization from the owner. (Violation of privacy).
Data destruction: Damage caused to the network through the introduction of viruses, logic bombs, etc.
Violation database copy: Unauthorized use of information stored in a database.
Interception of e-mail: Reading an e-mail others.
Transfer of funds: Deceptions in the conduct of such transactions.
Espionage: Unauthorized access to computer systems of government and big business and interception of emails.
Terrorism: anonymous posts used by groups.
Traffic computer key obtained by unlawful means.
Unauthorized reproduction of software protected.
Characteristics, techniques and ways to combat computer fraud
• There are many cases and few complaints, and all because the same lack of regulation by law.
• Are occupational activities, as is often done when the subject is working?
• Are actions of chance, in that it takes an occasion created or highly intensified in the world of functions and organization of technological and economic system?
• They cause serious economic losses, as almost always produce "profits of more than five figures to those who perform them.
• Provide time and space facilities, as in a split second and without a physical presence needed can consume.
• Most are negligent and do not necessarily committed with intent.
• Provide facilities for their commitment to the mentoring of age.
• They tend to grow more and more, thus requiring an urgent regulation.
• For the time being remain unpunished manifestly illegal under the law.
• Are criminogenic behaviors, while only a certain number of people with certain skills (technical here) can be committed.
• keep the network locked with a security code
• always leave the team with only trusted users
Measures to prevent frauds
• Make a backup or Backus: It is important that you periodically back up. You can do it manually, saving data to removable media or with programs created to make backups.
• Avoid giving information dare e-mail, telephone, never fill out forms arrive blank e-mail dare.
• Passwords not easily decipher is important that the password contains uppercase and lowercase letters and numbers. Never send passwords by e-mail, IM, chats, etc.Do not use the same password for all services and change the password periodically.
• Enable MAC distinguishing number that does not belong to the computer, but the device connected to the network, called the MAC number. It is therefore possible to enable a filter to only connect to our network devices with a MAC number.
• Typical applications are not personalized phishing. Unlike your bank or company that issued your credit card, which may include your name and / or an identifier or type of account, requests for phishing usually keep the health and information about you in a generic way .
• Be suspicious of numeric web addresses or URLs. In general, the Web address or URL of a company includes part of the company name followed by. Com,. Org or. Net. A fake Web site that uses a Web address (or IP address) that contains a numeric or symbol "@" in the address can be a warning that it is a fraudulent site
• Get to know the websites you visit frequently and mark them as favorites.
• Learn about Internet scams. Keep abreast of the allegations of fraud, trends and examples of fraudulent e-mail messages today can help prevent becoming a victim.
What are computer viruses
Computer viruses are small software programs designed to spread from one computer to another and to interfere with the operation of equipo.Un virus can damage or delete data on your computer.
Classes of viruses and how they act
File Virus
This virus is responsible for infecting programs or executable files (files with. Exe or. Com). When running one of these programs, the virus becomes active and produces harmful effects. The majority of Existing viruses are of this type.
• Residents Virus
They stay in the RAM of the computer waiting for it to run any program they infected.RAM loses its contents when you turn off or restart the computer, therefore, some of these viruses disappear as soon as this happens, others, however, modify the system to be reinstalled every time you turn on your computer.
• Boot Virus
They affect the boot sector of the computer and are transmitted through floppy disks. They hide in the first sector of a disk and loaded into RAM. Thus take total control to hide, spread and cause damage. Usually replace the contents of the boot sector with their own content and move the original area to another area of the disk. To remove them, you need to boot the computer from an uninfected diskette and proceed to remove a virus, and if necessary replace the infected area with the original boot sector.
• Macro Virus
Are 80% of all viruses in the world. They are completely independent of the operating system. The macro-viruses are small programs written in the language of a program. So we can find macro-virus for text editors, spreadsheets and utilities that specialize in image manipulation. The macro virus infections performed on files that were created with certain applications or programs, such as text editors, database managers, spreadsheet programs, etc.This type of virus is activated when you open an infected file into the word processor or spreadsheet.
• Virus "Bug-ware"
These are programs that were not intended to be a virus, but for specific functions within the system. Bug-ware programs are not viruses at all. They are really buggy programs, but the result is similar to the virus.
• Worms
Worms are programs that replicate themselves from system to system without using a file to do so. In this they differ from viruses, which need to be extended by an infected file. A computer worm is a standalone program capable of distributing copies of itself to other computer systems (usually via network connections). Its aim is simply to self replicate and not to cause damage. Introduce garbage characters on screen, documents and work files. Exploit security holes in e-mail programs to infect computers.
Do not need a separate program execution to be activated, but enter and infect the computer simply viewing an email.
Trojans (Trojan horses)
Trojans are programs that look innocent are actually harmful activity .Trojan horses contain malicious code that, when activated, causes loss or data theft. For a Trojan horse is necessary to extend leave to enter the system, such as opening an email attachment.
Attachments sent in unsolicited messages or downloaded files are likely to be Trojan horses. These viruses cause the victim of the attack run a program (virus server), which installs itself in the system waiting for the user to connect your computer to the Internet. Once connected, the client program (hacker), has all the tools needed to use the computer away from his victim, to manage part of their resources and obtain the information stored in its storage units.
Usually used for spying, using the technique to install a remote access software that enables the user to monitor what the computer does legitimate and, for example, capture keystrokes to obtain passwords or other sensitive information.
Chameleons
Chameleons can perform all the functions of the legitimate programs they replace (act as product demonstration programs, which are simulations of real programs). A chameleon software could, for example, to emulate a program to access remote systems (rlogin, telnet) performing all the actions they perform, but as an additional task (and hidden from the user) is stored in a file different logins and passwords so that later can be retrieved and used illegally by the virus writer chameleon.
Breeding rabbits
the breeding rabbits consistently reproduce once they are fully implemented, while supplies last (with offspring) disk space or memory of the system.
The sole function of this virus is to create clones and run for them to do the same. The purpose is to exhaust system resources, especially in a networked multiuser environment, to the extent that the host can’not continues normal processing.
Logic Bombs
a logic bomb is computer software that is installed on a computer and remains hidden until one or more conditions met then reprogrammed to perform an action. Unlike a virus, logic bomb never play alone. Examples of predetermined conditions are specific days of the week, specific time, pressing a key or key sequence specific. And examples of actions that may be performed: delete the hard disk information, display a message on the screen, play a song or send us an email.
Retro-virus or antivirus Virus
a retro-virus attempts to directly attack the antivirus program included in the computer.
Retroviruses generally seek virus definition file and remove it, making it impossible to identify their antivirus enemies. Other retro-virus program detected the virus in memory and try to hide or initiate a damage routine before the antiviruses manage to find. Some even change the environment so that it ends up affecting the operation of the antivirus.
Virus multipuntitos
Multipuntitos viruses attack the boot sectors and executable files. When an infected application is run with one of these viruses, it infects the boot sector. The next time you boot the computer, the virus will attack any program running.
Who created the virus
• they are created, mostly by people who want to demonstrate their computer skills, but for obvious reasons, tend to remain anonymous.
Currently, there are programs that any user, without any programming knowledge can create your own or viruses themselves, giving the name and features you want. And even there are certain websites that offer this possibility
as the virus can be prevented
• Make regular backups of our data.
• Do not accept non-genuine or pre-installed without the original media.
• write-protect disks, especially the system.
• If possible, select the hard drive as default boot in the BIOS to prevent boot sector viruses.
• Scan all new records that we introduce in our system with a virus, including blank discs (they may contain virus in boot sector).
• Review periodically the hard drive booting from the original system disk to avoid that a virus is loaded into memory prior to analysis.
• Update anti-virus patterns every one to two months.
• Try to get the program requiring official Internet sites.
• Be particularly careful with files that can be included in our email.
• Analyze and document archives also.
As viruses are detected
• to detect the presence of a computer virus can employ various types of antiviral programs. Screening programs can recognize the characteristics of the computer code of a computer virus and look for these features in computer files.
• The only programs are the checksum, calculations employing more than detect all mathematical computer virus to compare the state of the executable programs before and after running. If the checksum changes, the system is not infected.
• The integrity programs established shell layers which must pass any order of execution of a program. Inside the shell integrity is automatically performed a checksum, and if found infected programs are not allowed to run.
What are the antivirus and how they work
• Are programs whose function is to detect and eliminate computer viruses and other malware, antivirus basically a code compares each file with a database of codes (signatures or vaccines), of known viruses. So it is important to update regularly to prevent a new virus is not detected
• Monitor the computer files as they be opened or created to ensure that they are infected. This is a real-time protection, which can affect the performance of the computer
Types of cybercrime
unauthorized access: Unlawful use of passwords and the entry of a computer system without authorization from the owner. (Violation of privacy).
Data destruction: Damage caused to the network through the introduction of viruses, logic bombs, etc.
Violation database copy: Unauthorized use of information stored in a database.
Interception of e-mail: Reading an e-mail others.
Transfer of funds: Deceptions in the conduct of such transactions.
Espionage: Unauthorized access to computer systems of government and big business and interception of emails.
Terrorism: anonymous posts used by groups.
Traffic computer key obtained by unlawful means.
Unauthorized reproduction of software protected.
Characteristics, techniques and ways to combat computer fraud
• There are many cases and few complaints, and all because the same lack of regulation by law.
• Are occupational activities, as is often done when the subject is working?
• Are actions of chance, in that it takes an occasion created or highly intensified in the world of functions and organization of technological and economic system?
• They cause serious economic losses, as almost always produce "profits of more than five figures to those who perform them.
• Provide time and space facilities, as in a split second and without a physical presence needed can consume.
• Most are negligent and do not necessarily committed with intent.
• Provide facilities for their commitment to the mentoring of age.
• They tend to grow more and more, thus requiring an urgent regulation.
• For the time being remain unpunished manifestly illegal under the law.
• Are criminogenic behaviors, while only a certain number of people with certain skills (technical here) can be committed.
• keep the network locked with a security code
• always leave the team with only trusted users
Measures to prevent frauds
• Make a backup or Backus: It is important that you periodically back up. You can do it manually, saving data to removable media or with programs created to make backups.
• Avoid giving information dare e-mail, telephone, never fill out forms arrive blank e-mail dare.
• Passwords not easily decipher is important that the password contains uppercase and lowercase letters and numbers. Never send passwords by e-mail, IM, chats, etc.Do not use the same password for all services and change the password periodically.
• Enable MAC distinguishing number that does not belong to the computer, but the device connected to the network, called the MAC number. It is therefore possible to enable a filter to only connect to our network devices with a MAC number.
• Typical applications are not personalized phishing. Unlike your bank or company that issued your credit card, which may include your name and / or an identifier or type of account, requests for phishing usually keep the health and information about you in a generic way .
• Be suspicious of numeric web addresses or URLs. In general, the Web address or URL of a company includes part of the company name followed by. Com,. Org or. Net. A fake Web site that uses a Web address (or IP address) that contains a numeric or symbol "@" in the address can be a warning that it is a fraudulent site
• Get to know the websites you visit frequently and mark them as favorites.
• Learn about Internet scams. Keep abreast of the allegations of fraud, trends and examples of fraudulent e-mail messages today can help prevent becoming a victim.
What are computer viruses
Computer viruses are small software programs designed to spread from one computer to another and to interfere with the operation of equipo.Un virus can damage or delete data on your computer.
Classes of viruses and how they act
File Virus
This virus is responsible for infecting programs or executable files (files with. Exe or. Com). When running one of these programs, the virus becomes active and produces harmful effects. The majority of Existing viruses are of this type.
• Residents Virus
They stay in the RAM of the computer waiting for it to run any program they infected.RAM loses its contents when you turn off or restart the computer, therefore, some of these viruses disappear as soon as this happens, others, however, modify the system to be reinstalled every time you turn on your computer.
• Boot Virus
They affect the boot sector of the computer and are transmitted through floppy disks. They hide in the first sector of a disk and loaded into RAM. Thus take total control to hide, spread and cause damage. Usually replace the contents of the boot sector with their own content and move the original area to another area of the disk. To remove them, you need to boot the computer from an uninfected diskette and proceed to remove a virus, and if necessary replace the infected area with the original boot sector.
• Macro Virus
Are 80% of all viruses in the world. They are completely independent of the operating system. The macro-viruses are small programs written in the language of a program. So we can find macro-virus for text editors, spreadsheets and utilities that specialize in image manipulation. The macro virus infections performed on files that were created with certain applications or programs, such as text editors, database managers, spreadsheet programs, etc.This type of virus is activated when you open an infected file into the word processor or spreadsheet.
• Virus "Bug-ware"
These are programs that were not intended to be a virus, but for specific functions within the system. Bug-ware programs are not viruses at all. They are really buggy programs, but the result is similar to the virus.
• Worms
Worms are programs that replicate themselves from system to system without using a file to do so. In this they differ from viruses, which need to be extended by an infected file. A computer worm is a standalone program capable of distributing copies of itself to other computer systems (usually via network connections). Its aim is simply to self replicate and not to cause damage. Introduce garbage characters on screen, documents and work files. Exploit security holes in e-mail programs to infect computers.Do not need a separate program execution to be activated, but enter and infect the computer simply viewing an email.
Trojans (Trojan horses)
Trojans are programs that look innocent are actually harmful activity .Trojan horses contain malicious code that, when activated, causes loss or data theft. For a Trojan horse is necessary to extend leave to enter the system, such as opening an email attachment.
Attachments sent in unsolicited messages or downloaded files are likely to be Trojan horses. These viruses cause the victim of the attack run a program (virus server), which installs itself in the system waiting for the user to connect your computer to the Internet. Once connected, the client program (hacker), has all the tools needed to use the computer away from his victim, to manage part of their resources and obtain the information stored in its storage units.
Usually used for spying, using the technique to install a remote access software that enables the user to monitor what the computer does legitimate and, for example, capture keystrokes to obtain passwords or other sensitive information.
Chameleons
Chameleons can perform all the functions of the legitimate programs they replace (act as product demonstration programs, which are simulations of real programs). A chameleon software could, for example, to emulate a program to access remote systems (rlogin, telnet) performing all the actions they perform, but as an additional task (and hidden from the user) is stored in a file different logins and passwords so that later can be retrieved and used illegally by the virus writer chameleon.
Breeding rabbits
the breeding rabbits consistently reproduce once they are fully implemented, while supplies last (with offspring) disk space or memory of the system.
The sole function of this virus is to create clones and run for them to do the same. The purpose is to exhaust system resources, especially in a networked multiuser environment, to the extent that the host can’not continues normal processing.
Logic Bombs
a logic bomb is computer software that is installed on a computer and remains hidden until one or more conditions met then reprogrammed to perform an action. Unlike a virus, logic bomb never play alone. Examples of predetermined conditions are specific days of the week, specific time, pressing a key or key sequence specific. And examples of actions that may be performed: delete the hard disk information, display a message on the screen, play a song or send us an email.
Retro-virus or antivirus Virus
a retro-virus attempts to directly attack the antivirus program included in the computer.
Retroviruses generally seek virus definition file and remove it, making it impossible to identify their antivirus enemies. Other retro-virus program detected the virus in memory and try to hide or initiate a damage routine before the antiviruses manage to find. Some even change the environment so that it ends up affecting the operation of the antivirus.
Virus multipuntitos
Multipuntitos viruses attack the boot sectors and executable files. When an infected application is run with one of these viruses, it infects the boot sector. The next time you boot the computer, the virus will attack any program running.
Who created the virus
• they are created, mostly by people who want to demonstrate their computer skills, but for obvious reasons, tend to remain anonymous.
Currently, there are programs that any user, without any programming knowledge can create your own or viruses themselves, giving the name and features you want. And even there are certain websites that offer this possibility
as the virus can be prevented
• Make regular backups of our data.
• Do not accept non-genuine or pre-installed without the original media.
• write-protect disks, especially the system.
• If possible, select the hard drive as default boot in the BIOS to prevent boot sector viruses.
• Scan all new records that we introduce in our system with a virus, including blank discs (they may contain virus in boot sector).
• Review periodically the hard drive booting from the original system disk to avoid that a virus is loaded into memory prior to analysis.
• Update anti-virus patterns every one to two months.
• Try to get the program requiring official Internet sites.
• Be particularly careful with files that can be included in our email.
• Analyze and document archives also.
As viruses are detected
• to detect the presence of a computer virus can employ various types of antiviral programs. Screening programs can recognize the characteristics of the computer code of a computer virus and look for these features in computer files.
• The only programs are the checksum, calculations employing more than detect all mathematical computer virus to compare the state of the executable programs before and after running. If the checksum changes, the system is not infected.
• The integrity programs established shell layers which must pass any order of execution of a program. Inside the shell integrity is automatically performed a checksum, and if found infected programs are not allowed to run.
What are the antivirus and how they work
• Are programs whose function is to detect and eliminate computer viruses and other malware, antivirus basically a code compares each file with a database of codes (signatures or vaccines), of known viruses. So it is important to update regularly to prevent a new virus is not detected
• Monitor the computer files as they be opened or created to ensure that they are infected. This is a real-time protection, which can affect the performance of the computer
jueves, 3 de noviembre de 2011
History of computer
History of computer
The computer or computer is not a figment of someone, but the evolutionary result of ideas and achievements of many people related to areas such as electronics, mechanics, semiconductor materials, logic, algebra and programming.
First Generation (1951 to 1958)
the first generation computers used to process information bulbs.
Programming is done through the machine language. The memories were made of thin tubes of liquid mercury and magnetic drums. The operator enters the data and programs in special code via punched cards. Internal storage was achieved by rapidly revolving drum on which a device read / write magnetic marks placed. These computers used vacuum valve. As computers were very large, heavy and generated much heat. The first generation starts with the UNIVAC commercial facility built by Eckert and Mauchly. The UNIVAC processor weighed 30 tons and required the entire space of a room 20 by 40 feet.
the first generation computers used to process information bulbs.
Programming is done through the machine language. The memories were made of thin tubes of liquid mercury and magnetic drums. The operator enters the data and programs in special code via punched cards. Internal storage was achieved by rapidly revolving drum on which a device read / write magnetic marks placed. These computers used vacuum valve. As computers were very large, heavy and generated much heat. The first generation starts with the UNIVAC commercial facility built by Eckert and Mauchly. The UNIVAC processor weighed 30 tons and required the entire space of a room 20 by 40 feet.
Second Generation (1959-1964)
Limited compatibility Transistor replaced the vacuum tube used in the first generation. The second generation computers were faster, smaller and with less need for ventilation. These computers also used magnetic core networks instead of rotating drums for primary storage. These nuclei contain small rings of magnetic material, linked together, where they could store data and instructions.
Computer programs also improved. COBOL developed during the 1st generation was already commercially available. Programs written for a computer could be transferred to another with minimal effort. Writing a program is no longer required to fully understand the computer hardware.
Third Generation (1964-1971)
Integrated Circuits, Computer Support Staff, Multiprogramming, Minicomputer
The computers of the third generation emerged with the development of integrated circuits (silicon chips) that are placed in thousands of electronic components, integration in miniature. New computers became smaller, faster, gave off less heat and they were more energy efficient.
Before the advent of integrated circuits, computers were designed for math or business applications, but not both. Integrated circuits enabled computer manufacturers to increase the flexibility of programs and standardize their models.
The IBM 360 one of the first commercial computer that used integrated circuits, numerical analysis was performed either as management or file processing.Customers were able to scale their systems IBM 360 models were larger and still run your existing programs. The computers work so fast that provided the ability to run more than one program simultaneously (multiprogramming).
Fourth Generation (1971 to 1981)
Microprocessor, memory chips, microminiaturization
Two improvements in computer technology marks the beginning of the fourth generation: the replacement of magnetic core memories with, for the silicon chip and the placement of many more components on a Chip: microminiaturization product of the electronic circuit . The small size of chip microprocesadory made possible the creation of personal computers (PC)
In 1971, Intel Corporation, which was a small manufacturing company in Silicon Valley semiconductors ubicada introduced the first microprocessor chip or 4 bits, in a space of approximately 4 x 5 mm containing 2 250 transistors. The first microprocessor shown in Figure 1.14 was named the 4004.
Silicon Valley (Silicon Valley) was an agricultural region south of San Francisco Bay, which by its very production of silicon from 1960 becomes a fully industrialized area on which sits a large number of semiconductor companies and microprocessors. Is now known worldwide as the most important region for industries related to computing: software development and component manufacturing.
These days there is a huge number of manufacturers of microcomputers or personal computers, which use different architectures estructuraso literally fight the computing market, which has come to grow so that it is one of the largest worldwide, above all, Since 1990, when achieved with advances in Internet.
This generation of computers is characterized by great technological advances in a very short time. In 1977 appeared the first microcomputers, including the most famous were those manufactured by Apple Computer, Radio Shack and Commodore Business Machines. IBM joins the microcomputer market with its Personal Computer (Figure 1.15), where they have become as synonymous with the name of PC, and most importantly, it includes a standardized operating system, MS-DOS (Microsoft Disk Operating System).
Generating FIFTH "NY ARTIFICIAL INTELLIGENCE (1982-1989)
It is becoming more difficult to identify the generations of computers, because the major advances and new discoveries are no longer strike us as happened in the mid twentieth century. Some consider that the fourth and fifth generations are over, and place them between the years 1971-1984 the fourth, and fifth from 1984-1990.They believe that the sixth generation is in development since 1990 to date.
Following the track of technological developments in computer and information, we can point out some dates and features which could be the fifth generation of computers.
Based on the major technological developments in microelectronics and computer science (software) and CADI CAM, CAE, CASE, artificial intelligence, expert systems, neural networks, chaos theory, genetic algorithms, fiber optics, telecommunications, etc.., A the decade of the eighties laid the foundation of what can be known as the fifth generation of computers.
We must mention two major technological advances, to serve as a parameter for the start of this generation: the creation in 1982 of the first supercomputer with parallel processing capability, designed by Seymour Cray, who has experimented since 1968 with supercomputers, and based on 1976, Cray Research Inc., and the announcement by the Japanese government of the "fifth generation", which was established in the agreement with six of the largest Japanese computer companies, should be completed in 1992.
The parallel process is one that takes place on computers that have the ability to work simultaneously with multiple microprocessors. While in theory work with multiple microprocessors should be much faster, it is necessary to conduct a special program that allows you to assign different tasks of the same process to the various chips involved.
You should also adjust the memory so you can meet the requirements of the processors at the same time. To solve this problem had to design modules able to allocate shared memory cache area for each processor.
Under this project, which was joined by more technologically advanced countries to keep pace in Japan; the main feature would be the application of artificial intelligence (Al, Artificial Intelligence). The computers of this generation containing a large number of microprocessors working in parallel and can recognize voices and images. They also have the ability to communicate with a natural language and will acquire the ability to make decisions based on learning processes grounded in expert systems and artificial intelligence.
The storage is done in magneto-optical devices with capacities of tens of Gigabytes, you set the DVD (Digital Versatile Disk or Digital Videodisk) as a standard for storing video and audio, the data storage capacity is growing exponentially allowing store more information in one of these units that all that was in the Library of Alexandria. The components of current microprocessors use technologies and ultra-high integration, called VLSI (Very Large Sca / e Integration) and ULSI (Ultra Large Scale Integration).
However, regardless of these "miracles" of modern technology, the gap does not distinguish where he finished fifth and sixth generation begins. I personally have not seen the full realization of what transpired in the Japanese project because of the failure, perhaps momentary, artificial intelligence.
The only forecast that has been going on without interruption during this generation, is the connectivity between computers, that from 1994, with the advent of the Internet and World Wide Web, has become vital in large , medium and small enterprises and between individual users of computers.
The purpose of AI is to equip computers with "human intelligence" and the ability to reason to find solutions. Another key design factor, the capacity of the computer to recognize patterns and sequences of processing that has been found previously (scheduling heuristics) that allows the computer to recall previous results and include them in the processing, in essence, the computer will learn from their own experiences will use their original data to get the answer by reasoning and keep those results for further processing tasks and decision making.
Generating SIXTH "N 1990 TO DATE
As supposedly the sixth generation of computers has been underway since the early nineties, we should at least outline the features that should have the computers of this generation. Also mentioned are some of the technological advances of the last decade of the twentieth century and what is expected to achieve in the XXI century. The computers of this generation have combined architectures Parallel / Vector, Vector microprocessors with hundreds of working at the same time have created computers capable of performing more than one million floating point arithmetic operations per second (teraflops) networks Global Area (Wide Area Network, WAN) continue to grow exorbitantly using media through fiber optics and satellites, with bandwidths impressive. This generation technologies have been developed or are give in that process. Some of them are: intelligence / artificial distributed, chaos theory, fuzzy systems, holography, optical transistors, and so on.
As supposedly the sixth generation of computers has been underway since the early nineties, we should at least outline the features that should have the computers of this generation. Also mentioned are some of the technological advances of the last decade of the twentieth century and what is expected to achieve in the XXI century. The computers of this generation have combined architectures Parallel / Vector, Vector microprocessors with hundreds of working at the same time have created computers capable of performing more than one million floating point arithmetic operations per second (teraflops) networks Global Area (Wide Area Network, WAN) continue to grow exorbitantly using media through fiber optics and satellites, with bandwidths impressive. This generation technologies have been developed or are give in that process. Some of them are: intelligence / artificial distributed, chaos theory, fuzzy systems, holography, optical transistors, and so on.
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