Unidad VI

Parte “a”

Viruses. Zip for Windows


What is a virus?


A virus is a piece of programming code usually disguised as something else that causes some unexpected and usually undesirable event. A virus is often designed so that it is automatically spread to other computer users. Viruses can be transmitted as attachments to an e-mail note, as downloads, or be present on a diskette or CD. The source of the e-mail note, downloaded file, or diskette you've received is often unaware of the virus. Some viruses wreak their effect as soon as their code is executed; other viruses lie dormant until circumstances cause their code to be executed by the computer. Some viruses are playful in intent and effect ("Happy Birthday, Ludwig!") and some can be quite harmful, erasing data or causing your hard disk to require reformatting.


Generally, there are three main classes of viruses:


File infectors. Some file infector viruses attach themselves to program files, usually selected .COM or .EXE files. Some can infect any program for which execution is requested, including .SYS, .OVL, .PRG, and .MNU files. When the program is loaded, the virus is loaded as well. Other file infector viruses arrive as wholly-contained programs or scripts sent as an attachment to an e-mail note.


System or boot-record infectors. These viruses infect executable code found in certain system areas on a disk. They attach to the DOS boot sector on diskettes or the Master Boot Record on hard disks. A typical scenario (familiar to the author) is to receive a diskette from an innocent source that contains a boot disk virus. When your operating system is running, files on the diskette can be read without triggering the boot disk virus. However, if you leave the diskette in the drive, and then turn the computer off or reload the operating system, the computer will look first in your A drive, find the diskette with its boot disk virus, load it, and make it temporarily impossible to use your hard disk. (Allow several days for recovery.) This is why you should make sure you have a bootable floppy.


Macro viruses. These are among the most common viruses, and they tend to do the least damage. Macro viruses infect your Microsoft Word application and typically insert unwanted words or phrases.


The best protection against a virus is to know the origin of each program or file you load into your computer or open from your e-mail program. Since this is difficult, you can buy anti-virus software that can screen e-mail attachments and also check all of your files periodically and remove any viruses that are found. From time to time, you may get an e-mail message warning of a new virus. Unless the warning is from a source you recognize, chances are good that the warning is a virus hoax.




EXERCISE: Read the text carefully; then, answer the questions in Spanish.               


1.  How does a virus spread in the Web?    

2.  Do viruses act immediately?

3.  What kind of files do file infectors infect?

4.  How do macro viruses operate?

5.  How can we best protect ourselves from viruses?








Zip for Windows


Installing the WinZip Wizard

We will refer to the on-screen panels using the title that appears at the top of each panel.

1. In the WinZip Setup panel, choose Start with the WinZip Wizard and click Next. The Search for Favorite Zip Folders panel will appear.

2. In the Search for Favorite Zip Folders panel, choose Search Entire Hard Disk so the Wizard can search your system for Zip files (this is the recommended option). You will see the search progress, and then a panel that says something like "17 folders were added to your 'Favorite Zip Folders'". Click Next.

3. The Wizard will open an Explorer window displaying the WinZip program group icons. Click Next to continue, and the Wizard Welcome panel will appear.

4. In the Wizard Welcome panel, click Next again, and the Select Activity panel will appear.

That's it, you have installed WinZip, and you're ready to begin using the WinZip Wizard. The sections below describe using the Wizard for unzipping and zipping files.


Using the WinZip Wizard

If you have just installed WinZip and selected the WinZip Wizard interface, then at this point the Select Activity panel is on the screen.
If you have previously installed WinZip, you can start a WinZip session using the WinZip program item in the WinZip program group, the Start menu, or the WinZip icon on your desktop.
Here is a brief introduction to the features of the WinZip Wizard.


Quick Unzipping with the WinZip Wizard

1. In the Select Activity panel, choose Unzip or install from an existing Zip file and click Next. The Select Zip File panel will appear.

2. In the Select Zip File panel, click on the Zip file you want to work with and click Next. The Unzip panel will appear.

3. In the Unzip panel, click Unzip Now to open the files in the archive. The WinZip Wizard will open a Windows Explorer window showing the unzipped files.

That's it, you've just unzipped (extracted) a Zip file using the WinZip Wizard. You can now work with the unzipped files, or click Next to choose another activity within WinZip, or close the WinZip Wizard window.

Quick Zipping with the WinZip Wizard

1. In the Select Activity panel, choose Create a new Zip file and click Next.

2. In the Choose Zip Name panel, type the name you want to use for your new Zip file and click Next. For example, if you are creating a Zip file that will contain some files related to yearly reports, you might type "1999 reports" as the name for your Zip file.

3. In the Select Files panel, click Add files to add files to your Zip file, then select the files you want to add and click OK.

4. Click Zip Now to create the new Zip file.

That's it, you've just created a Zip file using the WinZip Wizard. You can now click the WinZip Classic button if you would like to examine the contents of your new archive, or click Next to choose another activity within WinZip, or close the WinZip Wizard window.


EXERCISE: Read the text carefully; then, answer the questions in Spanish.   


1.  ¿Qué usaremos para referirnos a los paneles en pantalla?


2.  ¿Qué tipo de ventana abrirá el asistente (el Wizard)?


3.  Si ya has instalado WinZip y seleccionado la interfase con asistente, ¿Qué aparecerá en pantalla?


4.  ¿Qué debemos hacer en el panel "Select Zip File" para obtener el panel "Unzip"?


5.  ¿Cuál es el primer paso para comprimir un archivo usando el asistente?