Wednesday January 27, 1999

Some additional topics

Filenames. Recall the way that the DOS operating system named files. A complete file name consists of three components. The first component is a character string (letters or numbers) of up to 8 characters. The next component is a dot. The last component is a character string (letters or numbers) of up to 3 characters. There are several DOS commands which we can use in Windows 95. The first and last components are normally called the filename and extension, respectively.

DIR will list all files in your directory.

COPY will copy a file from a source to a destination.

DEL will delete a file.

MD will create a directory.

CD will allow you to change between directories.

A directory is DOS is equivalent to a folder in Windows 95. Windows 95 allows us to use the GUI so that navigation is easier. There are two special directories, . is the current directory, .. is the parent directory.

Windows 95 does not restrict us the way DOS did. We can use long filenames in the GUI. However, when we view the file in a DOS shell, the filename will be truncated so that it fits the DOS convention.

One useful feature of these commands is that we can use wildcards. A wildcard is represented by an asterisk. So let us look at some examples of using the commands.

Within Windows 95 you can access a DOS shell. This means that you can temporarily leave the GUI and go to a command line environment (where you type commands). You can usually find the MS DOS shell when you click the Start Button and select Programs.

Try the following in a DOS shell.

1. List all files with an extension of txt.

2. Create a directory called myfiles.

3. Change into that directory and determine how many files are contained in that directory.

4. Copy all the files in C:\windows to the directory you created.

5. Determine how many files were copied and how much space they have taken up.

Windows Explorer

There is a special feature of Windows 95. It is called the Windows Explorer. It is the counterpart of File Manager in Windows 3.1. You may open the Windows Explorer by right clicking the My Computer icon and choosing Explore.

Using Windows Explorer we can browse floppy drives, hard drives, and CD-ROMs. When you begin Windows Explorer, you normally see a list of all of these drives. There are two special symbols that we should be aware of. When a folder has a + sign in front of it, that means that the contents of the folder are not shown. When there is a minus sign in front of the folder it means that the contents of the folder are shown. You may spend some time now experimenting with the Windows Explorer.

One additional thing to note about windows in Windows 95 is that there is a shortcut to get to items on the Menu Bar. Notice that on the menu bar one letter of the Menu Option is underscored. If you hit the ALT key together with the letter that is underscored, that is a shortcut to bring down the menu. When you bring down the menu it will probably tell you about other keyboard shortcuts.

Another thing to notice is that when selecting folders in the GUI to copy normally they have to all be together in order for us to drag the group. If you want to select files that are not together, then hold down the CTRL key. This will also be something that will be useful to us when we discuss Microsoft Excel.

Review for Exam 1

Computer Concepts

The four major functions of a computer

Input
Output
Processing
Storage

Definitions

Hardware - The physical components of a computer system
Software - The programs which control the hardware
Data - Raw facts
Information - Raw facts processed into a meaningful form

A computer transforms data into information.

Input

Keyboard
- Enter Key
- Function Keys
- Navigation Keys
- Insert/Delete, Backspace Key
- CTRL, ALT, DEL / Escape Key
- Start Button Key
Mouse
- Left Button
  - Double-Click
  - Click
  - Point
  - Click and Drag
- Right Button
  - Quick Menus

Processing

Recall that processing inside of a computer takes place in the CPU ( Central Processing Unit)

Some of the responsibilities of the CPU are

Interpreting Instructions
Arithmetic and Logic Operations
Controlling Input and Output Operations

It is necessary sometimes for the CPU to store data temporarily. Therefore, computer memory is an important consideration. There are two types of memory inside a computer.

ROM - Read Only Memory - Non-volatile - is not erased when the power off
RAM - Random Access Memory - temporary memory - volatile - is erased every time the power is turned off.

Output

Monitor
Printer
Speaker

Storage

Units of Storage
- Bit - binary digit - 0 or 1 - the smallest unit of data
- Byte - 8 bits
- Kilobyte (KB) - 1024 bytes
- Megabyte (MB) - approximately 1 million bytes
- Gigabyte (GB) - approximately 1 billion bytes
- Terabyte (TB) - approximately 1 trillion bytes
A file is a collection of data. Files can be created, edited, and saved.
Data can be moved between files using the Cut/Copy/Paste feature. The clipboard is a temporary storage area. Cut removes the current data and copies it to the clipboard. Copy makes a copy of the current data on the clipboard. You can then use paste to remove the data from the clipboard to the destination.
Files can be stored externally on disks
- Some common types of disk are DS/HD Double-Sided/High-Density
- The disks are called floppies because the first ones were physically floppy.
- In order for a floppy to be used, it must be formatted.
- When formatted, a floppy is divided into tracks and sectors. Recall that a track is a circular section of the floppy, and a sector is a pie-shaped wedge of the floppy. The intersection of a track and a sector is called a track sector. Depending on the operating system, a cluster is from 2 to 8 track sectors. A cluster is the smallest unit of physical storage on a floppy. The recording density determines how much data can be stored on the floppy.
- Also created when a floppy is formatted is a root directory and FAT (File Allocation Table). A FAT is a special area of the floppy that contains information such as name, size, last date modified, and location of clusters contained in a file. It also contains information about bad clusters.
In Windows 95, the letters A and B normally designate floppy drives on the system, and the letter C normally is reserved for the hard drive. A hard drive is a fixed drive. D is either used for either a hard drive or a CD-ROM drive.
Peripherals are devices which are connected to a computer such as a printer.

Computer Software

Applications Software
- Word Processing
- Spreadsheet
- Database
- Graphics
- Communications
System Software
- Operating System
  - OS2
  - MS-DOS
  - Windows 95
  - Windows 98
  - Windows NT
  - UNIX
- The purpose of an operating system
  - Boots Computer
  - Provide an interface between a user and the computer
  - Coordinates Access to Devices
  - Runs Programs
- Virus Protection - Recall that we need to be aware there is a threat of computer viruses. There exist software packages which will detect and remove known computer viruses.
Program files contains instructions that tell the computer what to do.

Windows 95

Start Button
- Programs - contains a menu of all the executable programs on the hard drive. Some of the important programs are applications programs like Microsoft Word or Netscape Communicator, Accessory programs like Notepad, and an MS-DOS Prompt
- Documents - contains a list of all recenlty opened documents
- Settings - shortcut to Control Panels, Printers, and Taskbar
- Find - allows us to search the entire hard drive or any part of the hard drive for certain files. We may use wildcards if we are not sure of the name
- Help - contains a list of all tutorials on the hard drive, an index of all help topics, and an advanced index
- Run - allows us to run an application just as we would at an MS-DOS Prompt
- Shutdown - brings up a menu that allows us to either shut the machine down, restart the machine, restart the machine in MS-DOS mode, or close all programs and log on as a different user. The proper way to shut down a Windows 95 session in a networked environment is to close all programs and log on as a different user.
Desktop - a comprehensive view of computer contents/resouces.
- Parts of the Desktop
  - Icons - Small pictures that represent objects. Double-clicking on an icon either open the file and its associated application or opens the folder. When the operating system is busy processing a command, an hourglass icon appears. The icons representing the drives on the system are similar but different.
  - Taskbar
    - Buttons that represent running or open applications.
    - Allows you to switch back and forth between running applications.
    - The Active window is represented by a highlighted title bar. Notice that also we have a dimmed button on the taskbar for the window in some cases. Only one window is active at a time.
    - We can customize the taskbar can be done through the settings command on the start button.
    - We can also customize the taskbar by right clicking on an open area of the taskbar. We also get the option of Cascase Icons, Tile Horizontally, or Tile Vertically. The Cascade option allows open windows to be placed on top of each other. The tile horizontal and tile vertical make all windows visible simultaneously on the screen.
  - Recycle Bin - allows you to throw away files or folders. Recall that once you throw a file in the recycle bin, it is not gone until you empty the recycle bin. When a file or folder is in the recycle bin, it can be recovered.
  - When we drag and drop an icon of a file to another folder on the hard drive the file is moved to the other location on the harddrive.
  - Windows
    - Parts of a window - title bar, maximize/restore button, minimize button, close button, status bar.
    - Title bar contains the name of window and the maximize, minimize/restore, and close button.
    - Minimize keeps the application open but reduces it to a button on the taskbar. Maximize allows the window to take the full screen. Restore restores the window to its previous size.
    - To move a window move the mouse pointer to the title bar of the window, hold down the mouse pointer, and drag the window to the new location. To reshape or resize a window move the mouse pointer to one of the window's corners until the mouse pointer becomes a double-pointed arrow. Then hold down the left mouse button and drag the mouse.
    - A window only contains scroll bars when there is not enough room to display the contents of the folder.
    - There are usually 4 menu items, File, Edit, View, and Help. Under view we can choose how we view icons. We can list by name, size, type, date of last modification. If you want to see information about a file you need to select details. Under File we can Save and Open.
  - Dialog boxes - appear after we click an option containing three dots ... called ellipses. Contains several frames that are tabbed. It also contains a What's This? Button and a Close Button. The What's This? Button is symbolized by a question mark. If we click the What's This? Button and move the mouse pointer to an option in the current frame we get a rectangle that describes the option.
  - Options that are dimmed means they aren't applicable.
  - Screen Saver - protects the computer monitor by displaying a constantly changing image after a certain period of inactivity.
  - Windows Explorer - allows us to see all files on any drive and do various things such as copy or delete. A folder with a plus sign means that the folder has additional folders that are not displayed.
Communications - need a modem and communications software to connect to a remote computer. There is a phone dialer application in Windows 95 that requires a modem be installed. Modem speed is measured in bits per second. A fast modem is the best. We can upload and download files. When we download, we leave ourselves at the risk of downloading a computer virus. We can receive e-mail. E-mail is stored on a server. We do not have to be online for someone to send us e-mail. We can retrieve our e-mail when we log onto the server.
Local Area Networks - contains a machine which acts a server or host machine. It allows us to share files and resources. We are usually required to have a password on a network system. We shouldn't choose a password which is too easy to guess. Normally a combination of characters and numbers is a good password. A server may contain data files or program files which can be shared among users. A server acts as a host computer on a local area network. When storing files on a LAN you may store them on your PC or on a network drive in which you have permission to store things.