- VB Development Environment
- Add Form ' Add a new blank form
- Add Module ' Add a new empty module
- Save Form ' Save current form
- Save Project ' Save current project
- Add File ' Include a Form from another project. You may need
to save a copy of it in current directory
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- Sometimes you want to concentrate on a single Form window and want it
to take as much room on the screen as possible. Click the square box near the top right
corner as shown below:
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- When you want to display several Form windows at the same time
to make it easy to copy some controls or code from one Form window to another, click the
double square box near the top right corner as shown on the left.
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- Remove Form ' Remove a form from this project, the Form file
still exists
- Copy ' Copy highlighted text to clipboard (Ctrl-C)
- Cut ' Delete highlighted text and keep it in clipboard
(Ctrl-X)
- Paste ' Paste the text from clipboard to where cursor is
(Ctrl-V)
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- Bookmark ' Mark here to come back later with Next Bookmark
command
- Help: Highlight a keyword then press F1 to get help on that
keyword.
- To obtain the list of available VB constants and functions type
"VBA" followed by a period "."
- Press F4 to obtain Properties of current Control.
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- Slice then let another task of same priority take over.
- File Manager handles the use of the disks, organises the file
system.
- Disk Formatting subdivides estate on disk
- Drivers: Every piece of hardware interface placed on the
motherboard needs a driver. This is the program
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- How to Submit your
homework
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- Keep all the files belonged to a homework project in the same folder.
To submit your home work Zip all the files in the folder of your homework project then
attach the resultant Zip file to an Email that you send to your tutor. You can also do
this when you’re stuck in the middle of your program. In that case include some
description of the problem in your email. Additionally, when error occurs in your program
and shows some message that you don’t understand press the PrintScreen key (near the
top right corner of your keyboard) to copy the image of the screen into the windows
clipboard, then paste that image into a MS Word document and type a description of what
you did before the error came up.
- When the tutor receives your email, he Unzips the attached file into
a folder then looks at your VB project, including the MSWord document about the problem if
you had created it before. If he made quite a few changes in the code to show you how to
fix the bugs, he might Zip all the files in the project folder and send it back to you as
an attached file of the Email.
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- Internal data
presentation
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- ASCII Characters: Each character is represented by one byte
(i.e. 8 bits). This is the number sent to the computer each time you press a key on the
keyboard. The character for SPACE is represented by number 32 internally. Characters whose
ASCII value is less than 32 are non-printable and are also called control characters. Eg:
The ASCII value for Enter is 13, LineFeed is 10, Bell is 7, etc..
- Note that "1" is different from 1. Internally "1"
is represented by number 49 (31 hex)
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- Binary Numbers use only two symbols, 0 and 1, to represent any
number
- Eg: 1101 represents 13 because (1*8 + 1*4 + 1 = 13 )
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- Hexadecimal numbers use sixteen symbols, 0 ..9,A,B,C,D,E and F
to represent any number. Every 4 bits can be grouped into a Hex digit.
- Eg: AB represents 10101011
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- Graphic presentation
- SVGA memory requirement depends on the resolution and the maximum
number of colours required.
- A screen resolution of 800x600 means that it has 800 dots across and
600 dots vertically. If a dot could have 256 colours it would require one byte (8 bits)
per dot. Thus an 800x600 screen would need nearly 0.5 MB Ram on the SVGA card.
- Graphic File Formats: JPG and GIF require much less memory
than BMP
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- Overview of Operating
System
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- Kernel or Executive looks after Scheduling and inter task
communication and other services.
- Task Priority: Task with highest priority has the CPU until it
does a timing or I/O wait.
- Round Robin, Time Slice: Tasks of same priority take turn to
have the CPU. A task can run for a Time
- that enabled the operating system drive the hardware.
- Multitasking means many tasks can run concurrently. A program
may be loaded many times, each time a task is created.
- Real-time means the operating system can guarantee the
real-time performance of the task. The operating system uses Event Interrupt and other
schemes to schedule the tasks, letting them have sufficient CPU time to carry out their
operations.
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- The
Difference between MSDOS and Windows
- Windows is multitaskingỔit can run more than one program at any
time. The programs can run independently or in a coordinated manner. Windows manages the
use of hardware resources ie.Which program gets access to the screen? How is memory
shared? Which program gets keyboard input? Which one gets mouse input? Which program uses
the serial I/O ports?
- Windows is event driven. Many real-time MSDOS programs are written as
loops that perform I/O operations as needed. The program periodically checks for keyboard
or mouse input (it’s called Polling). Windows programs can receive external events at
almost any time. These events would be handled by the appropriate routines. A program can
do other things without waiting for an event.
- Windows is device independent. DOS programs frequently need to take
into account every possible printer or graphics device type. Windows provides a graphics
device interface (called GDI) that makes it possible to support virtually any graphics
deviceỔthe individual drivers are provided separately by hardware manufacturers. GDI
translates graphics commands so that they appear the same on all hardware devices.
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