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Lesson#1
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Windows Programming
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Operating Systems History and
overview................................................................ 2
About
MS-DOS.............................................................................................................
2
MS-DOS
Programmes.................................................................................................
2
Features of DOS
programming..................................................................................
2
Windows
History...........................................................................................................
3
Features of Windows
Programming..........................................................................
3
Difference between MS-DOS and Windows programming
................................... 3
Levels of Computer
Languages.................................................................................
3
Summary
.......................................................................................................................
5
Tips................................................................................................................................
5
Operating Systems History and overview
Operating System is a software package which tells the computer how to
function. It is
essentially the body of the computer. Every general-purpose computer
requires some type
of operating system that tells the computer how to operate and how to
utilize other
software and hardware that is installed onto the computer.
GUI - Graphical User Interface operating systems are operating systems that
have the
capability of using a mouse and are graphical. To establish a point of
reference, all
computers must have an OS. The OS controls input and output; makes
reasonable effort
to control peripherals; and in short acts as the interface between you the
user, the
software, and the hardware.
About MS-DOS
Microsoft DOS (Disk Operating System) is a command line user interface.
MS-DOS 1.0
was released in 1981 for IBM computers and the latest version of MS-DOS is
MS-DOS
6.22 released in 1994. While MS-DOS is not commonly used by itself today, it
still can
be accessed from Windows 95, Windows 98 or Windows ME by clicking Start /
Run and
typing command or
CMD in Windows NT, 2000 or XP.
MS-DOS Programs
DOS programs generally expect themselves to be the only program running on
the
computer, so they will directly manipulate the hardware, such as writing to
the disk or
displaying graphics on the screen. They may also be dependent on timing,
since the
computer won't be doing anything else to slow them down. Many games fall
into this
category.
Features of DOS programming
• It ”owns” the system
• Provides direct device access
• Non-portability across machines
• Status polling
• No multitasking
• No multithreading- Single path of execution
• DOS launches User Application; when done, control returned to DOS
• Assumes the current program is in total control of the hardware
• Supports the File Allocation Table (FAT) file system
• “Real-Mode” OS that is limited to the 8086 Address Space of 1 MB
3
Windows History
On November 10, 1983, Microsoft announced Microsoft Windows, an extension of
the
MS-DOSŪ operating system that would provide a graphical operating
environment for
PC users. Microsoft called Windows 1.0 a new software environment for
developing and
running applications that use bitmap displays and mouse pointing devices.
With
Windows, the graphical user interface (GUI)
era at Microsoft had begun.
The release of Windows XP in 2001 marked a major milestone in the Windows
desktop
operating system family, by bringing together the two previously separate
lines of
Windows desktop operating systems.
Features of Windows Programming
• Resource sharing
• Device independent programming
• Message driven operating system
• GDI (Graphics Device interface)
• Multitasking
• Multithreading
Difference between MS-DOS and Windows
programming
In 32-bit windows programming, we are freed from the curse of 64k segments,
far and
near pointers, 16-bit integers and general limitations.
With this power, though, comes responsibility: we no longer have exclusive
control over
the machine. In fact, we don't have direct access to anything: no
interrupts, no video
ports, and no direct memory access.
Ultimately, the difference between these two types of programmes is who has
control
over the system. Moreover, by taking into account the message driven
operating system,
you would be better able to know what happens behind the scenes and how the
system
interacts with the internal and external messages.
Levels of Computer Languages
Low level languages are more close to machine language or computer
understandable
language while the high level language are more close to human
understandable
language.
4
Note that from one of the middle level language i.e. C / C++, two
programming
languages have emerged, MFC programming and Win32 API programming. Both of
these programming languages have got their basis from C / C++.
MACHINE
LANGUAGE
C / C ++
middle level
language
WIN32 API
PROGRAMMING
MFC
PROGRAMMING
OTHER
ADVANCED
LANUGUAGES
ASSEMBLY
LANGUAGE
low level language
Levels of Computer Languages
5
Tips
• During programming, take into account which
operating system you are using so
that you can make use of all the available resources in the best possible
way.
• Windows programs are considered to be more
secure and reliable as no direct
access to the hardware is available.
Summary
In this section, we have discussed a brief overview of MS-DOS and Windows
operating
systems. We have also pointed out the main features of DOS and Windows
Programming. Only one DOS program can be executed at a given time and these
programs owns the system resources. While in Windows, we can execute several
different programs simultaneously. Windows operating system don’t give us
the direct access to interrupts, video ports and memory etc. |
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