What is DOS or Disk Operating System? It commonly refers to the family of closely related operating systems which dominated IBM PC compatible market between 1981 and 1995 (or until 200, if Windows version 95, 98, and ME are included).

Also note the term Turbo Pascal which is the compiler and an Integrated Development Environment or IDE for the Pascal Programming Language running mainly on MS-DOS which was developed by Borland. The name Borland Pascal was generally reserved for the high end packages (with more libraries and standard library source code) while the original cheap and widely known version was sold as Turbo Pascal. The name Borland Pascal is also used more generically for Borland’s dialect of Pascal.

The Macintosh or Mac is a line of personal computers designed, developed, manufactured and marketed by Apple Computer, Inc. It was named after the Macintosh Apple. The original Macintosh was released on January, 24, 1984. It was the first commercially successful personal computer to use a graphical user interface or GUI and mouse instead of the then-standard command line interface. The command line interface or CLI is a tool for interacting with computers, often using a text terminal. Commands are entered as lines of text (that is, sequences of typed characters) from a keyboard, and output is also received as text. CLI’s originated when teletype machines were connected to computers in the 1950’s. in the term of immediate interaction and feedback, they represented an advance over the use of punch cards. The current range of Macintoshes varies from Apple’s entry level MacMini desktop, to a mid-range server, the Xserve. Macintosh systems are mainly targeted towards the home, education, and creative professional markets. Production of the Macintosh is based upon a vertical integration model in that Apple facilities all aspects of its hardware and creates its own operating system. This is in contrast to PCs, where different brands of hardware run operating systems such as Microsoft Windows.

In 1986, Borland introduced similar extension, also called Object Pascal, to the Turbo Pascal product of Macintosh, and in 1989 for Turbo Pascal 5.5 for DOS. When Borland refocused from DOS to Windows in 1994, they created a successor to Turbo Pascal, called Delphi and introduced a new set of extensions to create what is now known as the Delphi Language. It featured an incompatible syntax using the keyword class in preference to object, the Create constructor and a virtual Destroy destructor (and negating having to call the new and Dispose procedures), properties, method pointers, and some other things. These were obviously inspired by the ISO (International Standards Organizations) working draft for object-oriented extensions, but many of the differences to the Turbo Pascal’s dialect (such as the draft’s requirement that all methods be virtual) were ignored. The Delphi programming language continued to evolve through out the years to support new language concepts such as 64-bit integers and dynamic arrays.


History
Since the researchers used Delphi 7, the history of the language would be mostly focusing on the said version of Delphi.
The chief architect behind Delphi, and its predecessor, Turbo Pascal, was Anders Hejlsberg until he was headhunted by Microsoft in 1669, where he worked on Visual J++ then subsequently became the chief designer of C# and a key participant in the creation of the Microsoft.NET framework or platform. Anders Hejlsberg is an influential Danish software engineer who co-designed several popular and commercially successful programming languages and development tools. He currently works for Microsoft, where he is the lead architect of the C# programming language. The Visual J++, mentioned above, is Microsoft’s implementation of Java. Optimized for the Windows Platform, J++ programs, can run on the MSJVM or Microsoft Virtual Machine for Java), which was Microsoft’s attempt at a faster interpreter. Syntax, keywords, and grammatical conventions are the same to Java. The one major difference was that Visual J++ applications could only run on Microsoft’s Virtual Machine. Lastly, C# is an object-oriented programming language developed by Microsoft as part of their .NET initiative, and later approved as a standard by ECMA and ISO. C# has a procedural, object-oriented syntax based on C++ that includes aspects of several other programming languages (most notably Delphi, Visual Basic and Java) with a particular emphasis on simplification (fewer symbolic requirements than C++, fewer decorative requirements than Java).

In 2001 a Linux version known as Kylix became available. It is Linux version of Delphi and C++ Builder—Borland’s integrated development environments for Windows. Kylix supports application programming using Object Pascal and C++; you can use it to write command line utilities, Apache modules, and especially, GUI applications, but you can’t use it to write device drivers or kernel modules.

Kylix went through three versions, none of which were of particularly high quality. The first version, in particular, struck many people as a beta that should never have been released. Versions 2 and 3 fixed some bugs, and ported the remaining "enterprise" and C++ Builder features of the Delphi 5 model. However, low quality and a high price lead to poor sales, and Kylix was ultimately abandoned; despite occasional Borland references to Linux, there are no indications that another Kylix version is forthcoming. There is no upgrade path to Delphi 2005 nor Delphi 2006, and neither seem to include support for CLX. Furthermore, the last official supported Linux distributions are: Red Hat Linux 7.2, SUSE Linux 7.3 and Mandrake Linux 8.2. With some tweaking, it is possible to run Kylix on Slackware Linux 8.x and 9.x. Kylix will run under more recent Linux distributions but requires some research and additional configuration (eg. have an older version of glibc available, and make other changes to the default environment.

The support for Linux and Windows cross platform development (through Kylix and the CLX component library) was added in 2001 with the release of Delphi 6. Delphi 8 on the other hand was released December 2003 which was a .NET-only release that allowed developers to compile Delphi Object Pascal code into .NET MSIL or Microsoft Intermediate Language. It was also significant in that it changed it IDE for the first time since its conception from the multiple floating window on desktop style IDE to a look and feel similar to Microsoft’s Visual Studio.NET.

Although Borland fulfilled one of the biggest requests from developers (.NET support), it was criticized both for making it available too late, when a lot of former Delphi developers had already moved to C#, and for focusing so much on backward compatibility that it was not very easy to write new code in Delphi. Delphi 8 also lacked significant high-level features of the C# language, as well as many of the more appealing features of Microsoft’s Visual Studio IDE.

The subsequent version, Delphi 2005 (Delphi 9), included the Win32 and .NET development in a single IDE reiterating Borland’s commitment to Win32 developers. Delphi 2005 includes design-time manipulation of live data from a database. It also includes an improved IDE and added a for…in statement to the language. However, it was criticized by some for its bugs; both Delphi 8 and Delphi 2005 had stability problems when shipped, which were only partially resolved in service packs.

In late 2005, Delphi 2006 was released and federated development of C# and Delphi.NET, Delphi Win32 and C++ into a single IDE. It was much more stable than Delphi 2005 when shipped, and improved even more after the service packs and hotfixes.

On February 8, 2006, Borland announced that it was looking for a buyer for its IDE and database line of products, which include Delphi, to concentrate on its ALM line. The news met with voluble optimism from the remaining Delphi users.

On September 6, 2006, the Developer Tools Group (the working name of the not yet spun off company) of Borland Software Corporation released single language versions of Borland Developer Studio, bringing back the popular Turbo moniker. The Turbo product set includes Turbo Delphi for Win32, Turbo Delphi for .NET, Turbo C++, and Turbo C#. Each version is available in two editions: Explorer—a free downloadable version—and Professional—a relatively cheap version which opens access to the thousands of third-party components. Unlike earlier Personal editions of Delphi, new Explorer editions can be used for commercial development.

Strengths and Weaknesses of Delphi Programming Language
The object-oriented features, support for pointers and complex datatypes, and language structure provided by Object Pascal are among Delphi’s greatest strengths. In addition to the standard datatypes, Object Pascal allows the creation of any type of pointer, including pointers to user-defined classes and structures, (records, in Pascal terminology). Pointers are allowed within complex datatypes and class definitions, as well.

Class declarations in Object Pascal are very similar to C++ declarations. The ability to declare member data elements and private functions improves encapsulation and allows information hiding. Also, in the C++ tradition, Delphi’s model of inheritance allows base class functions to be overridden by descendants, allowing polymorphic behavior in user-defined classes. Unfortunately, the support for overloaded member functions seems to be lacking in the language.

Another strong feature of the Object Pascal is its support for structures exception handling. An exception instance is never destroyed until it is handled. User-defined exceptions can also be declared and thrown.

Delphi’s weaknesses are few, considering that it is a first version of a fairly complicated development tool. Aside from the occasional UAE and some bugs in the security features of the local database server, Delphi seems to be a stable solid product. The database objects, while easy to use, seem to be geared more to desktop applications than client/server development, with heavy emphasis on bound controls. However, SQL traces will show that it makes very efficient use of the ODBC API in certain situations. This is because it maps to the API more cleanly than most Windows development tools’ OBDC layers, which typically don’t provide methods for using prepared execution. The close relationship to ODBC is somewhat surprising considering that IDAPI drivers are shipped with the product. For developers that are already familiar with the ODBC API, this should make a switch to IDAPI nearly transparent.
Overall, Delphi goes a long way toward living up to its billing as “the RADical performance tool”. The IDE is fairly intuitive, the object hierarchy is well-designed, and the Object Pascal programming language is arguably the best among the desktop development tools. The easy-to-configure ODBC connectivity and support for stored procedures make it a good choice for developing client applications to interface with Oracle.

Significance of Delphi Programming Language
Delphi is a product of Borland International. It is a native code compiler that runs under Windows and provides visual computer career programming tools, somewhat similar to those found in Microsoft Visual Basic. But the twist in the creation of Delphi programming language was the fact that it was obviously Borland’s attempt to compete with Microsoft. It sort of served as Borland’s edge to even with Microsoft when it comes to visual computer programming.

Now, it wouldn’t be worth Borland’s time to bring out an inferior product. Note that Visual Basic was developed as a programming language and development environment to take full advantage of Windows, Microsoft’s premier product. In the opinion of at least some programmers familiar with both languages, Delphi is superior. Delphi was developed to correct Visual Basic’s shortcomings and was made to take the identity of being “Visual Basic on steroids.”
Delphi is a very recent language, just brought out in 1995 but it descended from an earlier language, called Pascal, also adopted by Borland International. Borland brought out different versions from Turbo Pascal to Object Pascal.

Pascal was a well regarded language, but now is used mainly in colleges for teaching students programming before they set out on their computer careers. It is not used much for real world programs. Coincidentally, so Basic, the forerunner of Microsoft’s Visual Basic.
Delphi is the only visual development tool that was written by itself. It is considered easy to learn. The biggest task is learning the many built-in components that are included with it.
Delphi is currently not the big commercial success that Visual Basic is, and this is reflected in the number of computer jobs open for its programmers as compared to the demand for Visual Basic programmers.

Borland does not swing the same weight as Microsoft and, to be fair, it has not been out as long as Visual Basic.

However, if it proves to the marketplace that it can indeed solve problems with greater programming strength than Visual Basic, many companies will want to apply this tool to their businesses. In time, this growing demand could make Delphi programming skills and experience a premium plus in your computer career.