Turbo Pascal

[3][4][5] Philippe Kahn first saw an opportunity for Borland, his newly formed software company, in the field of programming tools.

Historically, the vast majority of programmers saw their workflow in terms of the edit/compile/link cycle, with separate tools dedicated to each task.

In the early IBM PC market (1981–1983) the major programming tool vendors all made compilers that worked in a similar fashion.

Kahn's idea was to package all these functions in an integrated programming toolkit designed to have much better performance and resource utilization than the usual professional development tools, and charge a low price for a package integrating a custom text editor, compiler, and all functionality needed to produce executable programs.

On its launch in the United States market, Turbo Pascal retailed for US$49.99, a very low price for a compiler at the time.

The edit/compile/run cycle was fast compared to other Pascal implementations because everything related to building the program was stored in RAM, and because it was a one-pass compiler written in assembly language.

"[8] Borland sold about 250,000 copies of Turbo Pascal in two years, which Bruce F. Webster of Byte described as "an amazing figure for a computer language".

[10] Jerry Pournelle wrote in the magazine in February 1984 that Turbo Pascal "comes close to what I think the computer industry is headed for: well documented, standard, plenty of good features, and a reasonable price".

While cautioning that it was not suitable for developing very large applications, he concluded that Turbo Pascal "is well written, fun to use at times, and fast enough to make up for its few shortcomings ... it is a bargain that shouldn't be passed up".

He said that "Turbo Pascal has got to be the best value in languages on the market today", and that Borland led the industry in "delivering excellent products at reasonable costs".

[14] Despite finding what the magazine called "a serious bug" in 3.0, and decreased compatibility with PC clones, Byte in February 1986 stated that "it is hard to avoid recommending Turbo to anyone who wants to program in Pascal", citing improved speed and graphic routines.

[17] Webster praised the language, stating in August 1985 that Turbo Pascal "is best known for its small size, incredible compile speeds, and fast execution times".

It praised the software's low price, speed, and unusually good documentation for a compiler, and noted the existence of many utilities for Turbo Pascal from other companies.

The review stated that the IDE that simplified the edit-compile-run-debug loop made Turbo Pascal accessible, like BASIC, to new programmers.

Citing Anacreon as "a good example of how complex a program you can write in Pascal", and the many libraries from Borland and other developers, he wrote "I think it may well be the language for the rest of us".

[20] Scott MacGregor of Microsoft said that Bill Gates "couldn't understand why our stuff was so slow" compared to Turbo Pascal.

"He would bring in poor Greg Whitten [programming director of Microsoft languages] and yell at him for half an hour" because their company was unable to defeat Kahn's small startup, MacGregor recalled.

This language backwards compatibility means much old Turbo Pascal code can still be compiled and run in a modern environment today.

[22] Support for the various x86 memory models was provided by inline assembly, compiler options, and language extensions such as the "absolute" keyword.

The IDE provided several debugging facilities, including single stepping, examination and changing of variables, and conditional breakpoints.

For cases where the relatively simple debugging facilities of the IDE were insufficient, Turbopower Software produced a more powerful debugger, T-Debug.

Standard Pascal is designed to be platform-independent, so prescribes no low-level access to hardware- or operating system-dependent facilities.

[28] A patch was produced when machines became too fast for the original method, but failed as processor speeds increased yet further, and was superseded by others.

There were different versions of Turbo Pascal for computers running DOS, CP/M, or CP/M-86 with 64 KB of memory and at least one floppy disk drive.

The installer, lister, and compiler with its IDE, and the source code for a simple spreadsheet program called MicroCalc written by Philippe Kahn as a demonstration, would fit on a single floppy disc.

Borland produced a small application suite called Sidekick that was a TSR letting the user keep a diary, notes, and so forth.

[34] It supported the 8087's long real data types with a range of 1.67E-307 to 1.67E+308 to 14 significant figure precision but with a much greater processing speed.

[38] Colour displays were replacing monochrome; Turbo Pascal version 5.0, released 24 August 1988,[37] introduced blue as the editor's default background color, used by Borland's DOS compilers until the end of this product line in the mid-1990s.

Other changes to IDE include the addition context-sensitive help with description of all built-in functions, and the ability to copy code fragments from the help to edit window.

[42][43] Much like versions 1 to 3 for other operating systems, it was written in compact assembly language and had a very powerful IDE, but no good debugger.