Editing Turbo Pascal (section)

===CP/M and DOS versions===
====Version 1====
[[File:Turbo pascal 30 cover.jpg|thumb|Turbo Pascal 3.0 manual front cover]]

Version 1, released on 20 November 1983, was a basic all-in-one system, working in memory and producing [[COM file|.COM]] executable files for DOS and CP/M, and equivalent [[CMD file (CP/M)|.CMD]] executables for CP/M-86 (totally different from .CMD batch files later used in 32-bit Microsoft Windows). Source code files were limited to 64&nbsp;KB to simplify the IDE, and DOS .COM files were limited to 64&nbsp;KB each of code, stack and global (static) variables. Program source code could be extended by using the include facility if the source code exceeded the memory limit of the editor.
 
There were different versions of Turbo Pascal for computers running DOS, CP/M, or CP/M-86 with 64&nbsp;KB of memory and at least one floppy disk drive. The CP/M version could run on the many CP/M machines of the time with [[Zilog Z80|Z80]] processors, or an Apple II with Z80 card. The DOS and CP/M-86 versions ran on the many [[Intel 8086|8086]] and [[Intel 8088|8088]] machines which became available, including the IBM  PC. 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. A disc copy without MicroCalc would accommodate the source code and compiled executable of a reasonable-sized program—as it was common at the time for users to have only a single floppy drive as [[mass storage]], it was a great convenience to be able to fit both the compiler and the program being written on a single disc, avoiding endless disc swapping.

The [[Computer architecture|architecture]] of the various machines running MS-DOS additionally limited the maximum user memory to under 1&nbsp;MB (e.g., [[IBM PC compatible|machines hardware-compatible with the IBM PC]] were limited to 640&nbsp;KB).

The Turbo Pascal IDE was very advanced for its day. It was able to perform well and compile very fast with the amount of RAM on a typical home computer. The IDE was simple and intuitive to use, and had a well-organized system of menus. Early versions of the editor used [[WordStar]] key functions, which was the [[de facto]] standard at the time. Later versions of the IDE, designed for PCs with more disk space and memory, could display the definitions of the keywords of the language by putting the cursor over a keyword and pressing the F1 key (conventionally used to display help). Many definitions included example code.

In addition to standard executable programs, the compiler could generate [[terminate-and-stay-resident]] (TSR) programs, small utilities that stayed in memory and let the computer do other tasks—running several programs at the same time, [[Computer multitasking|multitasking]], was not otherwise available. Borland produced a small application suite called [[Borland Sidekick|Sidekick]] that was a TSR letting the user keep a diary, notes, and so forth.

==== Version 2 ====
Version 2, released a few months later on 17 April 1984, was an incremental improvement to the original Turbo Pascal, to the point that the reference manual was at first identical to version 1's, down to having 1983 as the copyright date on some of the compiler's sample output, but had a separate "Addendum to Reference Manual: Version 2.0 and 8087 Supplement" manual with separate page numbering.<ref name=turbop>{{cite book |url=http://bitsavers.org/pdf/borland/turbo_pascal/Turbo_Pascal_Version_2.0_Reference_1984.pdf |title=Turbo Pascal version 2.0}}</ref> Additions included an [[Overlay (programming)|overlay system]], where separate overlay procedures would be automatically swapped from disk into a reserved space in memory. This memory was part of the 64kB RAM used by the program's code, and was automatically the size of the largest overlay procedure.<ref name=turbop/> Overlay procedures could include overlay sections themselves, but unless a RAM disk was used, the resulting disk swapping could be slow. 2.0 also added the Dispose procedure to manage the [[Heap (programming)|heap]], allowing individual dynamic variables to be freed, as an alternative to the more primitive 'Mark/Release' system and increased compatibility with WordStar commands plus use of the numeric keypad on the IBM PC and compatibles.<ref name=turbop/> Such PCs also had new text window and [[Color Graphics Adapter|CGA]] graphics mode commands as well as being able to use the PC's speaker for tones. Finally, DOS and CP/M-86 machines with an [[8087]] maths coprocessor (or later compatible) had an alternative TURBO-87 compiler available to purchase.<ref name=turbop/> 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. The manual notes that although source code for the Turbo Pascal's software real data types offering a range of 1E-63 to 1E+63 to 11 significant figures, these were incompatible at a binary level: as well as having a much larger range, the software reals took six bytes in memory and the 8087 ones were eight.

Version 2 for CP/M-80 only runs on Z80-based [[CP/M]] machines.<ref name="rodman198409">{{Cite magazine |last=Rodman |first=Richard |date=1984 |title=Turbo Pascal v2.0 |url=https://archive.org/details/Computer_Language_Issue_01_1984-09_CL_Publications_US/page/n79/mode/1up?view=theater |access-date=2025-04-06 |magazine=Computer Language |pages=78–79 |volume=1 |issue=1}}</ref>

==== Version 3 ====

Version 3 was released on 17 September 1986.<ref name="tp302"/> Turbo Pascal 3 supported [[turtle graphics]].<ref>{{cite web|url=https://cs.nyu.edu/cs/faculty/marateck/turtle.html|title=Using Turtle Graphics Under Turbo Pascal |first=Nathan |last=Hull}}</ref> In addition to the default software real numbers and 8087 edition of the compiler, Borland also offered a [[binary-coded decimal]] (BCD) version (TURBOBCD) which offered the same numeric range as real data types but to 18 significant figures.<ref name="tp302"/>