Why did Turbo Pascal implement its own heap manager?

Newsgroups	comp.lang.pascal.borland
Date	2017-02-08 15:31 -0800
Message-ID	<ed1b7454-1574-488f-ba8c-43de064a0d2c@googlegroups.com> (permalink)
Subject	Why did Turbo Pascal implement its own heap manager?
From	Jim Leonard <MobyGamer@gmail.com>

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As the subject says.  Since MS-DOS ever since version 2.0 has memory management functions (INT 21h/AH=48h, INT 21h/AH=49h, and INT 21h/AH=4Ah), why did Borland feel it necessary to implement their own heap manager?

The only possible reason I can think of is that Borland's management only uses 8 bytes of overhead instead of DOS's 16 bytes per overhead (per MCB), so I guess the advantage was that you could use 8 less bytes per allocation, and also allow a minimum allocation of 8 bytes instead of DOS's 16 bytes.  The thing is, the heap manager compiles to nearly 1K, so it seems like this would have eaten up any savings gained by a smaller heap structure...?  Any thoughts or comments welcome.

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Why did Turbo Pascal implement its own heap manager? Jim Leonard <MobyGamer@gmail.com> - 2017-02-08 15:31 -0800
  Re: Why did Turbo Pascal implement its own heap manager? "Gene Buckle" <gene.buckle@bbs.retroarchive.org.remove-101r-this> - 2017-02-14 14:17 -0800
    Re: Why did Turbo Pascal implement its own heap manager? Jim Leonard <mobygamer@gmail.com> - 2017-03-08 08:49 -0800
  Re: Why did Turbo Pascal implement its own heap manager? Marco van de Voort <marcov@toad.stack.nl> - 2017-03-09 09:22 +0000
  Re: Why did Turbo Pascal implement its own heap manager? sillyluis <sillyluis@gmail.com> - 2017-03-14 10:31 -0700

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