Editing Star Trek project (section)

=={{anchor|DR DOS}}Architecture==
Star Trek was designed as a hybrid of Apple's [[classic Mac OS|Macintosh]] [[operating system]], made to run as an [[operating system shell|operating system GUI shell]] application upon Novell's next in-development version of the [[DR&nbsp;DOS]] operating system.<ref name="Cortese_1993"/> It was designed so that a user could think of it as a standalone application platform and general computing environment, in a concept similar to Microsoft's competing [[Windows 3.1x]], running on top of DOS. This was a radical and tedious departure both technologically and culturally, because at that time, the Macintosh system software had only ever officially run on Apple's own computers, which were all based on the [[Motorola 68000]] architecture.

The system was built on the successor of [[Digital Research]]'s DR&nbsp;DOS 6.0 ([[BDOS]] level 6.7 and 7.1) and NetWare [[PalmDOS]] 1.0 (code named "Merlin", BDOS level 7.0), Novell's DR&nbsp;DOS "Panther" as a fully PC&nbsp;DOS compatible [[16-bit]] disk operating system (with genuinely DOS compatible internal data structures) for [[Bootstrapping|bootstrap]]ping, media access, [[device driver]]s and [[file system]] support.  The system would utilize DR&nbsp;DOS's new "Vladivar" Extended&nbsp;DOS component with [[Flat memory model|flat memory]] support, which had been under development since 1991.<ref group="nb" name="NB_Panther"/> "Vladivar" (<code>DEVICE=KRNL386.SYS</code><ref name="Schulman_1994_Undocumented-DOS"/> aka <code>DEVICE=EMM386.EXE /MULTI</code> + <code>TASKMGR</code>)<ref name="Caldera_1997_MULTI"/> was a dynamically loadable [[32-bit]]<ref name="Cortese_1993"/> [[protected mode]] system core for advanced [[memory management]], hardware [[virtualization]], [[scheduling (computing)|scheduling]] and domain management for [[preemption (computing)|pre-emptive]] [[Multithreading (software)|multithreading]] within applications as well as [[Computer multitasking|multitasking]] of independent applications running in different [[virtual DOS machine]]s (comparable to [[386 Enhanced Mode|Windows 386 Enhanced Mode]] but without a [[GUI]]).<ref name="Caldera_1997_MULTI"/>

Thereby, the previously loaded DOS environment including all its device drivers became part of the system domain under the multitasker.<ref name="Caldera_1997_MULTI"/> Unless specific protected mode [[VxD|virtual device driver]]s were loaded, hardware access got tunneled through this 16-bit sub-system by default.  For maximum speed at minimum resource footprint, the DR&nbsp;DOS [[BIOS]], BDOS [[kernel (operating system)|kernel]], device drivers, memory managers and the multitasker were written in pure x86 [[assembly language]].  Apple's port of [[System 7 (Macintosh)|System 7.1]] would run on top of this high-performance yet light-weight hybrid 32-bit/16-bit protected mode multitasking environment as a graphical system and shell in [[user space]]. Macintosh [[resource fork]]s and [[long filenames]] were [[File Allocation Table#ADS|mapped onto]] the [[FAT12]] and [[FAT16]] file systems.{{citation needed|date=November 2015}}