On Jul 12, 2016, at 9:25 AM, Cameron Kaiser <spectre at floodgap.com> wrote:
I'm really interested to
see how they reimplemented the Toolbox under these circumstances,
There?s nothing particularly special about the Mac Toolbox and Operating System per se.
Pretty much anyone could have attempted to develop a clean-room workalike using the
?Inside Macintosh? books:
- Implement each API described in the book to have the behavior described in the books,
- Dispatching each one using the A-trap and taking parameters in the registers described
in the books,
- And affecting the globals as described in the books.
Through System 6 there were only a few hundred and they were very well-understood, and
even things like trap patching were (relatively) well managed by developers of large scale
commercial apps because they had to work on everything from a Mac 512Ke to a Mac IIfx with
tons of RAM and disk and multiple displays under MultiFinder or A/UX.
Many companies actually developed portable workalikes to the System 6 APIs in order to
port their applications from one platform to another. QuarkXPress even used to provide a
Toolbox-workalike API as part of their Windows plug-in SDK.
The real killer was System 7, which doubled or tripled the number of available APIs via
the system, and did so with thorough integration and compatibility. Then there was the
PowerPC transition and System 7.1.2. And then the API set grew enormously again with
System 7.5? There was no way someone like NuTek could have kept up.
There were companies that developed later Mac API compatibility suites. One of them was
Altura, the same people who provided the Quick Help application that all of the MacOS
programming docs switched to (in lieu of Symantec?s THINK Reference); they provided an API
suite that you could use to port to Windows or UNIX and they had at least a minimally
working version for OPENSTEP after Apple bought NeXT and before Apple announced Carbon.
And of course Apple itself had a Mac API compatibility suite that was part of QuickTime
for Windows. I know of companies that used it to actually port Mac applications to
Windows, because it was fairly complete and licensing QuickTime for Windows for a
commercial product wasn?t a hassle.
-- Chris