Subject: Re: MachTen vs. MacBSD
To: Allen X Briggs <>
From: Anita Holmgren <>
List: macbsd-general
Date: 12/17/1993 11:45:06
At  9:18 PM 12/16/93 -0500, Allen X Briggs wrote:

>> With either flavor of MachTen the operation is much like that of
>> co-resident operating systems, with the Mach kernel and MacOS sharing the
>> processor.  When MachTen has control of the processor, it pre-emptively
>> multitasks Mach/Unix applications and when MacOS has control, it lets
>> Macintosh applications run in their normal cooperative sharing mode.
>How does it handle this?  Does MachTen run like any other Multifinder
>app, or does it wedge itself into the system more tightly?  In other
>words, does it take over input events/disk management/etc?  How well
>does it coexist with things like Superclock that aren't actually

In early versions of MachTen, our software was very tightly coupled with
MacOS and, yes, we did take over input events and disk management, but now
MachTen runs just like any other MultiFinder application.  We found that
'wedging' MachTen into MacOS raised incompatibilities without improving
performance to any appreciable extent.  The current architecture virtually
eliminates all incompatibilities, so, yes, MachTen coexists with Mac
applications, inits, and DAs.

Our architecture does not preclude us from low-level access, such as raw
disk management, where it makes sense.  For example, it would be possible
to interface directly to the block i/o disk device driver and build a
native BSD file system on a Mac disk partition that would run in parallel
with todays MachTen/MacOS single unified file system.
>Can you have hybrid applications?

Right now our MachTen development environment is a pure Unix development
environment.  We would like to be able to interface to the MacToolBox from
the Unix development environment for building hybrid applications. This
will be much easier to support on PowerPC hardware via dynamic library

>> Virtual memory is not necessarily needed for multitasking.  Since Personal
>True, but removing it from BSD would be quite a trick...  Also, I usually
>end up using swap space, and many Unix programs are poorly coded to not
>check for malloc() failures...  :-(

True porting software on our Personal MachTen does mean that sometimes
programs need to be modified.  Links are problematic and there is no
virtual stack space.  The advantage of course is that 68000s are supported.
Developers on small, unendowed machines seem to be happy to have a Unix
development capability and are willing to make software adjustments.  For
serious software development, we recommend Professional MachTen.

>BTW, what are the chances that MachTen'll run on a PPC?  ..

MachTen will definitely run on the PPC!  Personal, even in emulation mode,
needs minor modifications.  With Professional MachTen, we are focusing our
efforts on a native mode PPC port.

>Woof.  Congrats on what sounds like a fine product!


Best regards,

Tenon Intersystems
1123 Chapala Street
Santa Barbara, CA 93101
FAX: 805-962-8202