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From: csimmons@jewel.oracle.com (Charles Simmons)
Newsgroups: comp.arch
Subject: Re: Macintosh OS
Message-ID: <1990Jun2.132847.14292@oracle.com>
Date: 2 Jun 90 13:28:47 GMT
References: <1990May30.230248.6200@Neon.Stanford.EDU> <1935@key.COM> <30273@ut-emx.UUCP> <76700207@p.cs.uiuc.edu> <402@newave.UUCP>
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In article <1990May30.230248.6200@Neon.Stanford.EDU>,
philip@Kermit.Stanford.EDU (Philip Machanick) writes:
> From: philip@Kermit.Stanford.EDU (Philip Machanick)
> Subject: Re: Macintosh OS
> Date: 30 May 90 23:02:48 GMT
> 
> In article <1935@key.COM>, sjc@key.COM (Steve Correll) writes:
> > In article <402@newave.UUCP>, john@newave.UUCP (John A. Weeks III) writes:
> > > Can the Macintosh System be called an "Operating System"?  Ignoring
> > > system 7.0, the Mac is a collection of procedures, some of which are
> > > in ROM, that everyone agrees to call in the right order.  If anyone
> > > screws up, you get a bomb.  There is no real multi-tasking, no scheduler,
> > > no device or file locking, memory protection, processes, forking, etc.
> > 
> > Suppose you implemented the C library standalone on a bare machine,
> adding the
> > capability to execute multiple C programs by switching from one to another
> > during calls to the library. Would that be an operating system? People
> > accustomed to conventional timesharing systems might answer "no",
but people
> > accustomed to simple ROM-able operating systems might answer "yes".
> 
> This "is the Mac OS an OS" line seems to assume that an OS _only_ defines
> multitasking. I always thought it defined a whole bunch of abstractions, like
> the file system. The Mac does most of this conventional stuff, plus a sort
> of abstract machine model for graphics. Maybe the implementation is not great
> because you can break the abstractions too easily, but that's a different
> issue.
> 
> Philip Machanick
> philip@pescadero.stanford.edu

This "is the Mac OS an OS" line seems to assume that an OS defines a
gruntload of really strange abstractions:  like what your graphical user
interface should look like.  I always thought an OS should define a very
minimal number of abstractions:  like how the cpu resource is allocated
to different processes (scheduling); like how the memory resource is
allocated to different processes; and like how inter-process communications
is performed.  File systems?  Relational databases?  TCP/IP?  Let them
be done by user-level processes.

-- Chuck