[aclug-L] Re: BeOS? What is it?

[Tom Hull <thull@xxxxxxxxxxx>]

Lots of confusion here, and I may not be much help, given that
I have no interest in BeOS, NeXT, or anything Apple-related,
and limited knowledge thereof. But:

 1) Mach is what's called a "microkernel", which is a different,
    more modular approach to building kernels than the old standby,
    the belatedly named "monolithic kernel". For examples, Linux
    and BSD are monolithic kernels; GNU Hurd is based on a micro-
    kernel (probably Mach). All of these look pretty much the same
    to the outside world, but are different inside.

 2) NeXT is based on Mach. Although Mach has been used to create
    some genuine Unix-like kernels (e.g., OSF-1 and MkLinux), Mach
    can just as well support very un-Unix-like kernel interfaces.
    Ergo, NeXT is not Unix-like simply because it is based on Mach.
    Nor is NeXT's kernel equivalent to Mach, so it is a bit dis-
    ingenuous for NeXT to refer to its kernel as Mach.

 3) I think BeOS is a monolithic kernel, but am not sure. (I've
    never looked at it.) However, since Be likes to talk about
    how "modern" the design of BeOS is, it probably has some
    overarching modularity similar to microkernel designs. (NT
    is an example of a kernel which likes to think it's micro-
    kernel based, but isn't really.)

 4) What makes NeXT and BeOS somewhat Unix-like is that both are
    Posix.1 compatible. Posix.1 is a standard loosely based on
    legacy Unix systems: it includes a shell (like bash), shell
    commands, system calls, and libraries. In a real Unix system,
    Posix.1 is a subset of the native command line and programming
    interfaces. However, there are several systems which claim to
    be Posix.1 compatible, but do so with gerry-rigged libraries
    that make them second-class interfaces (e.g., NT, VMS). NeXT
    and BeOS are Posix.1 compatible; that may make them look like
    Unix, but one needs to dig deeper to get to the real story.

 5) There are other standards as to what a Unix system is, such
    as the Unix95 and Unix98 specifications from X/Open. These
    are effectively a much-extended superset of Posix, largely
    based on Unix SVR4. The Unix TM is owned by X/Open, which
    permits use on certified Unix98-conforming systems. Neither
    Linux nor BSD meet these requirements (partly because some
    of them are pretty dumb).

 6) As someone mentioned, NeXTSTEP is just a GUI layer. I don't
    know how closely it is bound to NeXT's kernel, but it has
    been ported elsewhere, so it's probably cleanly layered.

 7) Apple has something called OS X, which uses a lot of BSD
    code, but I don't know what that means. In any case, it
    is different from MacOS. I don't know whether MacOS is
    based on Mach nowadays, but if it is, that would explain
    why MkLinux is Mach-based.

 8) BeOS originally ran on Apple hardware, but does not run on
    more recent Apple hardware. Apple stopped documenting their
    hardware, and Be was forced to switch to Intel hardware.
    Despite all the hype, Be is just another closed source,
    proprietary software company, trying to trap people into
    a product which is far less useful and less valuable than
    a free alternative: Linux.

 9) Be and NeXT are basically cultural satellites of Apple. Why
    anyone would feel any emotional attachment to a company like
    Apple mystifies me, but evidently there are people who at
    long last realize that Apple is only out to screw them who
    still feel they must embrace something Apple-like; first
    NeXT, now Be. (There is a similar cloud around VMS, which
    resulted in many/most VMS customers choosing NT over OSF-1
    or Linux; now that Microsoft has killed NT-on-Alpha, these
    same fools are heading back to VMS to avoid Unix.)

If anyone wants a novel kernel to play with, check out GNU Hurd.
At least it's free. Or if you're really ambitious, track down
Plan-9 (Ken Thompson's post-Unix OS). However, many of us could
still stand to learn more about Linux.

-- 
/*
 *  Tom Hull * thull@xxxxxxxxxxx * http://www.ocston.org/~thull/
 */