Is Unix not a PC operating system?

Question

I am doing my bachelor's degree at a university. In a written assignment, the professor posted the task: "Name three PC operating systems".

Well, I went on an included a variety of OSes (Linux, Windows, Mac OS X) and including Unix & Solaris. Today I received a mail from my professor saying:

Unix is not a PC operating system. Many Unix-variants are not PC-hardware compatible (like AIX & HP-UX. About Solaris: there was one PC-compatible version...)

I am kind of suprised: Even if many Unix-variants are PowerPC based and have a different bit-order – Those don't stop being PCs now, right?

The question was given in a written assignment! It was not a question that came up during the lecture!

---

_{Due to the original task being in German, I'll include it just to make sure nobody suspects an error in the translation.}

_{Frage: Nennen Sie 3 PC-Betriebssysteme.
Antwort: Unix ist kein PC-Betriebssystem, viele Unix-Varianten sind nicht auf PC-Hardware lauffähig (AIX, HP-UX). Von Solaris gab es mal eine PC-Variante.}

Answer 1

Without a hard definition of what a "PC" is, your assignment question is a lake of ambiguity. I used an AT&T 3B1 no later than 1987, which unequivocally ran UNIX and was marketed as a "UNIX PC".

Answer 2

It would depend on your definition of 'PC operating system' and subsequently on your definition of a personal computer itself. If the first refers to operating systems that run only on personal computers, you might as well rule out every imaginable one, including Windows, which also runs on mobile phones, PDAs, server machines, supercomputers and a bunch of other non-PC machinery. To my knowledge, there are no operating systems meeting this strict criterium, as part of the PC's definition may be in its use. An OS will or will not support a machine regardless of that.

Even a more objective, hardware-only classification will fail. There is no unambiguous set of PC hardware. You will need a more specific term, such as 'x86-64 architecture', but those are not necessarily the same. For instance, your professor's example of AIX not being compatible with PC hardware is false. AIX supports the PowerPC platform which is uncommon, but perfectly usable in PCs.

Any answer to a question as vague as 'name three PC operating systems' can be shot down.

Answer 3

I have two explanations for this:

1. The task was supposed to name three PC-only operating systems
2. Strictly put, Unix is not exactly an operation system - it's a family of operation systems, derived from the first one developed in 1969, and is not a PC operating System.

Answer 4

If your professor is one who simply makes up his own definitions (or one who doesn't believe in Wikipedia being the ultimate source of truth), you're basically at his/her mercy.

Otherwise, point him/her to these Wikipedia entries (or possibly their German counterparts):

• Personal Computer

A personal computer (PC) is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator.

• Operating System

An operating system (OS) is a set of programs that manage computer hardware resources and provide common services for application software.

• Unix

Unix (officially trademarked as UNIX, sometimes also written as Unix) is a multitasking, multi-user computer operating system [...].

If you both agree to the assumption that Wikipedia can be believed, then Unix is definitely an OS for PCs.

Answer 5

Your professor may have a different definition of a "PC" than you - which is not to say he is correct. Originally, PC simply meant "Personal Computer", and did not have any specific architecture. But his use of "PC Hardware" sounds like he is using a different definition that only includes IBM Intel-based PCs.

When IBM came out with their PC, they simply called it the IBM PC, and people began using PC to mean IBM PC. So "PC Compatible" was commonly used to mean IBM PC Compatible, as if IBM invented the personal computer, rather than just "legitimizing" it. I personally think your professor is either being unclear and unfair, or completely wrong (or both).

This was a Unix PC: AT&T Unix PC, and ran genuine AT&T Unix.

That said, I wouldn't really call Unix a PC operating system today; even though it can be, it's pretty rare.

Edit: There is also the possibility - which can only be deduced after his comments - that he meant ones that are designed only for a PC, such as MS-DOS, DR-DOS, PC-DOS, and the original Mac OS (and possibly OSX).

Answer 6

The "About Solaris: there was one PC-compatible version" statement is incorrect. From 1992 to 2011, there has been ten Solaris versions supporting x86 hardware (2.1, 2.4, 2.5, 2.5.1, 2.6, 7, 8, 9, 10 and 11), not to mention the various OpenSolaris/illumos based ones.

In any case, since its early design stage, Unix has been developed with portability in mind so is not, unlike most if not all competing OSes of that time, tied to a specific architecture.

Answer 7

First of all, I would not waste my time on people who think that "name three PC operating systems" is an interesting homework exercise. Or even something to talk about.

Your prof moves his definitions around to try to make perfectly rational, right thinking people around him appear to be wrong.

Oh, I meant "operating systems that exclusively have run on PC hardware".

PC compatible? No, no! I meant IBM PC! Not HP, not Compaq, not ACER, not your ASUS motherboard from Taiwan in a no-name brand case.

Did I say PC/AT? No, I mean PC! You know, 4.77 Mhz, 512 K memory, floppy drives only. No Not the XT with its 10 meg hard drive, not the AT, and not the PCjr. No 80x86 where x is not blank, and the 86 isn't 88.

Acceptable answers might be: PC-DOS, MS-DOS 2.0, CP/M 86 and MS-DOS 3.3.

:)

Answer 8

Mac OS X is Unix and the Leopard version is the first and only BSD variant to achieve Unix Certification, and that's certainly considered a PC operating system.

The various BSD variants are notable in that they are in fact descendants of UNIX, developed by the University of California at Berkeley with UNIX source code from Bell Labs. However, the BSD code base has evolved since then, replacing all of the AT&T code. Since the BSD variants are not certified as compliant with the Single UNIX Specification (except for Mac OS X 10.5 Leopard and Mac OS X 10.6 Snow Leopard), they are referred to as "UNIX-like".

So if your professor means UNIX as in the certified, branded version, that narrows the group considerably. If he means UNIX-like, that is a completely different semantic and opens the doors for way more things that run on PC hardware.

Answer 9

Let's take an average definition of "PC" being what the professor thinks it is -- an Intel desktop.

So he's trying to point out that Unix is a whole class of operating systems, many do not run on PCs... This is correct.

However, Windows is also a class of operating systems, and wow... many don't run on PCs!! Windows CE is a version of Windows, as are Windows Embedded and Windows Phone (with multiple versions).

Many versions of Linux don't run on PCs.

So the only "correct" way to answer his question would be to list instances--something along the lines of "Windows XP, Windows NT, Windows 7 and Windows 8" which is lame and he probably would have said something about these all being the same OS.

Linux is also a problematic answer, not all Linux builds are meant for PCs, although you could easily list 20 versions of Ubuntu made for PCs.

Mostly, the question should be, why do you have such a pointless and ambiguous question on your tests?

Answer 10

Is Unix a PC Operating system?

There were certainly (commercial) ports of Unix before Linux ever arrived on the PC scene, such as Interactive Unix and Santa Cruz Operations (aka SCO) Unix, that first ran on i386 and i486 PCs.

Answer 11

First, I quote two lines from Wikipedia about Unix. This will make it clear the differences between Unix and UNIX.

Unix (officially trademarked as UNIX, sometimes also written as Unix) is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna.

The term Unix (capital U) is often used informally to denote any operating system that closely resembles the trademarked system.

Your professor is not wrong. When UNIX was created computers were so expensive that no one had a personal version. People usually used to share a Unix system which was running on a mainframe or minicomputer. Before UNIX became cheap, the IBM PC was released and many people could afford to buy it. And the term PC (personal computer) was broadened. After that UNIX or Unix became cheap and people could use them in PC (this PC is a common noun, IBM-PC is a proper noun).

Answer 12

Maybe it is not a technical question but a political one.

Microsoft want us to believe that all other operating systems are old/slow/command-line only/hard to use/not used by anyone/…. I think that Microsoft has got to your professor.

This answer was sent from my Unix PC (Debian Gnu/Linux). Linux was originally an x86-only operating system. According to the owners of UNIX™ GNU/Linux is a Unix, but not a UNIX™.

Answer 13

Frage: Nennen Sie 3 PC-Betriebssysteme.

i'd guess PC in German is Einzelplatzrechner thus a single seat computer maybe

you might focus that computer cannot provide two seats but one - most MIDs with some embedded OS would be fine for today. Even windows is too functional in this regard.

or you want to thin PC is an IBM Personal Computer or similar.

Then you can name any system imaginable. OSX. Windows 95, FreeDOS (yes -apple systems can run windows also in place of OSX, just a bit costly)