TweetFollow Us on Twitter

May 99 Online

Volume Number: 15 (1999)
Issue Number: 5
Column Tag: MacTech Online

May 99 Online

by Jeff Clites <online@mactech.com>

Longtime Mac users are experiencing a bit of culture shock in facing the reality that Apple's new OS family, Mac OS X Server and the soon-to-exist Mac OS X, is built on a Unix foundation.

Developers who come from a computer science background will surely be no strangers to Unix and its command line - I doubt that the Macintosh was even mentioned in any of their classes. But for those of us who got here via a different, pure-Macintosh route, it can be disorienting. After all, Unix was one of the unfriendly operating systems that Apple had in mind when they dubbed the Macintosh the computer for "the rest of us", right?

But after you get past the initial strangeness it begins to make a lot of sense. Unix can form a stable core upon which to build an OS. And if you continue to think in the usual metaphors, you can look at it this way: you probably don't want to build your house entirely out of concrete (it would be pretty bleak), but you certainly want to build it on top of a concrete foundation. So if everything goes as planned, when the consumer release of Mac OS X arrives, casual users will be no more aware of its Unix underpinnings than your guests are of the concrete walls in your cellar.

But what does it really mean that Mac OS X is "built upon a Unix core"? This month we are going to try to answer this question and find out a little bit more about the history and culture of Unix, and track down some sources to help developers find out what they need to know to feel comfortable with this new facet of Apple's OS.

A Brief History of BSD

Unix originated in the late 1960s at AT&T Bell Labs. Due to liberal academic licensing policies, universities began using Unix for teaching and research, leading to the development of BSD (the Berkeley Software Distribution) at UC Berkeley. AT&T continued to develop their own version, System V, and these two versions have formed the basis of nearly all subsequent Unix derivatives. BSD, owing to its academic heritage, tended to be more experimental and innovative, but much cross-pollination continued after the initial division. 4.4 BSD-Lite was the last version to be released by UC Berkeley (the "Lite" refers to this version's freedom from any AT&T copyrighted code). The main currently-active systems derived from BSD are NetBSD and OpenBSD, which are available for various hardware platforms, as well as the Intel-centric FreeBSD and the commercial BSDI. You can read more about the history and current state of BSD at the following URLs.

Knowledge Base - Do you have a brief synopsis of Unix history?
http://kb.indiana.edu/data/acve.html
Knowledge Base - What is BSD Unix and what are FreeBSD, NetBSD, OpenBSD and BSD/OS?
http://kb.indiana.edu/data/agom.html
[comp.unix.bsd] NetBSD, FreeBSD, and OpenBSD FAQs
http://faqs.colombianet.net/386bsd-faq/top.html
The return of BSD - SunWorld - January 1999
http://www.sunworld.com/swol-01-1999/swol-01-bsd.html
Nick Moffitt's $7 History of Unix
http://crackmonkey.org/unix.html

The Kernel

Mac OS X Server is based on the Mach kernel, originally developed at Carnegie Mellon University. The kernel provides only very basic services: processor scheduling, interprocess communication, and management of virtual memory. Mach is designed to be small; this makes it easy to understand (and therefore debug), as well as fast and efficient. (I forget who first pointed out that the only real way to speed up code is to make it do less). All other system services are provided by a server application (or a set of them). This is how it is possible for both Mac OS X Server and MkLinux to be based on the Mach kernel (albeit different version) - in a very real sense, Mach is the operating system, and Linux and BSD are applications. Although it's invisible to the programmer, what would have been a system call under the MacOS (or 4.4 BSD) is really an interprocess message under Mach. So these are the two senses in which Mac OS X Server is "based on" Unix: the Mach kernel has a Unix heritage, and 4.4 BSD-based application compile and run by virtue of the BSD "personality".

You can get the official scoop on Mach and its relation to Mac OS X Server in Apple's developer documentation. Carnegie Mellon also has a Mach site with a collection of technical information and publications. Of special interest is the introductory paper "Unix as an Application Program". Also be sure to check out the Linux Journal article "Linux? On the Macintosh? With Mach?", by Vicki Brown.

Apple's Mach Reference
http://developer.apple.com/techpubs/macosxserver/System/Documentation/Developer/OperatingSystem/Mach.pdf
CMU CS Project Mach Home Page
http://www.cs.cmu.edu/afs/cs.cmu.edu/project/mach/public/www/mach.html
Unix as an Application Program (in PostScript form)
ftp://ftp.cs.cmu.edu/project/mach/doc/published/mach3_intro.ps
Linux? On the Macintosh? With Mach?
http://www.linuxjournal.com/issue37/2093.html

Getting Oriented

I would imagine that most Macintosh programmers have no intention of writing Unix-style applications just because they can (at least I hope not), but nonetheless they want to be comfortable with the Unix side of Mac OS X Server. In this light, I recently began to peruse three books which cover the spectrum of topics about which you are likely to be curious.

As its title implies, The Unix Philosophy, by Mike Gancarz (ISBN 1-55558-123-4) explains the motivation and culture behind the design of Unix systems. It's a pleasant read - it's short and non-technical, focussing on ideology. For a user-level introduction, Unix: Clearly Explained by Richard L. Petersen (ISBN 0-12-552130-8) covers the basics, including pipes, the most common command-line tools, the various shells, and the vi and emacs text editors. These two books could be read in either order, depending on whether you like conceptual background before concrete "how-to", or vice-versa. One thing they don't cover is the Pico text editor, which Apple has included with their distribution. If you are forced to boot into single-user mode and fix something via the command-line interface, then you will find Pico more friendly in your time of crisis than vi or emacs. Fortunately, NC State University has a nice online Pico tutorial, and Indiana University has a convenient reference guide that you can download in pdf format. (And of course, there are always the man pages.)

PICO tutorial
http://www2.ncsu.edu/ncsu/cc/pub/tutorials/pico_tutor/pico_intro.html
The Pico text editor under Unix: A quick guide
http://www.indiana.edu/~ucspubs/b103/b103.pdf

At the other end of the spectrum is The Design and Implementation of the 4.4BSD Operating System (ISBN 0-201-54979-4). Written by the original system architects, it covers all of the technical details of the design of BSD and the algorithmic choices which underlie it. It isn't programmer's documentation per se (it doesn't teach you how to write Unix applications), but it will answer all of the architectural questions that the curious developer might ask. It's heavy reading, especially if you are new to Unix, but it's kind of comforting to have the book with all the answers.

These and a truck load of other links are available from the MacTech Online web pages at www.mactech.com/online/.

 
AAPL
$100.96
Apple Inc.
-0.83
MSFT
$47.52
Microsoft Corpora
+0.84
GOOG
$596.08
Google Inc.
+6.81

MacTech Search:
Community Search:

Software Updates via MacUpdate

Airfoil 4.8.9 - Send audio from any app...
Airfoil allows you to send any audio to AirPort Express units, Apple TVs, and even other Macs and PCs, all in sync! It's your audio - everywhere. With Airfoil you can take audio from any... Read more
WhatRoute 1.13.0 - Geographically trace...
WhatRoute is designed to find the names of all the routers an IP packet passes through on its way from your Mac to a destination host. It also measures the round-trip time from your Mac to the... Read more
Chromium 37.0.2062.122 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. FreeSMUG-Free OpenSource Mac User Group build is... Read more
Attachment Tamer 3.1.14b9 - Take control...
Attachment Tamer gives you control over attachment handling in Apple Mail. It fixes the most annoying Apple Mail flaws, ensures compatibility with other email software, and allows you to set up how... Read more
Duplicate Annihilator 5.0 - Find and del...
Duplicate Annihilator takes on the time-consuming task of comparing the images in your iPhoto library using effective algorithms to make sure that no duplicate escapes. Duplicate Annihilator detects... Read more
jAlbum Pro 12.2 - Organize your digital...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code!... Read more
jAlbum 12.2 - Create custom photo galler...
With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly, with pro results Simply drag and drop photos into groups, choose a design... Read more
Quicken 2015 2.0.4 - Complete personal f...
Quicken 2015 helps you manage all your personal finances in one place, so you can see where you're spending and where you can save. Quicken automatically categorizes your financial transactions,... Read more
iMazing 1.0 - Complete iOS device manage...
iMazing (formerly DiskAid) is the ultimate iOS device manager with capabilities far beyond what iTunes offers. With iMazing and your iOS device (iPhone, iPad, or iPod), you can: Copy music to and... Read more
Xcode 6.0.1 - Integrated development env...
Apple Xcode is Apple Computer's integrated development environment (IDE) for OS X. The full Xcode package is free to ADC members and includes all the tools you need to create, debug, and optimize... Read more

Latest Forum Discussions

See All

View Source – HTML, JavaScript and CSS...
View Source – HTML, JavaScript and CSS 1.0 Device: iOS Universal Category: Utilities Price: $.99, Version: 1.0 (iTunes) Description: View Source is an app plus an iOS 8 Safari extension that makes it easy to do one key web developer... | Read more »
Avenged Sevenfold’s Hail To The King: De...
Avenged Sevenfold’s Hail To The King: Deathbat is Coming to iOS on October 16th Posted by Jessica Fisher on September 19th, 2014 [ permalink ] Just in time for Halloween, on October 16 Avenged Sevenfold will be launching | Read more »
Talisman Has Gone Universal – Can Now be...
Talisman Has Gone Universal – Can Now be Played on the iPhone Posted by Jessica Fisher on September 19th, 2014 [ permalink ] | Read more »
Tap Army Review
Tap Army Review By Jennifer Allen on September 19th, 2014 Our Rating: :: SHOOT EM ALLUniversal App - Designed for iPhone and iPad Mindless but fun, Tap Army is a lane-based shooter that should help you relieve some stress.   | Read more »
Monsters! Volcanoes! Loot! Epic Island f...
Monsters! Volcanoes! Loot! | Read more »
Plunder Pirates: Tips, Tricks, Strategie...
Ahoy There, Seadogs: Interested in knowing our thoughts on all this plundering and pirating? Check out our Plunder Pirates Review! Have you just downloaded the rather enjoyable pirate-em-up Plunder Pirates and are in need of some assistance? Never... | Read more »
Goat Simulator Review
Goat Simulator Review By Lee Hamlet on September 19th, 2014 Our Rating: :: THE GRUFFEST OF BILLY GOATSUniversal App - Designed for iPhone and iPad Unleash chaos as a grumpy goat in this humorous but short-lived casual game.   | Read more »
A New and Improved Wunderlist is Here fo...
A New and Improved Wunderlist is Here for iOS 8 Posted by Jessica Fisher on September 19th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Evernote Update for iOS 8 Adds Web Clipp...
Evernote Update for iOS 8 Adds Web Clipping, Quick Notes, and More Posted by Ellis Spice on September 19th, 2014 [ permalink ] | Read more »
Apple Names Ultimate Productivity Bundl...
Apple Names Ultimate Productivity Bundle by Readdle as the Essential Bundle on the App Store Posted by Jessica Fisher on September 19th, 2014 [ permalink | Read more »

Price Scanner via MacPrices.net

Updated Price Trackers
We’ve updated our Mac Price Trackers with the latest information on prices, bundles, and availability on systems from Apple’s authorized internet/catalog resellers: - 15″ MacBook Pros - 13″ MacBook... Read more
Mac Pros available for up to $260 off MSRP
Adorama has Mac Pros on sale for up to $260 off MSRP. Shipping is free, and Adorama charges sales tax in NY & NJ only: - 4-core Mac Pro: $2839.99, $160 off MSRP - 6-core Mac Pro: $3739.99, $260... Read more
13-inch 2.6GHz/256GB Retina MacBook Pros avai...
B&H Photo has the 13″ 2.6GHz/256GB Retina MacBook Pro on sale for $1379 including free shipping plus NY sales tax only. Their price is $120 off MSRP. Read more
Previous-generation 15-inch 2.0GHz Retina Mac...
B&H Photo has leftover previous-generation 15″ 2.0GHz Retina MacBook Pros now available for $1599 including free shipping plus NY sales tax only. Their price is $400 off original MSRP. B&H... Read more
21″ 2.7GHz iMac available for $1179, save $12...
Adorama has 21″ 2.7GHz Hawell iMacs on sale for $1179.99 including free shipping. Their price is $120 off MSRP. NY and NJ sales tax only. Read more
iOS 8 Adoption Rate Slower than iOS 7, 6, Hit...
Apple began pushing out iOS 8 updates to eligible devices around 1pm ET on September 17, 2014. However, unlike with iOS 7, which boasted a wide variety of differences from its predecessor iOS 6, in... Read more
LIkely Final Definitive OS X 10.9.5 Mavericks...
Apple has released what will almost certainly be the last incremental version number update of OS X 10.9 Mavericks (save for futire security updates) before OS X 10.10 Yosemite is released next month... Read more
Fingerprints, Apple Pay and Identity Theft Wa...
On Sep 9th, CEO Tim Cook unveiled Apple Pay, along with the new iPhone 6 and iWatch. Apple Pay is a newly developed technology that utilizes a near field communication (NFC) to enable customer... Read more
Amazon Introduces Two All-New Kindles
Amazon on Thursday introduced the 7th generation of its Kindle dedicated e-reader device: Kindle Voyage, its top-of-the-line e-reader, and the new $79 Kindle, with a 20% faster processor, twice the... Read more
Save up to $300 on the price of a new Mac wit...
Purchase a new Mac or iPad at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free,... Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Project Manager, *Apple* Financial Services...
**Job Summary** Apple Financial Services (AFS) offers consumers, businesses and educational institutions ways to finance Apple purchases. We work with national and Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.