TweetFollow Us on Twitter

May 99 Online

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

May 99 Online

by Jeff Clites <>

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?
Knowledge Base - What is BSD Unix and what are FreeBSD, NetBSD, OpenBSD and BSD/OS?
[comp.unix.bsd] NetBSD, FreeBSD, and OpenBSD FAQs
The return of BSD - SunWorld - January 1999
Nick Moffitt's $7 History of Unix

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
CMU CS Project Mach Home Page
Unix as an Application Program (in PostScript form)
Linux? On the Macintosh? With Mach?

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
The Pico text editor under Unix: A quick guide

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


Community Search:
MacTech Search:

Software Updates via MacUpdate

OmniPlan 3.0 - Robust project management...
With OmniPlan, you can create logical, manageable project plans with Gantt charts, schedules, summaries, milestones, and critical paths. Break down the tasks needed to make your project a success,... Read more
Yummy FTP 1.11 - FTP/SFTP/FTPS client fo...
Yummy FTP is an FTP + SFTP + FTPS file transfer client which focuses on speed, reliability and productivity. Whether you need to transfer a few files or a few thousand, schedule automatic backups, or... Read more
Tweetbot 2.1 - Popular Twitter client. (...
Tweetbot is a full-featured OS X Twitter client with a lot of personality. Whether it's the meticulously-crafted interface, sounds and animation, or features like multiple timelines and column views... Read more
MacPilot 8.0 - Enable over 1,200 hidden...
MacPilot gives you the power of UNIX and the simplicity of Macintosh, which means a phenomenal amount of untapped power in your hands! Use MacPilot to unlock over 1,200 features, and access them all... Read more
Typinator 6.7 - Speedy and reliable text...
Typinator turbo-charges your typing productivity. Type a little. Typinator does the rest. We've all faced projects that require repetitive typing tasks. With Typinator, you can store commonly used... Read more
Adobe Lightroom 6.2 - Import, develop, a...
Adobe Lightroom is available as part of Adobe Creative Cloud for as little as $9.99/month bundled with Photoshop CC as part of the photography package. Lightroom 6 is also available for purchase as a... Read more
ForeverSave 2.1.4 - Universal auto-save...
ForeverSave auto-saves all documents you're working on while simultaneously doing backup versioning in the background. Lost data can be quickly restored at any time. Losing data, caused by... Read more
VueScan 9.5.27 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more
AirPort Utility 6.3.6 - Set up and manag...
Note: Most recent release available only within OS X 10.11 El Capitan update. Use AirPort Utility to set up and manage your Wi-Fi network and AirPort base stations, including AirPort Express, AirPort... Read more
Quicksilver 1.3.1 - Application launcher...
Quicksilver is a light, fast and free Mac application that gives you the power to control your Mac with keystrokes alone. Quicksilver allows you to find what you need quickly and easily, then act... Read more

YAMGUN (Games)
YAMGUN 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: The invasion has begun! Protect the walls of the citadel against waves of enemies! But watch out, you will soon run out of ammo...... | Read more »
Royal Bounty HD (Games)
Royal Bounty HD 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: New World Computing Approved "Hi Guys! looks good so far! keep up the good work. I worked on HoMM 3 and 4 creating all of the... | Read more »
Swords & Crossbones: An Epic Pirate...
Swords & Crossbones: An Epic Pirate Story 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: | Read more »
Camel Up (Games)
Camel Up 1.0.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.0 (iTunes) Description: | Read more »
The Martian: Bring Him Home (Games)
The Martian: Bring Him Home 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Based on the best selling novel and critically acclaimed film, THE MARTIAN tells the story of Astronaut Mark... | Read more »
This Week at 148Apps: September 21-30, 2...
Leap Into Fall With 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice, standing out above... | Read more »
Tweetbot 4 for Twitter (Social Networki...
Tweetbot 4 for Twitter 4.0 Device: iOS Universal Category: Social Networking Price: $4.99, Version: 4.0 (iTunes) Description: *** 50% off for a limited time. *** | Read more »
Mori (Games)
Mori 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Stop, rewind and unwind with Mori. Time is always running, take a moment to take control. Mori is an action puzzle game about infinitely... | Read more »
100 Years' War (Games)
100 Years' War 1.0 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0 (iTunes) Description: | Read more »
Tower in the Sky (Games)
Tower in the Sky 0.0.60 Device: iOS Universal Category: Games Price: $1.99, Version: 0.0.60 (iTunes) Description: | Read more »

Price Scanner via

Save up to $350 with Apple refurbished iMacs
Apple has Certified Refurbished iMacs available for up to $350 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 27″ 3.5GHz 5K iMac – $1949 $350 off MSRP - 27... Read more
Mac Pros on sale for up to $300 off MSRP
B&H Photo has Mac Pros on sale for up to $300 off MSRP. Shipping is free, and B&H charges sales tax in NY only: - 3.7GHz 4-core Mac Pro: $2818.99, $181 off MSRP - 3.5GHz 6-core Mac Pro: $3699... Read more
5K iMacs on sale for up to $150 off MSRP, fre...
B&H Photo has the 27″ 3.3GHz 5K iMac on sale for $1899.99 including free shipping plus NY tax only. Their price is $100 off MSRP. They have the 27″ 3.5GHz 5K iMac on sale for $2149, $150 off MSRP... Read more
Twelve South Redesigns BookArc For Today’s Sm...
Twelve South has announced a redesigned version of their very first product, BookArc for MacBook. Tailored specifically for the newest generation of MacBooks, BookArc holds the new, smaller Apple... Read more
Phone 6s Tips & Tricks – Tips Book For iP...
Poole, United Kingdom based Tap Guides Ltd. has announced the release and immediate availability of iPhone 6s Tips & Tricks, an in-depth eBook available in the iBookstore that’s priced just $2.99... Read more
13-inch 2.5GHz MacBook Pro on sale for $994,...
Best Buy has the 13″ 2.5GHz MacBook Pro available for $994.99 on their online store. Choose free shipping or free instant local store pickup (if available). Their price is $105 off MSRP. Price valid... Read more
Is The iPad Pro Really A Serious Laptop Repla...
Probably not, at least for productive professionals and other power users. Steve Jobs declared that we’d entered the “post-PC Era” with the advent of the original iPad in 2010, a phrase we don’t hear... Read more
Wednesday Deal: 13-inch Retina MacBook Pros f...
Adorama has 13″ Retina MacBook Pros on sale for up to $130 off MSRP. Shipping is free, and Adorama charges sales tax for NY & NJ residents only: - 13″ 2.7GHz/128GB Retina MacBook Pro: $1199.99 $... Read more
uBar 3.0 for Mac OS X – Custom Dock Replaceme...
Brawer Software has announced the release of uBar 3.0, an important update to their popular app and window manager for Mac OS X. uBar allows users to position it whichever side of the screen they... Read more
13-inch 2.5GHz MacBook Pro (refurbished) avai...
Apple has Certified Refurbished 13″ 2.5GHz MacBook Pros available for $829, or $270 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.5GHz MacBook Pros... Read more

Jobs Board

*Apple* Retail - Multiple Customer Support P...
Job Description:Customer SupportSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the Read more
Software Engineer, *Apple* Watch - Apple (U...
…the team that is revolutionizing the watch! As a software engineer on the Apple Watch team, you will be responsible for building world-class applications and frameworks Read more
*Apple* Online Store UAT Lead - Apple (Unite...
**Job Summary** The Apple Online Store is a fast paced and ever evolving business environment. The User Acceptance Testing (UAT) lead in this organization is able to Read more
Hardware Systems Integration Engineer - *App...
**Job Summary** We are seeking an enthusiastic electrical engineer for the Apple Watch team. This is a design engineering position that entails working with Read more
Touch Validation Design (EE) - *Apple* Watc...
**Job Summary** Help launch next-generation Touch Technologies in Apple products. The Touch Technology team develops cutting-edge Touch solutions and technologies that Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.