TweetFollow Us on Twitter

June 93 - BE OUR GUEST

BE OUR GUEST

SYSTEM ENABLERS

C. K. HAUN

[IMAGE 107-108_Guest_col_rev1.GIF]

System 7.1 introducedsystem enablersto Macintosh system software architecture. Since their introduction on some of Apple's new machines, there's been some confusion about what system enablers are for, and developers have expressed interest in writing and using them. This column will shed some light on the subject.

THE BAD NEWS
Even before beginning to describe them, we have to emphasize that system enablers aresystem software,designed and intended solely for the use of Apple Computer. Detailed descriptions of their design and use will not be released. Their functionality and implementationwillchange; any developers who try to decipher enablers and implement their own are warned that they will fail in future system releases. Donot write your own enabler or modify a current one!

Kinda harsh, huh? But we really mean it: the functionality of system enablers makes sense only for system software. Also, modifying or creating an enabler without fully understanding how one works could cause the enabler mechanism to fail silently. This could result in a machine that appears to be working correctly but does not have the full enabler functionality active, causing very hard-to-isolate crashes or other problems.

OK, SO WHAT ARE THEY?
System enablers (which were called "gibblies" in early documentation and system development releases) replace the release strategy that Apple used in the past for minor system changes needed for new hardware. The old strategy was to release a new version of the system software, such as version 6.0.8 or 7.0.1. With enablers, the differences in hardware no longer require a new system release, but instead each new machine has its own enabler (if necessary) to make the system work for that hardware.

This change was made for two reasons:

  • Creating an enabler instead of a whole new system release reduces Apple's quality assurance and testing time. By creating an enabler, we're testing new code only on new machines; past machines aren't affected since the new enabler won't run on those machines. This also reduces your testing time as a third party, since you no longer have to install a new system release on all your older machines and test for compatibility; you know the system changes will affect only the newly released machines.
  • Enablers reduce user confusion and unnecessary upgrades. In the past, every time a machine was released, with its corresponding new software release, users of older machines were unsure whether they needed to upgrade to the new system. Many assumed that since it was newer, it was better. While this has been true occasionally, it usually isn't (upgrading from 7.0 to 7.0.1 on a Macintosh IIcx, for example, gives the user nothing new).

Apple will continue to use system extensions or components when new functionality is being added across the product line, as with QuickTime and Macintosh Easy Open. Enablers just broaden the range of options for enhancing the user's environment.

HOW DO THEY WORK?
Nope, no cheating -- we really won't be describing the internals of enablers. But here are some general rules about their behavior.

An enabler is essentially an extension to the System file; from a programmatic standpoint itis the System file. The Resource Manager was changed slightly to recognize references to the System file (CurResFile(0), for example) as being references to the System fileandthe current enabler. The code or other resources included in the enabler file appear to actually reside in the System file.

Any new machine may have a system enabler. The enabler will contain the system-level code necessary to implement changes required for that machine. A single enabler may be used for a family of machines, or a separate enabler may be created for each new machine.

If there are multiple enablers in a machine's System Folder, the system will use onlyoneof them. The system software (System file plus enabler) is responsible for arbitrating which enabler is used on a specific machine. It looks at the machine type it's currently running on, the machines that the enabler supports, and some enabler-internal applicability flags. Note that this is how the decision is currently made; as enablers are used for more machines and in different situations, more variables may be added to the decision process.

ENABLERS AND REFERENCE RELEASES
A specific enabler may not stay around forever. Apple has announced its intention to have "reference releases" every year to 18 months; these are the system upgrades that all users will be encouraged to install. Some enablers may be rolled into a reference release, so a machine that needed an enabler for System 7.1 may not need one for System 8. This is not a hard and fast rule; some enablers may stay around forever, depending on the functionality they enable.

THE BOTTOM LINE
System enablers make everyone's life easier by encapsulating system changes for new machines in one place. But they are not for non-Apple use, and developers cannot implement them with any hope of long-term success. The safest path to take is not to think of enablers as separate files. An enableristhe system; when you encounter one on a machine, you're looking at the System file. The traditional methods (INITs, cdevs, components, and so on) are still the only supported ways for developers to extend system functionality.

GIBBLY HISTORY

BY CHRIS DEROSSI
When system enablers were being designed, it was clear they were going to be a mechanism for extending the system. Engineers began calling them INITs, since they served much the same purpose. This caused some confusion with people who thought we really were talking about INITs, and issues were raised about possible conflicts with other INITs, loading order, and so on. (These issues don't apply to system enablers at all.)

It was obvious to me that we needed to change the name to differentiate system enablers from other types of system extension mechanisms. We couldn't use the term extension because that was the public name for INITs. We couldn't use addition because that term already referred to things like QuickDraw GX and AOCE.

So, I decided to use a made-up word. I wanted a word that would be memorable and one that would sound funny when used in all seriousness by executives and upper management. Hence the name "gibblies."

The engineering documentation for gibblies states that the singular is "gibbly" and the plural is "gibblies." It also states that the "g" may be pronounced hard or soft depending on the speaker's preference. In practice, the hard form (as in "give") became the one used by those in the know.

There you have it. And, yes, it was very amusing to hear the made-up word being used all over the company in serious conversation.

K. HAUN works in Apple Developer Technical Support, where he is the perennial winner of the coveted "Most Documentation Heaped on the Floor" award. Before coming to Apple he was a commercial developer, writing educational, game, and utility software on Macintosh, IBM, and Apple II platforms. His main focus in DTS is interapplication communication and application toolbox support. He's also single again; please see ad #298700 in the personal ads section of this issue.

We welcome guest columns from readers who have something interesting or useful to say. Send your column idea or draft to AppleLink DEVELOP or to Caroline Rose at Apple Computer, Inc., 20525 Mariani Avenue, M/S 75-2B, Cupertino, CA 95014.*

Thanks to Chris Derossi, Greg Marriott, and Dean Yu for reviewing this column. *

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

The beginner's guide to Warbits
Warbits is a turn-based strategy that's clearly inspired by Nintendo's Advance Wars series. Since turn-based strategy games can be kind of tricky to dive into, see below for a few tips to help you in the beginning. Positioning is crucial [Read... | Read more »
How to upgrade your character in Spellsp...
So you’ve mastered the basics of Spellspire. By which I mean you’ve realised it’s all about spelling things in a spire. What next? Well you’re going to need to figure out how to toughen up your character. It’s all well and good being able to spell... | Read more »
5 slither.io mash-ups we'd love to...
If there's one thing that slither.io has proved, it's that the addictive gameplay of Agar.io can be transplanted onto basically anything and it will still be good fun. It wouldn't be surprising if we saw other developers jumping on the bandwagon,... | Read more »
How to navigate the terrain in Sky Charm...
Sky Charms is a whimsical match-'em up adventure that uses creative level design to really ramp up the difficulty. [Read more] | Read more »
Victorious Knight (Games)
Victorious Knight 1.3 Device: iOS Universal Category: Games Price: $1.99, Version: 1.3 (iTunes) Description: New challenges awaits you! Experience fresh RPG experience with a unique combat mechanic, packed with high quality 3D... | Read more »
Agent Gumball - Roguelike Spy Game (Gam...
Agent Gumball - Roguelike Spy Game 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Someone’s been spying on Gumball. What the what?! Two can play at that game! GO UNDERCOVERSneak past enemy... | Read more »
Runaway Toad (Games)
Runaway Toad 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: It ain’t easy bein’ green! Tap, hold, and swipe to help Toad hop to safety in this gorgeous new action game from the creators of... | Read more »
PsyCard (Games)
PsyCard 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: From the makers och Card City Nights, Progress To 100 and Ittle Dew PSYCARD is a minesweeper-like game set in a cozy cyberpunk... | Read more »
Sago Mini Robot Party (Education)
Sago Mini Robot Party 1.0 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0 (iTunes) Description: -- Children's Technology Review Editor's Choice -- | Read more »
Egz – The Origin of the Universe (Games...
Egz – The Origin of the Universe 1.0.2 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0.2 (iTunes) Description: ►►► Special offer until 2nd may : get the game at 2.99€ instead of 3.99€ ! ◄◄◄ Egz is a mesmerizing mix... | Read more »

Price Scanner via MacPrices.net

Apple price trackers, updated continuously
Scan our Apple Price Trackers for the latest information on sales, bundles, and availability on systems from Apple’s authorized internet/catalog resellers. We update the trackers continuously: - 15″... Read more
SanDisk Half-Terabyte SSD Optimized for Every...
SanDisk Corporation has announced the SanDisk Z410 SSD, a cost-competitive, half-terabyte solid state drive (SSD) that enables manufacturers to design for a broad range of desktop PCs and laptops.... Read more
Churchill Downs Racetrack Selects VenueNext t...
Churchill Downs Racetrack has announced an agreement with VenueNext to implement its technology platform for the start of Churchill Downs 2016 Spring Meet, which includes the 142nd running of the... Read more
Record 700 Million Pounds of CE Recycled in 2...
The Consumer Technology Association (CTA) reports that a record-setting 700 million pounds of consumer electronics (CE) have been recycled under the eCycling Leadership Initiative (ELI). According to... Read more
Price drops on clearance 12-inch Retina MacBo...
B&H Photo has dropped prices on leftover 2015 12″ Retina MacBooks with models now available starting at $999. Shipping is free, and B&H charges NY tax only: - 12″ 1.1GHz Gray Retina MacBook... Read more
15-inch Retina MacBook Pros available for $20...
B&H Photo has 15″ Retina MacBook Pros on sale for up to $210 off MSRP. Shipping is free, and B&H charges NY tax only: - 15″ 2.2GHz Retina MacBook Pro: $1799 $200 off MSRP - 15″ 2.5GHz Retina... Read more
Target offers Apple Watch Sport for $50 off M...
Target has Apple Watch Sports on sale for $50 off MSRP for a limited time. Choose free shipping or free local store pickup (if available). Sale prices for online orders only, in-store prices may vary... Read more
Apple restocks Certified Refurbished Mac mini...
Apple has restocked Certified Refurbished 2014 Mac minis, with models available starting at $419. Apple’s one-year warranty is included with each mini, and shipping is free: - 1.4GHz Mac mini: $419 $... Read more
15-inch 2.2GHz Retina MacBook Pro on sale for...
Amazon.com has the 15″ 2.2GHz Retina MacBook Pro on sale for $1699.99 including free shipping. Their price is $300 off MSRP, and it’s the lowest price available for this model from any reseller (and... Read more
Apple Beats Microsoft at Own Game; Amazon Pri...
First quarter seasonality combined with an overall disinterested customer base led to an annual decline of 14.7% in worldwide tablet shipments during the first quarter of 2016 (1Q16). Worldwide... Read more

Jobs Board

Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
Simply Mac *Apple* Specialist- Service Repa...
Simply Mac is the largest premier retailer of Apple products in the nation. In order to support our growing customer base, we are currently looking for a driven Read more
*Apple* Retail - Multiple Positions - Apple,...
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
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.