TweetFollow Us on Twitter

NeXT Evolution
Volume Number:5
Issue Number:7
Column Tag:Developer's Forum

NeXT Evolution

By Paul Snively, Contributing Editor, Wheeling, IL

Evolution

Those of you who are waiting for the next (NeXT?) revolution in microcomputing are likely to be disappointed lately, and are probably going to remain that way for some time to come. That’s the news that I have to offer now that I have access to a NeXT computer. Before you go jumping out of your office windows or selling off your worldly goods and waiting for the end of the world to arrive, let me quickly add that this doesn’t mean that the picture is bleak. Far from it. Let me explain:

There’s a cube sitting about ten feet away from me. I won’t bore you with digitized pictures or a gushing description of how sexy it is; we’ve all seen the pictures, and we all know how sexy basic black can be (a fact that’s never been lost on the fashion world). The fact of the matter is that there are probably a fair number of people in MacTutor’s readership who remain without hands-on experience with this particular cube and would like some ideas from a fellow Macintosh developer as to just what this enigmatic little machine is like.

This Baby Ain't Portable!

For starters, the machine is, well, enigmatic. If you ever have to carry one of these things, the first thing that you realize is that the MegaPixel display that ships standard with every machine is far, far heavier than the computer itself is. Aside from that, there are virtually no physical problems with the machine. Putting one together is a simple matter of plugging the keyboard and mouse into the monitor, running a large cable between the computer and the monitor, and plugging the computer into the wall. Oh, by the way, you can plug the computer into the wall in the United States, England, Germany, or most other European countries with equal facility and no converters necessary.

25 mHz 68030 Processor

The computer itself, from an internal standpoint, is something of a throwback to a bygone era, at least in the microcomputer world: the case is simply a card cage. It consists of a power supply, an optical disk drive, optionally an internal Winchester hard disk, and a single card that literally can be described as the motherboard. The motherboard contains the obvious things: a 25 mHz MC68030 microprocessor, a similarly-clocked MC68882 floating-point coprocessor, and the by-now-famous Motorola DSP (Digital Signal Processor) chip. There are also two rather large custom VLSI chips that provide the I/O throughput that NeXT is so proud of. There’s also on-board Ethernet support for the thin-wire connector that sits on the backplane of every machine (and you thought AppleTalk on every machine was something).

Most of us are at least in touch with the hardware specs for the machine, and those who weren’t are now, after just two paragraphs of my lurid prose, so I’d better get to the point, which is this: the NeXT computer is a very nice 68030-based low-end workstation that supports a very nice version of UNIX (it’s Carnegie-Mellon’s MACH operating system, which consists of a rather small, tight kernel that provides a few new wrinkles in terms of memory management, networking, and multiprocessing, but manages to be compatible at the OS call level, not just the user level, with BSD4.3 UNIX). On top of MACH is Display Postscript, with a few NeXT wrinkles, such as fast bitmap compositing, thrown in for good measure (actually, even bitmap compositing isn’t entirely NeXT’s; it was jointly developed with Steve Jobs’ other little company, Pixar. By the way, if Pixar isn’t doing a chipset/card for the NeXT computer that’ll turn it into one of the hottest graphic workstations around, I’ll eat my shirt).

Ok, so we have what, from almost all outside appearances, is a 68030-based UNIX box running Display Postscript. Now what?

An Object-Oriented Computer From Ground Up!

“Now what” is what this article is really about. Because the reason that the NeXT computer is a piece of evolution that we should all be paying attention to as developers has nothing to do with the 68030, with the DSP, with optical storage, with UNIX or MACH, or any of that. It comes down to this:

The NeXT computer is an object-oriented computer almost from the ground up. Every machine ships with Stepstone, Inc.’s Objective-C, and the Free Software Foundation’s gcc (the GNU C compiler), gdb (GNU C source-level debugger), and GNU EMACS (as well as the Berkeley standard vi editor and NeXT’s own “Edit,” which is--as you might have guessed--a simple multi-window text editor based on NeXT’s windowing system, Display Postscript, etc.)

It doesn’t stop there. Each and every machine includes the Application Toolkit. The only way that I can describe the AppKit, as it’s called by NeXT, is that it’s what MacApp should have been. Again, this is nothing radical or new; it’s just the NeXT evolutionary step along the road that MacApp paved. The AppKit has a relatively small number of classes, and the hierarchy is fairly straightforward. The AppKit does what the AppKit should do: it makes the process of writing a NeXT application as painless as programming such a machine should be.

The reason that it’s so painless, however, is only partially a function of using Objective-C and the AppKit. The other important element in the development-tool arena is the Interface Builder.

Now, judging from the name alone, you wouldn’t think that the Interface Builder is anything special. In fact, it sounds an awful lot like ResEdit, doesn’t it? After all, ResEdit is a nice interactive utility for creating things that are, by and large, human interface elements, such as windows, dialog boxes, menus, strings, string lists, and the like. Certainly Interface Builder does all of these things, but more importantly, Interface Builder has some smarts about Objective-C and the AppKit. You can build dialogs in Interface Builder in the way you’d expect--by dragging buttons, sliders, fields, etc. to a window--but once you’ve done that, you can go a step or two further.

Interface Builder knows about objects that are part of the AppKit. It knows that applications have a main window and a main menu. It knows that there may be other windows, and submenus attached to the main menu. It knows about the standard behaviors that the AppKit defines for these objects (for example, it knows that when you click a button, the button should send some message to an object).

Non-human-interface objects--any object that isn’t part of the AppKit, in fact--Interface Builder knows nothing about by default. However, you can specify any custom object to Interface Builder, describing its methods in just enough detail to allow Interface Builder to use them in the process of connecting things.

To use a trivial example, let’s convert degrees Celsius to degrees Fahrenheit. To do this, we probably want a dialog that contains two text fields, Celsius and Fahrenheit, and a button, which we’ll title “>>Convert>>” to highlight the fact that we’re converting from Celsius to Fahrenheit.

All that we have to do to create this dialog is to drag two text fields and a button to our application’s main window. We should lay things out appropriately and label the fields and button appropriately. Then what we need to do is define a custom object, called “Converter,” to the Interface Builder. Converter isn’t a user-interface object--it’s the object that actually does the computation. It will only have one method, “convert,” which will take zero parameters, and it will have two “outlets,” input and output.

Outlets are the means by which non-user-interface objects communicate with user-interface objects. An outlet is an instance variable that an object possesses that gets initialized to the id of some other object so that the object owning the outlet can send messages to the other object. In this case, we will use the Interface Builder to connect the Celsius field to the Input outlet and the Fahrenheit field to the Output outlet. This way Converter’s convert method can refer to Input and Output to do the job without worrying about exactly what the objects being referred to are--Input could, after all, be connected to some object that provides a C-language-style float value based on a signal from an A/D converter attached to some sensor somewhere. Converter and its convert method shouldn’t--and don’t--care.

By now you may be wondering how all these connections are made. The Interface Builder includes a Connect panel that has square recessions to contain the sender object, the receiver object, and the outlet object. There are also two scrolling fields above the recessions. First, you would drag the button object to the sender recession and the Converter object to the receiver recession. The left-most scrolling text field would then list all of the messages that the Converter understand. We defined it to only understand one, convert. Clicking on that line in the scrolling field will cause a cable to appear between the button object and the Converter object, with separated screw and tab connectors in between. Clicking the cable closes the connection, indicating that clicking the button will send the convert message to the Converter object.

The right-most scrolling text field will list the outlets for the Converter object. Again, we defined two, Input and Output. We would drag the Celsius field to the outlet recession, then click on the line showing Input. A cable with separated male and female connectors would appear between the Converter object and the Celsius field. Clicking the cable would indicate that we want the Input instance variable initialized to refer to the Celsius text field in our dialog. We would repeat the process for the Fahrenheit field, connecting it to the Output outlet (read “instance variable.”)

It’s unfortunate that I can’t include NeXT screen dumps in this article; this whole process requires far too much verbiage to describe. Everything I’ve discussed so far can be done in Interface Builder in considerably less than sixty seconds. All that remains, then, is to save your work in Interface Builder and actually sit down and write the code for the Converter object.

I won’t go into massive details of the syntax and concepts behind Objective-C here, partially because this isn’t the time or place, and partially because my understanding of both is extremely incomplete at this point. In any case, the process consists of creating a new class, Converter, that will simply be a subclass of Object, since it doesn’t need to inherit anything special from anything else. Converter would have two instance variables, Input and Output, both of type id (all objects in Objective-C are of type id). We would then define the single method, convert. Convert will have two local variables of type float, c and f. The code for convert would then look something like this:

c = [Input getFloatValue];
f = (c *9.0 / 5.0) + 32.0;
[Output setFloatValue: f];
return(self);

Apart from declaring the class and its instance variables and the method and its local variables, that is all there is to converting from celsius to fahrenheit at literally the click of a button. The Interface Builder prevents you from having to write any more code than that to make your application work.

The question I have is this: why hasn’t anyone done anything like that for MacApp? Certainly parsing and generating Object Pascal code with some amount of “inside knowledge” of MacApp shouldn’t be that tough; anyone who’s ever used compiler-development tools such as yacc and lex knows that. Let’s not let this piece of evolution pass us by. With tools like this, programming can become much easier for all of us.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

BusyContacts 1.0.2 - Fast, efficient con...
BusyContacts is a contact manager for OS X that makes creating, finding, and managing contacts faster and more efficient. It brings to contact management the same power, flexibility, and sharing... Read more
Capture One Pro 8.2.0.82 - RAW workflow...
Capture One Pro 8 is a professional RAW converter offering you ultimate image quality with accurate colors and incredible detail from more than 300 high-end cameras -- straight out of the box. It... Read more
Backblaze 4.0.0.872 - Online backup serv...
Backblaze is an online backup service designed from the ground-up for the Mac.With unlimited storage available for $5 per month, as well as a free 15-day trial, peace of mind is within reach with... Read more
Little Snitch 3.5.2 - Alerts you about o...
Little Snitch gives you control over your private outgoing data. Track background activity As soon as your computer connects to the Internet, applications often have permission to send any... Read more
Monolingual 1.6.4 - Remove unwanted OS X...
Monolingual is a program for removing unnecesary language resources from OS X, in order to reclaim several hundred megabytes of disk space. If you use your computer in only one (human) language, you... Read more
CleanApp 5.0 - Application deinstaller a...
CleanApp is an application deinstaller and archiver.... Your hard drive gets fuller day by day, but do you know why? CleanApp 5 provides you with insights how to reclaim disk space. There are... Read more
Fantastical 2.0 - Create calendar events...
Fantastical is the Mac calendar you'll actually enjoy using. Creating an event with Fantastical is quick, easy, and fun: Open Fantastical with a single click or keystroke Type in your event details... Read more
Cocktail 8.2 - General maintenance and o...
Cocktail is a general purpose utility for OS X that lets you clean, repair and optimize your Mac. It is a powerful digital toolset that helps hundreds of thousands of Mac users around the world get... Read more
Direct Mail 4.0.4 - Create and send grea...
Direct Mail is an easy-to-use, fully-featured email marketing app purpose-built for OS X. It lets you create and send great looking email campaigns. Start your newsletter by selecting from a gallery... Read more
jAlbum Pro 12.6 - 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

Appy to Have Known You - Lee Hamlet Look...
Being at 148Apps these past 2 years has been an awesome experience that has taught me a great deal, and working with such a great team has been a privilege. Thank you to Rob Rich, and to both Rob LeFebvre and Jeff Scott before him, for helping me... | Read more »
MLB Manager 2015 (Games)
MLB Manager 2015 5.0.14 Device: iOS Universal Category: Games Price: $4.99, Version: 5.0.14 (iTunes) Description: Guide your favorite MLB franchise to glory! MLB Manager 2015, officially licensed by MLB.com and based on the award-... | Read more »
Breath of Light (Games)
Breath of Light 1.0.1421 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.1421 (iTunes) Description: Hold a quiet moment. Breath of Light is a meditative and beautiful puzzle game with a hypnotic soundtrack by... | Read more »
WWE WrestleMania Tags into the App Store
Are You ready to rumble? The official WWE WrestleMania app, by World Wrestling Entertainment, is now available. Now you can get all your WrestleMania info in one place before anyone else. The app offers details on superstar signings, interactive... | Read more »
Bio Inc's New Expansion is Infectin...
Bio Inc., by DryGin Studios, is the real time strategy game where you infect a human body with the worst virus your evil brain can design. Recently, the game was updated to add a whole lot of new features. Now you can play the new “Lethal”... | Read more »
The Monocular Minion is Here! Despicable...
Despicable Me: Minion Rush, by Gameloft, is introducing a new runner to the mix in their latest update. Now you can play as Carl, the prankster minion. Carl has a few new abilities to play with, including running at a higher speed from the start.... | Read more »
Dungeon of Madness (Games)
Dungeon of Madness 1.0.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0.0 (iTunes) Description: Dungeon of Madness is an action game where you rotate tiles to create our own route. Help the hero by connecting the... | Read more »
Filters for iPhone (Photography)
Filters for iPhone 1.0 Device: iOS iPhone Category: Photography Price: $.99, Version: 1.0 (iTunes) Description: | Read more »
Jump'N'Shoot Attack (Games)
Jump'N'Shoot Attack 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: A mobile game for gamers! Join Louise Lightfoot, the legendary "Master of Jumping and Shooting", on her mission to save... | Read more »
Space Bounties Inc. (Games)
Space Bounties Inc. 1.4 Device: iOS Universal Category: Games Price: $1.99, Version: 1.4 (iTunes) Description: SuperGameDroid: 4/5 "Satisfying futuristic RPG combat, high replay value, and a heavy dose of nostalgia make Space... | Read more »

Price Scanner via MacPrices.net

iMacs on sale for up to $205 off MSRP
B&H Photo has 21″ and 27″ iMacs on sale for up to $205 off MSRP including free shipping plus NY sales tax only: - 21″ 1.4GHz iMac: $1019 $80 off - 21″ 2.7GHz iMac: $1189 $110 off - 21″ 2.9GHz... Read more
Färbe Technik Offers iPhone Battery Charge LI...
Färbe Technik, which manufactures and markets of mobile accessories for Apple, Blackberry and Samsung mobile devices, is offering tips on how to keep your iPhone charged while in the field: •... Read more
Electronic Recyclers International CEO Urges...
Citing a recent story on CNBC about concerns some security professionals have about the forthcoming Apple Watch, John Shegerian, Chairman and CEO of Electronic Recyclers International (ERI), the... Read more
Save up to $380 with Apple refurbished iMacs
The Apple Store has Apple Certified Refurbished iMacs available for up to $380 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 27″ 3.5GHz 5K iMac – $2119 $... Read more
Logitech Says MX Master Is Its Most Advanced...
Logitech’s new MX Master Wireless Mouse incorporates the best of Logitech’s many computer mouse innovations into a striking hand-sculpted design. The company claims that the MX Master creates a new... Read more
Save up to $300 on a new Mac, $30 on an iPad,...
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
Apple refurbished 2014 MacBook Airs available...
The Apple Store lowered prices on Apple Certified Refurbished 2014 MacBook Airs recently, with models now available starting at $679. An Apple one-year warranty is included with each MacBook, and... Read more
Mac Notebook Evolution; A Desktop Replacement...
More often than not right from the beginning, Apple’s Macs have tended to skew toward small. The original Macs were called “compacts,”, and notwithstanding a few exceptions like the honking Big Mac... Read more
13-inch 1.4GHz/128GB MacBook Air (Apple refur...
The Apple Store has Apple Certified Refurbished 2014 13″ 1.4GHz/128GB MacBook Airs available for $759 including free shipping plus Apple’s standard one-year warranty. Their price is $240 off original... Read more
YEP! Alternative Browser for iOS Now Supports...
Pfaeffikon, Switzerland based Power App AG has announced the release of an update to their Yep! Web Browser (v1.3.0) for iOS8 iPhone and iPad. Yep! hit the App Store shortly after the release of iOS... 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
Sr. Technical Services Consultant, *Apple*...
**Job Summary** Apple Professional Services (APS) has an opening for a senior technical position that contributes to Apple 's efforts for strategic and transactional Read more
Lead *Apple* Solutions Consultant - Retail...
**Job Summary** Job Summary The Lead ASC is an Apple employee who serves as the Apple business manager and influencer in a hyper-business critical Reseller's store Read more
*Apple* Pay - Site Reliability Engineer - Ap...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
*Apple* Solutions Consultant - Retail Sales...
**Job Summary** As an Apple Solutions Consultant (ASC) you are the link between our customers and our products. Your role is to drive the Apple business in a retail Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.