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

Things 2.5.4 - Elegant personal task man...
Things is a task management solution that helps to organize your tasks in an elegant and intuitive way. Things combines powerful features with simplicity through the use of tags and its intelligent... Read more
NeoOffice 2014.10 - Mac-tailored, OpenOf...
NeoOffice is a complete office suite for OS X. With NeoOffice, users can view, edit, and save OpenOffice documents, PDF files, and most Microsoft Word, Excel, and PowerPoint documents. NeoOffice 3.x... Read more
iPhoto Library Manager 4.2 - Manage mult...
iPhoto Library Manager allows you to organize your photos among multiple iPhoto libraries, rather than having to store all of your photos in one giant library. You can browse the photos in all your... Read more
Web Snapper 3.3.8 - Capture entire Web p...
Web Snapper lets you capture Web pages exactly as they appear in your browser. You can send them to a file as images or vector-based, multi-page PDFs. It captures the whole Web page - eliminating the... Read more
TeamViewer 10.0.41404 - Establish remote...
TeamViewer gives you remote control of any computer or Mac over the Internet within seconds, or can be used for online meetings. Find out why more than 200 million users trust TeamViewer! Free for... Read more
Ableton Live 9.1.8 - Record music using...
Ableton Live lets you create and record music on your Mac. Use digital instruments, pre-recorded sounds, and sampled loops to arrange, produce, and perform your music like never before. Ableton Live... Read more
VOX 2.5 - Music player that supports man...
VOX is a beautiful music player that supports many filetypes. The beauty is in its simplicity, yet behind the minimal exterior lies a powerful music player with a ton of features & support for... Read more
OmniFocus 2.1.2 - GTD task manager with...
OmniFocus helps you manage your tasks the way that you want, freeing you to focus your attention on the things that matter to you most. Capturing tasks and ideas is always a keyboard shortcut away in... Read more
Adobe Flash Player 17.0.0.169 - Plug-in...
Adobe Flash Player is a cross-platform, browser-based application runtime that provides uncompromised viewing of expressive applications, content, and videos across browsers and operating systems.... Read more
iMazing 1.1.3 - Complete iOS device mana...
iMazing (was 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 from... Read more

Chainsaw Warrior: Lords of the Night has...
It's time to put the Darkness back in its place now that Chainsaw Warrior: Lords of the Night has officially made it to iOS. | Read more »
A World of Ice and Fire Lets You Stalk 2...
George R. R. Martin’s A World of Ice and Fire, by Random House, is a mobile guide to the epic series. The new update gives you the Journeys map feture that will let you track the movements of 25 different characters. But don't worry, you can protect... | Read more »
Gameloft Announces Battle Odyssey, a New...
Battle Odyssey, Gameloft's newest puzzle RPG, is coming to the App Store next week. Set in the world of Pondera, you will need to control the power of the elements to defend the world from evil. You'll be able to entlist over 500 allies to aid you... | Read more »
Fusion - HDR Camera (Photography)
Fusion - HDR Camera 1.0.0 Device: iOS Universal Category: Photography Price: $1.99, Version: 1.0.0 (iTunes) Description: Fusion creates HDR (high dynamic range) photos by capturing different exposures and then combining them into one... | Read more »
Sago Mini Toolbox (Education)
Sago Mini Toolbox 1.1 Device: iOS Universal Category: Education Price: $2.99, Version: 1.1 (iTunes) Description: Come build with the Sago Mini friends! Use a wrench, try a saw, or hammer some nails. From sewing hand puppets to... | Read more »
You Should Probably Grab Hitman GO While...
Hitman GO is a surprisingly cool (yet also incredibly drastic) departure from the Hitman series. It's well worth playing for any puzzle game fans out there, and at the moment you can get your hands - or garrotte if you will - on it for a mere $0.99... | Read more »
IFTTT is Bringing Do Button and Do Note...
IFTTT has announced Do Button and Do Note for the Apple Watch. Do Button lets you make your own personalized button that can connect to things like your Google Drive, control the temperature in your home with Nest Thermostat, or turn the lights on... | Read more »
How Many Days, Hours, and Minutes Are Le...
Countdown, by Yves Tscherry, is now available on the App Store. The app keeps track of countdowns to your favorite things such as someones birthday or days till the New Year. You can display the time in seconds, minutes, hours, days, weeks, months,... | Read more »
The All-New Misfit 2.0 App is Available...
Misfit has just given their app a complete overhaul. Misfit 2.0 now has a brand new interface with a sleek design and is easier to navigate. You'll be able to sync your Misfit device and look up health and fitness information faster than ever before... | Read more »
Halo: Spartan Strike (Games)
Halo: Spartan Strike 1.0 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0 (iTunes) Description: Delve into 30 challenging missions through cities and jungles using a devastating arsenal of weapons, abilities and... | Read more »

Price Scanner via MacPrices.net

Clearance 13-inch 2.6GHz Retina MacBook Pro a...
B&H Photo has clearance 2014 13″ 2.6GHz/128GB Retina MacBook Pros now available for $1099, or $200 off original MSRP. Shipping is free, and B&H charges NY sales tax only. Read more
Apple refurbished 2014 13-inch Retina MacBook...
The Apple Store has Apple Certified Refurbished 2014 13″ Retina MacBook Pros available for up to $400 off original MSRP, starting at $979. An Apple one-year warranty is included with each model, and... Read more
iMacs on sale for up to $205 off MSRP, NY tax...
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
Sale! 16GB iPhone 5S for $1 with service
Best Buy is offering 16GB iPhone 5Ss for $1.00 with 2-year activation at a participating cellular provider. Choose free home shipping and activation, or buy online and activate during in-store pickup... Read more
Apple refurbished 2014 MacBook Airs available...
The Apple Store has Apple Certified Refurbished 2014 MacBook Airs available starting at $679. An Apple one-year warranty is included with each MacBook, and shipping is free. These are currently the... Read more
27-inch 3.5GHz 5K iMac on sale for $2349, sav...
 Adorama has the 27″ 3.5GHz 5K iMac in stock today and on sale for $2349 including free shipping plus NY & NJ sales tax only. Their price is $150 off MSRP. For a limited time, Adorama will... Read more
Save up to $380 on an iMac with Apple refurbi...
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
iFixIt Teardown Awards 12-IInch Retina MacBoo...
iFixIt has posted its illustrated teardown of the new 12-inch MacBook Retina. They note that this new MacBook is less than half the thickness of the last Apple notebook called just “MacBook” back in... Read more
13-inch 2.5GHz MacBook Pro (refurbished) avai...
The Apple Store has Apple 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.... Read more
Faithful iPad 2 Gets A Second Career In Retir...
Finally, after four months’ transition, I handed my faithful old 2011 iPad 2 off to my wife at the end of March and switched whole-hog to using the iPad Air 2 I bought back in November. I’d found... Read more

Jobs Board

*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, 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
*Apple* TV Live Streaming Frameworks Test En...
**Job Summary** Work and contribute towards the engineering of Apple 's state-of-the-art products involving video, audio, and graphics in Interactive Media Group (IMG) at Read more
Event Director, *Apple* Retail Marketing -...
…This senior level position is responsible for leading and imagining the Apple Retail Team's global engagement strategy and team. Delivering an overarching brand 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.