TweetFollow Us on Twitter

Dec 98 Factory Floor

Volume Number: 14 (1998)
Issue Number: 12
Column Tag: From The Factory Floor

A PowerPlant Update, Part 3

by Frank Vernon and Dave Mark, ©1998 by Metrowerks, Inc., all rights reserved.

This month's column is the third installment in our series on PowerPlant. In the past two months, we heard from two key members of the PowerPlant team, Greg Dow and John Daub. This month, we'll hear from another key member of the team, Frank Vernon.

Frank Vernon has been working for Metrowerks since CW9. Before joining Metrowerks, Frank worked at Apple doing R&D for first eWorld and later Internet Services in their Boulder, Colorado group. When Frank joined Metrowerks, he took over the networking classes from Eric Scouten and completely rewrote them for CW11. The first of the Internet Classes were introduced around CW9 as well. Stuffit classes and Internet Config classes were added right after CW11.

Frank also worked on the 1.1 update to Marionet for Allegiant Software (SuperCard, etc.). Marionet is a faceless background application that utilized Apple events. It supported SMTP, POP3, NNTP, FTP, and a custom chat client/server.

In addition to his engineering background, Frank also has a degree in music.

Dave: Tell me a little bit about how you got started with PowerPlant.

Frank: Before MW I was doing R&D for Apple in a small autonomous group based in Boulder, Colorado. Our group initially began working on eWorld and later evolved into the Internet Services division as eWorld was being dismantled. This was an interesting R&D group to be involved with in that we did simultaneous technology R&D and business modeling. We were focused on creating technology directly applicable to the business models we thought would be successful rather than being a "pure" R&D technology group. I personally found this type of business and results driven R&D to be quite rewarding.

After leaving Apple in early 1996 and while at MacWorld San Francisco I heard a rumor that Eric Scouten, the original author of the PowerPlant Networking Classes, was looking for someone to take them over so he could concentrate on Constructor full-time. I eventually got in touch with Eric and began working on the classes. An interesting story here is that I still, to this day, have never met Eric face to face. Despite having worked relatively closely with him for almost 2 years, as I first started taking over the classes and then began rewriting them we have never met in person. We played "booth tag" that year while at MacWorld and have continued to miss each other at subsequent MacWorlds and Developer Conferences. The majority of our work was done via Email and occasionally we would have a phone call to hash out the nastier details.

Dave: Tell us about the evolution of the networking classes.

Frank: Long before working at Metrowerks, Eric Scouten had created a very nice set of MacTCP based networking libraries called TurboTCP. When OT was first being released, he had the idea to abstract MacTCP and OT into a single library so developers would not have to deal with developing seperately for both in their applications. Since he was working at Metrowerks at the time, he created them as PowerPlant classes. Being heavily involved in Constructor, however, he didn't have time to really get them into shape. In fact, when I took them over for the CW9 release they were still in the PowerPlant "In Progress" folder.

When I took over the Networking Classes the basic groundwork had been laid, but they did have several major limitations. The first thing I added was "Listen" support. This allowed them to accept incoming connections so they could be used for network servers. Prior to this they operated in client mode only. I was also fixing lots of bugs and preparing them for release outside of the "In Progress" folder.

Abstracting OT & MacTCP into a common interface was an interesting prospect to say the least. Besides the obvious complexity of trying to make the two disparate stacks behave in the same way, we also encountered numerous little problems. Not the least of which was simply testing them.

For each feature or bug we encountered they had to be tested in all possible combinations of MacTCP and OT, 68K and PPC, Asynchronous mode and Threaded mode, and with and without Interrupt notifications. This alone made for many long and frustrating nights of debugging. As anyone who's done network programming can tell you, even on a good day, debugging network code can be like searching for a needle in a needle factory.

In addition, Eric's initial designs were quite ambitious. Not only were we trying to support two radically different TCP/IP stacks through a single interface, but we were also attempting to address all of the common network programming styles such as asynchronous and threaded operations while also maintaining an interrupt driven notification model. These interrupt driven notifications were particularly difficult to manage due to their memory allocation limitations and debugging restrictions. While not impossible to comprehend, most developers simply didn't want to deal with all the complexity that these disparate paradigms introduced into the classes. After going through several releases we had a lot of feedback that they were simply getting too complex for the needs of most developers.

After CW10 Eric and I worked out a major overhaul to the classes which is what you see today in the Networking Classes. From the feedback we received we decided to streamline the classes and make them as stable and as easy to use as possible while still maintaining the initial design requirement of abstracting MacTCP and OT into a single interface.

One of the major advantages that we had in redesigning the classes was that the Thread Manager was also reaching maturity. Prior to this time, most network programmers used heavily asynchronous, event driven, programming models. Without having multiple threads available you simply couldn't block and wait for a network event to complete. This could tie up your application or even the entire machine for each call which of course meant that your interface and the whole machine would be unresponsive while you waited for completion.

By settling on a threaded model for the new classes we were able to make several major improvements. The present classes, for instance, hide 99% of the issues related to interrupt driven events and associated memory and debugging issues from the developer. Also, in my mind, the threaded model of network programming is much easier for casual network programmers to understand and work with.

The threaded model allows for radically simplified state machines with most higher level protocols. Code that might have been thousands of lines before could often be reduced to hundreds.

Subtle side effects of this model also allow for more sophisticated objects like the current LInternetAddress object. This object now transparently translates between canonical DNS and IP dotted decimal style addresses. Without the straight-forward flow control of the threaded model this would not possible.

For example, the simple act of converting an IP address into a canonical host name in the past would have required a multi-stage state machine to negotiate the DNS interaction to resolve the address. In the present Networking classes you can simply do the following:

LInternetAddress theAddress("208.226.102.11");
Str255 theConnonicalName;
theAddress.GetDNSDescriptor(theConnonicalName);

Dave: What about support for other networking protocols such as AppleTalk within the Networking classes?

Frank: For strictly historical reasons, the initial concept behind the Networking classes was only to abstract MacTCP and TCP/IP aspects of OT into a common library. We do receive sporadic requests to support other things like AppleTalk and some of the more sophisticated OT features from time to time. With Apple in the midst of major updates around Carbon and beyond we are in the process of considering our options for the future. We are actively seeking input from the developer community in this matter. As always, we encourage people to contact Metrowerks tech support with any suggestions and requests they have along these lines.

Dave: Speaking of the future, what about Apple's planned changes to a Sockets-based networking model? How will this effect the Networking classes?

Frank: As I mentioned, we are still in the process of determining how to move forward towards Carbon and beyond. I can tell you however that Metrowerks recognizes the importance and growing ubiquity of Internet protocols and networking in general to modern applications. We are going to do our best to support whatever paradigms Apple chooses moving forward.

Dave: Can you describe the difference between the Networking classes and the Internet classes?

Frank: Based of course on the Networking Classes, the Internet Classes address specific Internet protocols. Presently these classes support: HTTP, SMTP, POP3, FTP, NTP, FINGER, and IRC. In addition, they support associated standards such as Internet Config, MIME, MD5, BinHex, UUEncode/UUDecode, MacBinary II, URL's, and others.

The design philosophy behind the Internet protocols was to represent the protocols as faithfully as possible while also supplying simple interfaces. For instance, many protocols have interfaces such as LFTPConnection::PutFile which take all the necessary parameters such as the name of the remote host, username, password, the name of the file in question, etc. and simply send or retrieve the files. The developer doesn't need to know much if anything about the protocol itself. If however they need to do more sophisticated procedures they also have complete control over the protocol at each step in the process.

As much as possible I've also tried to leverage other features of PowerPlant to keep the usage of the Internet Classes familiar to anyone who has used PowerPlant. For example, I use the standard Broadcast/Listen mechanism for progress and status reporting during the protocol execution. This allows for easy and familiar interface creation just like any other control.

The Internet classes also have a few nice features like the transparent use of temporary file buffering to allow the sending and receipt of arbitrarily large files (up to available disk space.) This buffering mechanism (represented in LDynamicBuffer) will automatically and transparently make decisions about either keeping data in memory or swapping out to temporary files when necessary. This is all hidden behind standard PP Stream classes but the developer never need know if the data is in a file on disk or resident in application memory. This greatly simplifies things such as large FTP file transfers.

In addition to the simplified interfaces available with the protocols themselves, I have also recently added a new utility class called UInternetProtocol. These utility methods even further simplify the process by simply taking a standard URL and doing all the work behind the scenes. These methods will automatically do things such as creating a new thread, parsing the URL, and resolving the URL. These are especially useful for adding simple URL based Apple event support to any application. (Little known tip: The Internet Example application also demonstrates use of the GURL and FURL Apple events and includes the AETE resources. Try setting the Internet Example Application as your default FTP client in Internet Config and click on an FTP URL in your browser.)

   UInternetProtocol FTP Example:

         LURL theURL("ftp://user:pass@host/filepath");
         UInternetProtocol::FTP_GetFile(nil, theURL, nil);

These two lines are all that are necessary to get the FTP file at the host specified using the name and password imbedded in the URL. If no username and password are included then anonymous login will be attempted.

Wherever possible defaults from Internet Config will be used for all the UInternetProtocol methods. This includes download file directories, default servers, usernames, passwords, email addresses, etc.

Dave: What can you tell me about the StuffIt classes?

Frank: The StuffIt classes grew out of a number of requests we had to somehow integrate file compression and decompression into the Internet classes. The people at Aladdin were quite helpful in allowing us to include the API to the StuffIt engine with the CodeWarrior releases.

What I attempted to do with these classes was to simplify the StuffIt Engine API by making assumptions about some of the more common usage. For the most part these also hide a lot of the necessary API requirements about properly opening and closing the engine, handling error conditions, and properly navigating archives. I've also attempted to represent the Engine's API into OOP methodologies so C++ developers could easily integrate its usage into their applications.

   UStuffItSupport Example:

void
StuffItExample::StuffItGetFile()
{
   //Do a StandardGetFile for the file to Stuff
   StandardFileReply theReply;
   ::StandardGetFile(nil, -1, nil, &theReply);
   if (!theReply.sfGood)
      return;

   //Stuff the file assuming the same file name, etc.
   try {
      UStuffItSupport::StuffFile(theReply.sfFile);
   } catch (OSErr err) {
      DisplayStuffItError(err);
   }
}

By comparison, the direct interface to the StuffIt Engine API to stuff a file is:

extern   pascal   OSErr   StuffFSList (long magicCookie,
                           FSSpecArrayHandle fileList,
                           FSSpecPtr archiveSpec,
                           FSSpecPtr resultFSSpec,
                           Boolean compressOriginal,
                           Boolean deleteOriginal,
                           Boolean encryptOriginal,
                           Boolean resolveAliases,
                           Boolean noRecompression,
                           short conflictAction);

As you can tell, the StuffIt Classes go a long way towards simplifying the common usage of the StuffIt Engine.

Another class, LstuffItArchive, allows you to work directly with StuffIt Archive files. With this class you can walk an archive, insert or delete files from an archive, create new archives, etc..

By the way, I should mention that a license from Aladdin is still required to ship the StuffIt engine with an application.

Dave: I know you've done some work on email servers. What kinds of changes have you seen recently in email server technology?

Frank: Actually, there have not been a lot of significant changes in email server technology for quite a while. The basic protocol, SMTP, has remained virtually unchanged for quite some time. While extensions are added to SMTP from time to time, it has generally proved to be a very effective, if not sophisticated, protocol. I believe in fact that its lack of sophistication is probably directly responsible for its longevity. (A lesson from which we could probably all learn something.)

The primary change is that you are now seeing more and more customized servers acting as gateways into other non-SMTP based systems such as Lotus Notes.

In addition, many of the older servers were never designed to deal with the larger volumes of mail you now encounter on the rapidly growing Internet. Many of the larger ISPs for instance have a lot of problems simply with volume. These older mail servers often require either complex reconfigurations or complete rewrites to handle high volumes.

We're also beginning to see more task specific email servers. Servers that focus on mailing list management and other automated mail handling tasks.

There are lots of startup companies out there dealing with email issues. Things like automated mail responders for customer support, customized email reminder services, and purchase transaction systems just to mention a few.

Email is arguably the most popular protocol on the Internet. It's the original "Push" technology. It's strange in way that only now are people really concentrating on email as "the" way to interact directly with customers.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Macs Fan Control 1.4.4.0 - Monitor and c...
Macs Fan Control allows you to monitor and control almost any aspect of your computer's fans, with support for controlling fan speed, temperature sensors pane, menu-bar icon, and autostart with... Read more
calibre 2.69.0 - Complete e-book library...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more
Evernote 6.9.1 - Create searchable notes...
Evernote allows you to easily capture information in any environment using whatever device or platform you find most convenient, and makes this information accessible and searchable at anytime, from... Read more
jAlbum Pro 13.5 - Organize your digital...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. You can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly... Read more
jAlbum 13.5 - 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
Google Chrome 53.0.2785.143 - Modern and...
Google Chrome is a Web browser by Google, created to be a modern platform for Web pages and applications. It utilizes very fast loading of Web pages and has a V8 engine, which is a custom built... Read more
Chromium 53.0.2785.143 - 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. Version 53.0.2785.143: [Security Fix] High CVE-2016-... Read more
QuickBooks 2015 16.1.7.1524 R8 - Financi...
Save 20% on QuickBooks Pro for Mac today through this special discount link QuickBooks 2015 helps you manage your business easily and efficiently. Organize your finances all in one place, track... Read more
Sierra Cache Cleaner 11.0.1 - Clear cach...
Sierra Cache Cleaner is an award-winning general purpose tool for macOS X. SCC makes system maintenance simple with an easy point-and-click interface to many macOS X functions. Novice and expert... Read more
Default Folder X 5.0.7 - Enhances Open a...
Default Folder X attaches a toolbar to the right side of the Open and Save dialogs in any OS X-native application. The toolbar gives you fast access to various folders and commands. You just click on... Read more

3 tips to aid your journey in Banner Sag...
Stoic Games brings us another viking epic in the guise of Banner Saga 2 this week. It’s a sweeping tale, richly animated and draped in melancholy and moments of beauty. The game’s been received as a much improved follow up to the first entry in the... | Read more »
Pumped BMX 3: Beginner tips and tricks
There’s a whole lot more to Pumped BMX 3 than meets the eye. Your goal is to perform a wide array of sweet flips and tricks, but that’s easier said than done. It takes well practiced timing and coordination, and the game doesn’t really explain that... | Read more »
Cybird’s latest release - BFB Champions...
Launched in the UK in early September, BFB Champions’ newest update is loaded with great new features, and looks set to outshine the original version by taking it out of soft launch and giving it a new lease of life. | Read more »
3 apps to boost your focus
As someone who works from home, my workspace is a minefield of distraction. Cats, tasty snacks, the wind blowing past my window, that cleaning that I suddenly can’t put off any longer. If I let distraction takes its course, I find that soon half... | Read more »
Pumped BMX 3 (Games)
Pumped BMX 3 1.0 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0 (iTunes) Description: The final instalment of the smash hit #1 rated BMX game is here! Following on from the insane success of Pumped BMX 2, Pumped 3... | Read more »
4 games like Burly Men at Sea to inspire...
Burly Men at Sea is out today and it looks a treat. It tells the tale of three Scandinavian fishermen who leave the humdrum of their daily lives to go exploring. It’s a beautiful folksy story that unfurls as you interact with the environment... | Read more »
3 reasons you need to play Kingdom: New...
Developed by a tag team of indie developers - Thomas "Noio" van den Berg and Marco "Licorice" Bancale - Kingdom is a vibrant medieval fantasy adventure that casts players as a king or queen who must expand their empire by exploring the vasts lands... | Read more »
JoyCity have launched a brand new King o...
Great news for all of you Game of Dice fans out there - JoyCity have just released a brand new limited edition pack with a really cool twist. The premise of Game of Dice is fairly straightforward, asking you to roll dice to navigate your way around... | Read more »
Burly Men at Sea (Games)
Burly Men at Sea 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Burly Men at Sea is a folktale about a trio of large, bearded fishermen who step away from the ordinary to seek adventure. | Read more »
3 tips for catching the gnarliest waves...
Like a wave breaking on the shore, Tidal Rider swept its way onto the App Store charts this week settling firmly in the top 10. It’s a one-touch high score-chaser in which you pull surfing stunts while dodging seagulls and collecting coins. The... | Read more »

Price Scanner via MacPrices.net

CAZE Annouces New Zero 5 Case for Jet Black i...
Hong Kong basd CAZE has announced Zero 5 case for iPhone 7/ 7 Plus, one of the world’s thinnest clear hard cases, measuring just 0.5 millimeters. CAZE has been producing and improving the Zero 5... Read more
Nest Egg Inventory App for iOS Offers Conven...
Campbell, California based Winprogger LLC has announced the release and immediate availability of Nest Egg – Inventory 4.1.22, an important update to their easy-to-use, yet comprehensive inventory... Read more
Factor4, LLC Launches Apple iOS and Android G...
Factor4, LLC, which offers gift and loyalty services to the SMB marketplace, has released free mobile applications that enable merchants to process via all Apple and Android devices. The Apple and... Read more
15-inch Retina MacBook Pros on sale for $200...
B&H Photo has 15″ Retina Apple MacBook Pros on sale for $200 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
Apple refurbished iMacs available for up to $...
Apple has Certified Refurbished 2015 21″ & 27″ iMacs available for up to $350 off MSRP. Apple’s one-year warranty is standard, and shipping is free. The following models are available: - 21″ 3.... Read more
Check Apple prices on any device with the iTr...
MacPrices is proud to offer readers a free iOS app (iPhones, iPads, & iPod touch) and Android app (Google Play and Amazon App Store) called iTracx, which allows you to glance at today’s lowest... Read more
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
Apple refurbished 2016 13-inch MacBook Airs a...
Apple has Certified Refurbished 2016 13″ MacBook Airs available starting at $849. An Apple one-year warranty is included with each MacBook, and shipping is free: - 2016 13″ 1.6GHz/8GB/128GB MacBook... Read more
1.4GHz Mac mini on sale for $449, save $50
Adorama has the 1.4GHz Mac mini on sale for $50 off MSRP including free shipping plus NY & NJ sales tax only: - 1.4GHz Mac mini (Apple sku# MGEM2LL/A): $449 $50 off MSRP To purchase a mini at... Read more
Apple refurbished 2015 13-inch MacBook Airs a...
Apple has Certified Refurbished 2015 13″ MacBook Airs available starting at $759. An Apple one-year warranty is included with each MacBook, and shipping is free: - 2015 13″ 1.6GHz/4GB/128GB MacBook... Read more

Jobs Board

Systems Architecture Prototyping - *Apple*...
Changing the world is all in a day's work at Apple . If you love innovation, here's your chance to make a career of it. You'll work hard. But the job comes with more Read more
*Apple* Retail - Multiple Positions- Akron,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Hardware Design Validation Engineer - *Apple...
Changing the world is all in a day's work at Apple . If you love innovation, here's your chance to make a career of it. You'll work hard. But the job comes with more Read more
Systems Architecture Prototyping - *Apple*...
Changing the world is all in a day's work at Apple . If you love innovation, here's your chance to make a career of it. You'll work hard. But the job comes with more Read more
*Apple* Retail - Multiple Positions- South B...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.