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

Chromium 75.0.3770.142 - 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 75.0.3770.142: Release notes were... Read more
Viber 11.1.0 - Send messages and make fr...
Viber lets you send free messages and make free calls to other Viber users, on any device and network, in any country! Viber syncs your contacts, messages and call history with your mobile device, so... Read more
Wireshark 3.0.3 - Network protocol analy...
Wireshark is one of the world's foremost network protocol analyzers, and is the standard in many parts of the industry. It is the continuation of a project that started in 1998. Hundreds of... Read more
DEVONthink Pro 3.0beta4 - Knowledge base...
DEVONthink Pro is your essential assistant for today's world, where almost everything is digital. From shopping receipts to important research papers, your life often fills your hard drive in the... Read more
Adobe Creative Cloud 4.9.0.512 - Access...
Adobe Creative Cloud costs $20.99/month for a single app, or $52.99/month for the entire suite. Introducing Adobe Creative Cloud desktop applications, including Adobe Photoshop CC and Illustrator CC... Read more
SketchUp 19.1.174 - Create 3D design con...
SketchUp is an easy-to-learn 3D modeling program that enables you to explore the world in 3D. With just a few simple tools, you can create 3D models of houses, sheds, decks, home additions,... Read more
ClamXav 3.0.12 - Virus checker based on...
ClamXav is a popular virus checker for OS X. Time to take control ClamXAV keeps threats at bay and puts you firmly in charge of your Mac’s security. Scan a specific file or your entire hard drive.... Read more
BetterTouchTool 3.151 - Customize multi-...
BetterTouchTool adds many new, fully customizable gestures to the Magic Mouse, Multi-Touch MacBook trackpad, and Magic Trackpad. These gestures are customizable: Magic Mouse: Pinch in / out (zoom)... Read more
FontExplorer X Pro 6.0.9 - Font manageme...
FontExplorer X Pro is optimized for professional use; it's the solution that gives you the power you need to manage all your fonts. Now you can more easily manage, activate and organize your... Read more
Dropbox 77.4.131 - Cloud backup and sync...
Dropbox is an application that creates a special Finder folder that automatically syncs online and between your computers. It allows you to both backup files and keeps them up-to-date between systems... Read more

Latest Forum Discussions

See All

Upcoming visual novel Arranged shines a...
If you’re in the market for a new type of visual novel designed to inform and make you think deeply about its subject matter, then Arranged by Kabuk Games could be exactly what you’re looking for. It’s a wholly unique take on marital traditions in... | Read more »
TEPPEN guide - The three best decks in T...
TEPPEN’s unique take on the collectible card game genre is exciting. It’s just over a week old, but that isn’t stopping lots of folks from speculating about the long-term viability of the game, as well as changes and additions that will happen over... | Read more »
Intergalactic puzzler Silly Memory serve...
Recently released matching puzzler Silly Memory is helping its fans with their intergalactic journeys this month with some very special offers on in-app purchases. In case you missed it, Silly Memory is the debut title of French based indie... | Read more »
TEPPEN guide - Tips and tricks for new p...
TEPPEN is a wild game that nobody asked for, but I’m sure glad it exists. Who would’ve thought that a CCG featuring Capcom characters could be so cool and weird? In case you’re not completely sure what TEPPEN is, make sure to check out our review... | Read more »
Dr. Mario World guide - Other games that...
We now live in a post-Dr. Mario World world, and I gotta say, things don’t feel too different. Nintendo continues to squirt out bad games on phones, causing all but the most stalwart fans of mobile games to question why they even bother... | Read more »
Strategy RPG Brown Dust introduces its b...
Epic turn-based RPG Brown Dust is set to turn 500 days old next week, and to celebrate, Neowiz has just unveiled its biggest and most exciting update yet, offering a host of new rewards, increased gacha rates, and a brand new feature that will... | Read more »
Dr. Mario World is yet another disappoin...
As soon as I booted up Dr. Mario World, I knew I wasn’t going to have fun with it. Nintendo’s record on phones thus far has been pretty spotty, with things trending downward as of late. [Read more] | Read more »
Retro Space Shooter P.3 is now available...
Shoot-em-ups tend to be a dime a dozen on the App Store, but every so often you come across one gem that aims to shake up the genre in a unique way. Developer Devjgame’s P.3 is the latest game seeking to do so this, working as a love letter to the... | Read more »
Void Tyrant guide - Guildins guide
I’ve still been putting a lot of time into Void Tyrant since it officially released last week, and it’s surprising how much stuff there is to uncover in such a simple-looking game. Just toray, I finished spending my Guildins on all available... | Read more »
Tactical RPG Brown Dust celebrates the s...
Neowiz is set to celebrate the summer by launching a 2-month long festival in its smash-hit RPG Brown Dust. The event kicks off today, and it’s divided into 4 parts, each of which will last two weeks. Brown Dust is all about collecting, upgrading,... | Read more »

Price Scanner via MacPrices.net

Verizon is offering a 50% discount on iPhone...
Verizon is offering 50% discounts on Apple iPhone 8 and iPhone 8 Plus models though July 24th, plus save 50% on activation fees. New line required. The fine print: “New device payment & new... Read more
Get a new 21″ iMac for under $1000 today at t...
B&H Photo has new 21″ Apple iMacs on sale for up to $100 off MSRP with models available starting at $999. These are the same iMacs offered by Apple in their retail and online stores. Shipping is... Read more
Clearance 2017 15″ 2.8GHz Touch Bar MacBook P...
Apple has Certified Refurbished 2017 15″ 2.8GHz Space Gray Touch Bar MacBook Pros available for $1809. Apple’s refurbished price is currently the lowest available for a 15″ MacBook Pro. An standard... Read more
Clearance 12″ 1.2GHz MacBook on sale for $899...
Focus Camera has clearance 12″ 1.2GHz Space Gray MacBooks available for $899.99 shipped. That’s $400 off Apple’s original MSRP. Focus charges sales tax for NY & NJ residents only. Read more
Get a new 2019 13″ 2.4GHz 4-Core MacBook Pro...
B&H Photo has new 2019 13″ 2.4GHz MacBook Pros on sale for up to $150 off Apple’s MSRP. Overnight shipping is free to many addresses in the US: – 2019 13″ 2.4GHz/256GB 6-Core MacBook Pro Silver... Read more
AirPods with Wireless Charging Case now on sa...
Amazon has extended their Prime Day savings on Apple AirPods by offering AirPods with the Wireless Charging case for $169.99. That’s $30 off Apple’s MSRP, and it’s the cheapest price available for... Read more
New 2019 15″ MacBook Pros on sale for $200 of...
B&H Photo has the new 2019 15″ 6-Core and 8-Core MacBook Pros on sale for $200 off Apple’s MSRP. Overnight shipping is free to many addresses in the US: – 2019 15″ 2.6GHz 6-Core MacBook Pro Space... Read more
Amazon drops prices, now offers clearance 13″...
Amazon has new dropped prices on clearance 13″ 2.3GHz Dual-Core non-Touch Bar MacBook Pros by $200 off Apple’s original MSRP, with prices now available starting at $1099. Shipping is free. Be sure to... Read more
2018 15″ MacBook Pros now on sale for $500 of...
Amazon has dropped prices on select clearance 2018 15″ 6-Core MacBook Pros to $500 off Apple’s original MSRP. Prices now start at $1899 shipped: – 2018 15″ 2.2GHz Touch Bar MacBook Pro Silver: $1899.... Read more
Price drop! Clearance 12″ 1.2GHz Silver MacBo...
Amazon has dropped their price on the recently-discontinued 12″ 1.2GHz Silver MacBook to $849.99 shipped. That’s $450 off Apple’s original MSRP for this model, and it’s the cheapest price available... Read more

Jobs Board

Best Buy *Apple* Computing Master - Best Bu...
**696259BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Store Associates **Location Number:** 001076-Temecula-Store **Job Description:** The Read more
Business Development Manager, *Apple* Globa...
Business Development Manager, Apple Global Tampa, FL, US Requisition Number:73805 As a Global Apple Business Development Manager at Insight, you proactively Read more
*Apple* Systems Architect/Engineer, Vice Pre...
…its vision to be the world's most trusted financial group. **Summary:** Apple Systems Architect/Engineer with strong knowledge of products and services related to Read more
*Apple* IOS Systems Engineer - Randstad (Uni...
Apple IOS Systems Engineer **job details:** + location:Irvine, CA + salary:$45 - $55 per hour + date posted:Tuesday, July 16, 2019 + job type:Temp to Perm + Read more
Business Development Manager, *Apple* Globa...
Business Development Manager, Apple Global Tampa, FL, US Requisition Number:73805 As a Global Apple Business Development Manager at Insight, you proactively Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.