TweetFollow Us on Twitter

September 93 - KON & BAL'S PUZZLE PAGE

KON & BAL'S PUZZLE PAGE

I'M HERE TO SERVE

KONSTANTIN OTHMER AND BRUCE LEAK

[IMAGE 132-136_Puzzle_Page_rev1.GIF]

See if you can solve this programming puzzle, presented in the form of a dialog between Konstantin Othmer (KON) and Bruce Leak (BAL). The dialog gives cluesto help you. Keep guessing until you're done; your score is the number to the left of the clue that gave you the correct answer. These problems are supposed to be tough. If you don't get a high score, at least you'll learn interesting Macintosh trivia.

BAL Here's one for you, KON: I've got this server that I store builds on. It's a Macintosh ci running System 7.1 with File Sharing enabled, hooked up over Ethernet. The server runs an experimental MPW tool that spins the beach-ball cursor (don't they all?) waiting for a build to appear; then it renames the build with the next release number and makes it available to the public. Early on we had some problems with the tool and it would occasionally crash the server, but that seems to be working now.

KON So what's the problem?

BAL When I use the Finder to copy my latest build out there, it crashes the server. Yet when I use the duplicate command as part of the MPW build script for my project, it works.

KON I thought you did all your builds in THINK C.

BAL Of course, but I use MPW for file management just like the guys on the Finder team.

KON Chalk one up for MPW.

BAL But that's not all. When I use the Finder to copy other files out to the server it works fine. Solve me, KON. Over.

KON I'm suspicious of that MPW shell script running on the server. It's continuously making file system calls while File Sharing is trying to copy your file over in the background. There must be some contention caused by MPW trying to rename the file while it's still in the process of being copied.

BAL Come on, KON, what do you think we're running here? This is System 7 we're talking about. Don't you think we would get something like that right on the seventh try?

KON No comment.

100 BAL If I stop the MPW shell script running on the server or even quit MPW completely, the server still crashes when I use the Finder to copy my build to it.

KON Are the Finder copies that crash file-size dependent?

95 BAL Size doesn't seem to matter. The Finder can successfully copy files that are the same size, smaller, and bigger than mine without crashing the server.

KON So it's the server that's crashing?

BAL Yeah, the progress bar comes up on the client machine, the copy starts, and then almost immediately the server crashes and the client machine hangs in XPP's two- minute penalty box.

KON There's an updated version of the StopXPP dcmd that works with System 7 for all those MacsBugphiles. Install that baby and you're golden. When the client hangs because the server has gone away, just drop into MacsBug and type StopXPP to force the connection to time out immediately. Any other problems?

90 BAL Yeah, yeah, yeah. I've already got that dcmd. My machine isn't hung anymore, but the server is still crashed and your point total is still falling.

KON You packrat! You stole one of those rev J Apple Ethernet cards from Van Brink's garage. It's dropping bits, same as it ever did, and the way the Finder is slicing up your bit stream chokes it.

85 BAL Sorry, it's rev K of the card -- the one that only drops bits when you're running in 32- bit mode -- but the ci has only 8 megs of RAM and is running in 24-bit mode.

KON OK, I'll try Third-Party Cards for $200.

80 BAL KON, I use only Apple equipment. Throw the card out altogether, use LocalTalk, and it still happens. Get a life.

KON Are there any other cards in the ci that are dropping bits? Perhaps the Apple ci cache card?

75 BAL No cards, but if it makes you feel any better, I'll have Vanna swap in a new ci, keeping only the hard disk; it still happens.

KON I don't want a ci anymore. How 'bout we try an fx, or maybe even a Classic?

70 BAL Vanna's getting a little tired here. Bad news: it still happens on all of them.

KON What if we try one of those NuTek boxes?

65 BAL Fine. It crashes on boot. Next.

KON And swapping out the hard drive fixes it?

60 BAL Swapping out the hard drive stops the server from crashing. Any chance I can solve this problem and preserve my existing hardware investment?

KON So there's something wrong with your system software or the File Sharing software on that drive. I'll reinstall all that stuff and watch it work beautifully. Problem solved.

55 BAL Not! After you reinstall System 7.1 and all the bogus networking disks, and reinstall MacsBug and the dcmds from the virgin copies that came with that Debugging Macintosh Software book, ISBN #0-201-57049-1, it still happens.

KON I never really trusted installing over existing corrupt software. So I throw everything in the trash, empty the trash, and reinstall fresh.

50 BAL It still happens.

KON Maybe the volume allocation is messed up: you've got some bad I-nodes, circular B- tree references, or some other HFS mumbo jumbo. I'll confer with Dr. Norton and see what he thinks.

45 BAL Doctors Norton, Feldman, and Bruffey, Disk FirstAid, and others all give it a clean bill of health, though a few file dates were wrong and they've been fixed.

KON So maybe some part of the media went bad, producing bad sectors or ambiguous data. I'll do a media test using Silverlining.

40 BAL The media is fine. OK, KON. Quit screwing around. It's not a hardware problem.

KON But when I replaced the hard disk, the problem went away. What remains after I throw all the files away? Well, the driver persists. I'll update the driver with the utility software that came with the drive.

35 BAL It still happens. It doesn't have anything to do with the driver.

KON I'll try SneakerNet!

30 BAL Well, transferring the file by floppy disk doesn't work either, using the Finder on the server. Surprisingly, this most reliable means of networking doesn't work even though you aren't using high-density floppies. In this case paper clips don't even help.

KON OK, I reformat the drive and reinstall the software fresh.

25 BAL Now it works. So what's the bug?

KON Well, the reformatting changed the interleave, and there was some weird timing problem hosing you.

20 BAL Enough grasping at straws. Remember it only happens with my file or copies of my file. Get those rusty old gears turning.

KON I'll chop the file into pieces and see if those still crash the server when I copy them. I'll strip out all the CODE resources with ResEdit and try that file.

15 BAL The file is pretty small now, and it still crashes.

KON I strip out all the data by setting the EOF.

10 BAL It still crashes. Look, I can build it from scratch, I can build it on other machines, I can change the code that's in it, other people can build it on their machines, it happens with Ethernet, SneakerNet, LocalTalk, you name it -- it still crashes.

KON And people thought we'd run out of these puzzles.

BAL I got a great one for next time, too, but you've got to finish this one first.

KON So what makes my file my file? If it's not the name, the data in it, or the creation date, it's got to be the container info -- the icon, the file type, the creator, that stuff.

BAL Your puzzle, KON.

KON The Desktop Manager previously used only by AppleShare is used by the Finder in System 7, right?

5 BAL Yeah, there are two invisible data files: Desktop DB and Desktop DF. Desktop DF has the all the data for the icons, and Desktop DB has information for all files: the document-to-application binding, the file-to-icon binding, and the file-to-comment binding. For each application creator, it keeps a list of all the applications of that type with the newest one first. That way when you double-click a document, the Finder launches the newest version of the application that handles that document.

KON I get it. The desktop database got corrupted by the experimental MPW tool you had, and when the Finder tries to update the database, it reads bad data and chokes.

BAL It worked when copying files via MPW because MPW doesn't try to keep the desktop database up to date.

KON So you should be able to rebuild the desktop database by holding down the Command and Option keys while booting. Then everything will work great.

BAL I knew the AppleShare servers are the most reliable in the business, and I couldn't believe we got one to crash.

KON Well, if you want to write sleazy MPW tools that you haven't fully debugged, you get what's coming to you.

BAL In fact, for ultimate security on a network server, you should lock it in a room and not run any weird stuff that isn't endorsed by your AppleShare administrator.

KON Right! But if you insist on running untested code, you get what you pay for.

BAL Nasty.

KON Yeah.


KONSTANTIN OTHMER AND BRUCE LEAK spent some time in the county slammer this summer, BAL for bungee jumping off a Cupertino freeway overpass and KON for losing the landmark "KON versus Stockton Board of Health" tenants-rights trial. They were able to get reduced sentences by working as waiters in "Pro Bono," the prison's nouvelle cuisine restaurant, (see photo) and faithfully adhering to the Macintosh Human Interface Guidelines .*

SCORING

  • 75-100 Excellent! Link your résumé to DEVELOP.
  • 50-70 Not bad. Link your résumé to MACTECHMAG.
  • 25-45 Hmmm. Better sit on that résumé for a while.
  • 5-20 At least you beat KON's score!*

Thanks to Gary Davidian, Pat Dirks, scott douglass, Kevin Stinson, and Chris Zuleeg for reviewing this column. *

 
AAPL
$102.50
Apple Inc.
+0.25
MSFT
$45.43
Microsoft Corpora
+0.55
GOOG
$571.60
Google Inc.
+2.40

MacTech Search:
Community Search:

Software Updates via MacUpdate

Skype 6.19.0.450 - Voice-over-internet p...
Skype allows you to talk to friends, family and co-workers across the Internet without the inconvenience of long distance telephone charges. Using peer-to-peer data transmission technology, Skype... Read more
VueScan 9.4.41 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more
Cloud 3.0.0 - File sharing from your men...
Cloud is simple file sharing for the Mac. Drag a file from your Mac to the CloudApp icon in the menubar and we take care of the rest. A link to the file will automatically be copied to your clipboard... Read more
LibreOffice 4.3.1.2 - Free Open Source o...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
SlingPlayer Plugin 3.3.20.505 - Browser...
SlingPlayer is the screen interface software that works hand-in-hand with the hardware inside the Slingbox to make your TV viewing experience just like that at home. It features an array of... Read more
Get Lyrical 3.8 - Auto-magically adds ly...
Get Lyrical auto-magically add lyrics to songs in iTunes. You can choose either a selection of tracks, or the current track. Or turn on "Active Tagging" to get lyrics for songs as you play them.... Read more
Viber 4.2.2 - Send messages and make cal...
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,... Read more
Cocktail 7.6 - 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
LaunchBar 6.1 - Powerful file/URL/email...
LaunchBar is an award-winning productivity utility that offers an amazingly intuitive and efficient way to search and access any kind of information stored on your computer or on the Web. It provides... Read more
Maya 2015 - Professional 3D modeling and...
Maya is an award-winning software and powerful, integrated 3D modeling, animation, visual effects, and rendering solution. Because Maya is based on an open architecture, all your work can be scripted... Read more

Latest Forum Discussions

See All

Rhonna Designs Magic (Photography)
Rhonna Designs Magic 1.0 Device: iOS Universal Category: Photography Price: $1.99, Version: 1.0 (iTunes) Description: Want to sprinkle *magic* on your photos? With RD Magic, you can add colors, filters, light leaks, bokeh, edges,... | Read more »
This Week at 148Apps: August 25-29, 2014
Shiny Happy App Reviews   | Read more »
Qube Kingdom – Tips, Tricks, Strategies,...
Qube Kingdom is a tower defense game from DeNA. You rally your troops – magicians, archers, knights, barbarians, and others – and fight against an evil menace looking to dominate your kingdom of tiny squares. Planning a war isn’t easy, so here are a... | Read more »
Qube Kingdom Review
Qube Kingdom Review By Nadia Oxford on August 29th, 2014 Our Rating: :: KIND OF A SQUARE KINGDOMUniversal App - Designed for iPhone and iPad Qube Kingdom has cute visuals, but it’s a pretty basic tower defense game at heart.   | Read more »
Fire in the Hole Review
Fire in the Hole Review By Rob Thomas on August 29th, 2014 Our Rating: :: WALK THE PLANKUniversal App - Designed for iPhone and iPad Seafoam’s Fire in the Hole looks like a bright, 8-bit throwback, but there’s not enough booty to... | Read more »
Alien Creeps TD is Now Available Worldwi...
Alien Creeps TD is Now Available Worldwide Posted by Ellis Spice on August 29th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Dodo Master Review
Dodo Master Review By Jordan Minor on August 29th, 2014 Our Rating: :: NEST EGGiPad Only App - Designed for the iPad Dodo Master is tough but fair, and that’s what makes it a joy to play.   | Read more »
Motorsport Manager Review
Motorsport Manager Review By Lee Hamlet on August 29th, 2014 Our Rating: :: MARVELOUS MANAGEMENTUniversal App - Designed for iPhone and iPad Despite its depth and sense of tactical freedom, Motorsport Manager is one of the most... | Read more »
Motorsport Manager – Beginner Tips, Tric...
The world of Motorsport management can be an unforgiving and merciless one, so to help with some of the stress that comes with running a successful race team, here are a few hints and tips to leave your opponents in the dust. | Read more »
CalPal Update Brings the App to 2.0, Add...
CalPal Update Brings the App to 2.0, Adds Lots of New Stuff Posted by Ellis Spice on August 29th, 2014 [ permalink ] | Read more »

Price Scanner via MacPrices.net

Save up to $300 on an iMac with Apple refurbi...
The Apple Store has Apple Certified Refurbished iMacs available for up to $300 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free. These are the best prices on... Read more
The Rise of Phablets
Carlisle & Gallagher Consulting Group, a businesses and technology consulting firm focused solely on the financial services industry, has released an infographic depicting the convergence of... Read more
Eddy – Cloud Music Player for iPhone/iPad Fre...
Ukraine based CapableBits announces the release of Eddy, its tiny, but smart and powerful cloud music player for iPhone and iPad that allows users to stream or download music directly from cloud... Read more
A&D Medical Launches Its WellnessConnecte...
For consumers and the healthcare providers and loved ones who care for them, A&D Medical, a leader in connected health and biometric measurement devices and services, has launched its... Read more
Anand Lal Shimpi Retires From AnandTech
Anand Lal Shimpi, whose AnandTech Website is famous for its meticulously detailed and thoroughgoing reviews and analysis, is packing it in. Lal Shimpi, who founded the tech site at age 14 in 1997,... Read more
2.5GHz Mac mini, Apple refurbished, in stock...
The Apple Store has Apple Certified Refurbished 2.5GHz Mac minis available for $509, $90 off MSRP. Apple’s one-year warranty is included, and shipping is free. Read more
13-inch 2.5GHz MacBook Pro on sale for $999,...
B&H Photo has the 13″ 2.5GHz MacBook Pro on sale for $999.99 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Read more
Labor Day Weekend MacBook Pro sale; 15-inch m...
B&H Photo has the new 2014 15″ Retina MacBook Pros on sale for up to $125 off MSRP. Shipping is free, and B&H charges NY sales tax only. They’ll also include free copies of Parallels Desktop... Read more
Labor Day Weekend iPad mini sale; $50 to $100...
Best Buy has the iPad mini with Retina Display (WiFi models) on sale for $50 off MSRP on their online store for Labor Day Weekend. Choose free shipping or free local store pick up. Price is for... Read more
13-inch 1.4GHz MacBook Air on sale for $899,...
Adorama has the new 2014 13″ 1.4GHz/128GB MacBook Air on sale for $899.99 including free shipping plus NY & NJ tax only. Their price is $100 off MSRP. 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
*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
*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
*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
Senior Event Manager, *Apple* Retail Market...
…This senior level position is responsible for leading and imagining the Apple Retail Team's global event strategy. Delivering an overarching brand story; in-store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.