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
$94.27
Apple Inc.
+0.33
MSFT
$44.97
Microsoft Corpora
+0.13
GOOG
$598.71
Google Inc.
+9.23

MacTech Search:
Community Search:

Software Updates via MacUpdate

Macs Fan Control 1.1.12 - Monitor and co...
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
A Better Finder Rename 9.37 - File, phot...
A Better Finder Rename is the most complete renaming solution available on the market today. That's why, since 1996, tens of thousands of hobbyists, professionals and businesses depend on A Better... Read more
MacBook Air EFI Firmware Update 2.9 - Fo...
MacBook Air EFI Firmware Update is recommended for MacBook Air (Mid 2011) models. This update addresses an issue where systems may take longer to wake from sleep than expected and fixes a rare issue... Read more
FileZilla 3.9.0.1 - Fast and reliable FT...
FileZilla (ported from Windows) is a fast and reliable FTP client and server with lots of useful features and an intuitive interface.Version 3.9.0.1: MSW: Fix installation issue with locked DLLs... Read more
OS X Yosemite 10.10 DP4 - Developer Prev...
Note: This is a Developer Preview. You must be a registered Apple Mac Developer to download this update. OS X Yosemite is Apple's newest operating system for Mac. An elegant design that feels... Read more
FinderPop 2.5.6 - Classic Mac utility, n...
FinderPop is a Universal preference pane that extends OS X's contextual menus using a FinderPop Items folder much as the Apple Menu Items folder used to do for the Apple menu. It has other features... Read more
SpiderOak 5.1.7 - Secure cloud backup, s...
SpiderOak is a multi-platform secure online backup, storage, access, and sharing solution engineered for the consumer and small businesses. You must first sign up to use SpiderOak. Running natively... Read more
Espionage 3.6 - Simple, state of the art...
Espionage offers state-of-the-art encryption and plausible deniability for your confidential data. Sometimes, encrypting your data isn't enough to protect it. That's why Espionage 3 goes beyond data... Read more
calibre 1.45.0 - Complete e-library mana...
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... Read more
iFFmpeg 4.3.1 - Convert multimedia files...
iFFmpeg is a graphical front-end for FFmpeg, a command-line tool used to convert multimedia files between formats. The command line instructions can be very hard to master/understand, so iFFmpeg does... Read more

Latest Forum Discussions

See All

FlyCraft Herbie: Crazy Machines Review
FlyCraft Herbie: Crazy Machines Review By Jennifer Allen on July 22nd, 2014 Our Rating: :: TRICKY FLYINGUniversal App - Designed for iPhone and iPad A tough game of careful thrusting and navigation, FlyCraft Herbie: Crazy Machines... | Read more »
MTN Review
MTN Review By Jessica Fisher on July 22nd, 2014 Our Rating: :: ADORABLE, SERENE, AND AMUSINGUniversal App - Designed for iPhone and iPad MTN is an adorable, talking pet mountain that is less game and more zen garden.   | Read more »
Fly High with Ninja UP! Now Available o...
Fly High with Ninja UP! Now Available on the App Store Posted by Jessica Fisher on July 22nd, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Bio Inc. Review
Bio Inc. Review By Nadia Oxford on July 22nd, 2014 Our Rating: :: SICKENING - IN A COMPELLING WAYUniversal App - Designed for iPhone and iPad Bio Inc is about orchestrating the medical destruction of a single person. If that doesn’... | Read more »
HELMUT Review
HELMUT Review By Andrew Fisher on July 21st, 2014 Our Rating: :: TRUNDLE SIMULATOR 2014Universal App - Designed for iPhone and iPad HELMUT is a fun, fleeting time-sink that offers a momentary distraction and nothing else.   | Read more »
Walkr Review
Walkr Review By Jennifer Allen on July 21st, 2014 Our Rating: :: ORIGINAL WALKINGiPhone App - Designed for the iPhone, compatible with the iPad Walking is a bit more exciting thanks to this planet building/discovering sim reliant... | Read more »
Zombie Commando Review
Zombie Commando Review By Jennifer Allen on July 21st, 2014 Our Rating: :: MINDLESS SLAUGHTERUniversal App - Designed for iPhone and iPad Briefly fun but ultimately forgettable, Zombie Commando will scratch an itch then be... | Read more »
Swords & Poker Adventures Review
Swords & Poker Adventures Review By Jennifer Allen on July 21st, 2014 Our Rating: :: SOULLESS POKER PLAYUniversal App - Designed for iPhone and iPad Swords & Poker Adventures is a mishmash of Poker and RPGing, but it lacks... | Read more »
Warhammer 40,000: The Horus Heresy: Drop...
Warhammer 40,000: The Horus Heresy: Drop Assault Coming Soon to iOS Posted by Jennifer Allen on July 21st, 2014 [ permalink ] Coming soon to iOS will be an all-new Warhammer 40,000 tactical strategy game by the name of The Horus Heresy: Drop As | Read more »
A Life Worth Dying For Review
A Life Worth Dying For Review By Jordan Minor on July 21st, 2014 Our Rating: :: A BEAUTIFUL MINDUniversal App - Designed for iPhone and iPad A Life Worth Dying For is a fascinating portrait of a serious subject.   | Read more »

Price Scanner via MacPrices.net

Twelve South HiRise For MacBook – Height-Adju...
If you use your MacBook as a workhorse desktop substitute, as many of us do, a laptop stand combined with an external keyboard and pointing device are pretty much obligatory if you want to avoid... Read more
Why The Mac Was Not Included In The Apple/IBM...
TUAW’s Yoni Heisler cites Fredrick Paul of Network World whoi blogged last week that the Mac’s conspicuous absence from Apple and IBM’s landmark partnership agreement represents a huge squandered... Read more
Save $100 on 13-inch Retina MacBook Pros, plu...
Adorama has 13″ Retina MacBook Pros on sale for $100 off MSRP. Shipping is free, and Adorama charges sales tax in NY & NJ only: - 13″ 2.4GHz/128GB MacBook Pro with Retina Display: $1199 - 13″ 2.... Read more
Blurr it 2.3 for iOS – Quickly Blurs Selected...
Hyderabad, India based TouchLabs has announced a new update of Blurr it 2.3, their photography app for iOS users. Blurr it allows you to blur part of the image to hide potentially sensitive or... Read more
MacBook Airs on sale for $100 off MSRP, start...
Best Buy has the new 2014 MacBook Airs on sale for up to $100 off MSRP on their online store. Choose free home shipping or free local store pickup (if available). Prices valid for online orders only... Read more
Amazon Announces Kindle Unlimited: Unlimited...
Amazon.com has introduced Kindle Unlimited — a new subscription service which allows customers to freely read as much as they want from over 600,000 Kindle books, and listen as much as they want to... Read more
New Linksys Wireless Range Extenders Boost Wi...
Linksys has announced its new lineup of Linksys Wi-Fi Range Extenders. Consumers often experience a weak wireless signal in some parts of their house or apartment caused by blocking elements such as... Read more
MacBook Airs available starting at $719
The Apple Store has Apple Certified Refurbished 2013 & 2012 MacBook Airs in stock today starting at $719. An Apple one-year warranty is included with each MacBook, and shipping is free: 2013... Read more
Get the best deals on iPad minis with Apple r...
The Apple Store has Certified Refurbished 2nd generation iPad minis with Retina Displays available for up to $130 off the cost of new models, starting at $339. Apple’s one-year warranty is included... Read more
Best Buy’s College Student Deals: $100 off Ma...
Take an additional $100 off all MacBooks and iMacs, $50 off iPad Airs and iPad minis, at Best Buy Online with their College Students Deals Savings, valid through July 25th. Anyone with a valid .EDU... Read more

Jobs Board

*Apple* Computer Technician - Fairfield Coun...
Company DescriptionWe are an Apple Authorized Sales and Service Provider. We have been selling and servicing Apple computers in the Fairfield County area for over 20 Read more
*Apple* Computer Technician - Fairfield Coun...
Company DescriptionWe are an Apple Authorized Sales and Service Provider. We have been selling and servicing Apple computers in the Fairfield County area for over 20 Read more
Mac Expert - *Apple* Online Store Mexico -...
…MUST be fluent in English and Spanish to be considered for this position At Apple , we believe that hard work, a fun environment, creativity and innovation fuel the Read more
*Apple* Computer Technician - Fairfield Coun...
Company DescriptionWe are an Apple Authorized Sales and Service Provider. We have been selling and servicing Apple computers in the Fairfield County area for over 20 Read more
Mac Expert - *Apple* Online Store - Apple (...
**Job Summary** At Apple , we believe that hard work, a fun environment, creativity and innovation fuel the ultimate customer experience. We believe each customer Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.