TweetFollow Us on Twitter

Sep 92 Letters
Volume Number:8
Issue Number:5
Column Tag:Letters

Dialogue Box

By Neil Ticktin, Editor

Math Equations Ommission

I just received my writer's letter for my contribution to MacTutor. Thank you for the complimentary copy of July's MacTutor and thanks for the handsome cheque!

OOPs. Unfortunately you omitted the listing of the file CustomFn.c. In its place you printed Demo.c. CustomFn.c is an integral part of the compiler and the missing code will leave your readers wondering. [For those readers who need it, write to Xplain Corp. for the source code disk. This listing is on it. - Ed.]

- Dr. Kevin Raner

How many suggestions can you make in a letter?

l am very excited at the rebirth of MacTutor. As a person living in a foreign country, it is very difficult to find information on programming in English (especially stuff that does not cost a fortune). MacTutor provides a source of information on programming as well as tools that are available. l would like to offer my input on the following things.

1. Please make sure to include the fax and phone numbers for things mentioned in your magazine. [We give the fax numbers whenever we are given them. We’ll try even harder to get them in the future. - Ed.]

2. l would also like to see a classified listing in the magazine. For example, I am trying to do some programming in assembly language but l can not find any books in print regarding the subject. l would like to be able to place an ad requesting or offering these types of materials as well as others. [We are looking into such a section for later this year. - Ed.]

3. l would also like to see a greater diversity of types of programs. For example, programs that read and write data to the SCSI port, input device manipulation, and communications. [We are working on getting hardware articles that address some of these topics. - Ed.]

Again, l look forward to many interesting and helpful articles in the future and l wish MacTutor the best of luck.

- Brett Bibby, Kanebo, Ltd.

Modify Print Dialogs Article Corrections

First let me thank you for publishing my article “Modify Print Dialogs” in the June 1992 issue of MacTutor. It was a thrill to see it in print.

There where a couple of minor bugs in the code. The program usually operates “As Advertised”, but under some conditions the wrong radio button could be disabled.

In the DisableDraftMode routine there are three lines which look like:

if ((*the_title)  -=  (*draft_title))

This really only checks that the first letter of the title matches (in this case) draft_title. These lines should be changed to use strcmp, as in:

if (Istrcmp(the_title,  draft_title))

I also left out a small block of code at the end of the DisableDraftMode routine. After the end of the main for loop and before the ) which ends the routine, add the following lines:

/* 1 */
if (  draft_selected  )  {
/*  draft  mode  was  selected,  so  select  the  next  best  */ 
 if  (  better_item_no  )  item_no  =  better_item_no, else
 if  (  best_item_no  )  item_no  =  best_item_no,

GetDItem((DialogPtr)  theDialogPtr,  item_no,  &the_type,  &the_item, 
 &the_box), SetCtlValue((ControlHandle)  the_item,  1),

The variables better_item_no and best_item_no should also be initialized to zero at the start of the routine.

I hope this didn’t cause anyone too much grief. Boy, is my face red!

- Greg WiIson, Ontario , Canada

Two Seconds

I take 2 seconds to drop you a word:

Carry on the good work !!

We like and need you.

- JC Hadorn

How Long can an article be?

BigNum Article

You say you knew you were not including all the code? My goodness!! If you knew, you could have at least put in an editor's comment in brackets to tell readers where the code was. [You are right, we should have and will try to do so in the future. - Ed.]

I still think massive shrinking of the code to a very tiny size would be the best alternative to elimination of code. [Our readers have told us not to do this because they want to be able to read the code. If it is small they can’t read it.- Ed.]

I never send to MacTutor any code that is not relevant, and I explain in minute detail what's what.

[The reason that the code was cut was because the article was already 12 pages long and the rest of the code would not fit. Although Lisp is of interest to our readers, we need to make sure that we stay reasonable on the amount of Lisp in the magazine. If the code was put in, almost 25% of the magazine would have been Lisp. The real solution here is to give the readers the important information and not hold their hand through the code. Of course, as always, ALL the code is available on the source code disk which anyone can get by calling MacTutor. - Ed.]

- André van Meulebrouck

Sounds good to me!

I was in process of letting my MacTutor subscription drop (again) when you folks took it over. The first couple of issues look pretty good. I hope you work harder than the old owners at showing good, useful code and avoiding their tendency to send out buggy or compatibility-challenged stuff. It is somewhat depressing to see the only technical journal for the Mac publish stuff that consistently ignores both Apple HI and Apple Compatibility standards, because that comes back and hurts the readers when things start breaking (worse, apple gets blamed for it, even though mama apple said "no no!"). I also constantly got heebie-jeebies from the rampant typos and basic copy-editing mistakes (in my other life, I'm a writer). If they couldn't get the article right, how can you trust the code?

[Nowadays, we try to test the code and get a feel for whether it is any good. Although ultimately, the responsibility needs to be both the article’s author and yours because we cannot test every bit of code as extensively as you would like. In the meantime, we are keeping vigilant on reports of problems with code and printing that information. This way, we use the entire Macintosh community to check over code. We hear you and will do the best that we reasonably can. - Ed.]

I'd also like to see more of a focus on the primary languages (Think, MPW) and less on the esoterica (Lisp, Fortran, Forth). Make it a journal for the folks doing the leading edge, which the side languages aren't. They're hobbyist toys.

And does anyone really find the Mousehole stuff useful? I'd rather see a more focussed "Ask the expert" column where questions get real answers rather than a random data stream where I have no clue if they know what they're talking about. [We actually do get a lot of compliments on the Mousehole, but I will keep both your comments in mind. - Ed.]

It was cute when MacTutor was three guys in a garage, but this is a real magazine now.

Dave Mark is a great addition to the team. [We think so too. - Ed.]

Keep it up.

Good luck!

- Chuq Von Rospach

Speeding up Random Numbers

I was glad to see Jon Bell's recap of Lemer's method and Park and Miller's excellent paper on minimal standard random number generators (cacm v31n10). This is an important area for implementers to learn about since the effort required to do it right is very low, and the results of doing it wrong can be disasterous. The further excursion into assembly level coding leaves a bit to be desired, though. If speed is what you're after, the following routine

    MOVE.L  seed(A5), D1
    MULU.L#33614, D0:D1
 ; 33614 is 16807 * 2
    LSR.L   #1, D1
    ADD.L   D0, D1
    BPL.S   @1
    ADDI.L  #$80000001, D1
@1  MOVE.L  D1, seed(A5)

takes less than half as much time as the one presented in the article, and computes the same result. This code takes advantage of the fact that the modulus is one less than a power of two. There is no need in this case to perform a divide to find the remainder. To convince yourself that it works, think about multiplying mod 9 (one less than a power of 10). (3 * 4) mod 9 = 12 mod 9 = 3, note that 3 is 1 + 2, the digits of the result of the multiplication. The only complication is when the sum overflows (e.g., (8 * 8) mod 9 = 64 mod 9 = 1, 6 + 4 = 10... 1 + 0 = 1). In this case we need to "carry around" in the result as is done by the ADDI above.

Lemer's method is important when the facilities of a CISC processor are not available (as in Pascal or C), but carrying the technique into (CISC) assembly code is inappropriate. In particular, even without the power of two minus one requirement of my implementation, it is not necessary to do two separate multiplies in Update Seed since the M680x0 will do double precision multiplies and divides...

    MOVE.L  seed(A5), D0
    MULU.L  #a, D1:D0
    DIVS.L  #m, D1:D0
    MOVE.L  D1, seed(A5)

Also, neither of these UpdateSeed routines suffer from the need to artificially restrict the range of the multiplier “a” -- although I've never been tempted to search for my own values: I recommend you stick with the values tested and certified by the experts.


- Doug Currie

Flavors Technology, Inc.


Community Search:
MacTech Search:

Software Updates via MacUpdate

Apple GarageBand 10.1.3 - Complete recor...
The new GarageBand is a whole music creation studio right inside your Mac -- complete with keyboard, synths, orchestral and percussion instruments, presets for guitar and voice, an entirely... Read more
Apple Compressor 4.3 - Adds power and fl...
Compressor adds power and flexibility to Final Cut Pro X export. Customize output settings, work faster with distributed encoding, and tap into a comprehensive set of delivery features. Powerful... Read more
Xcode 8.1 - Integrated development envir...
Xcode includes everything developers need to create great applications for Mac, iPhone, iPad, and Apple Watch. Xcode provides developers a unified workflow for user interface design, coding, testing... Read more
Apple Numbers 4.0.5 - Apple's sprea...
With Apple Numbers, sophisticated spreadsheets are just the start. The whole sheet is your canvas. Just add dramatic interactive charts, tables, and images that paint a revealing picture of your data... Read more
Apple Keynote 7.0.5 - Apple's prese...
Easily create gorgeous presentations with the all-new Keynote, featuring powerful yet easy-to-use tools and dazzling effects that will make you a very hard act to follow. The Theme Chooser lets you... Read more
Apple iMovie 10.1.3 - Edit personal vide...
With an all-new design, Apple iMovie lets you enjoy your videos like never before. Browse your clips more easily, instantly share your favorite moments, and create beautiful HD movies and Hollywood-... Read more
Apple Motion 5.3 - Create and customize...
Apple Motion is designed for video editors, Motion 5 lets you customize Final Cut Pro titles, transitions, and effects. Or create your own dazzling animations in 2D or 3D space, with real-time... Read more
Apple Pages 6.0.5 - Apple's word pr...
Apple Pages is a powerful word processor that gives you everything you need to create documents that look beautiful. And read beautifully. It lets you work seamlessly between Mac and iOS devices, and... Read more
Paperless 2.3.7 - $49.95
Paperless is a digital documents manager. Remember when everyone talked about how we would soon be a paperless society? Now it seems like we use paper more than ever. Let's face it - we need and we... Read more
DEVONthink Pro 2.9.6 - Knowledge base, i...
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

Latest Forum Discussions

See All

The Lost Shield (Games)
The Lost Shield 1.0.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0.0 (iTunes) Description: The Lost shield is a brick break/adventure game. You play as a hero who must return a powerful but dangerous magic shield... | Read more »
The Forgotten Room (Games)
The Forgotten Room 1.0.1 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0.1 (iTunes) Description: Play as paranormal investigator John “Buster of Ghosts” Murr as he explores yet another mysteriously creepy house. This... | Read more »
5 Halloween mobile games for wimps
If you're anything like me, horror games are a great way to have nightly nightmares for the next decade or three. They're off limits, but perhaps you want to get in on the Halloween celebrations in some way. Fortunately not all Halloween themed... | Read more »
The 5 scariest mobile games
It's the most wonderful time of the year for people who enjoy scaring themselves silly with haunted houses, movies, video games, and what have you. Mobile might not be the first platform you'd turn to for quality scares, but rest assured there are... | Read more »
Lifeline: Flatline (Games)
Lifeline: Flatline 1.0.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.0 (iTunes) Description: The Lifeline series takes a terrifying turn in this interactive horror experience. Every decision you make could help... | Read more »
Game of Dice is now available on Faceboo...
After celebrating its anniversary in style with a brand new update, there’s even more excitement in store for Game of Dice has after just being launched on Facebook Gameroom. A relatively new platform, Facebook Gameroom has been designed for PC... | Read more »
4 addictive clicker games like Best Fien...
Clickers are passive games that take advantage of basic human psychology to suck you in, and they're totally unashamed of that. As long as you're aware that this game has been created to take hold of your brain and leave you perfectly content to... | Read more »
Smile Inc. Guide: How not to die on the...
As if Mondays weren't bad enough, at Smile Inc. you have to deal with giant killer donuts, massive hungry staplers, and blasting zones. It's not exactly a happy, thriving work environment. In fact, you'll be lucky to survive the nine to five.... | Read more »
Oh...Sir! The Insult Simulator (Games)
Oh...Sir! The Insult Simulator 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: | Read more »
WitchSpring2 (Games)
WitchSpring2 1.27 Device: iOS Universal Category: Games Price: $3.99, Version: 1.27 (iTunes) Description: This is the story of Luna, the Moonlight Witch as she sets out into the world. This is a sequel to Witch Spring. Witch Spring 2... | Read more »

Price Scanner via

Apple Unveils Redesigned MacBook Pro With Tou...
October 27, 2016 – Apple today introduced the thinnest and lightest MacBook Pro yet, along with a new interface innovation that replaces the traditional row of function keys with a Retina-quality... Read more
Apple Unveils New TV App for Apple TV, iPhone...
October 27, 2016 – Apple today introduced a new TV app, offering a unified experience for discovering and accessing TV shows and movies from multiple apps on Apple TV, iPhone and iPad. The TV app... Read more
Price drops on select refurbished 2015 13″ Re...
Apple dropped prices on select Certified Refurbished 2015 13″ Retina MacBook Pros by as much as $90. An Apple one-year warranty is included with each model, and shipping is free: - 13″ 2.7GHz/256GB... Read more
Apple reveals new next-generation 15″ and 13″...
Apple today revealed their next-generation 15″ and 13″ MacBook Pros. The new models are thinner and lighter than before with a new aluminum design featuring an enhanced keyboard with retina, multi-... Read more
Worldwide Smartphone Shipments Up 1.0% Year o...
According to preliminary results from the International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker, vendors shipped a total of 362.9 million smartphones worldwide in the third... Read more
TuneBand Arm Band For iPhone 7 and 7 Plus Rel...
Grantwood Technology has added the TuneBand for iPhone 7 and 7 Plus to its smartphone armband series. The TuneBand provides a lightweight and comfortable way to wear the iPhone while running,... 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
21-inch 1.6GHz iMac on sale for $999, save $1...
B&H has the 21″ 1.6GHz Apple iMac on sale for $999 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Read more
Macs’ Superior Enterprise Deployment Cost Eco...
IBM’s debunking of conventional wisdom and popular mythology about the relative cost of using Apple Mac computers as opposed to PCs running Microsoft Windows at the sixth annual Jamf Nation User... Read more
12-inch WiFi Apple iPad Pros on sale for $50-...
B&H Photo has 12″ WiFi Apple iPad Pros on sale for $50-$70 off MSRP, each including free shipping. B&H charges sales tax in NY only: - 12″ Space Gray 32GB WiFi iPad Pro: $749 $50 off MSRP -... 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
Software Engineering Intern: UI Applications...
Job Summary Apple is currently seeking enthusiastic interns who can work full-time for a minimum of 12-weeks between Fall 2015 and Summer 2016. Our software Read more
Security Data Analyst - *Apple* Information...
…data sources need to be collected to allow Information Security to better protect Apple employees and customers from a wide range of threats.Act as the subject Read more
*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 - Apple (United...
# Apple Solutions Consultant Job Number: 52812872 Houston, Texas, United States Posted: Oct. 18, 2016 Weekly Hours: 40.00 **Job Summary** As an Apple Solutions Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.