TweetFollow Us on Twitter

October 90 - Macintosh Q&A

Macintosh Q & A

MACINTOSH DEVELOPER TECHNICAL SUPPORT

QI am confused about the service routines and data areas passed in the _ADBOp call. What does it all mean?

A That 's a good question. The ADBOp call looks like this:

FUNCTION ADBOp (data:Ptr; compRout:ProcPtr; buffer:Ptr;
    commandNum:INTEGER) : oserr;

data is a pointer to the "optional data area." This area is provided for the use of the service routine (if needed).

compRout is a pointer to the completion or service routine to be called when the _ADBOp command has been completed. It has the same meaning as the service routine passed to the _SetADBInfo call.

buffer is a pointer to a Pascal string, which may contain 0 to 8 bytes of information. These are the 2 to 8 bytes that a particular register of an ADB device is capable of sending and receiving.

commandNum is an integer that describes the command to be sent over the bus.

There is some confusion over the way the completion routines are called from _ADBOp. You can call these routines in one of three ways, depending on what you want to do:If you do not wish to have a completion routine called, as in a Listen command, pass a NIL pointer to _ADBOp.

If you wish to call the routine already in use by the system for that address (as installed by _SetADBInfo), call _GetADBInfo before calling _ADBOp, and pass the routine pointer returned by _GetADBInfo to _ADBOp.

If you wish to provide your own completion routine and data area for the _ADBOp call, simply pass your own pointers to the _ADBOp call.

Remember, there should rarely be a reason to call _ADBOp. Most cases are handled by the system's polling and service request mechanism. In the cases where you must call _ADBOp, don't do it in a polling fashion, but as a mechanism for telling the device something (for example, telling the device to change modes or, in the case of the extended keyboard, to turn an LED on or off).

QThe AppleTalk spec claims a data rate of 230.4 kbaud, which should require a 3.6864 MHz input to the SCC, but RTxCB on the Macintosh carries a 3.672 MHz clock. How does the AppleTalk driver reconcile this discrepancy and what frequency should I use?

A The SCC contains a phase-locked loop that can lock on and synchronize with AppleTalk transmissions whose clock rates are not exactly to specifications, so everything is fine as long as both ends of the communication are using approximately the same clock frequency. If you are designing your own AppleTalk hardware from scratch, it's easiest to use a 3.6864 MHz oscillator and a Z8530. This has been tested and works just fine.

QWhen I fill in the fields of MPW's Name Binding Protocol (NBP) EntityName structure, AppleTalk doesn't recognize the entity, even though I know it's out there. What's going on?

A The real definition of EntityName is three PACKED strings of any length (32 is just an example). No offsets for Asm are specified since each string address must be calculated by adding the length byte to the last string ptr. In Pascal, string(32) will be 34 bytes long (fields never start on an odd byte unless they are only 1 byte long). So correct-looking interfaces for Pascal and C will be generated, but they won't be the same, which is OK since they aren't used.

The point here is that you should never try to access the fields of the EntityName field directly. The only reason the type is defined at all is so that you can allocate EntityName variables that will hold the largest possible EntityName. To fill in an EntityName record, you should call the NBPSetEntity routine.QHow do I determine which language is in use on the system?

A Every language has a corresponding KCHR resource. Inside Macintosh, volume I, page 499, lists the currently defined country codes, which are the resource IDs of the KCHR resources.

To find out which KCHR is in use, call the Script Manager function GetScript with the verb smScriptKeys. This call returns the ID of the KCHR resource in use (not the ID of the KEYC resource, as stated in Inside Macintosh, volume V, page 312).

Here's a bit of C code that determines which KCHR is being used:

#include <script.h>
...
kchrID = GetScript(smRoman, smScriptKeys);

kchrID will be 1 when booted in French, 2 when booted in British English, and so on.

QWhen I use DeleteRevision to remove old revisions from my Projector database, the actual size of the ProjectorDB file doesn't decrease much. How can I make the file smaller?

A Projector does not currently compact files. What it does is mark the areas of the database that are now free and put them into a free page list. This effectively puts holes into your database, holes that are subsequently filled up when you add more revisions.

Your database will get smaller only if the free pages are at the end of the file; then Projector will shrink the file. However, there is very little you can do about controlling this situation. If you absolutely must have a smaller database, then all you can do is check everything out, orphan the files, and create a new database. The disadvantage of this method is that you lose all your revisions and revision comments.

The Projector team is aware of the need to compact the database. The team is currently studying the feasibility of adding such a function.

QHow does MultiFinder decide the starting order when you set multiple applications to start up under MultiFinder with Set Startup? Is there any way to control the order?

A Here's the lowdown on MultiFinder application startup procedures.

From the Finder, launch, in order, application A, application B, and then application C. Switch to the Finder, choose Set Startup, and select Open Applications and DAs. The launch order is now application C, then application B, then application A. Regardless of the type of view from the Finder, the startup order is from top to bottom, respectively.

If you'rereally interested, the Finder Startup file in the System Folder contains the applications and files to be launched and the order in which they should be launched. This file contains a 'fndr' ID = 0 resource that stores the applications and their pathnames. The applications are launched in the order in which they are listed. You can use ResEdit to view the resource and see the filenames, the VRefNums, and the volume names of the startup applications. You can also tell the number of startup applications by the number at the beginning of the resource (that is, 0000 0001 means one item).

Remember, however, that this informmation is valid only for pre-System 7.0 MultiFinder environments.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

PDFKey Pro 4.3 - Edit and print password...
PDFKey Pro can unlock PDF documents protected for printing and copying when you've forgotten your password. It can now also protect your PDF files with a password to prevent unauthorized access and/... Read more
Kodi 15.0.beta1 - Powerful media center...
Kodi (was XBMC) is an award-winning free and open-source (GPL) software media player and entertainment hub that can be installed on Linux, OS X, Windows, iOS, and Android, featuring a 10-foot user... Read more
DiskCatalogMaker 6.4.12 - Catalog your d...
DiskCatalogMaker is a simple disk management tool which catalogs disks. Simple, light-weight, and fast. Finder-like intuitive look and feel. Super-fast search algorithm. Can compress catalog data... Read more
Macs Fan Control 1.3.0.0 - 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
Lyn 1.5.11 - Lightweight image browser a...
Lyn is a lightweight and fast image browser and viewer designed for photographers, graphic artists and Web designers. Featuring an extremely versatile and aesthetically pleasing interface, it... Read more
NeoOffice 2014.11 - Mac-tailored, OpenOf...
NeoOffice is a complete office suite for OS X. With NeoOffice, users can view, edit, and save OpenOffice documents, PDF files, and most Microsoft Word, Excel, and PowerPoint documents. NeoOffice 3.x... Read more
LaunchBar 6.4 - 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
Remotix 3.1.4 - Access all your computer...
Remotix is a fast and powerful application to easily access multiple Macs (and PCs) from your own Mac. Features Complete Apple Screen Sharing support - including Mac OS X login, clipboard... Read more
DesktopLyrics 2.6.6 - Displays current i...
DesktopLyrics is an application that displays the lyrics of the song currently playing in "iTunes" right on your desktop. The lyrics for the song have to be set in iTunes; DesktopLyrics does nothing... Read more
VOX 2.5.1 - Music player that supports m...
VOX is a beautiful music player that supports many filetypes. The beauty is in its simplicity, yet behind the minimal exterior lies a powerful music player with a ton of features and support for all... Read more

This Week at 148Apps: May 18-22, 2015
May Days at 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice, standing out above the... | Read more »
Biz Builder Delux (Games)
Biz Builder Delux 1.0.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.0 (iTunes) Description: Ah, there's nothing like the rhythmic bustle of a burgeoning business burg... especially when you're the one building it... | Read more »
Auroch Digital is Bringing Back Games Wo...
| Read more »
Blades of Brim is a New Endless Runner f...
SYBO Games, the minds behind the ever-popular Subway Surfers, have announced their latest project: Blades of Brim. [Read more] | Read more »
Carbo - Handwriting in the Digital Age...
Carbo - Handwriting in the Digital Age 1.0 Device: iOS Universal Category: Productivity Price: $3.99, Version: 1.0 (iTunes) Description: | Read more »
Draggy Dead (Games)
Draggy Dead 1.1 Device: iOS Universal Category: Games Price: $.99, Version: 1.1 (iTunes) Description: Ditch your dead end job and take up a rewarding career in Grave Robbing today!Guide the recently deceased to a fun filled life of... | Read more »
Bad Dinos (Games)
Bad Dinos 1.0.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.0 (iTunes) Description: | Read more »
The Apple Watch isn't Great as a Fi...
| Read more »
Show the World What You See With Stre.am...
Live broadcasting is getting popular on mobile devices, which is why you can now get Stre.am, by Infinite Takes. [Read more] | Read more »
PhotoTime's 2.1 Update Adds Apple W...
The latest PhotoTime update is adding even more functionality to the handy photo organizing app. Yep, including Apple Watch support. [Read more] | Read more »

Price Scanner via MacPrices.net

12-inch MacBook stock status for Monday, May...
The new 12″ Retina MacBooks are still on backorder at The Apple Store with a 3-5 week waiting period. However, a few models are in stock today at Apple resellers. Stock is limited, so act now if you’... Read more
New 27-inch 3.3GHz 5K iMac in stock with free...
Adorama has the new 27″ 3.3GHz 5K iMac in stock today for $1999 including free shipping plus NY & NJ sales tax only. Adorama will include a free copy of Apple’s 3-year AppleCare Protection Plan. Read more
Memorial Day Weekend Sale: New 27-inch 3.3GHz...
Best Buy has the new 27″ 3.3GHz 5K iMac on sale for $1899.99 this weekend. Choose free shipping or free local store pickup (if available). Sale price for online orders only, in-store prices may vary... Read more
OtterBox Maximizes Portability, Productivity...
From the kitchen recipe book to the boarsroom presentation, the OtterBox Agility Tablet System turns tablets into one of the most versatile pieces of handheld technology available. Available now, the... Read more
Launch of New Car App Gallery and Open Develo...
Automatic, a company on a mission to bring the power of the Internet into every car, has announced the launch of the Automatic App Gallery, an app store for nearly every car or truck on the road... Read more
Memorial Day Weekend Sale: 13-inch 1.6GHz Mac...
Best Buy has the new 13″ 1.6GHz/128GB MacBook Air on sale for $849 on their online store this weekend. Choose free shipping or free local store pickup (if available). Sale price for online orders... Read more
Memorial Day Weekend Sale: 27-inch 3.5GHz 5K...
Best Buy has the 27″ 3.5GHz 5K iMac on sale for $2099.99 this weekend. Choose free shipping or free local store pickup (if available). Sale price for online orders only, in-store prices may vary.... Read more
Sale! 16GB iPad mini 3 for $349, save $50
B&H Photo has the 16GB iPad mini 3 WiFi on sale for $349 including free shipping plus NY sales tax only. Their price is $50 off MSRP, and it’s the lowest price available for this model. Read more
Price drop on 2014 15-inch Retina MacBook Pro...
B&H Photo has dropped prices on 2014 15″ Retina MacBook Pros by $200. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $1799.99 save $200 - 15″ 2.5GHz... Read more
With a Mission to Make Mobile Free, Scratch W...
Scratch Wireless, claiming to be the world’s first truly free mobile service, has announced the availability of a new Scratch-enabled Android smartphone, the Coolpad Arise. The smartphone is equipped... Read more

Jobs Board

Payments Counsel, *Apple* Pay (mobile payme...
**Job Summary** Apple is looking for an atto ey to join Apple 's Legal Department to support Apple Pay. **Key Qualifications** 7+ years of relevant experience Read more
Touch Hardware Design and Integration Enginee...
…Summary** Design, develop, and launch next-generation Touch solutions in the new Apple Watch product category. The Touch team develops cutting-edge Touch solutions and Read more
*Apple* Solutions Consultant - Retail Sales...
**Job Summary** As an Apple Solutions Consultant (ASC) you are the link between our customers and our products. Your role is to drive the Apple business in a retail Read more
*Apple* TV Live Streaming Frameworks Test En...
**Job Summary** Work and contribute towards the engineering of Apple 's state-of-the-art products involving video, audio, and graphics in Interactive Media Group (IMG) at 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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.