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

Bartender 3.0.32 - Organize your menu-ba...
Bartender lets you organize your menu-bar apps by hiding them, rearranging them, or moving them to Bartender's Bar. You can display the full menu bar, set options to have menu-bar items show in the... Read more
Adobe Animate CC 2018 18.0.1.115 - Anima...
Animate CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Flash Professional customer). Animate CC 2018 (was Flash CC) lets you... Read more
Adobe Lightroom Classic CC 7.1 - Import,...
Adobe Lightroom is available as part of Adobe Creative Cloud for as little as $9.99/month bundled with Photoshop CC as part of the photography package. Lightroom 6 is also available for purchase as a... Read more
ExpanDrive 6.1.8 - Access cloud storage...
ExpanDrive builds cloud storage in every application, acts just like a USB drive plugged into your Mac. With ExpanDrive, you can securely access any remote file server directly from the Finder or... Read more
ExpanDrive 6.1.8 - Access cloud storage...
ExpanDrive builds cloud storage in every application, acts just like a USB drive plugged into your Mac. With ExpanDrive, you can securely access any remote file server directly from the Finder or... Read more
DiskCatalogMaker 7.2.7 - Catalog your di...
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 for... Read more
DiskCatalogMaker 7.2.7 - Catalog your di...
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 for... Read more
Iridient Developer 3.2.1 - Powerful imag...
Iridient Developer (was RAW Developer) is a powerful image-conversion application designed specifically for OS X. Iridient Developer gives advanced photographers total control over every aspect of... Read more
BusyContacts 1.2.7 - Fast, efficient con...
BusyContacts is a contact manager for OS X that makes creating, finding, and managing contacts faster and more efficient. It brings to contact management the same power, flexibility, and sharing... Read more
MegaSeg 6.0.5 - Professional DJ and radi...
MegaSeg is a complete solution for pro audio/video DJ mixing, radio automation, and music scheduling with rock-solid performance and an easy-to-use design. Mix with visual waveforms and Magic... Read more

Latest Forum Discussions

See All

The best deals on the App Store this wee...
A new week means new discounts on the App Store. This week's deals run the gamut of action-adventure titles, puzzle games, and one of the best narrative adventure series out there. If you're looking to fill out your mobile gaming library on a... | Read more »
What you need to know about Animal Cross...
We hope you've been hard at work on collecting all of those holiday items in Animal Crossing: Pocket Camp, because you're about to get a whole new list of fun things to do as the game receives its first big update sometime soon. There are a lot of... | Read more »
Reigns: Her Majesty guide - how to use e...
Ruling a kingdom isn't easy--doubly so for a queen whose every decision is questioned by the other factions seeking a slice of power. Reigns: Her Majesty builds on the original game's swipey tactics, adding items that you can use to move the story... | Read more »
The best new games we played this week -...
Friday has crept up on us once again, so it's time to honor the best new games we've played over the past few days. This past week was a pretty exciting one, with the debut of lots of beautiful new indies and some familiar faces returning to the... | Read more »
Portal Knights guide- beginner tips and...
Portal Knights is finally making the jump to iOS and Android, and it's already climbing the ranks to become the next big MMO experience on mobile. This sprawling sandbox game will let you pursue any adventure you wish, whether you want to sling... | Read more »
Reigns: Her Majesty guide - how to swipe...
Reigns: Her Majesty is storming the App Store this week, bringing more tinder-esque kingdom building to eager players everywhere. If you've played the original Reigns, you'll know that leading a kingdom is never easy. It's a careful balancing act... | Read more »
Getting Over It (Games)
Getting Over It 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: A game I madeFor a certain kind of person To hurt them. • Climb up an enormous mountain with nothing but a hammer and a pot.•... | Read more »
Reigns: Her Majesty (Games)
Reigns: Her Majesty 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: | Read more »
Pocket Legends Adventures guide - how to...
Pocket Legends Adventures is a fun action adventure RPG that takes control when you want it to, but also opens itself for player input, too, if you're looking to tkae a more active role in combat. Regardless of play style, the game can be quite... | Read more »
Portal Knights (Games)
Portal Knights 1.2.4 Device: iOS Universal Category: Games Price: $4.99, Version: 1.2.4 (iTunes) Description: Craft your adventure. Forge your hero. Become the ultimate Portal Knight! | Read more »

Price Scanner via MacPrices.net

Green Monday deal: 15″ 2.8GHz MacBook Pro on...
B&H Photo has the 15″ 2.8GHz Space Gray MacBook Pro on sale for $250 off MSRP for today only as part of their Green Monday/Holiday sale. Shipping is free, and B&H charges sales tax for NY... Read more
Green Monday sale: B&H offers 12″ Apple i...
B&H Photo has 12″ iPad Pros on sale for up to $150 off MSRP as part of their Green Monday/Holiday sale. Shipping is free, and B&H charges sales tax in NY & NJ only: – 12″ 64GB WiFi iPad... Read more
Holiday deal: 21″ and 27″ Apple iMacs on sale...
MacMall has 2017 21″ and 27″ Apple iMacs on sale for up to $200 off MSRP. Shipping is free: – 21″ 2.3GHz iMac: $999 $100 off MSRP – 21″ 3.0GHz iMac: $1199 $100 off MSRP – 21″ 3.4GHz iMac: $1379 $120... Read more
Holiday deal: Apple Mac minis for up to $150...
MacMall has Mac minis on sale for up to $100 off MSRP, each including free shipping: – 1.4GHz Mac mini: $399 $100 off MSRP – 2.6GHz Mac mini: $599 $100 off MSRP – 2.8GHz Mac mini: $949 $50 off MSRP... Read more
Beats by Dr. Dre – BeatsX Earphones on sale f...
Best Buy has BeatsX Earphones on sale for $109, $40 off, on their online store. Sale price for online orders only. Choose free store pickup, if available, or choose free shipping. Read more
10″ 64GB WiFi Apple iPad Pros on sale for $59...
MacMall has 10.5″ 64GB Apple iPad Pros on sale for $599 including free shipping. That’s $50 off MSRP and among the lowest prices available for these iPads from any Apple reseller. Read more
15″ 2.2GHz MacBook Pros on sale for $200-$300...
B&H Photo has the 15″ 2.2GHz MacBook Pro available for $200 off MSRP including free shipping plus NY & NJ sales tax only: – 15″ 2.2GHz MacBook Pro (MJLQ2LL/A): $1799 $200 off MSRP Apple has... Read more
Holiday sale: 15″ MacBook Pros for $200-$420...
MacMall has 15″ MacBook Pros on sale for $220-$300 off MSRP, each including free shipping: – 15″ 2.8GHz MacBook Pro Space Gray (MPTR2LL/A): $2179, $220 off MSRP – 15″ 2.8GHz MacBook Pro Silver (... Read more
Holiday sale: 13″ MacBook Airs for up to $150...
B&H Photo has 13″ MacBook Airs on sale for $100 off MSRP as part of their Holiday sale. Shipping is free, and B&H charges sales tax for NY & NJ residents only: – 13″ 1.8GHz/128GB MacBook... Read more
The best Holiday sale prices on 13″ MacBook P...
B&H Photo has 13″ MacBook Pros on sale this weekend, with models available for $100-$150 off MSRP. Shipping is free, and B&H charges sales tax for NY & NJ residents only: – 13-inch 2.3GHz... Read more

Jobs Board

*Apple* Retail - Multiple Positions - Apple,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, 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* Retail - Multiple Positions - Apple,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Information Security - Security Data...
# Apple Information Security - Security Data Analyst Job Number: 113119545 Austin, Texas, United States Posted: 10-Nov-2017 Weekly Hours: 40.00 **Job Summary** This 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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.