TweetFollow Us on Twitter

Boot Disk Icon
Volume Number:5
Issue Number:5
Column Tag:Programmer's Forum

Related Info: Finder Interface Device Manager

Change the Boot Disk Icon

By David Dunham, Goleta, CA

I’ve been asked several times how my bootDiskIcon INIT works. I told the questioners that I’d answer in MacTutor.

Also, this is a short article. MacTutor needs more of them -- I know how to initialize Managers and handle events, and I certainly don’t need to see pictures in hexadecimal. (This isn’t just a snide remark directed at the editor, it’s a plea to those with nifty ideas that don’t need an entire application to show them off. Write a one or two page article!)

bootDiskIcon is a hack that came about because I don’t own an HD20. Apple insists on portraying their internal hard disk as an HD 20 on my desktop. I got so disgusted with this that I wrote an INIT to show something else, anything but an HD 20. ICN# 256, in fact. bootDiskIcon is inferior to programs like Façade-- it’s less flexible, and may not work with all hard disks -- but it was better than nothing, and it’s easy to understand.

The key to bootDiskIcon is the way the Finder handles disk icons. A pedantic digression: how does one find out how Finder handles icons? It’s not in Inside Macintosh. Therefore, it must be in a Technical Note. But Finder isn’t a category in the table of contents. So it’s off to the index but it’s not listed under “icon.” Luckily, it was one of the “Finder” Tech Notes, number 28. How did I know to keep looking? Because I’d seen it years ago when it came out, and knew it was there somewhere. Always skim every Tech Note -- not to memorize them, but to remember that they’re there.

When the Finder wants a disk icon, it gives the disk driver a Control call with csCode = 21. The driver returns a pointer to an ICN#. My first inclination was, why write code when you can change data? The ICN# must be part of the disk driver. The disk driver is part of Apple HD SC Setup. I found it there (it’s not a resource), changed it, and reinstalled the driver. This failed utterly -- there’s apparently a checksum.

If I couldn’t change the ICN# on disk, how about changing it in memory? I can get its address in memory by giving the driver a csCode = 21 call, then simply change the data. This is what bootDiskIcon does.

Before I get to what you’re all waiting for, the source code, I’ll mention the difference between patches and INITs. A patch is a change to a piece of code, almost always one of the traps. An INIT resource is any piece of code that runs at startup time (typically in a file of type INIT, cdev, or rdev). An INIT frequently installs a patch, but it could do anything at all, like playing a tune or subverting a disk driver’s icon.

More ideological baggage: INITs should announce their presence. Paul Mercer has a good way to do this, called ShowINIT. I’m told the source code’s available on AppleLink. I’ve modified it to handle color icons, and compiled the whole thing as a separate resource, SHOW 0. bootDiskIcon calls this code. You’re welcome to use it in any non-commercial (free or shareware) programs -- just use ResEdit to paste SHOW 0 into your own INIT file. You may not use it in public domain programs. These are those without a copyright holder, and I don’t want my code in the public domain. Don’t make the mistake of calling your free program “public domain.” Once you do, you can’t get it back (despite what Adobe thinks).

We can almost get to the code, but you might be wondering how to test it. It’s real inconvenient to reboot, just to see if a change worked. Luckily, you don’t have to. Remember that an INIT is just a piece of code that happens to get executed at boot time. You can often execute the same code at any time, and instruct your development system to make an INIT resource when you’re finished debugging. In bootDiskIcon’s case, I simply executed it, juggled into the Finder layer, and verified that I’d chant the code. It starts out by calling my SHOW resource -- the parameters are reversed from the way they’re defined because my ShowICON is defined as a Pascal procedure. My sloppiness in not defining it as such in this C program probably works only because this is an INIT -- if I trash the stack, it doesn’t much matter, since I’ll be returning to INIT 31 very soon.

The real work begins with finding out the driver refNum and drive of the first mounted disk (now you know why it’s called bootDiskIcon -- I told you it was a quick hack). I then find the address of the driver’s ICN#, get an ICN# of my own choice, and overwrite the driver’s using BlockMove.

#include <deviceMgr.h>
#include <hfs.h>

#define NIL 0L

void  main(void);/* Always use prototypes! */

void main() {
 Ptr    icn;
 int    error;   /* Shouldn’t really be write-only  */
 HParamBlockRec  pb;
 cntrlParam cpb;
 Handle handle;

 /* Show icon on the bottom of the screen */
 handle = GetResource(‘SHOW’,0); /* Get handle to the PROC */
 if (handle == 0L) { /* Something’s wrong (couldn’t load) */
 SysBeep(32);    /* Let somebody know */
 return;/* Don’t try to call it! */
 }
 HLock(handle);  /* Hold down the PROC */
 (**(ProcPtr *)handle)(-1,128);  
 /* ShowICON() -- note reversed parameters */
 HUnlock(handle);/* Let it float in the heap again */

 /* Change the icon */
 pb.volumeParam.ioNamePtr = NIL;
 pb.volumeParam.ioVolIndex = 1;  /* First mounted volume */
 error = PBHGetVInfo(&pb,FALSE);
 cpb.ioRefNum = pb.volumeParam.ioVDRefNum;
 cpb.ioVRefNum = pb.volumeParam.ioVDrvInfo;  
 /* drive (ioDrvNum) */
 cpb.csCode = 21;
 error = PBControl(&cpb,FALSE);
 icn = *(Ptr *)(&cpb.csParam[0]);
 handle = GetResource(‘ICN#’,256);
 BlockMove(*handle,icn,256L);
}

Known Bugs

Actually, these are rumored bugs, because it works for me! I’m told it doesn’t work with Jasmine disks where the driver puts the SCSI ID inside the flower. It probably doesn’t work with a boot floppy, because the Finder normally special cases the disk icon. (Furthermore, Finder probably doesn’t consider floppies to be “foreign drives.”)

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Coda 2.5.11 - One-window Web development...
Coda is a powerful Web editor that puts everything in one place. An editor. Terminal. CSS. Files. With Coda 2, we went beyond expectations. With loads of new, much-requested features, a few surprises... Read more
Bookends 12.5.7 - Reference management a...
Bookends is a full-featured bibliography/reference and information-management system for students and professionals. Access the power of Bookends directly from Mellel, Nisus Writer Pro, or MS Word (... Read more
Maya 2016 - 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
RapidWeaver 6.2.3 - Create template-base...
RapidWeaver is a next-generation Web design application to help you easily create professional-looking Web sites in minutes. No knowledge of complex code is required, RapidWeaver will take care of... Read more
MacFamilyTree 7.5.2 - Create and explore...
MacFamilyTree gives genealogy a facelift: it's modern, interactive, incredibly fast, and easy to use. We're convinced that generations of chroniclers would have loved to trade in their genealogy... Read more
Paragraphs 1.0.1 - Writing tool just for...
Paragraphs is an app just for writers. It was built for one thing and one thing only: writing. It gives you everything you need to create brilliant prose and does away with the rest. Everything in... Read more
BlueStacks App Player 0.9.21 - Run Andro...
BlueStacks App Player lets you run your Android apps fast and fullscreen on your Mac. Version 0.9.21: Note: Now requires OS X 10.8 or later running on a 64-bit Intel processor. Initial stable... Read more
Tweetbot 2.0.2 - Popular Twitter client....
Tweetbot is a full-featured OS X Twitter client with a lot of personality. Whether it's the meticulously-crafted interface, sounds and animation, or features like multiple timelines and column views... Read more
Apple iBooks Author 2.3 - Create and pub...
Apple iBooks Author helps you create and publish amazing Multi-Touch books for iPad. Now anyone can create stunning iBooks textbooks, cookbooks, history books, picture books, and more for iPad. All... Read more
NeoOffice 2014.12 - 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

Rage of Bahamut is Giving Almost All of...
The App Store isn't what it used to be back in 2012, so it's not unexpected to see some games changing their structures with the times. Now we can add Rage of Bahamut to that list with the recent announcement that the game is severely cutting back... | Read more »
Adventures of Pip (Games)
Adventures of Pip 1.0 Device: iOS iPhone Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: ** ONE WEEK ONLY — 66% OFF! *** “Adventures of Pip is a delightful little platformer full of charm, challenge and impeccable... | Read more »
Divide By Sheep - Tips, Tricks, and Stre...
Who would have thought splitting up sheep could be so involved? Anyone who’s played Divide by Sheep, that’s who! While we’re not about to give you complete solutions to everything (because that’s just cheating), we will happily give you some... | Read more »
NaturalMotion and Zynga Have Started Tea...
An official sequel to 2012's CSR Racing is officially on the way, with Zynga and NaturalMotion releasing a short teaser trailer to get everyone excited. Well, as excited as one can get from a trailer with no gameplay footage, anyway. [Read more] | Read more »
Grab a Friend and Pick up Overkill 3, Be...
Overkill 3 is a pretty enjoyable third-person shooter that was sort of begging for some online multiplayer. Fortunately the begging can stop, because its newest update has added an online co-op mode. [Read more] | Read more »
Scanner Pro's Newest Update Adds Au...
Scanner Pro is one of the most popular document scanning apps on iOS, thanks in no small part to its near-constant updates, I'm sure. Now we're up to update number six, and it adds some pretty handy new features. [Read more] | Read more »
Heroki (Games)
Heroki 1.0 Device: iOS Universal Category: Games Price: $7.99, Version: 1.0 (iTunes) Description: CLEAR THE SKIES FOR A NEW HERO!The peaceful sky village of Levantia is in danger! The dastardly Dr. N. Forchin and his accomplice,... | Read more »
Wars of the Roses (Games)
Wars of the Roses 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: | Read more »
TapMon Battle (Games)
TapMon Battle 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: It's time to battle!Tap! Tap! Tap! Try tap a egg to hatch a Tapmon!Do a battle with another tapmons using your hatched tapmons! *... | Read more »
Alchemic Dungeons (Games)
Alchemic Dungeons 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: ### Release Event! ### 2.99$->0.99$ for limited time! ### Roguelike Role Playing Game! ### Alchemic Dungeons is roguelike... | Read more »

Price Scanner via MacPrices.net

Canon PIXMA MG3620 Wireless Inkjet All-in-One...
Canon U.S.A., Inc. has announced the PIXMA MG3620 Wireless (1) Inkjet All-in-One (AIO) printer for high-quality photo and document printing. Built with convenience in mind for the everyday home user... Read more
July 4th Holiday Weekend 13-inch MacBook Pro...
Save up to $150 on the purchase of a new 2015 13″ Retina MacBook Pro at the following resellers this weekend. Shipping is free with each model: 2.7GHz/128GB MSRP $1299 2.7GHz/... Read more
27-inch 3.5GHz 5K iMac on sale for $2149, sav...
Best Buy has the 27″ 3.5GHz 5K iMac on sale for $2149.99. Choose free shipping or free local store pickup (if available). Sale price for online orders only, in-store prices may vary. Their price is $... Read more
Apple now offering refurbished 2015 11-inch...
The Apple Store is now offering Apple Certified Refurbished 2015 11″ MacBook Airs as well as 13″ MacBook Airs (the latest models), available for up to $180 off the cost of new models. An Apple one-... Read more
15-inch 2.5GHz Retina MacBook Pro on sale for...
Amazon.com has the 15″ 2.5GHz Retina MacBook Pro on sale for $2274 including free shipping. Their price is $225 off MSRP, and it’s the lowest price available for this model. Read more
Finally Safe To Upgrade To Yosemite’?
The reason I’ve held back from upgrading my MacBook Air from OS X 10.9 Mavericks to 10.10 Yosemite for nearly a year isn’t just procrastination. Among other bugs reported, there have been persistent... Read more
Logo Pop Free Vector Logo Design App For OS X...
128bit Technologies has released of Logo Pop Free 1.2 for Mac OS X, a vector based, full-fledged, logo design app available exclusively on the Mac App Store for the agreeable price of absolutely free... Read more
21-inch 1.4GHz iMac on sale for $999, save $1...
B&H Photo has new 21″ 1.4GHz iMac on sale for $999 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Best Buy has the 21″ 1.4GHz iMac on sale for $999.99 on their... Read more
16GB iPad mini 3 on sale for $339, save $60
B&H Photo has the 16GB iPad mini 3 WiFi on sale for $339 including free shipping plus NY tax only. Their price is $60 off MSRP. Read more
Save up to $40 on iPad Air 2, NY tax only, fr...
B&H Photo has iPad Air 2s on sale for up to $40 off MSRP including free shipping plus NY sales tax only: - 16GB iPad Air 2 WiFi: $489 $10 off - 64GB iPad Air 2 WiFi: $559 $40 off - 128GB iPad Air... Read more

Jobs Board

*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* Fulfillment Operations Execution Ana...
**Job Summary** The AMR Apple Fulfillment Operations Team is seeking a talented team player to drive the Apple Online Store (AOS) fulfillment performance to ensure a Read more
Localization Producer - *Apple* HR and Reta...
…project manager to support the Retail Globalization team. You will participate in Apple exponential inte ational growth and drive global project initiatives for the Read more
*Apple* Online Store UAT Lead - Apple (Unite...
**Job Summary** The Apple Online Store is a fast paced and ever evolving business environment. A UAT lead in this organization is able to have a direct impact on one of Read more
Senior Payments Security Manager - *Apple*...
**Job Summary** Apple , Inc. is looking for a highly motivated, innovative and hands-on senior payments security manager to join the Apple Pay security team. You will Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.