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

RapidWeaver 6.0.8 - 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
Artlantis Studio 5.1.2.7 - 3D rendering...
Artlantis Studio is a unique and ideal tool for performing very high resolution rendering easily and in real time. The new FastRadiosity engine now lets you compute images in radiosity-even in... Read more
MacUpdate Desktop 6.0.5 - Search and ins...
MacUpdate Desktop 6 brings seamless 1-click installs and version updates to your Mac. With a free MacUpdate account and MacUpdate Desktop 6, Mac users can now install almost any Mac app on macupdate.... Read more
BitTorrent Sync 2.0.82 - Sync files secu...
BitTorrent Sync allows you to sync unlimited files between your own devices, or share a folder with friends and family to automatically sync anything. File transfers are encrypted. Your information... Read more
Google Drive 1.20 - File backup and shar...
Google Drive is a place where you can create, share, collaborate, and keep all of your stuff. Whether you're working with a friend on a joint research project, planning a wedding with your fiancé, or... Read more
Simon 4.0.3 - Monitor changes and crashe...
Simon monitors websites and alerts you of crashes and changes. Select pages to monitor, choose your alert options, and customize your settings. Simon does the rest. Keep a watchful eye on your... Read more
Vitamin-R 2.23 - Personal productivity t...
Vitamin-R creates the optimal conditions for your brain to work at its best by structuring your work into short bursts of distraction-free, highly focused activity alternating with opportunities for... Read more
iDefrag 5.0.0 - Disk defragmentation and...
iDefrag helps defragment and optimize your disk for improved performance. Features include: Supports HFS and HFS+ (Mac OS Extended). Supports case sensitive and journaled filesystems. Supports... Read more
PCalc 4.2 - Full-featured scientific cal...
PCalc is a full-featured, scriptable scientific calculator with support for hexadecimal, octal, and binary calculations, as well as an RPN mode, programmable functions, and an extensive set of unit... Read more
FileZilla 3.10.2 - Fast and reliable FTP...
FileZilla (ported from Windows) is a fast and reliable FTP client and server with lots of useful features and an intuitive interface. Version 3.10.2: Note: Now requires a 64-bit Intel processor.... Read more

Warner Bros. Interactive Entertainment A...
Warner Bros. has some exciting games coming down the pipe! | Read more »
GDC 2015 – Star Trek Timelines will Prob...
GDC 2015 – Star Trek Timelines will Probably Make Your Inner Trekkie Squeal With Glee Posted by Rob Rich on March 4th, 2015 [ permalink ] Any popular fictional universe has its fair share of fan fiction – where belo | Read more »
Protect Yourself from an Onslaught of Ca...
Surprise Attack Games has announced a Cat-astrophic new physics puzzler called Fort Meow! In the game, a young girl named Nia finds her grandfather’s journal which triggers an all mighty feline attack! Why do the cats want the journal? Who knows,... | Read more »
GDC 2015 – Jelly Reef will be Game Oven’...
GDC 2015 – Jelly Reef will be Game Oven’s Last Hurrah, and it Seems like a Good Note to Go Out on Posted by Rob Rich on March 4th, 2015 [ permalink ] It’s sad knowing that Game Oven ( | Read more »
daWindci Deluxe Review
daWindci Deluxe Review By Campbell Bird on March 4th, 2015 Our Rating: :: BLUSTERY PUZZLESUniversal App - Designed for iPhone and iPad This updated puzzle game offers some creative gameplay and new mechanics, but still suffers from... | Read more »
Dungeon Hunter 5 Coming on March 12
Gameloft has excitedly announced that Dungeon Hunter 5 is on its way! Once again, you will adventure across the land of Valenthia exploring dungeons and fighting monsters. The game will have a new asynchronous multiplayer mode called Strongholds... | Read more »
GDC 2015 – The Sandbox 2 is Coming, and...
GDC 2015 – The Sandbox 2 is Coming, and Now it has Textures! | Read more »
Warner Bros. Interactive Announces Mort...
Mortal Kombat X, by Warner Bros. and NetherRealm Studios, will be a a free-to-play fighting/card-battle Mortal Kombat game. The game promises card collecting, multiplayer team combat, classic characters such as Scorpion, Sub-Zero and Raiden, and the... | Read more »
GDC 2015 – Piloteer is Whitaker Trebella...
GDC 2015 – Piloteer is Whitaker Trebella’s Latest Project, and it’s Definitely Something DIfferent Posted by Rob Rich on March 3rd, 2015 [ permalink ] You know | Read more »
PangoLand Review
PangoLand Review By Amy Solomon on March 3rd, 2015 Our Rating: :: COME VISIT PANGO AND FRIENDSUniversal App - Designed for iPhone and iPad PangoLand is an open-ended world full of familiar characters, bright colors and interactive... | Read more »

Price Scanner via MacPrices.net

iPad: A More Positive Outlook – The ‘Book Mys...
It’s good to hear someone saying positive things about the iPad. I’ve been trying to bend my mind around how Apple’s tablet could have gone from zero to bestselling personal computing device on the... Read more
Mac Pros on sale for up to $279 off MSRP
Amazon has Mac Pros in stock and on sale for up to $279 off MSRP. Shipping is free: - 4-Core Mac Pro: $2725.87, $273 off MSRP (9%) - 6-Core Mac Pro: $3719.99, $279 off MSRP (7%) Read more
Sale! 13-inch Retina MacBook Pros for up to $...
B&H Photo has 13″ Retina MacBook Pros on sale for up to $205 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.6GHz/128GB Retina MacBook Pro: $1219.99 save $80 - 13″ 2.... Read more
Another Tranche Of IBM MobileFirst For iOS Ap...
IBM has announced the next expansion phase for  its IBM MobileFirst for iOS portfolio, with a troika of new apps to address key priorities for the Banking and Financial Services, Airline and Retail... Read more
Sale! 15-inch Retina MacBook Pros for up to $...
B&H Photo has the new 2014 15″ Retina MacBook Pros on sale for up to $250 off MSRP for a limited time. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $... Read more
WaterField Designs Introduces the Minimalist...
With Apple Pay gaining popularity, Android Pay coming in May 2015, and loyalty cards and receipts that can be accessed from smartphones, San Francisco’s WaterField Designs observes that it may be... Read more
Sale! 15-inch 2.2GHz Retina MacBook Pro for $...
 Best Buy has the 15″ 2.2GHz Retina MacBook Pro on sale for $1774.99 $1799.99, or $225 off MSRP. Choose free home shipping or free local store pickup (if available). Price valid for online orders... Read more
13-inch 2.5GHz MacBook Pro (refurbished) avai...
The Apple Store has Apple Certified Refurbished 13″ 2.5GHz MacBook Pros available for $170 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.5GHz... Read more
13-inch 2.5GHz MacBook Pro on sale for $100 o...
B&H Photo has the 13″ 2.5GHz MacBook Pro on sale for $999.99 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Read more
27-inch 3.5GHz 5K iMac in stock today and on...
 B&H Photo has the 27″ 3.5GHz 5K iMac in stock today and on sale for $2299 including free shipping plus NY sales tax only. Their price is $200 off MSRP, and it’s the lowest price available for... Read more

Jobs Board

*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
*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
Position Opening at *Apple* - Apple (United...
…Summary** As a Specialist, you help create the energy and excitement around Apple products, providing the right solutions and getting products into customers' hands. You Read more
Position Opening at *Apple* - Apple (United...
**Job Summary** The Apple Store is a retail environment like no other - uniquely focused on delivering amazing customer experiences. As an Expert, you introduce people 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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.