TweetFollow Us on Twitter

Heap Zones
Volume Number:3
Issue Number:1
Column Tag:ABC's of C

Peeking at Heap Zones

By Bob Gordon, Contributing Editor

Memory is the stuff of which there never is enough. To reduce problems due to lack of memory, most languages provide means to grab some memory for use and later release it. Standard C has a number of functions to manage memory allocation and deallocation. We are not going to discuss these in any detail because the Macintosh has a complete memory management system. We have been using the memory management routines indirectly every time we opened a window, but as we go further into Mac programming we need to manipulate memory directly.

Figure 1: Examining the heap

Macintosh Memory Organization

Just about every book on programming the Macintosh has pictures of the Macintosh memory map. For the 64K ROMS, it looks roughly like:

I left off the physical addresses because they are typically not important, and because many of them can change as a function of memory size. For the 128K ROMS, the arrangement is slightly different. The ROM trap dispatch table has been expanded and is now in two sections, with the second section between the system heap and the second system globals area.

For this discussion, the most important areas are the Application Heap and the Stack. The stack is where all C parameters and local variables reside (actually, this depends on the compiler. Some compilers will pass some parameters in registers, and programmers may specify variables to be register variables, and if a register is available, the variable will be placed in a register). The stack grows and shrinks with the function calls and returns.

The application heap is the area where memory is explictly reserved and released. Unlike the stack, memory reserved in the heap does not disappear when a function returns. This allows the creation of large, complex data structures "on the fly."

C Memory Allocation

Since C is used on systems other than the Mac (really, there are other computers!), you might want to know about the standard C memory functions.

malloc() allocates some memory. It receives one parameter, the number of bytes to allocate, and returns a pointer to the region of memory.

free() deallocates memory previously allocated. It receives one parameter, a pointer previously returned by malloc().

The actual names and implementation will vary somewhat by compiler. Lightspeed C provides eight allocation functions and five deallocation functions in its standard library. Most of these are there to provide compatibility with Unix. The other Macintosh C compilers with which I am familiar also provide the standard C functions.

Unless you are using your Mac to develop software to run on another system, it is not a good idea to use the standard C memory functions. The primary reason for this is that on the Mac there are two kinds of allocated memory, relocatable and non-relocatable. None of the C compilers I have seen make any attempt to relate the standard C memory functions to the Mac memory functions (I assume the standard C functions return pointers to non-relocatable blocks of memory, but this is not made apparent).

Macintosh Memory Allocation

Again, since information about the Mac memory management system is readily available, I am not going to attempt to cover all the details here. There are, however, several key concepts which probably deserve some attention.

As mentioned above, memory comes in two kinds, relocatable and nonrelocatable. A relocatable block may be moved around in the heap by the operating system to make room for additional allocations. Since it may be moved, you do not receive a pointer to the block but a handle that points to a master pointer that points to the block.

Since the master pointer does not move (it is nonrelocatable), the value of the handle remains constant. When you request a nonrelocatable block, you receive a pointer directly to the block since the operating system will not move it. In general it seems that relocatable blocks are preferred since the operating system can move them out of the way when needed. If there are many nonrelocatable blocks, the operating system may not be able to satisfy a memory request because there may be no single space available big enough to meet the need. Without the ability to move blocks in the heap around (compact the heap), you will run out of memory sooner.

One problem with relocatable blocks is that it takes two pointers to access the data. One can always obtain a pointer to the block, but the system may move the block while you are using it. This situation, known as a dangling pointer, can cause quite exciting and hard to diagnose problems. If you need to use a particular block a lot in a function, you may lock the block which makes it temporarily nonrelocatable. Be sure to unlock it when you are done.

Another option for relocatable blocks is to purge them from memory. The operating system will do this if it needs more memory than is available, but only if you have marked a block as purgeable. New relocatable blocks start out as not purgeable. Note that if a block is purged, you will still have the handle, but the pointer it contains will be set to zero. To reuse the block, it is necessary to reallocate the block and rebuild the data. There is a function that reallocates purged blocks; the data is the programmer's responsibility.

Memory management errors are available through the function MemError(). A value of zero (NoErr) means there was no error; negative values represent error codes.

printw

There were a few changes to printw. We have added the ability to print rectangle and point coordinates. This is useful when using graphics. This time I added hex output. It is also now a seperate file. I have found it useful, but we probably won't print the whole thing again after this month, since this is the second time we've seen this routine.

The Program

Our program this month makes a number of trap calls that deal with memory management. From these calls, we can display information about the application heap and see how the creation of handles and pointers affects the available heap space. To keep things simple, we have created a very minimal Mac program that just puts up a blank window. The real heart of the program is the memory functions menu that lets us create handles and pointers and free them so we can see the effect on the heap. Fig. 1 shows how we print the memory information in our debugging print window using the printw() routine we learned about in a previous issue of MacTutor.

When you run the program, use the Zone Info menu item to see the state of the heap. I left the abc window in (under the File menu). Make a window and then run Zone Info. The Show Zone item traces through the zone and gives a line of information about each block, telling if it is free, relocatable or non-relocatable. By the way, the information needed to trace through the heap is not ordinarily available so there is a structure defined just before main() that defines the information needed to understand the heap. This structure, called memheads, is actually the definition of a block header. The other menu items create handles and pointers using NewHandle and NewPtr, and then if the handle or pointer is valid, another menu item lets us dispose of those handles and pointers, using DisposHandle and DisposPtr. The Zone Info menu item should show the effect of each of these operations on the available space in the heap.

There is another "feature" to this program. Every time you reserve a relocatable block, the size reserved doubles. With zone info, you can watch the memory manager increase the size of the heap and eventually run out of memory.

The key to the program is the GetZone trap call. This returns a pointer to the current heap zone. Once we have this pointer, our ShowZone and CountZone routines will read and print information about the zone for us. See the domem(item) routine in the listing to see where this trail starts with the memory menu item.

The term zone is how the heap is divided. Each zone in the heap is divided into blocks. A block is an even number of bytes, the minimum of which is 12. When your application starts up, call MaxApplZone to expand the application heap zone to its limit. Normally, an application would only be concerned with a single heap zone for itself, but you can create additional zones in the heap. One of our menu items does call MaxApplZone so you can see if it has any effect depending on when you call it. We can find out the free space left in a heap zone by calling FreeMem.

Once we get a pointer to the current heap zone, then we can examine the zone. A heap zone contains a 52 byte zone header, the allocated blocks within the zone, and a final minimum size block at the end of the zone called the zone trailer. The zone header is a pascal record defined below:

Zone = RECORD
 bkLim: Ptr;{zone trailer block}
 purgePtr:Ptr;   {used internally}
 hFstFree:Ptr;   (first free master pointer}
 zcbFree: LONGINT; {number of free bytes}
 gzProc:ProcPtr; {grow zone function}
 moreMast:Integer; {master pointers to allocate}
 flags: Integer; {used internally}
 cntRel:Integer; {not used}
 maxRel:Integer; {not used}
 cntNRel: Integer; {not used}
 maxNRel: Integer; {not used}
 cntEmpty:Integer; {not used}
 cntHandles:Integer; {not used}
 minCBFree: LONGINT; {not used}
 purgeProc: ProcPtr; {purge warning proc}
 sparePtr:Ptr;   {used internally}
 allocPtr:Ptr;   {used internally}
 heapData:Integer{first usable byte in zone}
END;

The zone pointer is defined to be of type THz, which is simply declared to be ^Zone. HeapData is the first two bytes in the block header of the first block in the zone. Hence to find the first usable block, we can say @(myZone^.heapData), which is a pointer to the first block header. Or in c, we would use &zone->heapData. The block header is 8 bytes: the tag byte, a three byte block size, and a four byte identifier that indicates whether the block is relocatable, non-relocatable or free. The four byte identifier is actually a handle, pointer or unused depending on the nature of the block. The tag byte also contains information on the nature of the block in bits 6 and 7. We can examine the nature of every block in the heap zone by adding the block size to the address of the first block and going from block to block checking the two high order bits of the tag byte. All of this is discussed in great detail in the IM chapter on the memory manager. This is implemented in our program in the showzone(zone) routine. Our memhead structure actually combines the tag byte and block size into a single four byte field called physsize. The second four bytes in the block header are stored in our memhead structure in the relhand field. We decode the physsize field to obtain the tag byte, and the block size, then we break down the tag byte to obtain the block status, and the size correction. All of this is done in the showhead(head) routine. Study carefully the three routines showhead, showzone and countzone to see how the block headers are decoded and the block size, status and address are then printed in our print window.

Final Comments

Using the techniques shown in this program, you can construct your own heapshow utility or TMON heap display. A good discussion of how TMON examines and displays the heap, is available in Dan Weston's new book, Macintosh Assembly Language Programming, Vol. II. There are some useful memory management functions not included this month such as MoreMasters() which reserves space for master pointers needed by NewHandle(). These should be easy to include in the program if you need to get an idea of how they work.

Next time we'll return to quickdraw and try to draw polygons, regions, and pictures.

Figure 4: ShowZone gives a heap dump


/* mem.c
 * explore memory allocation
 * LS C by Bob Gordon
 */

 #include "abc.h"
 #include "MemoryMgr.h"
 #include "Quickdraw.h"
 #include "EventMgr.h"
 #include "WindowMgr.h"
 #include "MenuMgr.h"
 #include "FontMgr.h"
 
 /* defines for menu ID's */
 
 #defineMdesk    100
 #defineMfile    101
 #defineMedit    102
 #defineMmem103
 
 /* File */
 #defineiNew1
 #defineiClose   2
 #defineiQuit    3
 
 /* Edit */
 #defineiUndo    1
 #defineiCut3
 #defineiCopy    4
 #defineiPaste   5
 
 /* Memory */
 #defineiZone    1
 #defineiMzone   2
 #defineiInfo    3
 #defineiHand    4
 #defineiPtr5
 #defineiFreeH   6
 #defineiFreeP   7
 
 /* Global variables */
 
 MenuHandle menuDesk;/* menu handles */
 MenuHandle menuFile;
 MenuHandle menuEdit;
 MenuHandle menuMem;
 
 WindowPtrtheWindow;
 WindowRecord  windowRec;
 Rect   dragbound;
 Rect   limitRect;
 
/*
 * structure needed to examine heap not typically
 * supplied by Mac development systems because normal
 * applications do not need to examine the heap. 
 */
 struct memheads
 {
 long   physsize;
 long   relhand;
 };
  
main()
{
 initsys(); /* sys init */
 initapp(); /* appl init */
 eventloop();
}

/* system initialization  */
initsys() 
{
 InitGraf(&thePort); 
 InitFonts();    
 InitWindows();
 InitCursor();
 InitMenus();
 theWindow = Nil;/* no window */
 SetRect(&dragbound,0,0,512,250);
 SetRect(&limitRect,60,40,508,244);
}

/*
 * application initialization
 * Sets up menus.*/
initapp()
{
 setupmenu();
}

/*
 * set up application's menus
 * Each menu is a separate group
 * of lines.  
 */
setupmenu()
{
 menuDesk = NewMenu(Mdesk,CtoPstr("\24"));
 AddResMenu (menuDesk, 'DRVR');
 InsertMenu (menuDesk, 0);
 
 menuFile = NewMenu(Mfile, CtoPstr("File"));
 AppendMenu (menuFile, 
 CtoPstr("New/N;Close;Quit/Q"));
 InsertMenu (menuFile, 0);
 
 menuEdit = NewMenu(Medit, CtoPstr("Edit"));
 AppendMenu (menuEdit, 
 CtoPstr("(Undo/Z;(-;(Cut/X;(Copy/C;(Paste/V;(Clear"));
 InsertMenu (menuEdit, 0);
 
 menuMem = NewMenu(Mmem, CtoPstr("Memory"));
 AppendMenu (menuMem,
 CtoPstr("Show Zone;Max Zone;Zone Info;New Handle;New Pointer"));
 AppendMenu (menuMem,CtoPstr("Free Handle;Free Pointer"));
 InsertMenu (menuMem, 0);
 
 DrawMenuBar();
}
 
/* Event Loop 
 * Loop forever until Quit
 */
eventloop()
{
 EventRecordtheEvent;
 char   c;
 short  windowcode;
 WindowPtrww;
 
 while(True)
 {
 if (theWindow)      /* this code is here to */
 { /* prevent closing an */
 EnableItem(menuFile,2);  /* already closed window */
 DisableItem(menuFile,1);
 }
 else   
 { 
 EnableItem(menuFile,1);
 DisableItem(menuFile,2);
 }
 if (GetNextEvent(everyEvent,&theEvent))
   
 switch(theEvent.what)    
 { /* only check mouse */
 case mouseDown:
 domousedown(&theEvent);
 break;
 default:
 break;
 }
 }
}

/* domousedown
 * handle mouse down events
 */
domousedown(er)
 EventRecord*er;
{
 short  windowcode;
 WindowPtrwhichWindow;
 short  ingo;
 long   size;
 long   newsize;
 RgnPtr rp;
 Rect   box;
 Rect   *boxp;
 
 windowcode = FindWindow(er->where, &whichWindow);
 switch (windowcode)
 {
 case inDesk:
 if (theWindow notequal 0)
 {
 HiliteWindow(theWindow, False);
 DrawGrowIcon(theWindow);
 }
 break;
 case inMenuBar:
 domenu(MenuSelect(er->where));
 break;
 }
}
 
/* domenu
 * handles menu activity
 * simply a dispatcher for each
 * menu.
 */
domenu(mc)
 long   mc; /* menu result */
{
 short  menuId;
 short  menuitem;
 
 menuId = HiWord(mc);
 menuitem = LoWord(mc);
 
 switch (menuId)
 {
 case Mdesk : break; /* not handling DA's */
 case Mfile : dofile(menuitem);
  break;
 case Mmem  : domem(menuitem);
     break;
 }
 HiliteMenu(0);
}

domem(item)
 short  item;
{
 THz    zone;
 static longsize = 1024;
 static Handle   hand = 0;
 static Ptr ptr = 0;
 struct memheads *memhead;
 
 switch (item)
 {
 case iZone :
 zone = GetZone();
 printw("\nzone %ld ",zone);
 showzone(zone);
 break;
 case iMzone :
 MaxApplZone();
 break;
 case iInfo :
 zone = GetZone();
 countzone(zone);
 break;
 case iHand :
 hand = NewHandle(size);
 printw("\nhandle %ld pointer %lx error %d ",hand,*hand,MemError());
 printw(" free mem %ld ",FreeMem());
 size = size * 2;
 break;
 case iPtr :
 ptr = NewPtr(size);
 printw("\npointer %ld error %d free mem %ld",ptr,MemError(),FreeMem());
 showhead(ptr-8);
 break;
 case iFreeH :
 if (hand equals 0)
 printw("\nNo current handle to free");
 else
 {
 DisposHandle(hand);
 hand = 0;
 }
 break;
 case iFreeP :
 if (ptr equals 0)
 printw("\nNo current pointer to free");
 else
 {
 DisposPtr(ptr);
 ptr = 0;
 }
 }
}

showhead(head)
 struct memheads *head;
{
 uchar  tagbyte;
 
 printw ("\naddress %ld ",(char*)head + 8);
 tagbyte = head->physsize >> 24;
 printw ("size correction %d ",tagbyte & 0xF);
 tagbyte >>= 6;
 switch (tagbyte)
 {
 case 0:
 printw(" free block ");
 break;
 case 1:
 printw(" non rel    ");
 break;
 case 2:
 printw(" rel        ");
 break;
 }
 printw(" physical size %ld ",head->physsize & 0x00FFFFFF);
 return (tagbyte);
}

showzone(zone)
 THz    zone;
{
 struct memheads *memhead;
 short  tblocks = 0;
 short  tfree = 0;
 short  trl = 0;
 short  tnonrel = 0;
 
 memhead = (struct memheads*)&zone->heapData;
 while (memhead < (struct memheads*)zone->bkLim)
 {
 switch (showhead(memhead))
 {
 case 0 : tfree++; break;
 case 1 : tnonrel++; break;
 case 2 : trel++; break;
 }
 tblocks++;
 memhead = (struct memheads*)((char*)memhead + (memhead->physsize & 0x00FFFFFF));
 }
 printw("\n blocks %d free %d relocatable %d non-relocatable %d ",
   tblocks, tfree, trel,tnonrel);
}
 
countzone(zone)
 THz    zone;
{
 struct memheads *memhead;
 short  tblocks = 0;
 short  tfree = 0;
 short  trel = 0;
 short  tnonrel = 0;
 uchar  tagbyte;
 
 memhead = (struct memheads*)&zone->heapData;
 while (memhead < (struct memheads*)zone->bkLim)
 {
 tagbyte = memhead->physsize >> 24;
 tagbyte >>= 6;
 switch (tagbyte)
 {
 case 0 : tfree++; break;
 case 1 : tnonrel++; break;
 case 2 : trel++; break;
 }
 tblocks++;
 memhead = (struct memheads*)((char*)memhead + (memhead->physsize & 0x00FFFFFF));
 }
 printw("\n blocks %d free %d relocatable %d non-relocatable %d ",
   tblocks, tfree, trel, tnonrel);
}
 
/* dofile
 * handles file menu
 */
dofile(item)
 short  item;
{
 char   *title1; /* first title for window */
 Rect   boundsRect;
 
 switch (item)
 {
 case iNew :/* open the window */
 title1 = "ABC Window";
 SetRect(&boundsRect,50,50,400,200);
 theWindow = NewWindow(&windowRec, &boundsRect,
 CtoPstr(title1),True,documentProc,
 (WindowPtr) -1, True, 0);
 DrawGrowIcon(theWindow);
 PtoCstr(title1);
 DisableItem(menuFile,1);
 EnableItem(menuFile,2);
 break;
 
 case iClose :   /* close the window */
 CloseWindow(theWindow);
 theWindow = Nil;
 DisableItem(menuFile,2);
 EnableItem(menuFile,1);
 break;
 
 case iQuit :    /* Quit */
 ExitToShell();
 break; 
 }
}
 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Audio Hijack 3.2.0 - Record and enhance...
Audio Hijack (was Audio Hijack Pro) drastically changes the way you use audio on your computer, giving you the freedom to listen to audio when you want and how you want. Record and enhance any audio... Read more
FontExplorer X Pro 5.0.1 - Font manageme...
FontExplorer X Pro is optimized for professional use; it's the solution that gives you the power you need to manage all your fonts. Now you can more easily manage, activate and organize your... Read more
Calcbot 1.0.2 - Intelligent calculator a...
Calcbot is an intelligent calculator and unit converter for the rest of us. Featuring an easy-to-read history tape, expression view, intuitive conversion, and much more! Features History Tape -... Read more
MTR 5.0.0.1 - The Mac's oldest and...
MTR (was MacTheRipper)--the Mac's oldest and smartest DVD-backup app--is now updated to version 5.001 MTR -- the complete toolbox, not a one-trick, point-and-click extractor. MTR is intended for... Read more
LibreOffice 4.4.5.2 - Free, open-source...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
Adobe Lightroom 6.1.1 - Import, develop,...
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
File Juicer 4.41 - Extract images, video...
File Juicer is a drag-and-drop can opener and data archaeologist. Its specialty is to find and extract images, video, audio, or text from files which are hard to open in other ways. It finds and... Read more
A Better Finder Rename 9.52 - File, phot...
A Better Finder Rename is the most complete renaming solution available on the market today. That's why, since 1996, tens of thousands of hobbyists, professionals and businesses depend on A Better... Read more
OmniFocus 2.2.3 - GTD task manager with...
OmniFocus helps you manage your tasks the way that you want, freeing you to focus your attention on the things that matter to you most. Capturing tasks and ideas is always a keyboard shortcut away in... Read more
TinkerTool 5.4 - Expanded preference set...
TinkerTool is an application that gives you access to additional preference settings Apple has built into Mac OS X. This allows to activate hidden features in the operating system and in some of the... Read more

Rescue humanity from a Demon horde in An...
Angel Stone is Fincon's follow up to the massively successful Hello Hero and is out now on iOS and Android. You play as a member of The Resistance, a group of mighty human warriors who have risen up in defiance of the Demon horde threatening to... | Read more »
Gallery Doctor (Photography)
Gallery Doctor 1.0 Device: iOS iPhone Category: Photography Price: $2.99, Version: 1.0 (iTunes) Description: Free up valuable iCloud and iPhone storage with Gallery Doctor, the only iPhone cleaner that automatically identifies the... | Read more »
You Against Me (Games)
You Against Me 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: A simple game… You. Me. Claim, steal, lock, score, win! | Read more »
Yep, it's True - Angry Birds 2 is O...
The not exactly rumors were true and the birds are back. Angry Birds 2 has come to the App Store and the world will... well I suppose it'll still be the same, but now we have more bird-flinging options! [Read more] | Read more »
You Could Design Your Own Card for Chain...
If you've ever wanted to create your own item, weapon, trap, or even monster for Chainsaw Warrior: Lords of the Night, this is your chance. Auroch Digital is currently holding a contest so that fans can fight to the death (not really) to see which... | Read more »
Bitcoin Billionaire is Going Back in Tim...
If you thought you managed to buy everything there is to buy in Bitcoin Billionaire and make all the money, well you though wrong. Those of you who made it far enough might remember investing in time travel - and it looks like that investment is... | Read more »
Domino Drop (Games)
Domino Drop 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Domino Drop is a delightful new puzzle game with dominos and gravity!Learn how to play it in a minute, master it day by day.Your... | Read more »
OPERATION DRACULA (Games)
OPERATION DRACULA 1.0.1 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0.1 (iTunes) Description: 25% off launch sale!!! 'Could prove to be one of the most accurate representations of the Japanese bullet hell shmup... | Read more »
Race The Sun (Games)
Race The Sun 1.01 Device: iOS iPhone Category: Games Price: $4.99, Version: 1.01 (iTunes) Description: You are a solar craft. The sun is your death timer. Hurtle towards the sunset at breakneck speed in a futile race against time.... | Read more »
Tap Delay (Music)
Tap Delay 1.0.0 Device: iOS Universal Category: Music Price: $4.99, Version: 1.0.0 (iTunes) Description: Back in the “old days”, producers and engineers created delay and echo effects using tape machines. Tap Delay combines the warm... | Read more »

Price Scanner via MacPrices.net

Worldwide Tablet Market Decline Continues, Ap...
The worldwide tablet market declined -7.0% year-over-year in the second quarter of 2015 (2Q15) with shipments totaling 44.7 million units according to preliminary data from the International Data... Read more
TP-LINK TL-PA8030P KIT Powerline Featuring Ho...
Consumer and business networking products provider TP-LINK is now shipping its TL-PA8030P KIT AV1200 3-Port Gigabit Passthrough Powerline Starter Kit that expands your home’s network over its... Read more
Apple refurbished iPad Air 2s available for u...
The Apple Store has Apple Certified Refurbished iPad Air 2s available for up to $140 off the price of new models. Apple’s one-year warranty is included with each model, and shipping is free: - 128GB... Read more
Updated Apple iPad Price Trackers
We’ve updated our iPad Air Price Tracker and our iPad mini Price Tracker with the latest information on prices and availability from Apple and other resellers. Read more
Apple refurbished 2014 13-inch 128GB MacBook...
The Apple Store has Apple Certified Refurbished 2014 13″ MacBook Airs available starting at $759. An Apple one-year warranty is included with each MacBook, and shipping is free: - 13″ 1.4GHz/128GB... Read more
Apple’s Education discount saves up to $300 o...
Purchase a new Mac or iPad at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free,... Read more
Save up to $600 with Apple refurbished Mac Pr...
The Apple Store has Apple Certified Refurbished Mac Pros available for up to $600 off the cost of new models. An Apple one-year warranty is included with each Mac Pro, and shipping is free. The... Read more
12-inch MacBooks in stock for $20 off, save o...
Adorama has 12″ Retina MacBooks in stock for $20 off MSRP including free shipping plus NY & NJ sales tax only. For a limited time, Adorama will include a free Apple USB-C to USB Adapter, free 4-... Read more
College Student Deals: Additional $100 off Ma...
Take an additional $100 off all MacBooks and iMacs at Best Buy Online with their College Students Deals Savings, valid through August 8, 2015. Anyone with a valid .EDU email address can take... Read more
2015 13-inch 2.7GHz Retina MacBook Pro on sal...
B&H Photo has the new 2015 13″ 2.7GHz/128GB Retina MacBook Pro on sale today for $1199 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
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 (US) - A...
Job Description: Sales. Specialist - Retail Customer Service and Sales. Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Engineering Manager, Search Relevance, *Appl...
**Job Summary** Apple 's new Spotlight Suggestions service provides fast, relevant search results from the Inte et in Spotlight and Safari on iOS and OS X. We are looking Read more
Lead Infrastructure Engineer - *Apple* /Mac P...
…of a team * Requires proven problem solving skills Preferred Additional: * Apple Certified System Administrator (ACSA) * Apple Certified Technical Coordinator (ACTC) Read more
*Apple* Retail - Multiple Positions (US) - A...
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.