TweetFollow Us on Twitter

High Res Timer
Volume Number:8
Issue Number:1
Column Tag:c workshop

Related Info: Time Manager

A High-Resolution Timer

A simple package for measuring small intervals of time for performance analysis

By Martin Minow, Arlington, Massachusetts

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

Introduction

Volume 6 of Inside Macintosh - which is to say late System 6.0 and System 7 - describes the extended TimeManager and a drift-free timer function that lets an application measure durations with a finer resolution than the 1/60 second system tick count.

In order to simplify measuring small intervals for performance analysis, I wrote a simple package that allows recording the “time of day” at its highest resolution. Using this as a base, you can record the start and end of an event of interest (such as a subroutine call) and, by using one of the subroutines in the package, determine the elapsed time.

For my particular purposes, elapsed times are recorded in integers with microsecond resolution, giving a maximum interval of just over 35 minutes, since 231 is greater than (35 * 60 * 1000000). If you need to record longer intervals, you need only redo the DeltaTime subroutine (as shown in the demo application) so it returns a floating-point (double-precision) value.

The demo program shows some of the calls and lets you get an idea of the amount of time needed to setup and call the timer service. On my Macintosh IIci with the THINK C debugger enabled, the average time is about 160µsec, which is not shabby at all. Of course, you should not assume that microsecond resolution means microsecond accuracy.

InitializeMicrosecondTimer will return an error if the drift-free timer is not supported on your system. Because of the way it calls Gestalt, you must compile it on a modern system (THINK C 5.0) as the “glue” that calls Gestalt now includes code to check for the Gestalt trap presence.

In order to ensure that the timer routine’s periodic task is removed when your application exits, InitializeMicrosecondTimer patches the ExitToShell trap for the removal function. Because of the way THINK C installs its own ExitToShell trap, be sure to call InitializeMicrosecondTimer before calling any THINK C routines from the standard I/O or THINK Class libraries.

Acknowledgments

This is a revision of a program I first wrote for the IBM 7090 in 1964. OK, maybe it was 1965. Some of the Macintosh specific code can be traced to a timing routine in the MacDTS “FracApp” demonstration program by Keith Rollin and Bo3b Johnson, while the exit handler is based on code in the atexit function in the THINK C library.

Listing:  MicrosecondTimer.h

/* MicrosecondTimer.h*/
/*
 * Time measurement.
 * Copyright © 1991 Martin Minow.  All Rights Reserved
 *
/*
 * Definitions for the Millisecond timer
 */
#ifndef _H_MsecTimer
#define _H_MsecTimer

#define MSEC_PER_TICK1

typedef struct MicrosecondEpoch {
 unsigned long time; /* Time of day*/
 signed longmicrosecond;  /* Residual*/
} MicrosecondEpoch, *MicrosecondEpochPtr;

/*
 * Initialize the clock - call once when your
 * application starts.
 */
OSErr   InitializeMicrosecondTimer(void);
/*
 * Cancel the clock - this is called automatically
 * when your application exits.
 */
void    CancelMicrosecondTimer(void);
/*
 * Return the current extended time value.
 */
void    GetEpoch(MicrosecondEpochPtr result);
/*
 * Compute the difference between two epoch’s. The
 * result is in deltaTime (in microseconds).
 * deltaTime is positive if epoch2 is later than epoch1.
 *
 * Returns TRUE if the time can be represented in
 * microseconds (less than 35 minutes difference). 
 * If it returns FALSE, deltaTime is likely to be garbage.
 */
Boolean DeltaTime(
 MicrosecondEpochPtr epoch1,
 MicrosecondEpochPtr epoch2,
 signed long*deltaTime
 );
/*
 * Compute the difference between two epoch’s. The
 * result is returned as a floating-point number
 * of seconds.
 */
double  DoubleDelta(
 MicrosecondEpoch*start,
 MicrosecondEpoch*finish
 );

/*
 * Format an epoch value as “hh:mm:ss.fraction”
 */
void EpochToString(
 MicrosecondEpochPtr epochPtr,
 StringPtrresult
 );
/*
 * Use an extended time value to adjust the
 * local clock.  Unfortunately, we can only adjust
 * the clock by an integral number of seconds.
 */
void AdjustClock(
 signed longadjustment
 );
#endif
Listing:  MicrosecondTimer.c

/* MicrosecondTimer.c*/
/*
 * Time measurement.
 * Copyright © 1991 Martin Minow.  All Rights Reserved
 *
 * This function creates a high-resolution “time of day”
 * timer that is (or, at least, ought to be) synchronized
 * with the system time of day value.  It uses the
 * new time manager calls.
 *
 * In order to keep our timer in reasonable synchronization
 * with the system time of day, we shadow that value at
 * each time-of-day trap.
 * 
 * Usage:
 * InitializeMicrosecondTimer(void);
 * Call this - once - when your program starts. It
 * installs the timer interrupt routine. It returns
 * noErr if successful, or unimpErr if the Extended
 * Time Manager is not supported on this system.
 *
 * Important: if you are using the THINK C ANSI,
 * console, or class libraries, be sure to call
 * InitializeMicrosecondTimer before calling any
 * THINK C routines.  Otherwise, your program
 * may crash on exit under certain ill-defined
 * circumstances.
 *
 * CancelMicrosecondTimer(void)
 * This must be called before your application exits.
 * InitializeMSecTimer() establishes an exit handeler
 * to force its call, so you needn’t worry about it.
 *
 * GetEpoch(
 * MicrosecondEpoch *result
 * )
 * Call this to get the time of day. The result
 * consists of a time (seconds) value that is
 * intended to track GetTimeOfDay exactly, extended
 * by the number of microseconds past this second.
 *
 * DeltaTime(
 * MicrosecondEpoch*startTime,
 * MicrosecondEpoch*endTime
 * signed long   *difference
 * )
 * Compute the difference between two extended
 * time values, returning the result in the third
 * parameter (as a signed number of microseconds).
 * The result will be positive if time2 is later
 * than time1. DeltaTime returns TRUE if the
 * absolute value of the difference (in seconds)
 * is less than 35 minutes (a signed longword can
 * resolve a 34 minute interval). (You might want
 * to redo this to return a double-precision format
 * value, rather than a longword.)
 *
 * DoubleDelta(
 * MicrosecondEpoch*start,
 * MicrosecondEpoch*finish
 * )
 * Compute the difference between two extended
 * time values, returning the result as a double-
 * precision number of seconds.
 * 
 * EpochToString(
 * MicrosecondEpoch*epoch
 * Str255 result
 * )
 * Convert an extended time value to a fixed-width,
 * fixed-format Pascal string “hh:mm:ss.fraction”.
 *
 * Although the code has not been tested under MPW, it
 * ought to port easily: just re-do the asm stuff.
 *
 * Acknowledgements:
 * Parts of the time manager calls are based on a
 * timing module in the MacDTS FracApp demo program
 * by Keith Rollin an Bo3b Johnson.
 *
 * The exit handler is based on similar code in the
 * atexit() function in the THINK C support library.
 */

#include <GestaltEqu.h>
#ifndef THINK_C
#include <SysEqu.h>
#endif
#include <Timer.h>
#include <Traps.h>
#include “MicrosecondTimer.h”

/*
 * This is needed to establish an exit trap handler.
 */
typedef void(*MyProcPtr)(void);
typedef struct {
 short  jmp;
 MyProcPtrfunction;
} JumpVector;

static void *oldExitVector;
static JumpVector*jumpVector;
static void TimerExitHandler(void);

#define MILLION  (1000000L)

/*
 * This is a time manager record, extended to include a
 * shadow copy of the system time of day value that is
 * updated once a second.
 */
typedef struct TimeInfoRecord {
 TMTask TMTask;  /* The task record*/
 unsigned long epoch;/* Time of day info     */
} TimeInfoRecord, *TimeInfoPtr;

static TimeInfoRecordgTimeInfo;
#define TIME(gTimeInfo.TMTask)
static long gOverheadTime;
static pascal void TimeCounter(void);

static void Concat(StringPtr dst, StringPtr src);

/*
 * Install a timer interrupt procedure.
 */
OSErr
InitializeMicrosecondTimer()
{
 long   timeOfDay;
 long   gestaltResult;
 OSErr  status;
 
 if (TIME.tmAddr != NULL)
 status = noErr; /* Already installed*/
 else {
 status = Gestalt(
 gestaltTimeMgrVersion,
 &gestaltResult
 );
 if (status == noErr
  && gestaltResult < gestaltExtendedTimeMgr)
 status = unimpErr;
 if (status == noErr) {
 /*
  * Install a trap handler for ExitToShell
  */
 oldExitVector =
 (void *) GetTrapAddress(_ExitToShell);
 if (ROM85 >= 0) {
 SetTrapAddress(
 (long) TimerExitHandler,
 _ExitToShell
 );
 }
 else {
 /*
  * Install a trap handler
  * in the system heap.
  */
 jumpVector = (JumpVector *)
 NewPtrSys(sizeof (JumpVector));
 if (jumpVector == NULL) {
 status = memFullErr;
 goto exit;
 }
 else {
 jumpVector->jmp = 0x4EF9;
 jumpVector->function =
 TimerExitHandler;
 SetTrapAddress(
 (long) jumpVector,
 _ExitToShell
 );
 }

 }
 /*
  * Install the time manager task and
  * start it rolling.
  */
 TIME.tmAddr = (ProcPtr) TimeCounter;
 InsXTime(&TIME);
 /*
  * Align our timer to the system’s
  */
 timeOfDay = Time;
 do {
 gTimeInfo.epoch = Time;
 } while (timeOfDay == gTimeInfo.epoch);
 /*
  * We should really do this a bunch
  * of times and take the minimum.
  * gOverheadTime measures the amount
  * of time the PrimeTime/RmvTime sequence
  * requires, See the discussion in IM-VI.
  */
 PrimeTime(&TIME, -MILLION);
 RmvTime(&TIME);
 gOverheadTime = MILLION + TIME.tmCount;
 /*
  * Restart the timer
  */
 InsXTime(&TIME);
 PrimeTime(&TIME, 0);
 }
 }
exit: return (status);
}

/*
 * GetEpoch returns the current extended time of day.
 * It requires the drift-free time manager. See the
 * Time Manager discussion in Inside Mac VI for details
 * of the procedure.
 */
void
GetEpoch(
 MicrosecondEpochPtr result
 )
{
 RmvTime(&TIME); /* Stop Clock*/
 result->time = gTimeInfo.epoch; /* Get seconds    */
 /*
  * TIME.tmCount contains the residual number of
  * microseconds. This is a negative number (see
  * IM-VI). The following, then, computes the
  * number of microseconds that have elapsed in
  * the current second.
  */
 result->microsecond = 
 (MILLION + TIME.tmCount) /* Offset “now”    */
 - gOverheadTime;/* - call cost  */
 if (result->microsecond < 0) {  /* New second?    */
 result->time -= 1;/* Correct it.  */
 result->microsecond += MILLION;
 }
 InsXTime(&TIME);/* Drift-free*/
 PrimeTime(&TIME, 0);/* Timer start*/
}

/*
 * Return the difference between two (nearby) epochs.
 * The result is in microseconds and has a range of
 * up to about 35 minutes.
 *
 * DeltaTime returns TRUE if deltaTime is valid.
 */
Boolean
DeltaTime(
 MicrosecondEpochPtr epoch1,
 MicrosecondEpochPtr epoch2,
 signed long*deltaTime
 )
{
 long   seconds;
 long   microseconds;
 
 seconds = epoch2->time - epoch1->time;
 microseconds =
 epoch2->microsecond - epoch1->microsecond;
 *deltaTime = (seconds * MILLION) + microseconds;
 /*
  * The result is valid only if the
  * absolute value of the difference is
  * less than about 35 minutes.  I.e.
  *2^31 <= (35 * 60 * 10^6)
  */
 if (seconds < 0)
 seconds = (-seconds);
 return (seconds <= (34 * 60));
}

/*
 * Return the time difference as a double-precision
 * number of seconds.
 */
double
DoubleDelta(
 MicrosecondEpoch*start,
 MicrosecondEpoch*finish
 )
{
 double seconds;
 double microseconds;
 double result;
 
 seconds = finish->time - start->time;
 microseconds =
 finish->microsecond - start->microsecond;
 result = seconds
    + (microseconds / (double) MILLION);
 return (result);
}


/*
 * This local function formats hour:minute:second.
 */
static void
FormatTimeString(
 StringPtrresult,
 long   what,
 BooleanneedColon
 )
{
 Str255 value;
 
 if (needColon)
 result[++result[0]] = ‘:’;
 NumToString(what, value);
 if (value[0] == 1)
 result[++result[0]] = ‘0’;
 Concat(result, value);
}

/*
 * Convert the time of day to a consistent, fixed-width
 * format of hh:mm:ss.microseconds. This is always in
 * 24 hour format.
 */
void
EpochToString(
 MicrosecondEpochPtr epochPtr,
 StringPtrresult
 )
{
 unsigned int    i;
 DateTimeRecnow;
 Str255 value;

 Secs2Date(epochPtr->time, &now);
 result[0] = 0;
 FormatTimeString(result, now.hour,   FALSE);
 FormatTimeString(result, now.minute, TRUE);
 FormatTimeString(result, now.second, TRUE);
 NumToString(
 epochPtr->microsecond + MILLION,
 value
 );
 value[1] = ‘.’;
 Concat(result, value);
}

/*
 * String concatenator for Pascal strings.
 */
static void
Concat(
 StringPtrdst,
 StringPtrsrc
 )
{
 short  copySize;
 
 copySize = src[0];
 if ((copySize + dst[0]) > 255)
 copySize = 255 - dst[0];
 BlockMove(
 &src[1],
 &dst[dst[0] + 1],
 (long) copySize
 );
 dst[0] += copySize;
}

/*
 * Adjust the clock by adding the adjustment to the
 * current clock.  There is a built-in delay to
 * make sure our timer task gets to do its thing.
 *
 * Note: the right way to do this is to change the system
 * clock tick base from 1000000 and continually adjust
 * the clock a bit every second until it’s right.
 * Unfortunately, we don’t have access to the system
 * clock time manager record.
 */
void
AdjustClock(
 long   adjustment
 )
{
 MicrosecondEpochourEpoch;
 long   timeOfDay;

 GetEpoch(&ourEpoch);
 ourEpoch.time += (adjustment / MILLION);
 adjustment %= MILLION;
 if (ourEpoch.microsecond >= (MILLION / 2))
 ourEpoch.time += 1;
 else if (ourEpoch.microsecond <= (-(MILLION / 2)))
 ourEpoch.time -= 1;
 SetDateTime(ourEpoch.time);
 /*
  * Vamp until our shadow clock has a chance to
  * update the local value.
  */
 GetEpoch(&ourEpoch);
 timeOfDay = ourEpoch.time;
 do {
 GetEpoch(&ourEpoch);
 } while (timeOfDay == ourEpoch.time);
}

/*
 * This will be called automatically by the
 * ExitToShell trap.
 */
void
CancelMicrosecondTimer()
{

#if 0 /* Enable this to put a debug trap here                  */
 asm {
 nop
 }
#endif
 if (TIME.tmAddr != NULL) {
 RmvTime(&TIME);
 TIME.tmAddr = NULL;
 }
 if (oldExitVector != NULL) {
 SetTrapAddress(
 (long) oldExitVector,
 _ExitToShell
 );
 oldExitVector = NULL;
 if (jumpVector != NULL) {
 DisposPtr(jumpVector);
 jumpVector = NULL;
 }
 }
}

/*
 * This is called by the ExitToShell trap.
 * It cancels the timer service and removes
 * itself from the trap process, then re-calls
 * ExitToShell to allow other trap handlers to
 * execute.
 */
static void
TimerExitHandler()
{
 long   oldA5 = SetCurrentA5();

 CancelMicrosecondTimer();
 SetA5(oldA5);
 ExitToShell();  /* Call next exit handler   */
}

/*
 * This private routine is called by the TimeManager at
 * every clock tick. There is blood on every line of this
 * function - and on a number of lines of code that aren’t
 * here any more. This function will need to be rewritten
 * for MPW-C, as that compiler lacks an asm statement.
 */
static pascal void
TimeCounter()
{
 asm {
 /*
  * When we are called, A1 -> the time info
  * record which we have extended with our
  * “time of day” shadow. Update it with the
  * current system time-of-day value (so that
  * we remain coordinated with any changes
  * caused by SetDateTime or Control Panel
  * calls). This may mean that we are up to
  * one second out of step from the system, but
  * this probably can’t be helped.  TimeLM is
  * the system global “time of day” variable.
  * This variable has a different name in MPW-C.
  */
 move.l TimeLM,  \
 OFFSET(TimeInfoRecord,epoch)(a1)
 move.l a1,a0    ;; a0 = TmTaskPtr 
 move.l #-MILLION,d0 ;; d0 = count
 dc.w 0xA05A;; _PrimeTime
 }
}
Listing:  MicrosecondTimerDemo.c

/* MicrosecondTimerDemo.c */
/*
 * This is a totally useless demo program that scribbles
 * the time of day as quickly as it can, then it tries
 * to determine the cost of calling the time routines.
 * Click on the mouse whenever you get bored.
 */
#include <stdio.h>
#include <console.h>
#include <limits.h>
#include <math.h>
#include “MicrosecondTimer.h”
#define MILLION  (1000000L)
#define HIST_MAX 100
#define HIST_SIZE(100L) /* 100 microseconds per bin      */
double  histogram[HIST_MAX];
double  overflow;

main(
 int    argc,
 char   **argv
 )
{
 MicrosecondEpochthen;
 MicrosecondEpochnow;
 MicrosecondEpochstart;
 MicrosecondEpochfinish;
 long   elapsed;
 long   smallest;
 long   biggest;
 double trials;
 double sum, sumSq;
 double mean, variance, sd;
 double seconds;
 double trialTime;
 register short  i,top;
 Str255 message;

 /*
  * Be sure to initialize the timer before calling
  * any THINK C stdio or THINK Class Library
  * routines.
  */
 InitializeMicrosecondTimer();
 argc = ccommand(&argv);
 printf(“Hit the mouse to stop\n”);
 GetEpoch(&then);
 while (Button() == FALSE) {
 SystemTask();
 GetEpoch(&now);
 EpochToString(&now, message);
 DeltaTime(&then, &now, &elapsed);
 printf(
 “%#s - %ld.%06ld\n”,
 message,
 elapsed / MILLION,
 elapsed % MILLION
 );
 then = now;
 }
 while (Button())
 ;
 printf(“Beginning timer resolution test.\n”);
 printf(“Hit the mouse to stop\n”);
 smallest = LONG_MAX;
 biggest = 0;
 trials = 0;
 sum = sumSq = 0;
 i = 0;
 GetEpoch(&start);
 while (Button() == FALSE) {
 if ((++i % 1000) == 0)
 SystemTask();
 GetEpoch(&then);
 GetEpoch(&now);
 DeltaTime(&then, &now, &elapsed);
 if (elapsed < smallest)
 smallest = elapsed;
 if (elapsed > biggest)
 biggest = elapsed;
 sum += elapsed;
 sumSq += (elapsed * elapsed);
 trials++;
 i = elapsed / HIST_SIZE;
 if (i >= HIST_MAX)
 ++overflow;
 else {
 ++histogram[i];
 }
 }
 while (Button())
 ;
 GetEpoch(&finish);
 top = HIST_MAX;
 if (overflow == 0) {
 while (top > 0 && histogram[top - 1] == 0)
 top -= 1;
 }
 printf(“Each histogram bucket contains %ld µsec.\n”,
 HIST_SIZE);
 for (i = 0; i < top; i++) {
 printf(“%5ld: %.0f\n”,
 i * HIST_SIZE, histogram[i]);
 }
 if (overflow > 0)
 printf(“%.0f overflow\n”);
 printf(“Timer minimum = %ld.%06ld,”,
 smallest / MILLION,
 smallest % MILLION
 );
 printf(“ maximum = %ld.%06ld\n”,
 biggest / MILLION,
 biggest % MILLION
 );
 printf(“%.0f trials”, trials);
 if (trials > 0) {
 mean = sum / trials;
 printf(“: mean %.2f µsec.”, mean);
 if (trials > 1.0)  {
 /*
  * No, this is not the proper way to
  * calculate the variance.
  */
 variance = (sumSq * trials) - (sum * sum);
 variance /= (trials * trials);
 sd = sqrt(variance);/* Std. deviation */
 printf(“, variance %0.2f,”, variance);
 printf(“ standard deviation %0.2f”, sd);
 }
 }
 printf(“\n”);
 seconds = DoubleDelta(&start, &finish);
 printf(“%0.3f seconds”, seconds);
 if (seconds > 0.0)
 printf(“, %0.2f trials/sec.”, trials / seconds);
 if (trials > 0.0) {
 trialTime = (seconds * (double) MILLION) / trials;
 printf(“, %.2f µsec./trial\n”, trialTime);
 printf(“%.2f µsec. mean test overhead”,
 trialTime - mean
 );
 }
 printf(“\n”);
}







  
 

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

Cosmonautica (Games)
Cosmonautica 1.1 Device: iOS Universal Category: Games Price: $6.99, Version: 1.1 (iTunes) Description: Cast off! Are you ready for some hilarious adventures in outer space? | 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 »

Price Scanner via MacPrices.net

Sale! 13-inch MacBook Pros on sale for $100 o...
B&H Photo has 13″ MacBook Pros on sale for $100 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.5GHz/500GB MacBook Pro: $999.99 save $100 - 13″ 2.7GHz/128GB Retina... Read more
Sale! Save $100 on 13-inch MacBook Airs this...
B&H Photo has the 13″ 1.6GHz/128GB MacBook Air on sale for $899.99 including free shipping plus NY tax only. Their price is $100 off MSRP, and it’s the lowest price available for this model.... Read more
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
Mac Pros on sale for up to $260 off MSRP
B&H Photo has Mac Pros on sale for up to $260 off MSRP. Shipping is free, and B&H charges sales tax in NY only: - 3.7GHz 4-core Mac Pro: $2799, $200 off MSRP - 3.5GHz 6-core Mac Pro: $3719.99... 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* Online Store UAT Lead - Apple (Unite...
**Job Summary** The Apple Online Store is a fast paced and ever evolving business environment. The User Acceptance Testing (UAT) lead in this organization is able to Read more
*Apple* MAC Support Services Subject Matter...
Title: Apple MAC Support Services Subject Matter Expert Location: Pleasanton, CA Type of position: Temporary Contract for approximately 6 weeks Tasks The tasks for the 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.