res page 22 - Dave's Blog

Grocery Shopper Data Use

QFC, the grocery store closest to me, has those irritating shoppers cards. They try to motivate me to use it with discounts, but that just makes me want to use a card, I don't care whose card and I don't care if the data is accurate. They should let me have my data or make it useful to me so that I actually care.

I can imagine several useful tools based on this: automatic grocery lists, recipes using the food you purchased, cheaper alternatives to your purchases, other things you might like based on what you purchased, or integration with dieting websites or software. At any rate, right now all I care about is getting the discount from using a card, but if they made the data available to me then the grocery store could align our interests and I'd want to ensure the data's accuracy.

Comcast Digital Switch Impact on My Windows Media Center

Irritatingly out of line with what their commercials say, in my area Comcast, under the covers of the national broadcast digital switch, is sneaking in their own switch to digital, moving channels above 30 to their own digital format. Previously, I had Windows 7 Media Center running on a PC with a Hauppauge PVR500 which can decode two television signals at once setup to record shows I like. The XBox 360 works great as a Media Center client letting me easily watch the recorded shows over my home network on my normal TV.

Unfortunately with Comcast's change, now one needs a cable box or a Comcast digital to analog converter in order to view their signal, but Comcast is offering up to two free converters for those who'd like them. The second of my two free converters I hooked up to the Media Center PC and I got the IR Blaster that came with my Hauppauge out of the garage. I plugged in the USB IR Blaster to my PC, connected one of the IR transmitters to the 1st port on the IR Blaster, and sat the IR transmitter next to the converter's IR receiver. I went through the Media Center TV setup again and happily it was able to figure out how to correctly change the channel on the converter. So I can record now, however:

1. I can only record one thing at a time now
2. Changing the channel is slow taking many seconds (no flipping through channels for me)
3. The Hauppauge card can't know if the channel change worked. So if it tries to change to HBO (I get it for free with one of the Comcast packages) which is encrypted and the converted won't show, the channel doesn't change but the PC doesn't know it and ends up recording some other channel.

Time/Date Conversion Tool

I built timestamp.exe, a Windows command line tool to convert between computer and human readable date/time formats mostly for working on the first run wizard for IE8. We commonly write out our dates in binary form to the registry and in order to test and debug my work it became useful to be able to determine to what date the binary value of a FILETIME or SYSTEMTIME corresponded or to produce my own binary value of a FILETIME and insert it into the registry.

For instance, to convert to a binary value:

[PS C:\] timestamp -inString 2009/08/28:10:18 -outHexValue -convert filetime
2009/08/28:10:18 as FILETIME: 00 7c c8 d1 c8 27 ca 01

Converting in the other direction, if you don't know what format the bytes are in, just feed them in and timestamp will try all conversions and list only the valid ones:

[PS C:\] timestamp -inHexValue  "40 52 1c 3b"
40 52 1c 3b as FILETIME: 1601-01-01:00:01:39.171
40 52 1c 3b as Unix Time: 2001-06-05:03:30:08.000
40 52 1c 3b as DOS Time: 2009-08-28:10:18:00.000

[PS C:\] timestamp -inHexValue  "40 52 1c 3b" -convert guess
40 52 1c 3b as DOS Time: 2009-08-28:10:18:00.000

When I first wrote this I had a bug in my function that parses the date-time value string in which I could parse 2009-07-02:10:18 just fine, but I wouldn't be able to parse 2009-09-02:10:18 correctly. This was my code:

success = swscanf_s(timeString, L"%hi%*[\\/- ,]%hi%*[\\/- ,]%hi%*[\\/- ,Tt:.]%hi%*[:.]%hi%*[:.]%hi%*[:.]%hi", 
&systemTime->wYear,
&systemTime->wMonth,
&systemTime->wDay,
&systemTime->wHour,
&systemTime->wMinute,
&systemTime->wSecond,
&systemTime->wMilliseconds) > 1;

To convert between these various forms yourself read The Old New Thing date conversion article or Josh Poley's date time article. I previously wrote about date formats I like and dislike.