Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!ub!uhura.cc.rochester.edu!uhura!saaf From: saaf@joker.optics.rochester.edu (Lennart Saaf) Newsgroups: comp.sys.mac.programmer Subject: Daylight savings time in PRAM??? Message-ID: Date: 17 Mar 91 18:39:23 GMT Sender: news@uhura.cc.rochester.edu Distribution: comp Organization: The Institute of Optics, University of Rochester Lines: 29 I have written a couple of Hypercard XCMDs to read and write the latitude, longitude, and time zone information from/to the parameter RAM. I used the Script Manager supplement to IM for reference. There is, however, one point on which the docs are not clear. There is a signed byte that defines the "daylight savings time delta." That's about all the docs say. The GMT delta is 3 bytes, I believe, (I don't have it in front of me) and is measured in seconds--this works fine. Is the daylight savings time delta used by anything? If so is is supposed to be expressed in minutes? The byte is normally 0x00, and putting various values into it appears to have no effect. Any clues? Is there no support for daylight savings time on the Mac? Is this an incredible lapse? :-) At present I am using a nice freeware cdev/init called "Daylight" that senses a time change since the last power-up and changes the time accordingly. The switchover times are configurable (e.g., start DST at 2AM on the last Sunday in March). But it doesn't change the time zone information in the PRAM (I admit I haven't tried it, but I'll go out on a limb :-)). Thanks for any help, Len P.S. The XCMDs mentioned above are available via anonymous ftp from joker.optics.rochester.edu (128.151.240.1). -- ------------------------------------------------------------------------ | Len Saaf, The Institute of Optics, Univ. of Rochester, Rochester, NY | | Internet: saaf@joker.optics.rochester.edu Bitnet: SAAF@UOROPT | ------------------------------------------------------------------------