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1A04

Category: BIOS

INT 1A - TIME - GET REAL-TIME CLOCK DATE (AT,XT286,PS)

	AH = 04h
	CF clear to avoid bug (see below)
Return: CF clear if successful
	    CH = century (BCD)
	    CL = year (BCD)
	    DH = month (BCD)
	    DL = day (BCD)
	CF set on error
Notes:	DR-DOS 7.02 (after 1998-06-06) and 7.03 hook this function and correct
	  the century to 20xx if the reported year is 1900..1980 to auto-fix
	  ROM-BIOSes which are not Year 2000 compliant. On a running system,
	  it would also correct the rollover bug from 1999/12/31 to 2000/01/01.
	  The latter can be turned off using the new CONFIG.SYS YEAR2000=ON|OFF
	  command, as hooking INT 1Ah can sometimes cause compatibility
	  problems with 3rd party software, e.g. NCR/Symbios/LSI Logic-based
	  SDMS PCI SCSI drivers (including all OEM drivers like from Asus,
	  Noma, etc.), some Flash-BIOS software like Asus PFLASH, Quarterdeck's
	  QEMM Stealth and Quick-Boot features.
	Using EXCLUDESTEALTHINT=1A, though, will allow QEMM's Stealth features
	  to coexist with the DR-DOS Year 2000 rollover support.
	Actually, the Y2K-fix is provided since OpenDOS 7.02 BETA 2+
	  (1997-08-13), but although these older releases corrected the
	  ROM-BIOS, they didn't pass all Y2K-test suites and had some obscure
	  and inexplicable PCI problems due to the fact that the original
	  INT 1Ah was called via indirect means.  Newer releases, however, use
	  a dynamically fixed-up direct jump to avoid these problems.
	PC DOS 7 plus Y2K fixes and PC DOS 2000 provide similar, though not
	  identical means, which cannot be switched off.
	MS-DOS and older issues of PC DOS do not provide any such means, and
	  thus requires extra Y2K-TSRs to be loaded when run on buggy BIOSes.
BUG:	some BIOSes, such as the 1998/07/25 system ROM in the Compaq Deskpro
	  EP/SB, leave CF unchanged if successful, so CF should be cleared
	  before calling this function
SeeAlso: AH=02h,AH=04h"Sperry",AH=05h,INT 21/AH=2Ah,INT 4B/AH=02h"TI"

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  Copyright 2000   by Ralf Brown     Updated Jul 2000