Continued Clock/Calendar Functionality for AT&T PC 6300



          What's wrong with the AT&T PC 6300?  Very little!  In this era

  of "major strides" in personal computer technology, the AT&T PC 6300 I

  bought in 1985 has passed the test of time.  With disk accelerator

  software and a little extra memory above 640K, my machine seems to run

  anything I want, and it still does it very well. 



          The only notable incompatibility has been the lack of a good

  clock/calendar driver so you can boot up with anybody's DOS without

  having to enter the current time and date. 



          Standard DOS versions provide a way to fix all this and the

  accompanying device driver does just that.  It works with version 2.11

  thorugh version 5.0 of DOS.  It can be AT&T DOS, MS-DOS or PC-DOS.  It

  only works, however, on an AT&T PC 6300 machine.  The original clock

  chip and ROM-BIOS must be present for proper function. 



  **** WARNING! ******* WARNING! ******** WARNING! ******** WARNING! ****

  ** DO NOT INSTALL THE DRIVER ON ANYTHING BUT AN AT&T PC6300 MACHINE. **

  **      USE ON OTHER MACHINES MAY CAUSE LOSS OF DATA, AND WORSE.     **

  *********** WARNING! ******************* WARNING! ********************* 



          Installing the driver.  Edit the CONFIG.SYS file on your hard

  disk so it includes the line: 

                    device=attclk.sys /1988 

  Now copy the file ATTCLK.SYS to the root directory of the hard disk.

  When you re-boot the system (or turn it off and then on), the driver

  installs and initializes itself. 









          Usefulness.  It allows use of dates beyond 12/31/91 which the

  original AT&T (Phoenix) driver could not do.  It passes time and date to

  DOS at start-up and anytime you need it, such as when you create or

  write to a file. 

          After start-up it keeps only about 290 bytes of code resident,

  saving precious memory for your applications programs.  And it doesn't

  care what brand of standard DOS you are using. 



          How it works.  If your BIOS and clock chip are functioning

  normally, you must set the date and time once after re-booting

  (Ctrl-Alt-Del) with the new driver.  Use the DOS time and date commands

  for this.  You will see the current date and time whenever you

  subsequently turn on the computer. 



          There are three quirks which are due to the design of the clock

  chip and the AT&T ROM-BIOS: 



          (1) You must set the date to the new year once every January.

  The clock chip can't advance the year at midnight December 31. 



          (2) Whenever you set the time or date the seconds registers of

  the clock chip will be reset to zero.  To avoid inaccuracies it is

  necessary to enter the new date or time just as the second-hand of your

  time source passes zero. 



          (3) The clock/calendar chip functions normally over an eight-

  year time span.  This is true despite the fact that DOS allows you to

  set any date between 1980 and 2099.  At start-up then, the driver

  interprets the current hardware setting as one of the years in the

  eight-year period beginning with the year you specified in CONFIG.SYS. 








          The fully functional version of this driver--which you can

  purchase cheap--allows any legal DOS date (1/1/80 to 12/31/2099) to be

  set.  And, by changing the CONFIG.SYS file appropriately, it can

  recognize any legal DOS date at start-up, as well. 


  NOTE:  The code and compiled driver available from my website, at:

    http://www.jps.net/adahlman/programs/Programs.html#ATTClock

  should be the fully functional versions, free.


          This software is distributed "as is" without any implied or

  expressed warranty.  Due to the low price, absolutely no liability can

  be assumed by the author, other than replacement of media damaged in

  the mail. 



  The following are registered trademarks of the following: 

    IBM and PC-DOS                International Business Machines Corp. 

    MS-DOS                        Microsoft Corporation 

    AT&T                          American Telephone & Telegraph Corp. 

    Personal Computer 6300        product of AT&T Corp.






















          Registration and License.  I copyrighted this code in 1991.  As

  the author and owner of the copyright, in 1995 I declared the code to be

  "public domain", such that any use of the code after 12-95 is free of

  charge.  All disclaimers continue to apply:  I make no warranties or claims

  and take no responsibility for how anyone uses this code after 12-95.