Computers That Do Not Maintain Date/Time with MS-DOS 5 or 6 (78672)

The information in this article applies to:
    Microsoft MS-DOS operating system 5.0
    Microsoft MS-DOS operating system 5.0a
    Microsoft MS-DOS operating system 6.0
    Microsoft MS-DOS operating system 6.2
    Microsoft MS-DOS operating system 6.21
    Microsoft MS-DOS operating system 6.22

This article was previously published under Q78672


When upgrading some MS-DOS versions (primarily original equipment manufacturer [OEM] versions) to MS-DOS 5.0, 6.0, or 6.2 the time and date are no longer maintained when the computer is rebooted.


The CMOS (complementary metal oxide semiconductor) chip was introduced as a standard for storing hardware information (including time and date) with AT-class machines. When XT machines were introduced, there was no standard for saving/accessing the date and time information. Computer manufacturers (OEMs) often added hardware to store and maintain the date and time settings. To then access this hardware, those OEMs had to modify MS-DOS. Thus, when the upgrade to MS-DOS 5.0, 6.0, or 6.2 is made, the modifications are overwritten and the time and date are no longer accessible.


Some OEMs have developed device drivers and hardware for their machines that allow the time and date to function properly, but others do not support time and date in MS-DOS 5.0, 6.0 and 6.2.

The following is a list of computers that have been found to lose the date and/or time when booting with MS-DOS 5.0, 6.0, and 6.2. The Workaround column lists device drivers/cards that may be used to work around this limitation.
Manufacturer's Phone       Workaround
--------------------       ----------

8088 Sperry Model 20       Not supported with MS-DOS 5.0, 6.0, or 6.2
(800) 448-1424

AT&T 6300                  ATTCLOCK.SYS
(908) 769-6397

AT&T 6300 WGS              ATTCLOCK.SYS
(908) 769-6397

Canon A200 (8088)          Not supported with MS-DOS 5.0, 6.0, or 6.2
(800) 423-2366

Hyundai XT                 RTCCLK.SYS
Model 16T,16E,16X
Contact dealer

Leading Edge Model D       CLKDVR.SYS
(900) 370-4800

PC Limited XT        SETCLOCK.SYS
(512) 338-4400
BBS: (512) 338-8528

Vendex Headstart XT        8 bit clock card
(900) 454-5554

Tandy 1400 LT,FD, HD       Not supported with MS-DOS 5.0, 6.0, or 6.2
(817) 878-6875

Zenith 183 or 184 laptop   Not supported with MS-DOS 5.0, 6.0, or 6.2
(800) 842-9000
For more information on workaround device drivers, query on the computer name, model, and driver names in the Microsoft Knowledge Base.

The products included here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.

Modification Type: Major Last Reviewed: 5/10/2003
Keywords: KB78672