In general UNIX systems are not as susceptible to Year 2000 problems as some other operating systems. Dates and times are typically stored as the number of seconds since 00:00 on January 1st 1970 or the number of years since 1900. There's nothing special about the year 2000 either way. The rollover of the date from 1999 to 2000 should be no more significant than any other new year.

Individual applications are, of course, free to misuse or misinterpret the date and time formats supported by the system. For example, an incorrectly written application may not allow the input of 4-digit years and may assume that all years input are within the range 1900 to 1999. Misinterpretation of the system supported time formats can result in such errors as the year 2000 being output as 19100.

Whilst the problem of date and time related bugs in applications is not UNIX specific, it is the case that some vendors have distributed applications and utilities in the past which are not fully Year 2000 compliant as part of their UNIX operating systems. Many vendors recommend upgrading to a newer version of the operating system or installing patches to ensure Year 2000 readiness.

UNIX systems running on PC (X86) hardware (e.g. Linux, FreeBSD and others) may have problems setting the initial date/time when booting if the PC's BIOS is not Year 2000 compliant. A good solution is to use NTP (the Network Time Protocol) to set the date and time on bootup. Another possibility is that setting BIOS/CMOS clock to the right date once will fix the problem, although this is obviously not the case if the BIOS doesn't know that the year 2000 is a leap year.

Digital UNIX Version 4.0D and subsequent versions are Year 2000 ready. Previous versions can be patched to enhance the date command, however you must be running Version 4.0D or later to have full Y2K support.

FreeBSD is believed by it's developers to be 100% Y2K compliant. However, they do recommend that you perform tests to see how your system will respond.

HP-UX 11.0, 10.20, 10.10 and 10.01 are all Year 2000 Compliant with customer action, as is HP-UX 9.10 running on the HP 9000 Series 300 and Series 400 systems. All of these releases require the customer to install Year 2000 patches to be compliant. HP-UX 9.04 will not be made Year 2000 compliant.

Debian 2.0 is Year 2000 ready. Debian 1.3 is dependent on the PC's BIOS behaving correctly. If you expect to run your 1.3 system through the millennium, you can get a copy of the "hwclock" program from 2.0 and replace the "clock" program presently on your system.

Red Hat Linux versions 4.1 and beyond will not produce errors in date data related to the Year 2000 change. Customers using prior versions may upgrade to more recent and up-to-date versions at no charge.

Systems utilities and OS kernel are Year 2000 compliant.

SCO provides Y2K warranties, fixes, upgrades and on-site consulting services.

IRIX 6.5 is compliant. IRIX 5.3, 6.2, 6.3, and 6.4 can be patched. Previous releases are not supported in the year 2000 and beyond, and they have not been rigorously tested for Year 2000 complicance. In particular, IRIX 4.0.5 is known to have significant Year 2000 bugs and should not be used after the end of 1999.

Older hardware platforms (e.g. Indigo R3000) have not been tested and are not supported for year 2000 compliance.

Solaris 2.6, 2.5.1, 2.5, 2.4 and 2.3 are compliant with patches. SunOS 4.1.4 and 4.1.3_ul Version B can also be patched.

Sun 3 Series hardware is not supported for Year 2000 compliance. Some hardware requires firmware upgrades to be compliant.

• Perl
• Apache
• 1999/2000 status with GNU software
• The Year 2000 FAQ