Epochalypse Now — or how to deal with Y2K38

[harlan4096]

What is the year 2038 problem — also known as “Unix Y2K” — and how to prepare corporate IT systems for it?
 
Millions of IT systems — some of them industrial and IoT — may start behaving unpredictably on January 19. Potential failures include: glitches in processing card payments; false alarms from security systems; incorrect operation of medical equipment; failures in automated lighting, heating, and water supply systems; and many more less serious types of errors. The catch is — it will happen on January 19, 2038. Not that that’s a reason to relax — the time left to prepare may already be insufficient. The cause of this mass of problems will be an overflow in the integers storing date and time. While the root cause of the error is simple and clear, fixing it will require extensive and systematic efforts on every level — from governments and international bodies and down to organizations and private individuals.

The unwritten standard of the Unix epoch

The Unix epoch is the timekeeping system adopted by Unix operating systems, which became popular across the entire IT industry. It counts the seconds from 00:00:00 UTC on January 1, 1970, which is considered the zero point. Any given moment in time is represented as the number of seconds that have passed since that date. For dates before 1970, negative values are used. This approach was chosen by Unix developers for its simplicity — instead of storing the year, month, day, and time separately, only a single number is needed. This facilitates operations like sorting or calculating the interval between dates. Today, the Unix epoch is used far beyond Unix systems: in databases, programming languages, network protocols, and in smartphones running iOS and Android.

The Y2K38 time bomb

Initially, when Unix was developed, a decision was made to store time as a 32-bit signed integer. This allowed for representing a date range from roughly 1901 to 2038. The problem is that on January 19, 2038, at 03:14:07 UTC, this number will reach its maximum value (2,147,483,647 seconds) and overflow, becoming negative, and causing computers to “teleport” from January 2038 back to December 13, 1901. In some cases, however, shorter “time travel” might happen — to point zero, which is the year 1970.

This event, known as the “year 2038 problem”, “Epochalypse”, or “Y2K38”, could lead to failures in systems that still use 32-bit time representation — from POS terminals, embedded systems, and routers, to automobiles and industrial equipment. Modern systems solve this problem by using 64 bits to store time. This extends the date range to hundreds of billions of years into the future. However, millions of devices with 32-bit dates are still in operation, and will require updating or replacement before “day Y” arrives.

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