# real-time clock

> computer clock in the form of an integrated circuit that keeps track of the current time

**Wikidata**: [Q862594](https://www.wikidata.org/wiki/Q862594)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Real-time_clock)  
**Source**: https://4ort.xyz/entity/real-time-clock

## Summary
A real-time clock (RTC) is a computer clock in the form of an integrated circuit that keeps track of the current time. It serves as a dedicated hardware component for maintaining accurate timekeeping in computer systems, even when the main system is powered off.

## Key Facts
- A real-time clock is classified as both computer hardware and a timepiece
- It functions as an integrated circuit specifically designed for timekeeping
- The entity has 25 sitelinks across different language versions of Wikipedia
- It has multiple aliases including RTC, real time clock, and translations in various languages
- It is distinct from real-time computing systems
- Wikipedia articles about real-time clocks exist in at least 10 languages including Catalan, Czech, German, English, Spanish, Estonian, Persian, Finnish, French, and Hungarian
- The Commons category for real-time clocks is "Real-time clocks"
- It has a Freebase ID of /m/02mmb2

## FAQs
### Q: What is the difference between a real-time clock and a regular computer clock?
A: A real-time clock is a dedicated hardware component in the form of an integrated circuit that maintains time even when the computer is powered off, whereas a regular computer clock typically relies on software and loses time accuracy when the system is shut down.

### Q: Why do computers need a real-time clock?
A: Computers need real-time clocks to maintain accurate timekeeping across reboots and power cycles, enabling features like scheduled tasks, proper file time-stamping, and maintaining system time consistency.

### Q: What are some manufacturers of real-time clock integrated circuits?
A: The source material mentions Dallas Semiconductor as a manufacturer of real-time clock integrated circuits, specifically referencing the DS1287 Real-Time IC.

## Why It Matters
Real-time clocks are fundamental components in computing that solve the critical problem of maintaining accurate time across power cycles. Without them, computers would lose track of time when powered off, disrupting essential functions like file time-stamping, scheduled tasks, and system logging. They enable precise timekeeping in embedded systems, security applications, and data logging equipment. The existence of multiple language Wikipedia entries and 25 sitelinks indicates the widespread importance and adoption of real-time clock technology across different computing platforms and regions worldwide.

## Notable For
- Being a dedicated hardware solution for timekeeping rather than software-based
- Maintaining time accuracy even when the main computer system is powered off
- Having multiple language Wikipedia documentation, indicating international relevance
- Being distinct from real-time computing systems despite similar naming
- Integration into various computer systems including the Apple II

## Body
### Definition and Classification
A real-time clock is a computer clock implemented as an integrated circuit that keeps track of the current time. It is classified as both computer hardware and a timepiece, serving as a dedicated component for timekeeping functions in computing systems.

### Technical Implementation
The real-time clock exists in the form of an integrated circuit, providing hardware-based timekeeping capabilities. This implementation allows the clock to maintain accurate time even when the main computer system is powered off, addressing the limitations of software-based timekeeping solutions.

### Manufacturers and Examples
The source material references Dallas Semiconductor as a manufacturer of real-time clock integrated circuits, specifically mentioning the DS1287 Real-Time IC. Additionally, Apple II system clocks are noted as early examples of computer real-time clock devices.

### Language and Documentation
The real-time clock entity has documentation in multiple languages, with Wikipedia articles available in at least 10 languages including Catalan, Czech, German, English, Spanish, Estonian, Persian, Finnish, French, and Hungarian. The Commons category for real-time clocks is "Real-time clocks," and the entity has 25 sitelinks across different language versions.

### Related Entities
The real-time clock is related to several other entities:
- Computer hardware (parent class)
- Timepiece (parent class)
- Apple II system clocks (early examples)
- Dallas Semiconductor Real-time clocks (manufacturer class)
- 512 series integrated circuits (Soviet digital circuits for watches, clocks and timers)
- Real-time computing (distinct from real-time clock)

## References

1. [Source](https://github.com/JohnMarkOckerbloom/ftl/blob/master/data/wikimap)
2. Freebase Data Dumps. 2013
3. Quora
4. National Library of Israel Names and Subjects Authority File