Questions tagged [rtc]

Timekeeping hardware that maintains the calendar (wall-clock) time, its hardware interface and batteries that maintain its state.

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3 answers
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How exactly did Amigas without a RTC "work around" this to produce "internally consistent" timestamps? [duplicate]

I recently read about how even the non-RTC-equipped Amiga computers has some sort of "clever trick" in them which caused the timestamps for saved files and whatnot to still be "...
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25 votes
5 answers
3k views

Why did the stock Amigas not have a battery for keeping the time/date?

The Amiga computers were advanced machines meant to do all sorts of things, including file management. They had a GUI OS (Workbench) and everything right from the very start. They were not some games-...
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28 votes
1 answer
4k views

How did anti-Y2K-bug boards work?

During the Y2K bug hype, I remember seeing a store announcing some kind of board that one would connect to the motherboard of a PC and the problem would be fixed. Were these devices legit and, if so, ...
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  • 289
15 votes
4 answers
3k views

How was the real-time clock implemented in the original IBM PC and PC/XT?

I know that the IBM PC/AT added a battery backed real-time clock chip that independently maintained time whether the system was powered or not. I've also seen many of those big DS1287 clock chips on ...
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4 votes
1 answer
130 views

Quadram odd IBM PC card bracket

I came across an early IBM PC ISA realtime clock/calendar card made by Quadram called the "Chronograph" (picture). It's basically the same clock feature they incorporated into their ...
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2 votes
1 answer
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Did the RTC in certain cartridges get power over the GBA bus?

Some GBA games, like Pokemon Ruby, contained an internal RTC with a small button battery to power it. When the cartridges were inserted and the GBA was powered on, did the RTC continue to run on the ...
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26 votes
3 answers
6k views

Why does DOS ask for the current date and time upon booting?

In most versions of DOS, when they are started from a medium that lacks an AUTOEXEC.BAT file, the very first thing COMMAND.COM does is ask the user to confirm the current date and time: Starting PC ...
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1 vote
2 answers
406 views

Performing 16-bit port I/O on the RTC

Why can’t the RTC (0x70, 0x71) read and write 16 bits at a time? For example: mov ax, 0xa8f out 0x70, ax I have found in a 286 BIOS that did this (BIOS ID string: S286-6181-...
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2 votes
1 answer
195 views

Can I change laptop's RTC and backup battery with generic Ni-MH?

I got old Toshiba 100CS for a good price. After some inspection, I noticed that AutoResume backup battery and RTC battery are already gone bad, and seems can't hold charge. I've checked eBay for ...
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12 votes
3 answers
724 views

Will using a clockport RTC card on an Amiga 1200 clash with the RTC on an accelerator card?

I have an accelerator card fitted to my Amiga 1200. The accelerator includes a real-time clock, but I noticed that the soldered-on rechargeable battery was in danger of leaking, so I cut it off before ...
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