Questions tagged [rtc]

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

Filter by
Sorted by
Tagged with
9 votes
1 answer

x86 PC/Dallas Semiconductors RTC style general purpose NVRAM usage

The RTCs of x86 PCs commonly include some amount of general purpose NVRAM, e.g. the DS12885 has 144 bytes general purpose (GP) NVRAM. The ACPI Specification specifies some RTC also with GP NVRAM, ...
maxschlepzig's user avatar
14 votes
3 answers

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 "...
Schoettle's user avatar
  • 141
25 votes
5 answers

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-...
Superfrog's user avatar
  • 251
29 votes
1 answer

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, ...
Guest's user avatar
  • 299
15 votes
4 answers

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 ...
smitelli's user avatar
  • 1,561
4 votes
1 answer

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 ...
640KB's user avatar
  • 1,287
2 votes
1 answer

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 ...
forest's user avatar
  • 1,999
26 votes
3 answers

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 ...
user3840170's user avatar
  • 21.6k
1 vote
2 answers

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-...
lgj1107's user avatar
  • 61
2 votes
1 answer

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 ...
Kamome's user avatar
  • 163
12 votes
3 answers

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 ...
Richard Downer's user avatar