The DS12887 is a drop in replacement for real time clocks on many older pentium and other PC boards. In my case, I needed it to replace a depleted RTC on a Tektronix TLA711 logic analyser.
While the operation of desoldering and removing the existing DS12887 from the circuit board is fairly difficult (especially while trying to not damage the pcb tracks), once the original one is removed, it is straight forward to solder this 28 pin IC in place.
The battery on the DS12887 should last at least 10 years. This means that replacing the RTC should last the remaining life of the instrument/computer.