NVRAM
The SPARCstation 1 uses an M48T02 battery-backed RTC with RAM chip which handles the real time clock and boot parameter storage. The only problem with this chip is that the battery is internal, which means the entire chip must be replaced when its battery runs out. As all SPARCstation 1s made are now older than the battery life of this chip, a substantial number of these systems now refuse to boot. Additionally, the SPARCstation 1 design used the reserved bits in the M48T02's NVRAM in a non-standard way; since later revisions of the M48T02 chip exert stricter control over these bits, a current M48T02 will store the NVRAM data, but the RTC will not function correctly.
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