IBM Personal System/2 60 Technical Reference page 46

Low and High Base Memory Bytes (Hex 015 and 016): These bytes
define the amount of memory below the 640KB address space.
The value from these bytes represents the number of 1 KB blocks of
base memory. For example, hex 0280 is equal to 640KB. The low
byte is hex 15; the high byte is hex 16.
Low and High Expansion Memory Bytes (Hex 017 and 018): These
bytes define the amount of memory above the 1MB address space.
The hexadecimal values in these bytes represent the number of 1KB
blocks of expansion memory. For example, hex 0800 is equal to
2048KB. The low byte is hex 17; the high byte is hex 18.
Reserved Bytes (Hex 019 through 031): These bytes are reserved.
Configuration CRC Bytes (Hex 032 and 033): These bytes contain the
cyclic-redundancy-check data for bytes hex 010 through hex 031 of the
64-byte CMOS RAM. The low byte is hex 33; the high byte is hex 32.
Reserved Bytes (Hex 034 through 036): These bytes are reserved.
Date Century Byte (Hex 037): Bits 7 through 0 of this byte contain the
BCD value for the century. Refer to the IBM Personal Systeml2 and
Personal Computer BIOS Interface Technical Reference for
information about reading and setting this byte.
Reserved Bytes (Hex 038 through 03F): These bytes are reserved.
3-20 Model 60 System Board