
This is the third BIOS for the IBM 5170.
It is dated 15NOV85.
It is found in type 2 motherboards running at 8 Mhz.

U27 has the IBM part number of 61X9266, and is 32K in size
U47 has the IBM part number of 61X9265, and is 32K in size

8 bit checksum of 61X9266 = 10
8 bit checksum of 61X9265 = F0
                           ----
                    added = 00



There are two BIN files in this ZIP file:
1. BIOS_5170_15NOV85_U27_61X9266_27256.BIN  --> Use this to create a U27 using a 27256 EPROM (rated at 150nS or faster)
2. BIOS_5170_15NOV85_U47_61X9265_27256.BIN  --> Use this to create a U47 using a 27256 EPROM (rated at 150nS or faster)



NOTE: There is at least one other 15NOV85 BIOS set for the IBM 5170.
      In that set, the part numbers of U27 and U47 are 62X0820 (U27) and 62X0821 (U47).
      When the two sets are compared the differences are:
          1. The part numbers (in as strings) are different
          2. The last byte in U47 (used to adjust the 8 bit checksum) is different
      And so there is no functional difference.
      But 62X0820/62X0821 are PROMS whereas 61X9266/61X9265 are EPROMs.

