Images of BIOS ROMs for
IBM 5150/5155/5160/5162/5170
Information on the contents of the BIOS ROMs of the 5150 and 5160 and 5170 can be found at:
Vintage Computer Forums - 5150 BIOS
Vintage Computer Forums - 5160 BIOS
Vintage Computer Forums - 5170 BIOS
5150 (IBM PC)
The BIOS is contained in chip U33.
There were three revisions of the BIOS.
1. First revision - 04/24/81
2. Second revision - 10/19/81
3. Third revision - 10/27/82
Note that the files in the above links contain the BIOS only (chip U33). BASIC (chips U29 to U32) is not included.
5155 (IBM Portable PC)
The 5155 contains a 5160 motherboard, the one that has the 11/08/82 BIOS.
5160 (IBM XT)
The BIOS (together with BASIC) is contained in chips U18 and U19.
1. First revision - 11/08/82
2. Second revision - 01/10/86
3. Third revision - 05/09/86
ROMs can be created using standard 27256 EPROMs rated at 250 ns (or faster).
Some information sources indicate that there was an additional revision of the BIOS, one dated 08/16/82. For that BIOS, we expect chip U18 to have the IBM part number of 5000026 on it. I have yet to see a "5000026" stamped U18 chip. It is possible that the BIOS was never released.
5162 (IBM XT Model 286)
The BIOS (together with BASIC) is contained in chips U34 and U35.
There was only one BIOS released (21APR86).
Only revision - 04/21/86
ROMs can be created using standard 27256 EPROMs rated at 150 ns (or faster).
5170 (IBM AT)
The BIOS (together with BASIC) is contained in chips U27 and U47.
There were three revisions of the BIOS.
In the final revision, there are two known variations. They have different part numbers and an inspection of the contents shows that they are functionally the same - only the embedded part number strings differ (and checksum byte). The differing part numbers may be due to the fact that one variation is supplied as PROMs whereas the other is supplied as EPROMs.
1. First revision - 01/10/84 - 6MHz machine - Type 1 motherboard
2. Second revision - 06/10/85 - 6MHz machine - Type 2 motherboard
3. Third revision - 11/15/85 - 8MHz machine - Type 2 motherboard - variation 1
4. Third revision - 11/15/85 - 8MHz machine - Type 2 motherboard - variation 2
ROMs can be created using standard 27256 EPROMs rated at 150 ns (or faster).
AMI BIOS FOR 5170
AMI released a BIOS specifically for 8 MHz 5170's. From memory, it was used when the IBM hard/floppy controller was replaced by a third party board (which results in a "601-Diskette error" error).
The BIOS is dated 04/30/89. This BIOS has built-in CMOS setup functionality, a user defined hard drive
type (type 47), and diagnostics (includes hard disk format). This BIOS
will no doubt run in all 5170's.
On startup, the following is seen at the top of the screen:
286-BIOS (c)1989 American Megatrends Inc
On startup, the following is seen at the bottom of the screen: D286-1277-043089-K0
AMI release D286-1277-043089-K0
AWARD BIOS FOR 5170
This generic 286 'IBM compatible' BIOS made by Award was found in a 6 MHz 5170 with the type 1 motherboard. Although dated 10/20/87, it reports a BIOS date of 11/15/85 which is the same date as IBM's third BIOS release for the 5170. This BIOS will no doubt run in all 5170's. This BIOS has built-in CMOS setup functionality. CTL-ALT-ESC at start-up will take you into the CMOS setup. This BIOS defines 40 different hard drive types, and does NOT have a user defined hard drive type.
Within the BIOS code is:
IBM COMPATIBLE 286 BIOS
COPYRIGHT Award Software Inc. 10/20/87
286 Modular BIOS Version 3.03GS
AWARD release 3.03GS