| I/O Address (Hex) | Function | I/O Device |
| 0000-000F | DMA controller 1 | 82357 |
| 0020-0021 | Interrupt controller 1 | 82357 |
| 0022-0023 | DRAM controller registers | 82359 |
| 0026-0027 | CLASIC indexed registers (relocatable to 0C26-0C27) | CLASSIC |
| 0040-0043 | Interval timer 1 | 82357 |
| 0048-004B | Interval timer 2 | 82357 |
| 0060,0064 | Keyboard/mouse controller | 8742 |
| 0061 | NMI status register | 82357 |
| 0070 | NMI enable register (write only) | 82357 |
| 0070-0071 | Real-time clock | DS 1287 |
| 0078 | CLASIC BIOS counter | CLASIC |
| 0080-008F | DMA low page register | 82357 |
| 0092 | CLASIC control port A | CLASIC |
| 00A0-00A1 | Interrupt controller 2 | 82357 |
| 00C0-00DF | DMA controller 2 | 82357 |
| 00F0 | Numerics coprocessor | i486/i847SX |
| 00F8-00FF | ||
| 01F0-01F7 | IDE interface ports | IDE drive |
| 02F8-02FF | Serial port 2 | WD 16C552 |
| 0378-037F | Parallel port | WD 16C552 |
| 03B0-03DF | Onboard video controller | WD 90C30 |
| 03F0-03F7 | Floppy disk controller | 82077AA |
| 03F8-03FF | Serial port 1 | WD 16C552 |
| 0400-040F | DMA controller 1 extended registers | 82357 |
| 0461 | Extended NMI and Reset control register | 82357 |
| 0462 | Software NMI register (write only) | 82357 |
| 0464-0465 | Last Bus Master granted (read only) | 82357 |
| 0480-048F | DMA high page register | 82357 |
| 04C2-04CF | DMA controller 2 extended registers | 82357 |
| 04D0-04D1 | Interrupt edge/level control | 82357 |
| 04D4-04D7 | DMA controller 2 extended registers | 82357 |
| 04E0-04EF | DMA controller stop registers | 82357 |
| 04F4-04FF | ||
| 0C02 | CLASIC control port B | CLASIC |
| 0C03 | CLASIC control port C | CLASIC |
| 0C26-0C27 | CLASIC registers (optional, see 0026-0027) | CLASIC |
| 0C80-0C83 | System board ID bytes (read only) | |
| 0CB0-0CB7 | LAN control registers | 82596CA |
| 0CB8-0CBF | LAN glue registers | GLUE |
| 0CC0-0CFF | SCSI control registers | NCR 53C700 |