The original QDOS memory map is shown below. This is still valid on the old black boxes, but Trump Cards, Gold Cards, Super Gold Cards, Aurora etc may/will have changed things about. I currently have no information on these devices so I cannot document them here. I have requested details using the QL newsgroup and as information arrives, I shall add it here.
| From address | To address | Usage |
|---|---|---|
| $C0000 | $FFFFF | Peripheral ROMS - up to 16 each a maximum of 16Kb in size. |
| $40000 | $BFFFF | Expansion RAM up to 512 KB. |
| $30000 | $3FFFF | Remainder of original 128Kb RAM |
| $28000 | $2FFFF | System variables & screen 2 - total 32K |
| $20000 | $27FFF | Screen 1 - 32 Kb |
| $1C000 | $1FFFF | External I/O |
| $18000 | $1BFFF | Internal I/O |
| $10000 | $17FFF | External I/O |
| $0C000 | $0FFFF | External ROM slot - 16Kb |
| $00000 | $0BFFF | Internal 48K ROM |