Service manual

1-24 AlphaServer 4000/4100 Service Manual
1.12 Memory Addressing
Alpha system memory addressing is unusual because memory address space is
determined not by the amount of physical memory but is calculated by a
multiple of the size of the memory pair in slot MEM0x.
Figure 1-16 How Memory Addressing Is Calculated
0
512 Mbyte
1024 Mbyte
1536 Mbyte
2028 Mbyte
Fourth pair address space
512 Mbyte space empty
Second pair address space
512 Mbyte 1/2 occupied
(2 B3020-DA - 128 Mbyte/mod)
Third pair address space
512 Mbyte 1/2 occupied
(2 B3020-DA - 128 Mbyte/mod)
First pair defines
total address space
always fully occupied
(2 B3020-EA 256 Mbyte/mod)
Address
hole
PKW0424-96