29 Oct
1998
29 Oct
'98
5:17 a.m.
< Address bus should be as wide as you think you
might need plus a bit mor
< As Allison said (again! Why oh why did I delete her post?) you want you
< processor to be able to think about huge memories even if you can't buil
< them and have to swap to disk.
Actually the addres bus can be smaller than register
size. For example
we could build an 80 bit machine with 60bit address busses. The 60 bits
is more than enough to address most likely memory needs for a long while
yet if you need to do address math or other math 80bit long registers may
make it much easier. The datapath bus can be any size as well but larger
is generally better.
Just remember the enhancement of the /370 address space
from 24 Bit to 31 Bit (with a short intermediate phase
of the 25 Bit machines - 16M user and 16M system RAM).
And the funny thing is that still a mayor part of all
/370 Software is only 24 Bit aware.
The assumption of symetry is likely the most false.
Right.
Gruss
H.
--
Ich denke, also bin ich, also gut
HRK