18 Dec
2018
18 Dec
'18
4:30 p.m.
From: Paul Koning <paulkoning at comcast.net>
>> core memory details such as destructive read
weren't visible to the
>> CPU
DATAIP/DATAO on the Unibus doesn't depend on the
destructive read
property.
Yes, the CPU can't tell what the memory is doing.
The reason it existed is that it allows core memory to
optimize the
timing
In other words, it's only there to allow the CPU to act in a way that works
well with core memory. Whether that means that the way core operates is
"visible" to the CPU is a debate about definitions.
Put it another way - do any modern CPU's do 'read-modify-write' cycles (other
than for interlocks in a multi-CPU system)?
Noel