On 10 Nov 2008 at 22:37, dwight elvey wrote:
Reading shouldn't be too difficult. Outputs could
be recorded by
a digital scope. The rise times of the address and inhibit lines
are mostly to be slow enough that it doesn't cause the sense
amplifier to trip on the coupling in the selected address line.
Other addresses are protected by the matching signal on the inhibit
line. Any reasonably slow ramp would work since one is using a
scope to record and not a sense amp.
Putting to bed the idea of the "core rope" program store, the 1964
document on the launch computer is pretty clear that this is ordinary
read-write core storing the program:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730063841_19730
63841.pdf
In particular, item 2-37 begins "Reading a ferrite-core memory
destroys the information in the memory." It then goes on to describe
the restore part of a read operation. No mention of "core rope" is
made. The document, all 200-some pages contains a great deal of
detail on the computer, including memory operation and organization.
Cheers,
Chuck