Specifically, they read the voltage pulse produced on the 'Z' wire which caused by the 'intersection' of the 1/2 currents on the X and Y wires during a magnetic core memory read cycle ... The 'summed' (intersected) current at a particular 'core' (little magnetic donut core) caused the donut to possibly change states and a voltage to *possibly* be generated thereby allowing the 'data bit' to be read out ... after reading that bit (if it were, say, a 1) it had to be "written" back in ... I remember the first MCCR (memory control and current reg cards) I worked on - part of a "TIPI" computer (Tactical Interpretation of Photo Information) manufactured by TI for a defense app ... Jim ----- Original Message ----- From: "Dale Botkin" To: Sent: Thursday, February 28, 2002 6:23 PM Subject: Re: [OT]: Old Chips > On Thu, 28 Feb 2002, Harold M Hallikainen wrote: > > > sense amplifiers (remember what they were sensing?) > > Usually magnetics, often core memory, wasn't it? > > Dale > > -- -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.