It is funny that the most common memory used today is a DRO type memory. The read destroys much of the charge on a DRAM cell, requiring a write back of the data. Dwight
________________________________ From: cctalk <cctalk-boun...@classiccmp.org> on behalf of Jon Elson via cctalk <cctalk@classiccmp.org> Sent: Sunday, October 20, 2019 10:22 AM To: Nigel Johnson <nw.john...@ieee.org>; gene...@ezwind.net <gene...@ezwind.net>; Discussion@ <ezwind.net:On-Topic and Off-Topic Posts cctalk@classiccmp.org> Subject: Re: plated wire memory On 10/20/2019 09:45 AM, Nigel Johnson via cctalk wrote: > I remember an IBM engineer talking about this at our ham > radio club. The wire was coiled inside a drum and pulses > were sent down the wire. The 'read head' was a magnetic > pickup at the other end of the coil - and access time was > however long it took the pulse to arrive at the other > end. Therefore storage capacity was inversely > proportional to data quantity, however at that time I was > working with 660kB Univac FH330 drums for swapping and the > 2-ton Fastrand for 164kB of long-term storage, so it has > to be taken in context! > No, that is acoustic delay line memory, and is a serial access type of data storage All data is lost if the equipment is powered down. Plated wire memory is a random-access type of memory using principles similar to core memory, except the magnetic material is a magnetic film plated onto the copper wires. There are a few other forms of NDRO such as Biax that use cores with two holes in them, one for the sense/inhibit wire and one for the select wires. Jon
