Glass memory?

[Brent Hilpert]

On 2022-Apr-01, at 10:52 AM, Chuck Guzis via cctalk wrote:
> On 4/1/22 10:27, Paul Koning wrote:
>> 
>>> On Apr 1, 2022, at 1:25 PM, Chuck Guzis via cctalk <cctalk at classiccmp.org> wrote:
>>> 
>>> Wasn't some of this glass delay line memory used in early raster-scanned
>>> computer video displays?
>> 
>> I don't know about that one, but a delay line is a key component of a PAL (European) system color TV receiver.
> 
> I know that the CRT display controller on the CDC 200 series terminal
> (INTERCOM, Export/Import 200 software) used a 10 msec magnetostrictive
> delay line.for image storage.    Glass would seem to be a more
> mechanically robust storage medium.
> 
> See:page 1-5
> http://bitsavers.org/pdf/cdc/terminal/82128000_200_User_Terminal_Hardware_Reference_Jul68.pdf
> 
> Later raster terminals used MOS shift register memory.
> 
> The STAR-100 stations used a track on the station microdrum for video
> refresh.



CRT monitors would seem like a likely target application for them.

Their higher speed may have worked to advantage to reduce the total memory requirement. The MOS-shif-register-memory displays typically had two R/W memories: a frame buffer and a character-line buffer, the line buffer captured one line of characters from the frame buffer as it cycled by, so it could be rescanned several times for the multiple H-scan lines forming a character. The higher speed of the glass memories perhaps would have eliminated the need for the line buffer.