[cctalk] Re: Drum memory on pdp11's? Wikipedia thinks so....

There was drum storage for the early PDP-8 the "Straight 8", PDP-9 and PDP-10.  Each drum stored 32,768 words.  Up to 8 of them could be connected for a total storage of 262,144 words of storage. IBM made a 5BM drum storage unit that was the side of a small refrigerator: The RAMAC's disk storage unit, the IBM 350, weighed over a ton, had to be moved around with forklifts, and was delivered via large cargo airplanes. It stored approximately 5MB of data: *five million 8-bit characters on fifty 24-inch-diameter disks*, a form of drum memory. On 4/15/2024 11:06 AM, Douglas Taylor via cctalk wrote: > At the VFC East just a few days ago a young man came up to me, I had a PDP11/53 on display, and > showed me pictures of his 11/45 and PDP-8 that he had just acquired and needed to learn about.  > It was impressive, he said the 11/45 was missing the memory boards.  If he shows up here on the > list please help him.  To me, it look like he had stumbled into a Unicorn. > Doug > > On 4/13/2024 5:26 PM, Christopher Zach via cctalk wrote: >> Was reading the Wikipedia article on Drum memories: >> >> https://en.wikipedia.org/wiki/Drum_memory#External_links >> >> And came across this tidbit. >> >>  As late as 1980, PDP-11/45 machines using magnetic core main memory and drums for swapping were >> still in use at many of the original UNIX sites. >> >> Any thoughts on what they are talking about? I could see running the RS03/RS04 on a 11/45 with >> the dual Unibus configured so the RS03's talk to memory directly instead of the Unibus, but >> that's not quite the same as true drum memory. >> >> Closest thing I remember was the DF32 on a pdp8 which could be addressed by word as opposed to >> track/sector. >> >> Thoughts? >> C > >