As readers of the bLob will know I'm interested in moving "back in time", learning about the history of computing before the Personal Computer revolution. I've recently been reading the book "A New History of Modern Computing", it's a textbook but quite enjoyable. It's written in an interesting way, instead of trying to follow all the development streams in chronological order they approach the development of computing from the different groups of users, scientists, data processing, personal use, etc. I'm only about 1/3 of the way through, but I highly recommend this book.
One of the interesting things I was reading about was the development of memory technologies, specifically of core memory in the mid to late 1950's. I first learned about core memory at my first job out of college. Some of the older engineers had worked with the technology earlier in their careers. I wish I'd recorded what they told me then, but if I recall correctly they had told me that there was a preference to continue to use core memory in military aircraft long after industry had abandoned it because it was nonvolatile. If an aircraft crashed the core memory could be recovered, the state of memory could be recovered from the time that the computer stopped. This was the original meaning of "core dump". This data could be used in crash investigations.
But other that these conversations, I have never seen core memory in use or even had a solid grasp of the principles of operation. When I learned of Andy Geppert's Core64 kit, I was intrigued. This kit is great idea, as it gives the builder hands on experience of making a core memory. In my experience nothing helps me understand an unfamiliar technology better than getting hands on with it. Building 64 bits of core inspires tremendous respect for the men and women who made core memory. For example, the PDP8-i had 4048 12 bit words of core (so 48,576 bits of core had to be woven, 759 times more than the Core64 kit!).
I got a great deal of enjoyment from the process of building the Core64 kit. The documentation is excellent and by tackling a small amount of the weaving process over a few days I was able to complete the assembly that works well and looks really cool because of the interactive nature of Andy's design.
I'd recommend the kit to anyone looking to get a more intuitive grasp of how this technology works. Here's my unit assembled and operating...
See the kit webpage here for instructions and ordering information if you'd like your own...
https://www.core64.io/
Do you have any connection with core memory technologies? Let me know via email or in the comments if you ever used a Digital Equipment PDP-8i, or another computer with core.
In the beginning there was not any computer memory to speak of. The original Univac computer in the early 1950s used Mercury Vapor Tanks as it's main memory. Core memory is a very interesting technology that was used up through the late 1960s and early 1970s until DRAM chips came along. The Apollo 11 Lunar Lander Computer contained about 70K of memory, most of which was hand wired Core Memory programs. The Core64 projects seems to a good mixed of education and history lesson rolled into one.
ReplyDelete