by Darius Kazemi, March 31 2019
A resource to be shared
The technical content
the original purpose of the ARPANET was to do resource sharing and we were to be a resource to be shared.
This RFC is the first attempt of the CCN to invite the world to share in their resources via the ARPANET. It documents some of the services they made available to RAND and invites “requests and comments from other sites” for further services.
The CCN site offers an IBM 360 Model 91. This computer was extremely different from the computers at other ARPANET sites. As Braden explains in the 2014 interview referenced above:
The IBM system is a batch processing system, so we could supply batch remote job entry service over the ARPANET with the IBM mainframe. Almost all the other ARPAnet sites were computer science research outfits, usually university departments, who almost always had DEC 10, TOPS 10 systems; and used ASCII. Of course, IBM used EBCDIC character encoding, so there was a fundamental communication barrier. The IBM operating system wasn’t programmed, wasn’t designed, to be easily extended by customers. As a result our relationship with IBM was dicey at times, there was a little bad blood. For example, the first thing we had to do was to “invent” interprocess communication for OS/MVT. IPC is a fundamental function in an operating system, but it did not exist in the IBM system, so we designed one, the Exchange, and added it to the kernel as a Supervisor call. I say we; we didn’t invent IPC, of course, I was aware of the concept from the Project Mac work.
The computer offered a bunch of programming language compilers and assemblers, and file utilities. They also had an implementation of the Culler-Fried On-Line System available so users could do things like plot complex mathematical functions.
The CCN uses the RJS system described in RFC-88 (co-authored by Braden) for remote access.
The CCN offered about “500 M bytes” of storage at a rate of “5s per kilobyte per month”. Assuming that's 500 million bytes, and I'm not sure what “5s” is but assuming that's $0.05, we are looking at $250/month which works out to about $1,570/month in 2019 dollars. And that's just the storage cost, though I imagine people used a fraction of the maximum per-user allotment.
According to this RFC, “Batch charges are based upon t(CPU time), I(number of I/O requests), and R(core memory region size).”
On the topic of funding, Braden mentions in the 2014 interview that
Connecting to the ARPANET was in a sense a hobby; ARPA did not pay for it. They said, “You make your money from sellingtime and we expect you to fund the software development yourselves.” At that point we needed ARPA’s money to survive financially, so we did the software.
Bob Braden died in April 2018. For more on Braden:
- a long, fascinating interview with him at the Charles Babbage Institute (quoted above)
- an audio interview with him from 1993 that I have yet to listen to
- the IETF blog post written on news of his passing