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Thanks for the link. For those who prefer to read, there is a transcript[0]. [0] https://archive.computerhistory.org/resources/access/text/2017/06/102717169-05

Thanks for the link. For those who prefer to read, there is a transcript[0]. [0] https://archive.computerhistory.org/resources/access/text/2017/06/102717169-05-01-acc.pdf https://archive.computerhistory.org/resources/access/text/20...

kragen 2y ago
thank you! i should have posted that
Animats 2y ago
Oh, Norm Hardy's wife. Tymnet was interesting. It was a virtual circuit-switched system for keyboard terminals. There was a central control machine, and a bunch of dumb switching nodes. The central control machine (an SDS-945 originally) would set up a route and send out "route channel 24 to channel 57" commands to each node. The nodes just forwarded packets per the set route. If the control machine went down, all routes stayed working, but new ones could not be set up. There was a second control machine that could take over if needed. Nodes had a queue for each virtual circuit, and flow control. It wasn't end to end raw packets. In the days of expensive long haul bandwidth, this was essential. Pure datagram networks only work because our long-haul connections today have huge bandwidth. Datagram networks can't really handle congestion in the middle of the network. Virtual circuit networks can. Which is why, in the early 1970s, it looked like virtual circuit networks were the future. Even the original ARPANET had node to node flow control. The Tymnet "backbone" was originally only 2400 to 4800 baud, so they had major lag problems. To help with this, they used local echo when possible, so local typing didn't lag. You'd type in a line, and at the end of the line, the whole line went across the network. The connection could shift from local to remote echo seamlessly. (Telnet, for the Internet, can do local echo, too, but Berkeley didn't put that in their BSD Telnet, so it fell out of use as network bandwidth increased. That worked in pre-BSD UNET, and echo would be local until you used some program, such as "vi", which enabled "raw mode".) Here's a summary of the Tymnet technology.[1] [1] http://cap-lore.com/Tymnet/TOCN.html http://cap-lore.com/Tymnet/TOCN.html
- kragen 2y ago
  > Oh, Norm Hardy's wife. she has some funny stories in that interview about people saying things like that :) but in this interview she's not talking about his work except briefly; she's talking about her own she goes into some detail on the history of the evolution of the tymshare systems you're describing in that interview, though not as much as i had hoped. they continued evolving after la roy's article. thanks for posting a link to it!
- sillywalk 2y ago
  From the same cape-lore website, Tymshare also devloped GNOSIS (Great New Operating System In the Sky[0] which became KeyKos. A secure capability-based operating system with transparent persistence. KeyKOS inspired EROS ( Extremely Reliable Operating System). http://www.cap-lore.com/Agorics/Library/keykosindex.html http://www.cap-lore.com/Agorics/Library/keykosindex.html https://en.wikipedia.org/wiki/EROS_(microkernel) https://en.wikipedia.org/wiki/EROS_(microkernel) [0] Sky .. like "clouds" existed in the 1970s? :)
  - kragen 2y ago
    it also inspired e, cheri, a lot of the design of current js, and the security architecture of current implementations of liedtke's l4, including sel4. ann was ceo of agorics

kragen 2y ago

thank you! i should have posted that

Animats 2y ago

Oh, Norm Hardy's wife. Tymnet was interesting. It was a virtual circuit-switched system for keyboard terminals. There was a central control machine, and a bunch of dumb switching nodes. The central control machine (an SDS-945 originally) would set up a route and send out "route channel 24 to channel 57" commands to each node. The nodes just forwarded packets per the set route. If the control machine went down, all routes stayed working, but new ones could not be set up. There was a second control machine that could take over if needed. Nodes had a queue for each virtual circuit, and flow control. It wasn't end to end raw packets. In the days of expensive long haul bandwidth, this was essential. Pure datagram networks only work because our long-haul connections today have huge bandwidth. Datagram networks can't really handle congestion in the middle of the network. Virtual circuit networks can. Which is why, in the early 1970s, it looked like virtual circuit networks were the future. Even the original ARPANET had node to node flow control. The Tymnet "backbone" was originally only 2400 to 4800 baud, so they had major lag problems. To help with this, they used local echo when possible, so local typing didn't lag. You'd type in a line, and at the end of the line, the whole line went across the network. The connection could shift from local to remote echo seamlessly. (Telnet, for the Internet, can do local echo, too, but Berkeley didn't put that in their BSD Telnet, so it fell out of use as network bandwidth increased. That worked in pre-BSD UNET, and echo would be local until you used some program, such as "vi", which enabled "raw mode".) Here's a summary of the Tymnet technology.[1] [1] http://cap-lore.com/Tymnet/TOCN.html http://cap-lore.com/Tymnet/TOCN.html

kragen 2y ago
> Oh, Norm Hardy's wife. she has some funny stories in that interview about people saying things like that :) but in this interview she's not talking about his work except briefly; she's talking about her own she goes into some detail on the history of the evolution of the tymshare systems you're describing in that interview, though not as much as i had hoped. they continued evolving after la roy's article. thanks for posting a link to it!
sillywalk 2y ago
From the same cape-lore website, Tymshare also devloped GNOSIS (Great New Operating System In the Sky[0] which became KeyKos. A secure capability-based operating system with transparent persistence. KeyKOS inspired EROS ( Extremely Reliable Operating System). http://www.cap-lore.com/Agorics/Library/keykosindex.html http://www.cap-lore.com/Agorics/Library/keykosindex.html https://en.wikipedia.org/wiki/EROS_(microkernel) https://en.wikipedia.org/wiki/EROS_(microkernel) [0] Sky .. like "clouds" existed in the 1970s? :)
- kragen 2y ago
  it also inspired e, cheri, a lot of the design of current js, and the security architecture of current implementations of liedtke's l4, including sel4. ann was ceo of agorics