[joelberman]

I was one of the first sailors to go through DS A school at Mare Island. Previously the DS went through ET school first. We learned the purpose of every gate in the UDT a 15-bit computer with 512 words of memory before stepping up to the 642A and 642B computers. This was in 1967 when it was still possible to know how every bit of hardware and software worked.

[bell-cot]

'67...wow. I'd bet I understand the reason for that kind of training. Folks who remembered (for instance) the Second Naval Battle of Guadalcanal (14–15 November, 1942) would still be serving. And the vast differences in the performances of the battleships USS Washington and USS South Dakota in that battle. Admiral Lee, aboard the Washington, had an incredibly detailed understanding of the ship and its systems. He made "Sink enemy battleship while taking no damage" look easy. Vs. the South Dakota's massive screw-ups in her electrical switchboard room - just before the battle got interesting - converted her into a helpless, easy target for enemy fire.

[mwint]

Sounds interesting, do you know of any good places to read about this?

[albatross13]

Now that is cool- I have to ask, is there a moment in your memory where looking back you kind of realized "Wow, I can no longer keep track of everything going on with these computers?" (in regards to it being possible to know how every bit of hardware/software worked).

[segmondy]

It's still possible to do so. Just get an EE degree, you will understand hardware down to the gate level. Take a solid CS course and you will understand software down the basic levels. Understanding hardware to OS is something that a lot of people still know, what is difficult to know these days is the layers of software by 3rd parties running on the OS.

[cptnapalm]

From what I've read from others a PDP-8 or maybe a PDP-11 is about the limit. They got a 12-bit computer with 32 KiW to be a time sharing system for 17 users with TSS-8. So they were still quite capable.

[GrumpyYoungMan]

Contrary to some sibling posts, datapath width isn't really the limiting factor for comprehension IMO; everything is "wider" but not more difficult to understand. For example, undergraduate computer engineering students could and did design pipelined in-order 32 bit processors as part of their studies.

At least IMO superscalar + out of order execution was when things really became too complex to hold comprehension of the entire processor in one's head.