7 Mar
2022
7 Mar
'22
10:04 p.m.
Interesting question below...
On 2022-03-07 21:56, Thomas DeBellis wrote:
After I sent the below, I found that I couldn't
get that ancient SPR
response off my mind. I was surprised that I was still mystified after
nearly four decades and decided to revisit the issue. In summary, I've
realized that I had been missing some key use cases that make a 36 bit
CTY special.
First of all, you didn't need to login to the front end (RSX20F), so if
you did get to the CTY and typed a Control-\, you could run a program
(say from floppy) that could basically do what it wanted, so my 'fix'
wasn't really a complete 'cure' at all nor could it be. This also
exists in simulators and you can also deposit or examine whatever you
feel like.
Under Tops-10, the situation might be considered to be worse (but I
believe that term to be unfair). That is, the operating system has no
control over what might be examined or deposited from the front panel.
There, the CTY is even more special: it doesn't need a password for
/any/ login. You can do an _I [1,2]_ and you are now an operator (I.E.,
root). However, for many years, I thought this was just neat...
What about other DEC multi-user operating systems? Do you have
'magic' consoles?
In RSX, when the system boots up, the console terminal is logged in, and
start running the SYSTARTUP.CMD script. If people are lazy/sloppy that
script just finishes, and the terminal is still logged in, and
privileged. If so, you can do anything there.
However, the sane person finishes the SYSTARTUP.CMD with the BYE
command, which logs out the console terminal.
At that point, it's just like any other terminal. But with the addition
that by default system messages are printed on that terminal. That can
be directed to some other terminal, if wanted, though.
So it's basically just that at boot, the console terminal is special,
since that's the one that is running things. Nothing beyond that.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt(a)softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol