so the question of pseudo tty came up today.
My memory is that it started with TOPS-10, though I doubt I know enough.
Vague memory says there was a PTY: device.
Further, I believe pty came in from UCB ca 1977 or so?
I'm wondering if people who were Present at the Creation can fill in the
gaps.
Thanks
[Note: A few folks Cc'ed directly]
This is not exactly a Unix history question, but given the close
relationship between C's development and that of Unix, perhaps it is
both topical and someone may chime in with a definitive answer.
Starting with the 1990 ANSI/ISO C standard, and continuing on to the
present day, C has specified that signed integer overflow is
"undefined behavior"; unsigned integer arithmetic is defined to be
modular, and unsigned integer operations thus cannot meaningfully
overflow, since they're always taken mod 2^b, where b is the number of
bits in the datum (assuming unsigned int or larger, since type
promotion of smaller things gets weird).
But why is signed overflow UB? My belief has always been that signed
integer overflow across various machines has non-deterministic
behavior, in part because some machines would trap on overflow (e.g.,
Unisys 1100 series mainframes) while others used non-2's-complement
representations for signed integers (again, the Unisys 1100 series,
which used 1's complement), and so the results could not be precisely
defined: even if it did not trap, overflowing a 1's complement machine
yielded a different _value_ than on 2's complement. And around the
time of initial standardization, targeting those machines was still an
important use case. So while 2's complement with silent wrap-around
was common, it could not be assumed, and once machines that generated
traps on overflow were brought into the mix, it was safer to simply
declare behavior on overflow undefined.
But is that actually the case?
Thanks in advance.
- Dan C.
my memory is the major differences between the research RFS and USG’s RFS was the support of ioctls (as mentioned) and, Research RFS supported exporting file trees with an abstract name rather than the path on the source machine - a small but very useful change.
research RFS could (i feel) be seen as the direct ancestor of plan9’s 9p protocol.
-Steve
CSIRO is an Australian government research agency with a long history.
Siromath, a commercial spinoff, had a binary redistribution license
for Unix. The Siromath Unix was called SIRONIX.
The Australian Unison computer was sold with SIRONIX.
Siromath was also going to provide a version of Unix for
the DCR/CSIRONET workstation. At some point they switched to
a port of System V/68 from Neology/Softway. Does anyone know why?
Or if the CSIRONET workstation got beyond the prototype stage? Did
it get cancelled when CSIRONET was privatised?
For more background notes see
https://github.com/jonathangray/csiro-unix
