41–50 of 59 posts
Used several of these at school in the 90's. IIRC intro classes used VAX/VMS (was the machine called VAX-1170?). But all the higher undergrad classes used Unix on PDP-11/70's, like in the picture. Of course, I hardly ever saw one up close. :p
In 1997-1998, I was working for a small company in Atlanta who did tape backup systems. At a client in maybe Knoxville (?), a hospital had a PDP-11/70 live in their machine room. Amusingly, right next to racks of then super-fancy Cisco gigabit fiber networking.
I was told that the PDP handled payroll. Guess that was important. Wonder how long it lasted there?
What happened if you used auto-decrement addressing with the PC? Did that hang the computer?
x: mov -(pc), -(pc)
reads an instruction from x, increments the PC to x+2, then decrements the PC back to x and reads the same instruction, then decrements it again to x-2 and writes it, then it executes from x-2 ......
There's a parallel worldline out there where the PDP-11 made the transition into a desktop PC[0] and the IBM PC didn't take over the world. In that worldline our servers are from the PDP-11 lineage, and not the IBM PC. [0] https://en.wikipedia.org/wiki/DEC_Professional_(computer)
I'd suggest the Datapoint 2200 as the most influential minicomputer of all time since half of you are using an instruction set based on it and it is largely responsible for the creation of the microprocessor. Now mostly forgotten, the Datapoint 2200 was a programmable desktop computer introduced in 1970. It had a processor built from TTL chips, along with shift-register memory from Intel. Datapoint discussed with Int…
The 6809 (and its clone the 6502) would also be strong contendors. And if Motorola were 6 months faster with the successor 68000 compared to Intels 8086, the IBM PC would be 68000 based and Intel would today be known as a memory chip company. We’d be big endian with no legacy in 2026 of segmented memory architecture in mainstream processors. And with big 3 companies using 68000 (IBM, Apple and C=), we definately woul…
I’m not quite old enough to have grown up with the PDP-11. They were gone from university (or at least the parts I had access to) by the time I arrived. But I did see exactly one in the wild. In 1997-1998, I was working for a small company in Atlanta who did tape backup systems. At a client in maybe Knoxville (?), a hospital had a PDP-11/70 live in their machine room. Amusingly, right next to racks of then super-fanc…
Earlier quoted context omitted.
014747 makes me smile I built the PDP-11/70 emulator that controls the nuclear reactors in Ontario. That was 20 years ago and I'm probably still the youngest person who can read PDP-11 assembly (and the raw octal)
There's a decent chance you're younger than me, but I can still read it. Coincidentally about 20 years ago I got asked to fix a bug in some PDP11 code that ran on real hardware because it was tripping up an emulated system. Nothing wrong with the emulator as such, it was just a logic bug in the program that they no longer wanted to work around. I made the fateful mistake of saying "Sure, sounds fun, how hard could it…
The FPGA emulator we made had to pass the xxdp test suite which was provided to me on punched tape and microfiche. The emulator had a specific test for FDIV overflow which even tested the accuracy of the partial result. None of the software emulators I tested did this. I emailed Gordon Bell who introduced me to Bob Supnkk, and we found the original flowcharts for it so I could replicate the divider logic precisely. Imagine a nuclear reactor dependent on this lol.
Earlier quoted context omitted.
The 6809 (and its clone the 6502) would also be strong contendors. And if Motorola were 6 months faster with the successor 68000 compared to Intels 8086, the IBM PC would be 68000 based and Intel would today be known as a memory chip company. We’d be big endian with no legacy in 2026 of segmented memory architecture in mainstream processors. And with big 3 companies using 68000 (IBM, Apple and C=), we definately woul…
The 6502 isn't a 6809 clone; it was largely inspired by the 6800.
I'd suggest the Datapoint 2200 as the most influential minicomputer of all time since half of you are using an instruction set based on it and it is largely responsible for the creation of the microprocessor. Now mostly forgotten, the Datapoint 2200 was a programmable desktop computer introduced in 1970. It had a processor built from TTL chips, along with shift-register memory from Intel. Datapoint discussed with Int…
a) the PDP-11 CPU was also implemented in TTL logic, like the Datapoint,
b) there were later implementations of the PDP-11 as NMOS microprocessors:
https://en.wikipedia.org/wiki/DEC_T-11
https://en.wikipedia.org/wiki/PDP-11#LSI-11_integrated_circu...
c) the VT100 terminal was based on the Intel 8080 microprocessor
https://en.wikipedia.org/wiki/VT100
There was appreciation and exchange between Intel and DEC.