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A brief tour of the PDP-11, the most influential minicomputer of all time (2022)

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Re: A brief tour of the PDP-11, the most influential minicomputer of all time (2022)

#11

Post by getpost »

not2b wrote: post #9

It was the preferred lab computer in the mid to late 1970s and into the 80s. I got my first job because I knew PDP-11 assembly language, and worked with both DEC's operating systems for them (RT-11 and RSX-11) and later Unix (the lab I worked with had some machines running Version 6, though Version 7 was the first that I used seriously. It had a very clean and symmetric instruction set that used the program counter a…

Ha! The instruction that copies itself. I posted also posted it, 6 years ago. https://news.ycombinator.com/item?id=24820583

Re: A brief tour of the PDP-11, the most influential minicomputer of all time (2022)

#12

Post by ggm »

I'd argue the pdp8 opened the floodgates. That's when the cost of digital computing dropped to the point a research grant or even just discretionary spending in a university department could pay for one, and you didn't need a special room and power supply.

the 11 was when it became more useful. But the 8 was how people realised you could move beyond a calculator to a computer.

Re: A brief tour of the PDP-11, the most influential minicomputer of all time (2022)

#13

Post by amirhirsch »

not2b wrote: post #9

It was the preferred lab computer in the mid to late 1970s and into the 80s. I got my first job because I knew PDP-11 assembly language, and worked with both DEC's operating systems for them (RT-11 and RSX-11) and later Unix (the lab I worked with had some machines running Version 6, though Version 7 was the first that I used seriously. It had a very clean and symmetric instruction set that used the program counter a…

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)

Re: A brief tour of the PDP-11, the most influential minicomputer of all time (2022)

#14

Post by mrandish »

not2b wrote: post #9

It was the preferred lab computer in the mid to late 1970s and into the 80s. I got my first job because I knew PDP-11 assembly language, and worked with both DEC's operating systems for them (RT-11 and RSX-11) and later Unix (the lab I worked with had some machines running Version 6, though Version 7 was the first that I used seriously. It had a very clean and symmetric instruction set that used the program counter a…

> It had a very clean and symmetric instruction set

Indeed. Motorola's 68000 CPU took so much inspiration from the PDP-11's ISA, it was almost a spiritual successor. The 68000's 8/16-bit little brother, the 6809, widely considered the most powerful 8-bit CPU ever - was also heavily inspired by the PDP-11.

Re: A brief tour of the PDP-11, the most influential minicomputer of all time (2022)

#15

Post by ErroneousBosh »

amirhirsch wrote: post #13
not2b wrote: post #9

It was the preferred lab computer in the mid to late 1970s and into the 80s. I got my first job because I knew PDP-11 assembly language, and worked with both DEC's operating systems for them (RT-11 and RSX-11) and later Unix (the lab I worked with had some machines running Version 6, though Version 7 was the first that I used seriously. It had a very clean and symmetric instruction set that used the program counter a…

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 possibly be...?"

Re: A brief tour of the PDP-11, the most influential minicomputer of all time (2022)

#16

Post by larsbrinkhoff »

themafia wrote: post #7
kens wrote: post #3

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 Internet (mostly), the C language, the Unix Operating System were all developed and deployed on PDPs. The BASIC language /and/ an 8080 emulator was developed on a PDP in order to deploy to the Altair. I would argue that Intel was so highly influenced by Datapoint due to sheer proximity and early inexperience in the field.

BASIC was developed on GE mainframes.

Re: A brief tour of the PDP-11, the most influential minicomputer of all time (2022)

#17

Post by ErroneousBosh »

ggm wrote: post #12

I'd argue the pdp8 opened the floodgates. That's when the cost of digital computing dropped to the point a research grant or even just discretionary spending in a university department could pay for one, and you didn't need a special room and power supply. the 11 was when it became more useful. But the 8 was how people realised you could move beyond a calculator to a computer.

> That's when the cost of digital computing dropped to the point a research grant or even just discretionary spending in a university department could pay for one

I've mentioned this before, but the PDP8 launched in the US about the same time as JCB launched their first (and arguably the first really practical and useful) backhoe loader in the UK, which was about three and a half grand at the time.

Can you imagine the paradigm shift with either of those machines? Not just it's possible to do that work, but you can do that work with *your own one*.

At some point someone has looked at a shiny new PDP8 or a JCB 3C in the showroom and gone "you know what, I'm just going to buy one", and got the chequebook out.

Re: A brief tour of the PDP-11, the most influential minicomputer of all time (2022)

#18

Post by throwaway27448 »

kens wrote: post #3

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…

You can see the influence of the PDP-11 on C more than any other ISA. That alone I think qualifies it as the most influential microprocessor of all time.

Re: A brief tour of the PDP-11, the most influential minicomputer of all time (2022)

#19

Post by larsbrinkhoff »

ggm wrote: post #12

I'd argue the pdp8 opened the floodgates. That's when the cost of digital computing dropped to the point a research grant or even just discretionary spending in a university department could pay for one, and you didn't need a special room and power supply. the 11 was when it became more useful. But the 8 was how people realised you could move beyond a calculator to a computer.

Then maybe also give a nod to the LINC, showing DEC a small 12-bit computer could be made.

Re: A brief tour of the PDP-11, the most influential minicomputer of all time (2022)

#20

Post by smallstepforman »

kens wrote: post #3

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 wouldnt have WinTel.
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