Incompatible Timesharing System

https://github.com/PDP-10/its

by rbanffy • 6 years ago

71 27 6 years ago

github.com

fiddlerwoaroof2• 5 years ago

Has anyone attempted to port these pre-Unix oses to modern hardware?

klyrs• 5 years ago

I found some here https://www.inwap.com/pdp10/emulators/

This is the 5,376th access to this page.

Hope we don't hug it too hard

fiddlerwoaroof2• 5 years ago

I know about emulators, but I’d think someone would have found porting ITS or Multics to x86 or Arm a fun hobby project

gumby2• 5 years ago

Remember ITS was written in assembly language for the PDP-10, a 36-bit machine with an 18-bit address space (yes, it was also intended to run Lisp efficiently). It was a fun machine to program in assembly code, emulatable on a 64-bit machine sure. But not something you would "port" to a different architecture.

musicale3• 5 years ago

I bet you could write a translator to convert PDP-10 code to x86 code or something.

You could also probably rewrite it manually.

lhjn• 5 years ago

I remember studying CTSS, ITS, Multics and some other historical OSs and being amazed at how much of the current OS features/design come from the 60s. Then I learned about Lisps and their history, and remember being amazed at how much current languages are grafting from them. The 50s and 60s hold a very special place in my heart wrt technology. The boldness and beauty of the ideas expressed in those years is something we rarely see these days (I feel).

7373737373• 5 years ago

This might be of interest to you: "Why KeyKOS is fascinating" - https://github.com/void4/notes/issues/41

svat2• 5 years ago

Wikipedia article on this OS: https://en.wikipedia.org/w/index.php?title=Incompatible_Time...

See also the lesser known west-coast alternative: WAITS (at Stanford): https://en.wikipedia.org/w/index.php?title=WAITS&oldid=99028...

musicale3• 5 years ago

WAITS is a great name for an OS.

kzrdude3• 5 years ago

Why a permalink?

svat2• 5 years ago

Probably doesn't matter much here but I try to always use a permalink when linking to Wikipedia, as a matter of policy. This is because:

1. The permalink is the link to the Wikipedia page as I actually saw it (and can sort of vouch for). Without a permalink, when someone visits the Wikipedia page weeks, years, or even minutes later, they may see something entirely different: maybe it has been (temporarily) vandalized, or sections removed or substantially rewritten, or the whole page has been made a redirect to some other page, or worse.

2. Even if the above reasons don't apply (and someone may actually want to see the latest version), it's very easy to go from the permalink to the current version (there's a prominent notice at the top of the page), while it's hard to go in the other direction (find the version at the time my comment was posted). So the permalink version carries "more information" / is less "lossy".

Taken to an extreme, this reasoning would suggest doing the same when linking to any page on the internet: save it on the Wayback Machine and use that URL. (People have suggested this: https://news.ycombinator.com/item?id=24406193) The reason I don't (so far) do that is:

1. On Wikipedia, permalinks are really quick and easy to obtain (it's in the sidebar to the left, and you can even just right-click and copy URL) -- saving something to the Wayback Machine takes several seconds,

2. In the case of Wikipedia, it's clear that the site owner actually intends for the permanent link to be used. (No concerns about losing clicks or whatever.) As a corollary, the permalink URL is guaranteed to work equally well (in terms of uptime, how fast it loads, CSS/JS, etc) as the current version of the page itself. Can't say the same for arbitrary websites.

3. Sites other than Wikipedia don't keep changing all the time, and there's a lower risk of being rewritten as a result of my linking to it, or being replaced by some vandalism or defacement. (Most pages on Wikipedia are very good at reverting vandalism in minutes at most, but still...)

gumby2• 5 years ago

ITS was a true hacker OS. The "command shell" (as it would be called today) was the debugger (DDT). So when your program crashed instead of getting a core dump you'd typically end up in the debugger. Hence that same behavior in the lisp machines.

Also it had no security. In fact you didn't even have to log in; all that did really was set your default directory.

kzrdude3• 5 years ago

rms mentions ITS in the movie Revolution OS, I think

miohtama• 5 years ago

How to learn Lisp, ‘82 edition:

https://github.com/PDP-10/its/blob/master/src/teach/lesson.i...

The good times when programming was few orders of magnitudes simpler with less abstraction layers.

jonjacky• 5 years ago

... and when you could invite random strangers from the Internet (well, the Arpanet) to play around on your system:

This memo is aimed at users unfamiliar not only with the Emacs editor, but also with the ITS operating system. ... Emacs runs on the ITS machines, AI, ML, MC, and DM. For people coming from an Arpanet TIP, the host numbers are: 134 (AI), 198 (ML), 236 (MC), and 70 (DM). If you don't have a regular username there, ... (use) the WHOIS program: :WHOIS XYZ. If WHOIS didn't find any regular user XYZ, you can use that name. :LOGIN XYZ. You are now talking to DDT, the top-level, monitor program ...

From https://web.archive.org/web/20110723033542/http%3A//www.burl... An Introduction to the Emacs Editor by Eugene Ciccarelli, AI Memo No. 447, January 1978, Artificial Intelligence Laboratory, MIT

musicale3• 5 years ago

This is amazing. I've been wanting to run this for years.

Fantastic piece of computing history.

Incompatible Timesharing System

Related Stories