X-Git-Url: http://git.subgeniuskitty.com/simh-images/.git/blobdiff_plain/3af0054c1c0460f3308e9ffbc8f7a6f648071f92..a5f697610318f65a7ca663e041a8df818c5a13be:/pdp11-V5_UNIX/README.md diff --git a/pdp11-V5_UNIX/README.md b/pdp11-V5_UNIX/README.md new file mode 100644 index 0000000..51fb35f --- /dev/null +++ b/pdp11-V5_UNIX/README.md @@ -0,0 +1,110 @@ +# Overview # + +This directory contains a V5 UNIX system image for use with the PDP-11 +simulator included in SIMH. The image was taken from a PDP-11/45 with an RK05 +disk (2.4 MB). + +V5 UNIX was the first version licensed widely outside AT&T, largely due to +[Thompson and Ritchie's CACM +paper](https://www.bell-labs.com/usr/dmr/www/cacm.html) that had recently +introduced UNIX to the world. + +Version 5 still only targeted PDP-11s, but expanded to include those models +with an 18-bit physical address space, compared to the 16-bit address space of +previous models. This allowed up to 256 kB of RAM and greatly increased the +capabilities of the system, needed as UNIX reached "above 50" installations at +the time of this release. + +This is the second release of UNIX written in C, a language still in flux that +had only existed for a couple years. The system is self-hosting using the +included compiler but there are many differences from modern C visible in the +on-disk source code. + +Old enough to predate the Bourne shell from Steve Bourne, V5 UNIX ships with +the Thompson shell written by Ken Thompson. This was the first UNIX shell, +mainly a command interpreter rather than the interpreted language that most +UNIX shells became. Intentionally minimal, commands like `if` and `goto` are +implemented as separate executables rather than as built-in shell commands. This +shell was replaced by the Bourne shell in V7 UNIX and by the C shell in 2BSD, +leading to its rapid decline in popularity. + +Several now common commands were first introduced in this release, including +`dd`, `pwd`, and `wump` (Hunt the Wumpus). At this stage it's starting to +*feel* like a UNIX system. + +Then there's the editor, `ed`. A UNIX classic, it's a little like using `vi` +with your eyes shut. If you've never used it before, check out my [guide to +ed](https://subgeniuskitty.com/development/pdp-11/guide-to-ed-text-editor). + + +# Status # + +Fully tested on SIMH 3.9-0. + + +# Instructions # + + +## Power On ## + +To power up a simulated PDP-11/45 and run this V5 UNIX disk image, simply +un-gzip the disk image file and start up SIMH with the provided configuration +file. + + % gunzip unix_v5_rk.dsk.gz + % pdp11 simh.conf + + PDP-11 simulator V3.9-0 + Disabling XQ + . + .Type kernel filename at the '@' prompt. + .For example: @unix. + .UNIX username is 'root'. + .No password. + . + @ + +The `@` prompt is from the bootloader, to whom we must pass a file to continue +the boot process. Our kernel is a file named `unix`, so type that here followed +by `ENTER`. + + @unix + + ;login: + +The system has now booted up and you may login as `root` (no password). + + ;login: root + # + +That's it! V5 UNIX is up and you're logged in. + + +## Power Off ## + +To power off, assuming you are logged in as `root` and the system is otherwise +inactive, use the `sync` command to flush any buffers to disk and then type +`Ctrl-e` to halt the simulation and `quit` to exit SIMH. + + # sync; sync + # + Simulation stopped, PC: 001726 (MOV (SP)+,177776) + sim> quit + Goodbye + +Note that you can also press `Ctrl-e` at any time and SIMH will halt the PDP-11 +simulation and drop to the `sim>` prompt where you can exit. However, doing +this is likely to corrupt a disk as it is equivalent to yanking the power cord +from the wall. To resume from the `sim>` prompt, simply type `go` and execution +will resume from where it left off.. + + +## Transfer Files ## + +Output to the line printer or input/output via the paper tape are one option. +The relevant options to enable that hardware in SIMH are commented out in +`simh.conf`. + +When offline, it is possible to mount the disk image and interact with it +directly. For example, use +.