[TUHS] What was your "Aha, Unix!" moment?

William Corcoran wlc at jctaylor.com
Sat Oct 26 10:57:57 AEST 2019

The year was 1986.  Top Gun was in the theaters. Lionel Ritchie was belting out “Say you, say me” on serious overplay.  

I was working on the coolest machine I ever saw.  The Motorola S290. Initially, we had System III and eventually System V.   At the time, I learned MS DOS months before I was exposed to UNIX.   I could not understand how a new small Motorola UNIX Super-microcomputer  could have such an extensive set of documentation.  I had to read these huge books to learn this same system could run computers from DEC and others.  These UNIX books were so extensive and I found there were two ways to use UNIX:  (1) sign on to the system at at work; or, (2) sign on to the system in my imagination.   Both were equally as fun.  

The Motorola S290 had a small DPU tower called Data Processing Unit and several other similar shaped small towers linked by a SCSI bus that housed 5.25” devices of the day.  This included 50MB hard disks, Wangtek Streaming Tape Drive.

Yes! You could mount a streaming tape as a block device!  It would “shoe shine” the tape heads if you “cd” into a formatted tape.  It was not practical as a block device, but it worked.  

The Motorola S290 DPU ran a primary operating system called ISOS. It was UNIX like. But not UNIX.  Boot disks had to have an ISOS partition and a UNIX partition.  

The Motorola S290 would first boot ISOS.  Then, UNIX would start afterwards.

ISOS has similar UNIX commands like “cd”, “ls”, and “ps”

After working in a UNIX shell one day, I signed on to ISOS.   I wanted to understand how UNIX integrated with ISOS. 

What blew my 1986 kid mind: After signing on to ISOS, I did a “ps”

123   2               “/UNIX”

Aha UNIX!   UNIX was a process running under ISOS!

Bill Corcoran 

> On Oct 10, 2019, at 4:56 PM, Warren Toomey <wkt at tuhs.org> wrote:
> All, we had another dozen TUHS suscribers to the list overnight. Welcome.
> A reminder that we're here to discuss Unix Heritage, so I'll nudge you
> if the conversation goes a bit off-topic.
> So I'll kick off another thread. What was your "ahah" moment when you
> first saw that Unix was special, especially compared to the systems you'd
> previously used?
> Mine was: Oh, I can:
>  + write a simple script
>  + to edit a file on the fly
>  + with no temporary files (a la pipes)
>  + AND I can change the file suffix and the system won't stop me!
> I was using TOPS-20 beforehand.
> Cheers, Warren

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