[Info-vax] DCL Integer Overflow

[Scott Dorsey]

Simon Clubley  <clubley at remove_me.eisner.decus.org-Earth.UFP> wrote:
[regarding CDC NOS]
>For the benefit of those of us who have never had to use this
>environment, can you describe how you would carry out some
>common tasks using this environment, so we can compare the
>syntax (and semantics) to the syntax/semantics used on VMS or Unix ?

It's a matter of verb,noun,noun.  So to copy a file from X to Y,
you would type:

COPY,X,Y.

Unless it was a binary file in which case you would do

COPYBF,X,Y.

And there were actually a dozen different copy commands allowing you to
split up records and blocks and copy to and from tape volumes.  Every file
on disk has a file pointer attached to it, so you have to type REWIND,FILE.
before starting to use it.  The file paradigm is very tape based even though
everything is on disk.

Character set is 6 bits in normal mode, but if you're in ASCII mode, some
characters are 6 bits and others as 12 bits.  Machine is word-addressed,
so there are from 5 to 10 characters at each address.  Handling characters
is very much an afterthought; the machine is intended to do floating point
very fast and everything else is kind of slopped together.

You don't actually talk to the CPU directly, your terminal is attached to a
small peripheral processor, and until you hit return on the terminal the CPU
doesn't see anything you type.  So the full screen editor has a huge amount of
inlined PPU code.  The I/O architecture was clearly never designed for 
interactive use, but it was designed to offload the CPU as much as possible so
the CPU could keep busy doing floating point in a batch environment.

>Also, is this environment actually _worse_ than IBM's JCL ?

Sort of.  Both CCL (Cyber Command Language) and JCL were intended for use
as scripting languages.  As a scripting language, I'd say JCL was worse 
because of all the position-dependent stuff.  However, CCL was also used for
interactive processing where it was totally inappropriate and just horrible.

One thing that IS nice about the Cyber is that if you got disconnected, your
process was put on hold, and you could log in later and recover that process.
I believe it was swapped out to disk when this happened (the system had no
virtual memory so memory was always at a premium) but I am not positive.

But in general a miserable user experience.  I am sure somewhere on 
cray-cyber.org there is a full NOS command manual.
--scott

-- 
"C'est un Nagra. C'est suisse, et tres, tres precis."