Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!decwrl!labrea!rutgers!bellcore!texbell!uhnix1!sugar!karl
From: karl@sugar.uu.net (Karl Lehenbauer)
Newsgroups: comp.os.misc
Subject: character-at-a-time I/O (was Re: Re^2: Unix bigotry)
Message-ID: <3472@sugar.uu.net>
Date: 20 Feb 89 04:38:30 GMT
References: <4434@freja.diku.dk> <5900004@hpfcdc.HP.COM>
Organization: Sugar Land Unix - Houston, TX
Lines: 71

In article <5900004@hpfcdc.HP.COM>, marc@hpfcdc.HP.COM (Marc 'Sphere' Sabatella) writes:
> There was a discussion (wasn't it here?) a while ago concerning single
> character I/O.  NOS doesn't support it, and that fact alone causes it to
> run X% faster than Unix on the same machine.  I would also claim that the 
> better support for batch-mode processing in NOS also makes it faster than 
> Unix, ...

(Yes, and I had been meaning to comment during that discussion and never got
around to it.)

While fighter planes are optimized for performance, they are missing many 
amenities like bathrooms, movies and in-flight meal and beverage service.  
If you want to go as fast as possible, you have to give up amenities.  If one 
had to spend eight hours a day, five days a week (or more) traveling in an 
airplane, one might quickly come to desire almost anything over an F-16.

These arguments, in fact, have been used in support of batch processing against 
timesharing since the invention of timesharing in the 1960s, and in support 
of assembly language programming over high-level language programming since 
the 1950s.

I leave it to the reader to contrast how the vast majority of people interact
with computers today, and how most programmers program, with these attitudes.

> ...and
> the numerous kludges necessary to get Unix to run on a machine with 60 bit
> words is also bound to slow it down a little more, etc.

64-bit words.  60-bit, ones-complement, 6600 emulation is thoughtfully 
provided for sites for whom converting their software is an overwhelming 
task.  For example, every PLATO site in the universe.

>If you are going to shell out the major $$$ for a Cyber 200, ETA-20, or Cray 2,
>you don't want to saddle it with an operating system that is not going to take
>full advantage of the hardware.

...depends on what I want to do.  Since most sites spend as much money on
software as on hardware, maybe I'll run a little slower but save a lot of
money on software, training, etc.

I have a theory that for a lot of sites, mainframes are not a win.  Consider
that if you're sharing a mainframe among too many people, you may not be
getting as many CPU cycles overall as you would if you had your own workstation.
(The mainframe guy willing to come in at midnight gets a lot of cycles, though.)

So it comes to a question of how many cycles are you getting, are you getting
enough (never), and what can you do with them.  I contend that, although it
is possible to get a lot of cycles from a mainframe, you don't always, and
when you do, you can't always use them in the ways you intend, as shown by
the fact that you can't do character-at-a-time I/O under a lot of mainframe
OSes, and mainframes have rotten timesharing environments in general.

Another thing, mainframes are harder to program.  At least, historically, user-
friendly software came from minis and PCs.

And finally, there is *the challenge* to mainframes.  How much (in scalar MIPS) 
faster is a Cyber 20x than a fast MIPS M2000 like the DECstation 3100?  Just a 
few times, right, like less than ten?  A Cyber costs several dozen times more, 
right?  (Granted, I/O and vector MFLOPS are another consideration, although 
there are some promising chip developments in this area, too, such as smart 
boards and fast buses for the former and the Intel N10 and Weitek chips for 
the latter.)  I'd rather have 15 MIPS waiting on my 'enter' key (and doing other
stuff, of course) than submit a batch job for 1/20th of 100 MIPS, not to say 
*some* people don't need them, just that a great many do not.

I'm not a luddite or anything, though, which is to say that I would not mind
having 100 MIPS waiting on my 'enter' key ;-)
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