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From: peter@sugar.UUCP (Peter DaSilva)
Newsgroups: comp.sys.amiga
Subject: Re: Amiga: Which replacment OS?/UN*X ??
Message-ID: <165@sugar.UUCP>
Date: Fri, 12-Jun-87 20:24:54 EDT
Article-I.D.: sugar.165
Posted: Fri Jun 12 20:24:54 1987
Date-Received: Sun, 21-Jun-87 05:54:04 EDT
References: <600@gryphon.CTS.COM> <1705@vdsvax.steinmetz.UUCP> <1576@stb.UUCP>
Organization: Sugar Land UNIX - Houston, TX
Lines: 68

> Un$x is an absolute PAIN to use floppies with. EVERY TIME you switch them,
> you have TWO commands to give.

Part of the solution to this is a write-through cache. The other... well with
3.25" disks you can mount them transparently. That is basically what the
Amiga does, you know?

> The file system is not safe. In particular, writes to the disk are buffered
> for an arbitrarily long time. I'd love to see the system changed to a write
> through disk cache, or else a small maximum delay (no more than 1 second).

That's an implementation detail. There are version of UNIX with write-through
caches. The system remains the same, you just take a performance hit. I would
like to see AmigaDOS with a UNIX-type cache & a "sync" entry in the menu, it
would cut seeking incredibly. At least you could use it for non-removable
media like hard disks.

> Programs do not have sufficient control over serial ports. I have yet to see
> a terminal program for un*x that even matches, not beats but matches, the
> terminal programs for a trs-80 model 1.

I have yet to see a terminal program for UNIX, period. Terminal emulation is
a matter for the terminal you're on. There are plenty of *modem* programs for
UNIX, however. Some are quite good.

> Programs cannot even guarantee sufficient response time. Although sys5 does
> have a terminal driver with all the features needed, each time you access it
> you have to switch from user to kernel space, which takes significant time.

UNIX is generally not a real-time system. This is correct. It could be made
one, but once again you would take a performance hit for CPU-intensive and
shell-type interactive use. REAL-time UNIXes do exist.

> Want to write any extensions (such as network support over a serial port)?
> Good luck making it work, let alone making it transparent.

You can make it semi-transparent (translucent) with either sockets or named
pipes. I think AmigaDOS has a number of advantages over UNIX here. I
particularly like the Amigados file naming conventions, which can be
slightly modified to become a transparent superset of UNIX's.

> Finally, the swapper has a very poor algorithm for it. A 512K un*x machine
> is limited by the swapper. A 512K Amiga is cramped, but usable. A 1Meg un*x
> machine still swaps. A 1Meg Amiga is bliss. (2 meg runs out of chip memory
> before it runs out of programs to run)

Have you ever used a UNIX machine single user? So long as you don't put gross
stuff into crontab you swap infrequently or not at all... but the ability is
still there. You're sounding like the ATARI-ST people claiming that
multitasking is a problem because of what happens if you misuse it.

> I can do with less hand holding. I program in C :-)

I want as much resource tracking as you can afford. I have used UNIX systems
with considerably less hardware than an Amiga and they ran quite well, so
obviously the 68000 can afford as much. I can do with more bounds checking.

I program in C.

****

Now then. I don't think you need UNIX on the Amiga for a simple reason:
AmigaDOS is already so good. It's not perfect, and there is a lot of stuff
I would like to change, but it's good enough that it's not worth the effort
of replacing it completely. On the other hand, there's no need to slam UNIX,
which isn't an O/S so much as a family of operating systems with a common
programmer and user interface: some of which are not appropriate for a machine
of the Amiga's capacity, and some of which are.