From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Sat,  2 Sep 1995 17:56:51 -0400
From: forsyth@plan9.cs.york.ac.uk forsyth@plan9.cs.york.ac.uk
Subject: plan9 on laptop
Topicbox-Message-UUID: 1eb52acc-eac8-11e9-9e20-41e7f4b1d025
Message-ID: <19950902215651.o06pl5KYBiRmAWKRJvsUsF9UOyIPbTkM8C7A39FSxE0@z>

>>It is said about compiler that floating point requires hardware fpu. Does
>>it mean that the system won't work with 486sx/slc, that is a frequent
>>chip to install in laptops?

there is no support in the 386/486 kernel for emulation of floating point.
the 486sx seems to return not-a-number (NaN) for floating-point operations,
if the processor is not set to trap on floating point operations (and
plan 9 does not set that bit).

although the bulk of the system will function quite happily without
a floating-point unit, there are important exceptions.  sometimes these
are surprising.  it has been some time since i tried a 486sx on the
cpu/terminal kernel, but i believe that either 8c or 8l will fail.
one of the more surprising programs to fail is troff, which now
uses floating-point (at least, it did in the old release, and i don't
think that's changed).  less surprising failures include awk.
the window system and editors weren't a problem.

>>Is it possible to install the system on a laptop with 4 Mb?

the installation system needs more than 4 Mbytes of memory to expand
the compressed diskette images.  it could be virtual memory, but
until things are set up, where is it safe to swap?  it declines
to guess (you see! they weren't after your linux partitions after all!).
if you install the system somewhere else, you can then fiddle with
things to adapt the installation images to add swap commands,
the invocation of the swap commands, etc.  that's hard work:
much easier is to install somewhere else, and use the first diskette
to install a subset system over the network.

at work, i use a 386sx16 with 4 Mbytes as my usual terminal
to access a larger Plan 9 network.  i run samterm and lightweight windows
like seemail on the terminal, and almost everything else on a CPU server.
that works adequately (it puts up windows faster than X11 on
a much faster workstation on my desk), but it needs to page.
it is cramped, and although part of the editor can run on the terminal,
i'd never expect to do compilations there as a matter of course.
(i did do that when bootstrapping the first edition's file server kernel
on to the PC, and it took 20 minutes to produce 9pcfs, which the
16Mbyte CPU server/file server combination produces in a fraction of
that time: the linker, for various reasons, uses lots of data space.)

because several local suppliers offer very reasonable deals on
386sx25 mono. notebooks, i have considered getting one to run a portable
Plan 9.  even so, i'd expect to do little more than edit on it,
and even compiling my things, not the kernel, i'd go for at least
6 Mbytes.

still, i'm probably the last person in the department doing
useful work with only a 386sx16/4meg on my desk.
try that with Windows 95 (or even linux with X11 -- i can use windows).
oh all right: i have got another computer on my desk, but because
it doesn't run plan 9, i don't do much with it at the moment, nice though it is.