Major milestone! Over the christmas break, I implemented paging to disk,
meaning that you could actually use gcc on a 2MB system. Some poor sod
(Robert Blum) wanted to use Linux on such a system, and couldn't get the
kernel to compile with anything less "bloated" than gcc.
[ Irony alert: this was back when gcc worked fine on a system with just
4MB. Gone are those days. _Loong_ gone. ]
The task size was still limited to 63 tasks of at most 64MB each, but
other than that we were actually getting usable.
Together with other improvements and fixes, 0.12 was actually a very
nice kernel. It was by now clearly more usable than Minix, which caused
us to think that a 1.0 release was imminent. The next kernel version
was to be named 0.95, which turned out to be less than a stellar idea.
This was also the point where we changed the copyright license. See the
attached original release notes.
Other changes:
- Ted Ts'o continued on his rampage, and implemented BSD process
control (ie ^Z) etc. This also introduced the process tree code,
with pointers between parents and children, rather than iterating
over the whole list of processes.
- Ted also did SVR4-style "saved uid/gid" handling.
- use the C preprocessor for assembly files, cleaning up a lot of
duplicate definitions etc.
- better boot loader diagnostics
- boot sequence now can change the size of the text display. Who the
hell is d88-man?
- fix nasty race condition between "truncate" and file IO.
- add support for shared libraries with the "uselib()" system call.
This (together with the fact that we could share clean executable
pages) cut down on memory usage a lot.
- supplemental group support. Hey, what can I say? Unix users expected
them.
- symbolic link handling. This was the first real extension to the
standard Minix disk layout, and was made possible by the fact that I
had written my own "mkfs" and "fsck". Before that, we were still on
crutches, in that a Linux system depended on a Minix installation for
these fundamental system tools.
- mkdir()/rmdir() isn't just for root, you know.. (Yes, seriously.
Old-style UNIX used to limit them to root-only, since they were just
special sequences of mknod's)
- Virtual terminals by Peter MacDonald (who was to do the SLS
distribution).
Before having X, this was a _big_ deal. The fact that Linux had
virtual terminals with a good vt100 emulation actually made Linux
stand out even among some of the big commercial unixes. The Linux
console was just _so_ much more pleasant to use that it isn't even
funny.
- first implementation of "select()", virtual terminals, and pty's.
These too were originally done by Peter MacDonald, based on some
patches that had been floating around for Minix for a long time (but
were never accepted into Minix).
They didn't get accepted into Linux either, but the patches _did_ end
up inspiring me to re-do the select/pty parts in a way that was more
palatable to me.
- restartable system calls
This was needed for Ted's code to do ^Z
- Math emulation! The code was a total crock, and didn't bother with
such unnecessary niceties as getting rounding right (or, to be
honest, even getting more than about 60 bits right), but let's face
it: it was enough to get work done.
My math emulation was eventually to be entirely replaced by a much
more complete, and much more precise implementation by Bill
Metzenthen. But my original stupid implementation actually ended
living on at least for a while in BSD - I ended up making it
available to the BSD people who couldn't use Bill's much better
implementation due to licensing reasons. I don't know whatever
eventually happened to it.
- support alignment check on i486+. Nobody seems to have ever used it,
though.
Original release notes:
RELEASE NOTES FOR LINUX v0.12
This is file mostly contains info on changed features of Linux, and
using old versions as a help-reference might be a good idea.
COPYRIGHT
The Linux copyright will change: I've had a couple of requests to make
it compatible with the GNU copyleft, removing the "you may not
distribute it for money" condition. I agree. I propose that the
copyright be changed so that it confirms to GNU - pending approval of
the persons who have helped write code. I assume this is going to be no
problem for anybody: If you have grievances ("I wrote that code assuming
the copyright would stay the same") mail me. Otherwise The GNU copyleft
takes effect as of the first of February. If you do not know the gist
of the GNU copyright - read it.
INSTALLATION
This is a SHORT install-note. The installation is very similar to 0.11,
so read that (INSTALL-0.11) too. There are a couple of programs you will
need to install linux: something that writes disk images (rawrite.exe or
NU or...) and something that can create harddisk partitions (fdisk under
xenix or older versions of dos, edpart.exe or something like that).
NOTE! Repartitioning your harddisk will destroy all data on it (well,
not exactly, but if you know enough to get back the data you probably
didn't need this warning). So be careful.
READ THIS THROUGH, THEN READ INSTALL-0.11, AND IF YOU ARE SURE YOU KNOW
WHAT YOU ARE DOING, CONTINUE. OTHERWISE, PANIC. OR WRITE ME FOR
EXPLANATIONS. OR DO ANYTHING BUT INSTALL LINUX - IT'S VERY SIMPLE, BUT
IF YOU DON'T KNOW WHAT YOU ARE DOING YOU'LL PROBABLY BE SORRY. I'D
RATHER ANSWER A FEW UNNECESSARY MAILS THAN GET MAIL SAYING "YOU KILLED
MY HARDDISK, BASTARD. I'M GOING TO FIND YOU, AND YOU'LL BE SORRY WHEN I
DO".
1) back up everything you have on your harddisk - linux-0.12 is still in
beta and might do weird things. The only thing I guarantee is that
it has worked fine on /my/ machine - for all I know it might eat your
harddisk and spit it out in small pieces on any other hardware.
2) Test out the linux boot-disk with the root file system. If it
doesn't work, check the hardware requirements, and mail me if you
still think it should work. I might not be able to help you, but
your bug-report would still be appreciated.
Test that linux can read your harddisk at least partly: run the fdisk
program on the root-disk, and see if it barfs. If it tells you about
any partitions at all, linux can successfully read at least part of
your harddisk.
3) Make sure that you have a free /primary/ partition. There can be 4
primary partitions per drive: newer DOS fdisks seem to be able to
create only 2 (one primary and one extended). In that case use some
other partitioning software: edpart.exe etc. Linux fdisk currently
only tells you the partition info - it doesn't write to the disk.
Remember to check how big your partition was, as that can be used to
tell which device Linux thinks it is.
4) Boot up linux again, fdisk to make sure you now have the new
partition, and use mkfs to make a filesystem on one of the partitions
fdisk reports. Write "mkfs -c /dev/hdX nnn" where X is the device
number reported by linux fdisk, and nnn is the size - also reported
by fdisk. nnn is the size in /blocks/, ie kilobytes. You should be
able to use the size info to determine which partition is represented
by which device name.
5) Mount the new disk partition: "mount /dev/hdX /user". Copy over the
root filesystem to the harddisk, eg like this:
# for i in bin dev etc usr tmp
# do
# cp +recursive /$i /user
# done
You caanot use just "cp +recursive / /user", as that will result in a
loop.
6) Sync the filesystem after you have played around enough, and reboot.
# sync
<wait for it to sync>
ctrl-alt-del
The folklore says you should do this three times before rebooting:
once should be enough, but I admit I do it three times anyway :) THIS
IS IMPORTANT! NEVER EVER FORGET TO SYNC BEFORE KILLING THE MACHINE.
7) Change the bootdisk to understand which partition it should use as a
root filesystem. See INSTALL-0.11: it's still the word at offset
508 into the image. You should be up and running.
That's it. Go back and read the INSTALL-0.11
New features of 0.12, in order of appearance
(ie in the order you see them)
Linux now prints cute dots when loading
WoW. Run, don't walk, to see this :). Seriously, it should hopefully now
load even on machines that never got off the ground before, but
otherwise the loading hasn't changed. Implemented by drew.
Super-VGA detection for extended alphamun modes
I cannot guarantee it, I didn't write it, but it works great on a ET400
SVGA card. I'm addicted to the new look with 100x40 character editing,
instead of a cramped 80x25. This only works on VGA-cards that support
higher text-resolutions, and which are correctly identified. Implemented
by d88-man.
Job Control.
Ok, everybody used to typing ^Z after they started a long command, and
forgot to put it in the background - now it works on linux too. Bash
knows the usualy job-control commands: bg, fg, jobs & kill. I hope
there will be no nasty surprises. Job control was implemented by
tytso@athena.mit.edu.
Virtual consoles on EGA/VGA screens.
You can select one of several consoles by pressing the left alt-key and
a function key at the same time. Linux should report the number of
virtual consoles available upon bootup. /dev/tty0 is now "the current"
screen, /dev/tty1 is the main console, and /dev/tty2-8 can exist
depending on your text-mode or card.
NOTE! Scrolling is noticeably much slower with virtual consoles on a
EGA/VGA. The reason is that no longer does linux use all the screen
memory as a long buffer, but crams in several consoles in it. I think
it's worth it.
The virtual consoles also have some new screen-handling commands: they
confirm even better to vt200 control codes than 0.11. Special graphic
characters etc: you can well use them as terminals to VMS (although
that's a shameful waste of resources).
pty's
Ok. I have to admit that I didn't get the hangup-code working correctly,
but that should be easy to add. The general things are there.
select
I've never used it, so I cannot say how well it works. My minor testing
seems to indicate that it works ok. vc's, pty's and select were
implemented by pmacdona, although I hacked it heavily.
387-emulation.
It's not complete, but it works well enough to run those gcc2.0 compiled
programs I tested (few). None of the "heavy" math-functions are
implemented yet.
Symbolic links.
Try out a few "ln -s xx yy", and ls -l. Note that I think tar should be
recompiled to know anout them, and probably some other programs too. The
0.12 rootimage-disk has most of the recompiled fileutilities.
Virtual memory.
In addition to the "mkfs" program, there is now a "mkswap" program on
the root disk. The syntax is identical: "mkswap -c /dev/hdX nnn", and
again: this writes over the partition, so be careful. Swapping can then
be enabled by changing the word at offset 506 in the bootimage to the
desired device. Use the same program as for setting the root file
system (but change the 508 offset to 506 of course).
NOTE! This has been tested by Robert Blum, who has a 2M machine, and it
allows you to run gcc without much memory. HOWEVER, I had to stop using
it, as my diskspace was eaten up by the beta-gcc-2.0, so I'd like to
hear that it still works: I've been totally unable to make a
swap-partition for even rudimentary testing since about christmastime.
Thus the new changes could possibly just have backfired on the VM, but I
doubt it.
projects / history.git / commit