People finally gave up on net-1, Ross Biro grew tired of the flames, and
net-2 appears with Fred van Kempen as maintainer.  This is the big
switch-over version.

fsync() isn't just a stub any more, and System V IPC is also showing up.

The "struct file" filetable is made dynamic, instaed of a static
allocation.  For the first time you can have _lots_ of files open.

Stub for iBCS2 emulation code.

[original announcement below]

I've finally released an official version of linux-0.99 patchlevel 10:
there have been various alpha versions floating around which differ in
details (notably networking code), which shouldn't be used any more.
The new linux version is available only as full source code: the diffs
would have been too big to be useful.  You can find linux-0.99.10.tar.z
(along with keytables.tar.z) on nic.funet.fi: pub/OS/Linux/PEOPLE/Linus
and probably on tsx-11 and other linux archives within a day or two (so
check there first if you are in the states).

Linux-0.99 pl10 has a number of new features and changes in interface.
The most notable of these are:

 - the networking code is reorganized (generally called "net-2",
   although unrelated to the BSD release).  The new code implements a
   lot of standard features lacking in net-1, and also changes the user
   interface to be closer to the BSD standards.  Notably, the old
   configuration binaries won't work, so to get the new networking to
   work you'll have to get the net-2 binaries as well.  The networking
   binaries are available on tsx-11.mit.edu (and mirrors) under the
   directory pub/linux/packages/net/net-2 (and the setup syntax has
   changed somewhat..)

   The networking code has been mainly organized and rewritten by Fred
   van Kempen, with drivers by Donald Becker.

 - serial line setup has been changed: linux 0.99 pl10 does *not* try to
   autodetect serial ports very agressively.  If you have other serial
   ports than the standard com1/com2, or nonstandard IRQ etc values,
   this means that it's less likely to work without any help.  The
   solution is not to recompile the kernel - you should get the
   "setserial" program available from tsx-11.mit.edu in the directory
   pub/linux/sources/sbin/setserial-2.01.tar.z that allows you to
   dynamically configure your serial ports to suit your setup.

   The main organizer behind the serial line changes is tytso (Theodore
   Ts'o).

 - Keyboard setup has changed: it is no longer hardcoded at compile
   time, but instead you can use the new "loadkeys" program to load in a
   new keyboard map on the fly.  The default keyboard map is the normal
   US keyboard (yes, I should have used the Finnish one by default, but
   after thinking of all the problems that would have resulted in I
   forgot about that idea).  The loadkeys code can be found in the
   "keytables.tar.z" archive, which also contains keymaps for most
   normal keyboard types.  To create a custom keyboard table is very
   easy - just take a 5 minute look at the existing map files (they
   resemble the ones used by xmodmap, so if you are familiar with
   those..)

   The loadable keymaps were mostly implemented by Risto Kankkunen.

There are a lot of other internal kernel changes, but they should be
mostly transparent, and noticeable only indirectly due to new features
or (hopefully) better/faster/whatever operation.  These include:

 - the SysV IPC patches are in by default: Krishna Balasubramanian.
   If you need these, you know what it's about (notably, dosemu 0.49
   wants them).
 - inode handling is updated: inodes and files are now dynamically
   allocated within the kernel, and use a hash table for faster lookup
   (along with a NFU algorithm for the inode cache).  Steven Tweedie.
 - Updated FPU emulation: mostly exception handling changes, making the
   emulator handle most exceptions the same way a 486 does.  The
   emulator is written by Bill Metzenthen.
 - a few ext2-fs updates by Remy Card and Steven Tweedie.
 - support for the 'fsync()' function (Steven Tweedie)
 - various (minor) SCSI patches to catch some error conditions, add
   support for VLB adaptec controllers without DMA and so on (different
   people).
 - other changes - I forget.

In addition to patches sent in by others, I've naturally made my own
changes (often *to* the patches sent in by others :-).  Among other
things, the pl10 buffer cache code now also tries to share pages with
executables, resulting in better cacheing especially of binaries (giving
noticeable improvements in kernel recompilation speed on some machines).
Also, I've changed a lot of low-level things around to help the iBCS2
project: this includes things like internal segment handling and the
signal stack (which now looks the same as on SysV i386 unixes).  All in
all, pl10 has a disturbing amount of new code, but will hopefully work
well despite (due to?) the number of changes.

The new networking code in particular will change the network setup a
lot - it now looks more standard, but if you were used to the old way of
doing things..  On the other hand, most people actively using the
networking features have hopefully gotten warnings about this on the NET
channel for the last few weeks.  Also, the networking code still isn't
perfect: Fred is still working on it, but it seems to have reached a
reasonably stable platform on which it will be easier to build.  Look
out for the new-and-improved networking manual, hopefully out soon(?).

Standard request: please try it all out, give it a real shakedown, and
send comments/bug-reports to the appropriate place (I'm always
appropriate, but you may want to send the report to the mailing lists
and/or the newsgroup as well).  I apologize for the lateness of the
release (forcing hlu to make interim gcc releases that relied on
nonstandard kernels etc), and the changes are somewhat bigger than I'd
prefer, so the more testerts that try it out, the faster we can try to
fix any possible problems.  The new kernel has gone through various
stages of ALPHA-diffs and some late ALPHA-pl10's, so there shouldn't be
any major surprises, but alpha releases tend not to get even close to
the coverage a real release gets...

                    Linus

net-1: paranoid queue checking to find more bugs.

configuration script version #1.

NFS filesystem client support by Rick Sladkey!

[Original announcement below]

0.99 has no major new features: the NFS client code is now in the
standard distribution, and the kernel configuration has changed, but
most of the rest of the changes are fixes - especially the tcp code
should now be pretty stable (knock wood).

Changes:

 - NFS is in. As are some stubs for the soud drivers, although it's only
   stubs right now.
 - various fixes around the place: the serial problems are hopefully
   gone, and there are patches to both TCP/IP and SCSI to make them more
   stable.
 - Minor fixes: the keyboard buglet introduced in 0.98pl6 should be
   gone, and some other bugs are also corrected.  The optimized
   read-ahead code in the filesystems (and the raw device read code) was
   too complicated and seemed to have problems with bad blocks, so I
   rewrote it, and it should hopefully work correctly now (this may have
   been the reason "mkfs -c" didn't work in all cases).  Thanks for some
   good bug-reports I've gotten: I've tried to correct all the problems
   I got reports on.
 - The kernel configuration has been re-thought: I decided to take
   advantage of the possibilities offered by GNU make etc.  This means
   that you no longer can compile the kernel using any other make, but
   there probably aren't many (if any) people doing that anyway.  This
   way I got rid of the extremely ugly SCSI setup, so it was probably
   worth it.

To configure the kernel for your setup, do a

        make config

and answer the yes/no questions. After that, do a

        make dep

to make the dependencies match your setup.  After that you should still
go edit the top-level Makefile for some of the configuration information
as before, but the remaining config things are pretty simple.  Then you
can make the kernel with a simple "make Image".

The new configuration utility (essentially a stupid shell script coupled
with some smarts in the Makefiles) tries to minimize compilations: if
you disable the SCSI code the scsi drivers won't even be compiled, much
less linked in.  This should be a win on slower machines.

NOTE!!! Use LILO-0.7 to load the 0.98pl5 and newer kernels: any older
version of lilo is liable to result in weird problems.

                Linus

Kai Makisara does the SCSI tape driver.  He's one of the few original
maintainers still around as such..

isofs introduced by Eric Youngdale, based on the minixfs code.  Eric was
a physicist, and you can tell he was new to C - he has been
Pascal-damaged, and has extra semi-colons at the end of block
statements.  But soon he ended up being one of the core maintainers
anyway, and took over SCSI maintenance.

More aggressive filesystem read-ahead introduced.

[Original announcement below]

Anyway, 0.98pl6 is hopefully the last release before 0.99: there are a
few known problems left in this release.  Most notable is the serial
code: it works for most people, but others still have problems with it.
I hope this will get fixed within a week (tytso is working on it).  It
also seems as if the PS/2 mouse code has some problems.

pl6 contains these fixes:

 - all the tcp/ip patches I've received (and I fixed one bug that
   gcc-2.3 seems to have found).
 - math-emu patch for the problem that resulted in FPU errors with some
   operations.
 - I fixed gcc-2.3 warnings as well as most of the old warnings.  You
   shouldn't get more than one or two warnings when recompiling the
   whole kernel.
 - /proc filesystem extensions.  Based on ideas (and some code) by
   Darren Senn, but mostly written by yours truly.  More about that
   later.
 - some tty_io fixes (there was a bug in the /dev/console handling when
   you changed VC's while using the general console device).
 - re-organization of the keyboard-driver internal data-structures.  The
   changes are mostly preliminary: they change the keyboard flags to be
   more easily adaptive to a reprogrammable keyboard driver.  No actual
   new features yet.
 - new SCSI drivers: reportedly much faster than the old ones (but not
   all drivers take advantage of it yet..)
 - various other fixes: pty's etc have minor changes.

I hope to make 0.99 in a week or so, and 1.0 after that has been tested
some.  I hope people will test out pl6 - 0.99 won't be much different,
and if you don't test pl6, any bugs relating to your particular hardware
may not be found in time for 0.99...

                Linus

Rename "malloc()/free()" as "kmalloc()/kfree()" to make people more
aware of some of the limitations.

Math emulator updates to handle the case that Linux (unlike the original
djgpp target) can get preempted by user space accesses.

Make "ll_rw_blk()" take an array of blocks to read/write.

VFS "notify_change()" callback, to allow the low-level filesystem to
decide what it wants to do about metadata changes.

Deprecate old "stat()" call by printing out a warning on use.

NR_OPEN is now 256 files per process, and the old "unsigned long" bitops
needed to go away. This causes lots of syntactic changes in select().

System call tracing implemented for ptrace().

[Original announcement below]

 - the inode caching bug (resulting in bad filesystem info when
   mounting/umounting devices) should be gone for good.

 - an elusive race-condition in the fs is fixed: this may have been the
   reason some people got fsck errors once in a while.  The
   race-condition was pretty hard to find, and depends on a lot of
   things (buffer cache size, speed of the disk and computer speed).

 - fpu emulator patches (mainly for the re-entrancy problem) by me and
   W. Metzenthen.

 - various wait-queue changes - the kernel uses the waiting mechanism
   more efficiently now.

 - the NFS client support code is there: the actual nfs code is still in
   alpha (although reported to be pretty stable) and has to be gotten
   separately.

 - NR_OPEN was changed from 32 to 256 (which is what SunOS seems to use,
   so I hope it won't need any further changes).  This has lead to some
   incompatibilities (GNU emacs and the term program seem to need
   recompilation to work correctly), as the 'select()' system call has a
   slightly changed interface due to the new fd_set definition.

 - the process kernel stack is now on a separate page (needed due to the
   fact that the task_struct has now grown to almost 3kB due to the
   NR_OPEN changes).  This also means 'ps' needs patches..  My patches
   to ps-0.98 are available as 'ps-diff.Z' in the same directory as the
   kernel sources and diffs.

 - various other changes: system call tracing by Ross Biro. Changed
   ll_rw_block interface (performance reasons: it will eventually be
   changed to accept several requests at once).  Malloc() was changed
   and renamed to kmalloc() due to the new interface.  Some tcp/ip
   patches (inode counting correction and some other changes).

0.98.4 should hopefully be pretty stable: the main problem areas are
probably still tcp/ip and some of the tty code.  I'd appreciate
comments, bug-reports etc.

                Linus

Ted Ts'o did extensive serial driver changes, and fixed up some of the
tty layer to match.  Tty's now allocated dynamically.

[Original announcement below]

This patch does not contain any major bug-fixes: it corrects named pipes
that broke with pl5, and has some minor changes in the IO-instructions
and the hd-driver, but those shouldn't matter for most of you.

It does contain all the scsi-patches that I've gotten so far, so if the
bootup sequence died on you in the scsi code, pl6 should correct this.

The major part of the patch is tytso's serial line changes, making the
tty structures dynamic.  No more NR_PTY's - the number of pty's is now
bounded only by the minor number setup (max 64 pty's) or the amount of
memory available (opening a pty requires a page of memory for tty
queues).  Similarly for serial lines.

The above just means that while pl6 can be useful, the changes to pl5
aren't big enough to worry about.  Most people don't use named pipes, it
seems, and the other changes are either cosmetic or hardware-dependent.
I still hope people upgrade, if only so that I can get new bug-reports.

I had hoped to release 0.98 this weekend, but studies and the scsi/hd
problems put an end to that.  0.98 should be out next weekend or so.
Expect the tcp/ip subdirectory and possibly some mm changes.

                Linus

Move <xxx.h> to <linux/xxxx.h>

Variable-sized buffer blocks and dynamic buffer cache allocation. The VM
knows how to shrink it automatically!

Add support for "fast" interrupt handlers for serial lines.

Update copyrights to say 1992 too.

Remove broken VESA video card handling.

Separate out partition handling code ("genhd").

Make init unkillable.

Norwegian keyboard map.

Future Domain SCSI controller driver by Rik Faith.

Changes in 0.97:

 - The VESA-support was removed.  I'd be happy to put it back once it
   works on all hardware.  Instead of the VESA-code, I finally put in
   the automatic SVGA setup patches.  See the top-level Makefile.

 - The IRQ code has solidified, and should work on all machines.  Not
   all of the SCSI drivers use it yet, so I expect patches for that..

 - Serial interrupts are handled slightly differently, and performance
   should be up.  I've sent out a few alpha-releases, and testing seems
   to indicate that's actually true this time.  Reactions have ranged
   from "nice" to "wonderful" :-)

 - The buffer-cache and memory management code has been edited quite a
   bit.  ps/free etc programs that reads kernel memory directly no
   longer work, and even a recompilation won't be enough.  They actually
   need editing before they work.

   The buffer-cache now grows and shrinks dynamically depending on how
   much free memory there is.  Shift+PrintScreen will give some memory
   statistics.  (Ctrl+PrSc gives task-info, ALT+PrSc gives current
   register values).

   The mm code changes removed some race-conditions in the VM code, and
   I also tried to make the Out-of-swapspace error less severe (better
   thrashing-detection etc).

 - The super-block code has been cleaned up.  Especially the extended fs
   needs to be edited a bit to take advantage of the new setup, and I
   expect Remy Card will have a patch out eventually.

 - include-files have been moved around some more: there are still some
   names that clash with the standard headers, but not many.

 - Unswappable processes implemented: by default only 'init' is
   unswappable.  This is a bit safer in low-memory conditions, as at
   least init won't die due to low memory.  I also made killing init
   impossible: if init doesn't recognize a signal, it simply won't get
   it.  Some other changes ("while (1) fork();" won't kill the machine
   for non-root users etc)

 - The new SCSI drivers are in.  These make the kernel noticeably
   bigger, but you can leave them out if you don't want them.

 - The floppy- and hd-drivers print out more debugging-info in case of
   errors: this might be irritating if you have hardware that works, but
   often gives soft-errors.  On the other hand, some old debugging-info
   was removed - notably for user-level protection errors etc.

 - Various minor fixes.  I haven't made cdiffs (and I haven't gotten any
   requests for them, so I probably never will), but they would be
   pretty big.

Things that I didn't have time for:

 - I wanted to rewrite the tty drivers to be more "streams-like" (ie not
   an actual streams-implementation, but some of the ideas from
   streams).  I never got around to it: there was simply too much else
   to do.

 - I got a lot of patches, and some went in, others didn't.  If you
   think your patch was important, please re-send it relative to the new
   version.

I'd like comments on the new system: performance / clarity of code etc.
0.97 should correct all known bugs (at least the ones I know about), but
I guess that's just wishful thinking.

Note that the dynamic buffer-code also handles differently-sized
buffers, but that the rest of the system (block device drivers,
filesystem code etc) cannot yet take advantage of this - there is still
some coding needed.

		Linus

More VFS layer work: remove more special cases, and take advantage of
the virtual VFS functions (close and select).  Add fchown/fchgrp and
[f]truncate.

Orest Zborowski shows up, and works on porting X11 to X.  This needs a
lot of infrastructure support: ioperm() for user-mode IO port access,
and SVR style virtual terminal ioctl's to make porting easier.  Perhaps
more importantly, the mmap() system call shows up, even if it right now
is limited only to a direct /dev/mem remapping.

[Original changelog below]

- truncate/ftruncate/fchmod/fchown system calls

        note that there aren't any library functions for these, so they
        aren't very useful yet...

        [f]truncate needed a change in the logic of the internal
        truncate VFS call - anybody that has any nonstandard filesystem
        probably needs to look it up.

- io-bitmap syscalls giving root-processes access to selected io ports
  from user space.  There is a "ioperm()" system call that lets the
  process select which ports it wants to enable/disable (all ports
  disabled as default) as well as a (standard sysv?) ioctl interface
  that X uses.

        again, no library stubs, but it allows things like reading and
        setting the cmos clock without using /dev/port, as well as
        control over the VGA registers...

- mmap for /dev/mem

        more things needed for X...

- the signal-handling fixes needed for gdb

        These aren't yet complete: serial lines still send signals under
        interrupts that can result in problems (ie ptrace doesn't
        correctly get them), but that's pretty unlikely (and will be
        fixed in the final 0.96).  Breakpoints should work etc..

- multiple shared libraries

        Up to 6 simultaneous shared libraries/process: the patches were
        originally by pmacdona, but they were heavily changed by me, and
        I think they work in a more natural manner now.  One user-level
        change is that the libraries are now checked for read and
        execute permissions for safety-reasons.

- cleaned up special files.

        read/write/ioctl no longer has special-case code: it is all
        handled with tables to functions.  This will mean that the SCSI
        patches won't patch in quite cleanly into 0.96: you'll need to
        add the code that sets up the functions.

        Again: device drivers and vfs-filesystem hackers need to look
        into the changes, although they are pretty logical (earlier
        versions just didn't implement all the vfs-routines)

        Note that the vfs-code for select is still not used: select is
        hardcoded for the devices it supports right now.

- ptrace() has a new interface

        as gdb for versions < 0.95c don't work on the new version, and
        gdb won't work very well at all on 0.95c[+], there was no reason
        not to break ptrace.  Thus 0.96 has a new calling convention for
        ptrace, and the old ptrace library function no longer works.
        I'm including the new ptrace library function at the end of this
        post.

- mount() takes 4 arguments, and checks that only the super-user can
  mount/umount things.

        Happily this shouldn't break any old binaries.

- some general cleanups

changed the IRQ routines and the serial code to be easier and cleaner
(and hopefully more efficient) and I thought that would be it. I was
wrong.

I got several patches (and one bug-report) again, and while I haven't
had time to check them all, some of them are in. Fixes:

 - Remy Cards correction to the out-of-space problem with the extended
fs is here. Most people using the ext-fs might already have applied
this patch, in which case you might have problems patching.

 - my ftruncate() fix is here. Again, if you already did the trivial
patch by hand, you'll get errors when patching.

 - almesber's implementation of read-only filesystems is here (after
editing by yours truly). The mount() system call now accepts a flags
integer as well as a pointer to some arbitraty data in user space for
some special mount() calls. The general flags allow (a) read-only
mounting, (b) disabling of suid executables (c) disabling of device
special files and (d) total disabling of executables on a per-filesystem
basis. The filesystem specific mount() info isn't currently used by any
fs, but can be used to specify additional information that depends on a
special fs type (a password or similar would be possible..)

 - the rename() system call had a bug in that it allowed moving over a
directory: I think the code to handle this was lost in the vfs editing,
and although the GNU mv utility checked it, a malicious (or just
unsuspecting) program can destroy the fs using this. Thanks for the
bug-report: it was very easy to add once I saw the problem.

 - support for vesa-standard svga cards in setup.S. I'm unable to test
this, but my svga card still works after the patch, so I left it in in
the hope that it doesn't break for anybody else.

 - various minor editing by me, or minor patches sent in by others.

The full cdiff is almost 50kB compressed, so this is a bigger-than-usual
patch. Hope there are no problems. People who are using the new SCSI
drivers might have problems with my changes to the SCSI irq-setup
changes, so be careful (actually using the original sources might be a
good idea, and then upgrading again). I hope to get the new SCSI
drivers into the kernel soon (definitely in time for 0.98).

I'd be interested to hear comments on serial line performance, bugs,
features, etc. As usual, I'm hoping this release won't contain any new
bugs while fixing all the old ones, but I guess that's likely to happen
right after the first winter olympics in Hell.

            Linus

Ext filesystem support! The VFS layer switchover was successful.
Ext support is a more FFS-like filesystem, although still quite heavily
influenced by my original Minix filesystem.  But it allows much bigger
filesystems (minixfs was limited to 64MB) and many more files (minixfs
had a 16-bit inode number).

Named pipes by Paul Hargrove (using the regular pipe code for actual IO).

[original announcement below]

0.96c is actually what I called patch3 earlier this week, but as the new
features were pretty big and the cdiff's are probably going to be bigger
than the normal patches, I decided I might as well make it a totally new
minor release and make a bootimage and complete source available.

0.96c contains:
 - bugfixes (tty, console driver, pty's, sockets)
 - fifo's (names pipes - Paul Hargrove & editing by me)
 - the alpha extended filesystem (Remy Card)
 - st_blocks implemented (ie du, ls give reasonable if not exact values
   for disk-space used)
 - Makefile cleanups and warnings at compile-time removed

Note that while the extended filesystem code is there, and this kernel
successfully mounts and uses the new filesystem (with long filenames and
>64MB partitions), it's still under testing: I haven't made the mkefs
program available, and the extended filesystem features shouldn't be
used for other than testing right now.

Some of the changes are just cleanups: most of the warnings when
compiling the new kernel should be gone (not counting the scsi code
which is still the old non-cleaned-up version), and the make'ing of the
kernel is more logical now.

The bugfixes include the corrected console.c driver, the socket
corrections (without which X sometimes locks up), some pty semantics
corrections (although I'm still not certain it's correct) and some
editing in the general tty driver (including fixing the bug introduced
in 0.96b.pl2 that caused a reboot with uninitialized tty devices).

While the extended filesystem support isn't "official" yet, I can
happily report that my limited testing hasn't found any problems with
long filenames etc.  It still needs a fsck program, but 1.0 looks like a
real possibility soon.

                Linus

First cut at core-dumping.  Also, do more dynamic boottime memory
allocation, rather than allocating data structures statically.

Allocate task structures at run-time rather than having a big array of
them.

First "obsolete" system call.  The old "stat()" system call was too
limited, due to "struct stat" having various 16-bit fields etc (notably
inode numbers).  We make a new stat() function, and keep the old one
around as "old_stat()" for binary compatibility.

We also need a bigger "utsname" to hold real node names.

Whoo! NR_OPEN is now 32 rather than 20.

itimer() support driven by X11 adoption (Darren Senn).

gcc starts using fsqrt, so that gets added to the FP emulation.  We're
still basing that on my trivial code.

[Original changelog below]

0.96b is not a new major release: it's pretty close to 0.96a with all my
patches (1-4).  However, as there has been 4 patches already, I decided
it would be time for a full kernel release along with a bootimage, so
that people who don't feel confident with patching can use the new
features.

If you already have 0.96a patchlevel 4, 0.96b will offer you these new
features:

 - the math-emulation now handles fsqrt, as gcc-2.2.2 generates that
   inline.  I haven't tested the kernel code at all: I tested the
   algorithm in user space, but I'm lazy, so I never turned off my 387
   to do real testing.  I hope it works.
 - better vt100 terminal emulation thanks to Mika Liljeberg.
 - I removed a possible race-condition in the buffer-cache code.
 - minor fixes

The vt100 emulation should now be complete enough for almost everything
(including vt100 test suites): as a result the setterm utility had to be
changed (as the old setterm codes aren't compatible with the full vt100
codes).  setterm-0.96b.tar.Z contains the new setterm.

The soon-to-be-released gcc-2.2.2 will need the 0.96b kernel: (a) due to
the fsqrt emulation and (b) it uses the new stat() system call.  So
upgrading is a good idea.  (If you have a co-processor, (a) isn't used,
but (b) still stands)

If you have an unpatched 0.96a, the differences to 0.96b are roughly
(not counting the above-mentioned new things):

 - corrected the disk-buffer-list bug with read/write-errors
 - fixed read-ahead warning messages at end of disk
 - better support for text-mode restoration after running MGR and X
 - full core-dumping, attach/detach etc debugging features
 - 16550A support
 - less low 1MB memory used for kernel structures
 - various minor fixes

Note that the fact that new versions (pl4 and above) use more memory in
the 1M+ area means that linux will report less free memory (it's used
for buffer-cache instead).  This could concievably be a problem on 2MB
machines.  The standard kernel comes with only 4 pty's though, and if
you use the standard 80x25 text modes instead of svga modes, the VC
buffers will be smaller.  Please contact me if there are problems even
with this minimal setup.

0.96b does /not/ contain: the new scsi drivers, new filesystems or some
other patches I have gotten (ibm character set mode, loop-devices etc).
If you have sent me any other patch, you might want to remind me about
it.

                Linus

I have just sent off the second patch to 0.96a: it should be on the
normal ftp-sites (nic, tsx-11 and banjo), although the only site which I
can make it directly readable on is banjo, so on the other sites it will
take the site-managers to make the patch available.

Patch 2 implements:

- itimers (by Darren Senn), which are now also used to implement the
  alarm() system call.

- ultrastor scsi driver patches (by gentzel)

- [f]statfs() system call is implemented (so df can be made fs-
  independent). Also some other minor fs-changes for the upcoming new
  filesystem. Patches by Remy Card.

- preliminary core-file dumping code (linux creates a core-file, but
  it's not in the correct format yet [*]).

- minor changes/bugfixes.

While patching in patch1 is a good idea for anybody, patch 2 isn't
really vital. I've made it available just so kernel hackers can keep up
with the kernel I have right now if they wish. Patch 2 is relative to
patch 1: you have to patch that in first.

[*] The current core-file is very simple, and the kernel code is there
just so that some enterprising character can expand it. A core-file
looks like this right now:

offset data
0x0000 "core-dump: regs=\n"
0x0040 struct pt_regs (see <sys/ptrace.c>)
0x0400 "floating-point regs:\n"
0x0440 struct i387 (see <linux/sched.h>)
0x0800 the first 1kB of user-space

Not very practical, but it /might/ help if the X-server dies of a
segmentation fault or similar (you can use pt_regs.eip to see where it
happened). The kernel code is very easy to change to accomodate for the
real core-file format, I just didn't know what it should be.

                Linus

More VFS cleanups.  Minixfs code reorganized to be more logical, and
split up into a few new files.

SCSI support!!

 - Drew Eckhardt does the SCSI stuff, and does the ST01/ST02 lowlevel
   driver.

 - Ultrastor driver by David Gentzel.

 - Tommy Thorn shows up again.  He did the Danish keyboard tables, now
   he does the AHA 1542 driver.  Ten years later we ended up being
   co-workers at Transmeta ;)

First networking code appears: X11 port needs UNIX domain sockets, and
thus the "socketcall()" system call.  It's not really meant for real
networking, although the code will eventually evolve to support that.
Which explains some of the bad early decisions..  ;)

Werner Almerberger starts taking over floppy driver maintenance.  Thank
Gods!

Johan Myreen translates my assembly-level keyboard driver into C code,
and adds support for diacriticals.

OMAGIC a.out format support

Syslog support for the kernel appears.  If I remember correctly, this
was Peter MacDonald, but no mention of that in the sources.

Bruce Evans shows up here quickly.

Bruce was the author of the Minix/386 patches, and had been one of my
sounding boards for my early development, so it was very gratifying to
see him get interested in Linux.  As it turned out, what he was _really_
interested in was the serial driver, and the Linux serial driver was
already in reasonably good shape.

As a result, Bruce went off to work on 386BSD instead (where the serial
driver was truly crappy), but here he worked on some boot loader cleanups.

Bruce was my hero.

Anyway...  More VFS work here: readdir, bmap and ioctl's are now virtual
operations, and the superblock code is properly virtualized.

Other changes:

 - James Wiegand writes initial parallell port printer driver

 - major/minor fault tracking

 - I rewrote big chunks of ptrace.c

This was the first kernel that got released under the GPL (0.12 had a
time-lapse to make sure the people involved accepted the license change:
nobody ever complained).

Because 0.12 had been so successful, this was supposed to be closer to
1.0.  Yeah, right.  1.0 was eventually released almost exactly two years
later..

The big change here is the first signs of a real VFS layer: while the
only available filesystem is still the Minix-compatible one, the code is
factored out, and the Minix-specific stuff is put in its own directory.
You can clearly see how the thing is moving towards having multiple
different filesystems.

The VFS changes also cause cleanups in various drivers, since we end
up having more clear inode operation structure pointer handling.

Superblock handling is still minix-specific..

NOTE! We also have /bin/init finally.  It still falls through to the old
"run shells forever" case if no init can be found, but it's starting to
look a whole more like real UNIX user-land now..

New developers: Ross Biro shows up, and does ptrace.  He will later end
up doing the first-generation networking code.

Other changes:

 - UK and Danish keyboard maps (and the keyboard driver supported
   "Application mode" keys from vt100+)
 - Make sure interrupts clear the 'D'irection flag
 - Floppy driver gets track buffer, which speeds it up immensely.  This
   was done based on patches by Lawrence Foard (entropy@wintermute.wpi.edu)
 - Lots of buffer cache cleanups.
 - support nonblocking pipe file descriptors
 - recursive symlink support
 - sys_swapon() means that we don't have to select the swap device
   at build (or boot) time ("Written 01/25/92 by Simmule Turner, heavily
   changed by Linus")
 - start some generic timer work (ugh, but these first timers were
   _horrible_ hardcoded things)
 - ptrace for debugging
 - console size query support with TIOC[G|S]WINSZ
 - /dev/kmem ("by Damiano")
 - rebooting (with ctrl-alt-del or sys_reboot()).

From the release notes:

              New features of 0.95, in order of appearance
                      (ie in the order you see them)

      Init/login

Yeah, thanks to poe (Peter Orbaeck (sp?)), linux now boots up like a
real unix with a login-prompt.  Login as root (no passwd), and change
your /etc/passwd to your hearts delight (and add other logins in
/etc/inittab etc).

      Bash is even bigger

It's really a bummer to boot up from floppies: bash takes a long time to
load.  Bash is also now so big that I couldn't fit compress and tar onto
the root-floppy: You'll probably want the old rootimage-0.12 just in
order to get tar+compress onto your harddisk.  If anybody has pointers
to a simple shell that is freely distributable, it might be a good idea
to use that for the root-diskette.

Especially with a small buffer-cache, things aren't fun. Don't worry:
linux runs much better on a harddisk.

      Virtual consoles on any (?) hardware.

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.

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), and the PF1-4 keys work somewhat
in the application-key mode.

      Symbolic links.

0.95 now allows symlinks to point to other symlinks etc (the maximum
depth is a rather arbitrary 5 links). 0.12 didn't like more than one
level of indirection.

      Virtual memory.

VM under 0.95 should be better than under 0.12: no more lockups (as far
as I have seen), and you can now swap to the filesystem as well as to a
special partition. There are two programs to handle this: mkswap to set
up a swap-file/partition and swapon to start up swapping.

mkswap needs either a partition or a file that already exists to make a
swap-area. To make a swap-file, do this:

      # dd bs=1024 count=NN if=/dev/hda of=swapfile
      # mkswap swapfile NN

The first command just makes a file that is NN blocks long (initializing
it from /dev/hda, but that could be anything). The second command then
writes the necessary setup-info into the file. To start swapping, write

      # swapon swapfile

NOTE! 'dd' isn't on the rootdisk: you have to install some things onto
the harddisk before you can get up and running.

NOTE2! When linux runs totally out of virtual memory, things slow down
dramatically. It tries to keep on running as long as it can, but at
least it shouldn't lock up any more. ^C should work, although you might
have to wait a while for it..

      Faster floppies

Ok, you don't notice this much when booting up from a floppy: bash has
grown, so it takes longer to load, and the optimizations work mostly
with sequential accesses.  When you start un-taring floppies to get the
programs onto your harddisk, you'll notice that it's much faster now.
That should be about the only use for floppies under a unix: nobody in
their right mind uses floppies as filesystems.

      Better FS-independence

Hopefully you'll never even notice this, but the filesystem has been
partly rewritten to make it less minix-fs-specific. I haven't
implemented all the VFS-patches I got, so it's still not ready, but it's
getting there, slowly.

      And that's it, I think.

Happy hacking.

                      Linus (torvalds@kruuna.helsinki.fi)

This was created from a re-packaged 0.11 tree.

Linux-0.11 has a few rather major improvements, but perhaps most
notably, is the first kernel where some other people start making
real contributions.

 - I fixed the buffer cache code, making it a lot more stable

 - demand-loading from disk. My comment proudly states:

        Once more I can proudly say that linux stood up to being changed: it
        was less than 2 hours work to get demand-loading completely implemented.

   This is a major milestone, since it makes the kernel much more
   powerful than Minix was at the time.  I also share clean pages.

 - we still don't have an /sbin/init, but we now load /etc/rc at bootup,
   and the kernel will loop, spawning shells forever. That makes it easier
   to test things.

 - scaffolding for math emulation introduced.

 - Ted Ts'o shows up as a coder. Ted implements:
        o "#!" escape handling for executables
        o fixes for some file permission handling
        o "sticky" directory bit
        o first "malloc()/free()" implementation.
          (this one is horrible: the free needs the size for good
           performance, which will result in years of "free_s()" pains)
        o adds BSD-style setreuid/gid() handling
        o allows us to specify root device at image build time
        o cleanups of some of the uglier direct %fs-register accesses

 - Galen Hunt shows up as a coder: he's added code to handle different
   video card detection (whereas my original one just handled VGA, we
   now handle CGA, MGA, EGA and VGA)

 - The console can beep now: John T Kohl (who also does the tty KILL
   char handling)

 - we also now have German (Wolfgang Thiel) and French (Marc Corsini)
   keyboard maps.  World Domination!

Btw, if you wonder what the "Urgel" comments are - I was still fairly
Swedish-speaking, and "Urgel" is what I would these days write as "Ugh".

It's a sign of trouble or ugly code.  The floppy driver in particular is
clearly not something I'm very proud of ;).

Likely correct 0.10: these were re-created from the RCS tree that Ted
Ts'o had, no known pristine 0.10 tree (or, sadly, 0.02 and 0.03 trees)
exist any more.

Linux-0.10 was actually a major step.  It was _almost_ able to host
itself, and if I remember correctly, a small patch I posted to the
newsgroup a few days later got the buffer cache handling stable enough
that Linux could now compile itself under itself without running out of
memory due to a memory leak.

Apart from bugfixes, the major update here is the support for
mount/umount.  But you can also tell that others are starting to test
out this thing, since the harddisk geometry is now auto-sensed, and we
support the US keyboard layout in addition to the Finnish one.

(This is also the first actual thing from the outside: the US keyboard
layout tables came from Alfred Leung, although with major editing by me.)

 - add copyright messages ("(C) 1991  Linus Torvalds")

   Nobody else is really doing coding (yet..) but clearly I'm starting
   to be a lot more aware of other people here.

 - split up boot/boot.s into boot/bootsect.s and boot/setup.s
 - autodetect floppy type for booting
 - make root device and boot device configurable

 - support up to 16MB of physical memory (instead of just 8MB ;)

   Whee. We're clearly moving into the "big iron" phase of Linux.

 - move drivers around.  We now have separate subdirectories for
   character device drivers (tty and memory) and block device drivers.

 - initial floppy driver support!

   You can see how the "block layer" interfaces evolved directly from
   moving parts of the original hd.c driver into ll_rw_block.c and
   making them "generic".

 - make file reading do simple read-ahead
 - make file writing avoid reading in blocks that are totally overwritten
 - add support for /dev/port and /dev/null (!!)
 - improve pipe throughput

 - add support for sigaction(), not just old-style signal()

   This also rewrites most of the signal code in C rather than assembly.

 - add "mknod()" and "mount()"/"umount()" system calls, and support
   for traversing over mount-points.

 - add "sessions" and setsid(), so that we get proper SIGHUP's

This is the initial 0.01 kernel as found on various history sites.

Fun facts:

 - kernel/Makefile still calls it the FREAX kernel

 - this was in a more innocent age, when the only copyright notice
   is a single "(C) 1991 Linus Torvalds" in lib/string.h

 - the keyboard driver was still in all assembly language, with a
   hardcoded map for (7-bit) Finnish keyboards. At least I had converted
   the VT100 emulation from assembly to C. Too bad I didn't keep the
   _really_ old code around for historical interest.

 - All the early kernels wanted a special version of gcc to compile: I
   had made extensions to gcc-1.40 to make it use the x86 string
   instructions for things like "memcpy()" using the "-mstring-insns"
   command line option.

 - Also, note that newer versions of gcc (which do have the inline
   intrisics, quite independently of my early -mstring-insns hack) will
   not accept the code: it needs a compiler that outputs old-style a.out
   format, and that accepts some of the strange inline assembly that I
   used.

 - In short: you really need some stone-age tools to actually compile
   this, if you actually want to.  And if you actually want to _run_ it
   too, you need to have some old hardware and most likely edit some of
   the hardcoded numbers too.  The harddisk driver has two different
   hardcoded settings: my harddisk, and Lasu's harddisk.

Statistics:

It's 88 files with about ten thousand lines, written by yours truly
except for the vsprintf routine which was co-written with Lars
Wirzenius.  Lasu wasn't as huge a fan of inline assembly as I was, thus
the comment

        "Wirzenius wrote this portably, Torvalds fucked it up :-)"

I think that comment pretty much sums it up ;)

Original release notes for 0.01 follow:

         Notes for linux release 0.01

         0. Contents of this directory

linux-0.01.tar.Z - sources to the kernel
bash.Z - compressed bash binary if you want to test it
update.Z - compressed update binary
RELNOTES-0.01 - this file

         1. Short intro

This is a free minix-like kernel for i386(+) based AT-machines.  Full
source is included, and this source has been used to produce a running
kernel on two different machines.  Currently there are no kernel
binaries for public viewing, as they have to be recompiled for different
machines.  You need to compile it with gcc (I use 1.40, don't know if
1.37.1 will handle all __asm__-directives), after having changed the
relevant configuration file(s).

As the version number (0.01) suggests this is not a mature product.
Currently only a subset of AT-hardware is supported (hard-disk, screen,
keyboard and serial lines), and some of the system calls are not yet
fully implemented (notably mount/umount aren't even implemented).  See
comments or readme's in the code.

This version is also meant mostly for reading - ie if you are interested
in how the system looks like currently.  It will compile and produce a
working kernel, and though I will help in any way I can to get it
working on your machine (mail me), it isn't really supported.  Changes
are frequent, and the first "production" version will probably differ
wildly from this pre-alpha-release.

Hardware needed for running linux:
        - 386 AT
        - VGA/EGA screen
        - AT-type harddisk controller (IDE is fine)
        - Finnish keyboard (oh, you can use a US keyboard, but not
          without some practise :-)

The Finnish keyboard is hard-wired, and as I don't have a US one I
cannot change it without major problems. See kernel/keyboard.s for
details. If anybody is willing to make an even partial port, I'd be
grateful. Shouldn't be too hard, as it's tabledriven (it's assembler
though, so ...)

Although linux is a complete kernel, and uses no code from minix or
other sources, almost none of the support routines have yet been coded.
Thus you currently need minix to bootstrap the system. It might be
possible to use the free minix demo-disk to make a filesystem and run
linux without having minix, but I don't know...

         2. Copyrights etc

This kernel is (C) 1991 Linus Torvalds, but all or part of it may be
redistributed provided you do the following:

        - Full source must be available (and free), if not with the
          distribution then at least on asking for it.

        - Copyright notices must be intact. (In fact, if you distribute
          only parts of it you may have to add copyrights, as there aren't
          (C)'s in all files.) Small partial excerpts may be copied
          without bothering with copyrights.

        - You may not distibute this for a fee, not even "handling"
          costs.

Mail me at "torvalds@kruuna.helsinki.fi" if you have any questions.

Sadly, a kernel by itself gets you nowhere. To get a working system you
need a shell, compilers, a library etc. These are separate parts and may
be under a stricter (or even looser) copyright. Most of the tools used
with linux are GNU software and are under the GNU copyleft. These tools
aren't in the distribution - ask me (or GNU) for more info.

         3. Short technical overview of the kernel.

The linux kernel has been made under minix, and it was my original idea
to make it binary compatible with minix. That was dropped, as the
differences got bigger, but the system still resembles minix a great
deal. Some of the key points are:

        - Efficient use of the possibilities offered by the 386 chip.
          Minix was written on a 8088, and later ported to other
          machines - linux takes full advantage of the 386 (which is
          nice if you /have/ a 386, but makes porting very difficult)

        - No message passing, this is a more traditional approach to
          unix. System calls are just that - calls. This might or might
          not be faster, but it does mean we can dispense with some of
          the problems with messages (message queues etc). Of course, we
          also miss the nice features :-p.

        - Multithreaded FS - a direct consequence of not using messages.
          This makes the filesystem a bit (a lot) more complicated, but
          much nicer. Coupled with a better scheduler, this means that
          you can actually run several processes concurrently without
          the performance hit induced by minix.

        - Minimal task switching. This too is a consequence of not using
          messages. We task switch only when we really want to switch
          tasks - unlike minix which task-switches whatever you do. This
          means we can more easily implement 387 support (indeed this is
          already mostly implemented)

        - Interrupts aren't hidden. Some people (among them Tanenbaum)
          think interrupts are ugly and should be hidden. Not so IMHO.
          Due to practical reasons interrupts must be mainly handled by
          machine code, which is a pity, but they are a part of the code
          like everything else. Especially device drivers are mostly
          interrupt routines - see kernel/hd.c etc.

        - There is no distinction between kernel/fs/mm, and they are all
          linked into the same heap of code. This has it's good sides as
          well as bad. The code isn't as modular as the minix code, but
          on the other hand some things are simpler. The different parts
          of the kernel are under different sub-directories in the
          source tree, but when running everything happens in the same
          data/code space.

The guiding line when implementing linux was: get it working fast. I
wanted the kernel simple, yet powerful enough to run most unix software.
The file system I couldn't do much about - it needed to be minix
compatible for practical reasons, and the minix filesystem was simple
enough as it was. The kernel and mm could be simplified, though:

        - Just one data structure for tasks. "Real" unices have task
          information in several places, I wanted everything in one
          place.

        - A very simple memory management algorithm, using both the
          paging and segmentation capabilities of the i386. Currently
          MM is just two files - memory.c and page.s, just a couple of
          hundreds of lines of code.

These decisions seem to have worked out well - bugs were easy to spot,
and things work.

         4. The "kernel proper"

All the routines handling tasks are in the subdirectory "kernel". These
include things like 'fork' and 'exit' as well as scheduling and minor
system calls like 'getpid' etc. Here are also the handlers for most
exceptions and traps (not page faults, they are in mm), and all
low-level device drivers (get_hd_block, tty_write etc). Currently all
faults lead to a exit with error code 11 (Segmentation fault), and the
system seems to be relatively stable ("crashme" hasn't - yet).

         5. Memory management

This is the simplest of all parts, and should need only little changes.
It contains entry-points for some things that the rest of the kernel
needs, but mostly copes on it's own, handling page faults as they
happen. Indeed, the rest of the kernel usually doesn't actively allocate
pages, and just writes into user space, letting mm handle any possible
'page-not-present' errors.

Memory is dealt with in two completely different ways - by paging and
segmentation.  First the 386 VM-space (4GB) is divided into a number of
segments (currently 64 segments of 64Mb each), the first of which is the
kernel memory segment, with the complete physical memory identity-mapped
into it.  All kernel functions live within this area.

Tasks are then given one segment each, to use as they wish. The paging
mechanism sees to filling the segment with the appropriate pages,
keeping track of any duplicate copies (created at a 'fork'), and making
copies on any write. The rest of the system doesn't need to know about
all this.

         6. The file system

As already mentioned, the linux FS is the same as in minix. This makes
crosscompiling from minix easy, and means you can mount a linux
partition from minix (or the other way around as soon as I implement
mount :-). This is only on the logical level though - the actual
routines are very different.

        NOTE! Minix-1.6.16 seems to have a new FS, with minor
        modifications to the 1.5.10 I've been using. Linux
        won't understand the new system.

The main difference is in the fact that minix has a single-threaded
file-system and linux hasn't. Implementing a single-threaded FS is much
easier as you don't need to worry about other processes allocating
buffer blocks etc while you do something else. It also means that you
lose some of the multiprocessing so important to unix.

There are a number of problems (deadlocks/raceconditions) that the linux
kernel needed to address due to multi-threading.  One way to inhibit
race-conditions is to lock everything you need, but as this can lead to
unnecessary blocking I decided never to lock any data structures (unless
actually reading or writing to a physical device).  This has the nice
property that dead-locks cannot happen.

Sadly it has the not so nice property that race-conditions can happen
almost everywhere.  These are handled by double-checking allocations etc
(see fs/buffer.c and fs/inode.c).  Not letting the kernel schedule a
task while it is in supervisor mode (standard unix practise), means that
all kernel/fs/mm actions are atomic (not counting interrupts, and we are
careful when writing those) if you don't call 'sleep', so that is one of
the things we can count on.

         7. Apologies :-)

This isn't yet the "mother of all operating systems", and anyone who
hoped for that will have to wait for the first real release (1.0), and
even then you might not want to change from minix.  This is a source
release for those that are interested in seeing what linux looks like,
and it's not really supported yet.  Anyone with questions or suggestions
(even bug-reports if you decide to get it working on your system) is
encouraged to mail me.

         8. Getting it working

Most hardware dependancies will have to be compiled into the system, and
there a number of defines in the file "include/linux/config.h" that you
have to change to get a personalized kernel.  Also you must uncomment
the right "equ" in the file boot/boot.s, telling the bootup-routine what
kind of device your A-floppy is.  After that a simple "make" should make
the file "Image", which you can copy to a floppy (cp Image /dev/PS0 is
what I use with a 1.44Mb floppy).  That's it.

Without any programs to run, though, the kernel cannot do anything. You
should find binaries for 'update' and 'bash' at the same place you found
this, which will have to be put into the '/bin' directory on the
specified root-device (specified in config.h). Bash must be found under
the name '/bin/sh', as that's what the kernel currently executes. Happy
hacking.

         Linus Torvalds "torvalds@kruuna.helsinki.fi"
         Petersgatan 2 A 2
         00140 Helsingfors 14
         FINLAND