Bottom half race condition fix.

Return ENODEV for nonexistent special devices.

Fix Unix domain sockets to properly check for target equality.

Add 'wchan' to /proc/stat

[Original announcement below]

Yes, as you've probably noticed, it's now 1993 and I still haven't
released 1.0.  Sorry about that, and I have only another patchlevel to
offer.  The new kernel should mainly fix some of the keyboard problems
people have experienced, but does contain some other minor fixes.

Linux 0.99.2 is available now at nic.funet.fi: pub/OS/Linux/PEOPLE/Linus
as both sources and diffs against 0.99.1 the diffs are essentially the
same as the second alpha-diffs I released for limited testing, with only
minor fixes to fs/exec.c and fs/open.c.

Please try out 0.99.2: the more feedback (hopefully positive) I get on
it, the faster 1.0 will be out.

Changes from pl1 are mainly:
 - pretty much rewritten low-level keyboard handling IO - this time
   actually trying to do it by the book.  It now handles resend requests
   from the keyboard etc.
 - you can run executables from filesystems without bmap support.  This
   mainly means NFS and msdos.  Note that while it's possible, it's
   slower and less memory-efficient than using a "normal" linux
   filesystem, and should generally be avoided.
 - /proc filesystem changes: /proc/kmsg can be used to log the kernel
   messages under X11 (instead of using the older system call to do the
   same), and there are changes to the statistics routines (WCHAN).

+ various minor fixes (non-existent devices are handled better, some
changes to socket bind behaviour etc).

                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

More networking updates.. Ross Biro is still struggling with net-1.

Michael Johnson (now RH kernel release manager) works on line printer
driver.

Locking function cleanups (for inodes, superblocks, buffer heads).  We
also now pass in the superblock pointer instead of the device number to
the filesystem routines.  That cleans up use and locking of
"get_super()" a lot.

[Original announcement below]

Ok, I already sent out an announcement last night, but due to the time
(6AM over here) I wasn't really in a mood to write a real annoucement.
Here it is.

linux-0.98.3 is available by anonymous ftp at least on nic.funet.fi:
pub/OS/Linux/testing/Linus, both as context diffs against 0.98.2 and the
pre-version of 0.98.3 and as complete source. The complete source
package was done by directly applying the diffs - this means that the
Makefile dependancies are probably not 100% up-to-date as I remove those
from the diffs. It shouldn't be any problem, and you can always do a
"make dep ; make clean" before actually compiling the kernel.

0.98 pl3 fixes several bugs, and should remove all known NULL-pointer
problems that made 0.98.2 unusable for most people. In addition to the
NULL pointer fixes, the following things have changed:

- removed most of the cli-sti pairs in the filesystem code by rewriting
  the locking routines to use a different algorithm, possible due to
  the rewritten wait-queue code that I did back in 0.96c or so.
  Interrupt latency should be better on slow machines, but I don't know
  if it's noticeable.
- Minor 387-emulation fixes by Bill Metzenthen - only noticeable under
  special conditions.
- Corrected various error-returns in the fs (thanks to Bruce Evans for
  running some error diagnostics). Error messages when opening (and
  renaming etc) files that had a non-directory in the path were wrong,
  and should be ok now (ie giving ENOTDIR instead of EACCESS or ENOENT).
  Some other problems reported by Bruce fixed.
- Changed the interface for some fs-related functions due to cleaning
  up super-block handling. Most noticeably, iget() and related
  functions no longer specify the inode with a device and inode number,
  but instead with a super-block pointer and inode number. This is
  more logical, and should make unnamed devices (ie internal
  filesystems like nfs and /proc) cleaner. Also note that the calling
  sequence for sb->s_op->put_inode() also has changed since 0.98. This
  is of interest only if you are writing filesystem drivers..
- ASK_SVGA was broken in 0.98.2 - it should be ok now.

Also, various minor fixes as usual. No new features, but I hope 0.98.3
will be a lot less bug-prone due to the changes since 0.98.1. Some
minor tcp/ip corrections (but most of them were in the pre-release), and
I removed a race-condition in the tty-handling code.

Note that people who use math without a co-processor should certainly
upgrade to 0.98.3: the new emulator is much better than my original one
both in speed and accuracy/exception handling. x11perf is very much
bearable now even without a 387, and things like ray-tracing etc
shouldn't be a problem any more. It's slower than hardware fp, of
course, but at least it works.

The new emulator also means there is no reason for a separate soft-float
library, so I'd assume that will be gone in the next gcc release for
linux.

As usual, a new kernel version probably means you'll have to recompile
'ps' and friends. But at least the same 'ps' sources that worked for
0.97.6 should still work.

                Linus

Start virtualizing real mmap() functionlity in the kernel.  The first
signs of me thinking about this already showed up as some unused header
files earlier, this fleshes things out some more.  No actual filesystem
code yet..

This also removes my old simple math emulator, and introduces the new
and much improved one from Bill Metzenthen.

Bill originally wrote it for the djgpp suite (DJ Delories gcc port to
DOS extenders).  It was much more accurate and well designed than my
hackish one, and I was happy to throw my old code away.  The new math
emulator also did things that I had never bothered with, notably the
more complex i387 functions (exponentials and trig).

I also fixed the static maximum memory limit: we now generate the kernel
page tables dynamically rather than having a 16M or 32M static limit.

SCSI updates: removable media support (which also implies re-reading the
partition table etc)

[Original announcement below]

patch-2 is >150kB compressed, as it contains several big changes. Most
notable are:

 - the new FPU-emulator by Bill Metzenthen.  It's bigger than the old
   one, but thanks to it, linux fpu emulation is no longer a quick hack,
   but a real emulator: it does all the 387(486) math instructions, and
   does them much faster than the old emulator + the soft library.

   The new math-emulator means that a separate soft-float library is no
   longer needed.  It also makes even a non-coprocessor system pretty
   useful for limited math-calcs - the complex functions are much faster
   when they no longer have to be calculated using simple functions, and
   even the simpler instructions that my old emulator handled are faster
   using the new one.

   The size of the new emulator may mean that people who have little
   RAM, but do have a coprocessor should probably recompile the kernel
   with the emulator disabled.

 - various minor mm fixes by me: trapping kernel NULL dereferences,
   cleaning up the page table initializations and the 16MB patches, and
   various other bugfixes.  get_free_page(GFP_ATOMIC) should preserve
   the interrupt flag, so malloc() should be safe now - hopefully no
   more of the tcp/ip memory management problems.

   The NULL pointer trapping may result in errors like:
        Unable to handle kernel paging request at address C0000???
        Oops: 0000
        ..... debugging info .....

   There were several NULL pointer dereferences in the serial and tty
   drivers, which should now be fixed.  I've also fixed any other errors
   I've seen, but if there are problems in the scsi drivers or similar
   things I cannot test, I'd like to hear about them.

 - scsi driver changes by Eric Youngdale.  Preliminary support for
   removable media, and some bug-fixes.  Due to white-space problems
   with eric's patches, the scsi patches are a bit bigger than
   necessary, but they should be ok even though I had to put them in
   partly by hand (and being unable to test them...)

 - The new tcp/ip patches that were sent to the NET channel not long
   ago.  Yes, they are alpha, but so is the whole tcp/ip directory, so I
   put them in even thought they haven't been extensively tested (and
   they did have a serious problem in the ioctl code, which I fixed).

 - psaux mouse patches by Dean Troyer, as well as the mouse.wait = NULL
   patch.

Before (or after) patching, you should remove the old math-emulator (ie
"rm -rf /usr/src/linux/kernel/math") as it is no longer needed.  You
should also do a "make dep" to update dependencies: as usual, I edited
out the dependancy-changes.  Do a "make clean", edit the main (and net)
Makefiles to suit your system, and compile.

And finally: I will no longer be making the bootdisks available -
they'll be made by hlu/jwinstead and will probably be boot+root-disks
using lilo, as done on the hlu disks.  That may mean that a bootimage
won't be available at once, but most people who want to use the
absolutely newest images probably compile them themselves anyway, so
that shouldn't be a problem.

                Linus

Real networking (TCP) merged! This is the now-called "net-1" code by
Ross Biro.  Boy, was it ugly, but it made for a big jump from not having
any at all.

(And add support for up the 32MB of memory ;)

[Original announcement below]

Sorry for being late - I can't even show any great new features in 0.98,
but at least it's out now, and available at the normal place (ie at
nic.funet.fi, pub/OS/Linux/testing/Linus).  So far there is only a
full-source version available, although I'll probably make it available
as a patch too tomorrow or so (but the patch won't contain the tcp/ip
stuff).

0.98 is essentially the same as 0.97.pl6 - the changes are mostly:
 - tcp/ip (0.8.1) is in.  It's not compiled into the standard bootimage,
   and you'd better be on the tcpip mailing-list to use it, but it's
   there. I've been unable to test it further than just watch it
   compile...
 - extfs patch to correct the problem with big directories with holes.
 - mouse patches (ie improved detection-routines)
 - minor scsi patches (ultrastor driver change)
 - swiss keyboard
 - some serial driver patches
 - the 32mb patches are in, so if you aren't using a DMA-SCSI driver,
   and have more than 16MB physical memory, you can get it recognized.
 - edited hd.c
 - corrected core-dumping routines

I didn't get my mm patches working yet, so they'll have to wait.  The
above are almost 100% by others - I have edited some of the patches, but
there is nothing major new by me.  Most of it is minor bug-fixes, and
the only thing that might be a bit of a problem are the hd.c changes:
but I hope they'll solve more problems than they cause.  Knock wood.

At nic.funet.fi you can currently find (a) the full sources (b) a
bootimage (US keyboard, floppy root, no tcp/ip) and (c) the protocols.h
file needed for compiling the tcp/ip directory (which should go into
/usr/include/netinet/).  I hope people try it out, and that there are no
new problems with this release.

                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

SCSI CD-ROM support by David Giller (based on sd.c by Drew)

Microsoft Busmouse support by Teemu Rantanen

Do the same buffer cleanups to extfs that we just did to Minixfs.

Efficient VGA emulation in dosemu wanted to know when we write
to the pseudo-VGA memory area. Add vm86 mode hooks for that.

[Original announcement below]

Patch 5 fixes the extended filesystem problems (thanks to Remy Card), as
well as including many smaller fixes (some more fs cleanups, the CDROM
patches and several other minor changes).  Pl5 finally removes even the
last few header-files that were incompatible with the normal headers, so
the "-nostdinc -I$(KERNELHDRS)" stuff is gone.

Patch 5 should also fix the problems with iopl() that resulted in the
X8514-server having problems with 0.97.pl2 and above.

In case people are wondering, my schedule for 1.0 looks something like
this:

 - 0.98 out in about a week: this is essentially 0.97.5 + the tcp/ip
   directory, as well as any fixes that may come up.  I'll try to get
   the loadable driver interface into it too.

 - 0.99 out after 0.98 has been shaken down: a month or so.

 - 1.0 will be the same as 0.99: the only changes will be eventual
   trivial bug-fixes in case 0.99 has some problems.  This is just to
   try to get over the "X.0" bug syndrome.

There are a few on-going projects: depending on circumstances these will
be implemented sooner or later, so I won't give any promises.  These
include: loadable drivers/fs's (alpha-patches already availabla), full
support for different block-sizes (some work still required), and a
extensive rewrite of the mm routines (I'll want to make a vmm interface
similar to the vfs interface for the filesystem routines).

                Linus

Hey, we switched to the GPL several months ago, but only now do we
include the license text itself.  Apparently everybody expected
everybody else to just know what the GPL was..

Add a README on compiling the kernel (by Lasu)

Add PS/2 mouse driver, make generic "mouse" infrastructure.

Add /proc filesystem, clean up minixfs block mapping.

sys_wait4() and swapoff().

VM gets a "secondary page free" list for things like interrupts
that want a page _now_ and can't wait for the regular free list
to fill up.

[Original announcement below]

Patch3 is almost 100kB even compressed, as there were quite big changes
in the mm and minix fs.  No major new features: there are two new system
calls: swapoff(const char * swapfile) and wait4(), and linux accepts
several swap-files, but the rest of the thing is mostly bug-fixes or
simply rewrites.

Major changes:
 - new swap-page handling: linux no longer uses just one bit to keep
   track of used swap-space, but a counter for each swap-page.  This
   allows processes to share swap-pages after a fork(), and should
   result in /major/ performance increases on machines with less memory.
   I've seen better performance even with 8MB - I wouldn't be surprised
   if 4MB machines would re-compile the kernel noticeably faster under
   pl3.  I'd be interested to hear numbers.
 - The low 1MB memory that isn't used directly by the kernel is now
   swappable memory, instead of being hardcoded for buffer cache.  The
   patches for this were originally by tytso, and I expanded on it a bit
   more.  This might also help better performance on 2-4MB machines.
   Note that this does /not/ mean that you can use 1M machines for
   linux: linux still needs some extended memory.
 - the dosfs has been upgraded to dosfs.8 - patches by almesber.
 - I edited the minix fs pretty heavily to remove a couple of race-
   conditions.  The same races still exist in the extended fs, as I
   didn't have time to edit that yet.  The minix-fs took precedence as I
   know that better, and extfs isn't "official" yet anyway.

other changes:

 - the mouse-driver now handles both Logitech (minor = 0) and PS/2
   (minor = 1) busmice.
 - there is a proc-fs for access to user memory/files etc.
 - better support for the tcp/ip patches (but see below...)
 - corrected symlink and /dev/[k]mem behaviour
 - Lars Wirzenius' README (with minimal comments by me) and the GNU
   COPYING notice are now part of the normal kernel setup, and can be
   found in the tar-archive.
 - the floppy ioctl() to get the FD parameters no longer requires root
   priviledges.  Thus, the msdos emulator runs even for a normal user.

Some comments on patchlevel 3:

        mm:

The swap-page handling resulted in a reduction of swap-file (or
partition) size to a maximum of 16MB per file.  It's nothing inherent to
the code, but it eased some algorithms, so I didn't bother coding around
it.  After all, 16MB is enough for most people, and if you want more,
you can have up to 128 swapfiles of 16MB each.  If I get enough
hate-mail about it, I might just try to find the energy to correct it.
Maybe.

Bigger swapfiles will still work, but linux will take advantage of only
the low 16MB.  Also, there is no nifty logic to try to optimize the
usage of the swap-files: pages are simply allocated from one swap-file
until it fills up, and then the next swap-file is used.

The memory management changes break ps/free once more, but not very
much.  Also, I changed the load-average counting, so 'w' also needs
slight editing.  On the other hand, I made '/dev/kmem' mmap()able, and
'ps' and 'free' should be edited to take advantage of that: it should
result in much faster operation, as well as possibly using less real
memory.

        fs:

The fs changes should remove at least two races - the races don't happen
very often, but they were theoretically possible, and might be the
reason for some fs corruption problems that have been reported.  The
changes are related to the use of bmap() - the bmap interface doesn't
really lend itself to some things that it was used for.  Re-writing
internal fs-functions not to use bmap not only should have removed any
races, but also actually resulted in cleaner code.

The proc-fs code isn't too beautiful, and I'll probably leave it out
from 0.98 unless I can make it loadable.  We'll see.  If anybody wants
to use it, you can do something like

  # mount -t proc /dev/ram /proc

Instead of /dev/ram you can use any block device - it's not used, and is
only a dummy as the proc-fs doesn't actually use any external device.
(but note that the device is still marked as mounted, so you cannot
mount it for anything else).

        kernel/mm/lib:

The TCP/IP patches are also essentially in 0.97.pl3 - not the full
TCP/IP directory, only the patches to the main kernel.  NOTE!! I don't
like the 'grab_malloc_pages()' function, so I left that out, and added a
GFP_ATOMIC priority to get_free_page() that should be used instead.  I
hope this will be used (Ross?), as it's a lot cleaner.

Also, I hope the tcp/ip people will clean up malloc() so that it doesn't
panic instead of returning NULL etc.  Ugly, ugly.  This is related to
the get_free_page(GFP_ATOMIC) changes, and I'd like to have patches as
soon as possible - tcp/ip won't be part of the standard kernel until
that can be cleaned up.

                Linus

Make the page allocator use a free page list instead of a silly
linear search.

Add sys_vhangup() and stubs for send/rcv/sendto/recvfrom/shutdown.
We're making ready for real networking..

Remove nonworking extfs bitmap allocators. We'll have them in ext2.

[Original announcement below]

Patch 1 is essentially a performance-release, but it also contains some
other patches: Ross Biro's tcp-ip stubs are there (but not the tcpip
subdirectory: alpha-testers should know where to find that), as are the
ext-fs superblock cleanups. The first header-file patch by hlu is also
in there.

The resulting patch is pretty big - it's also not as cleaned up as I'd
like it to be.  The swapping/buffer-block handling heuristics are
better, but could still do with some tuning.  Also, the idle task in
this version doesn't do very much: it will be expanded to do some more
page-table calculations.

I will be unable to hack on linux for a couple of weeks (I'll still
answer mails, read the newsgroup and fix bugs, but no heavy-duty
hacking) due to some "circumstances beyond my control".  That probably
means that this patch is the last one for a while (three weeks) unless
some bad bugs show up.

                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

The subject pretty much says it all: I've sent out the "weekly patch"
and I'd be very interested in comments. As with patch1, there are some
very fundamental changes in the kernel, and they might have some
problems. I'd want as many as possible to test out linux-0.96c.pl2, as
that has always been the best way to test out the changes. Everything
works on my machine, but that doesn't guarantee it will work on other
setups...

The MAJOR change in 0.96c.pl2 is the totally rewritten sleep/wakeup
code. That, together with the IRQ code introduced in pl1 and slightly
edited in pl2, means that two very fundamental things in the linux
kernel have changed in the last two weeks. The code is cleaner, easier
to add devices to, and hopefully faster, but it's still a bit risky to
change this kind of very low-level behaviour.

Select() is now implemented using the vfs jump tables, and thanks to the
better sleep/wakup interface, select() performance should be noticeably
better. At least xload seems to give lower load-averages, and I hope
ka9q will work better with the new kernel. Note that things like the
tty code doesn't yet take full advantage of the new features the
rewritten sleep offers, but I wanted to get a good testing-release out
before actually tweaking all the routines to use the new interface.

The IRQ routines have changed slightly, and all known bugs are fixed.

While I'm most interested to hear comments about the IRQ and
select/sleep/wakup code, there are a few other changes in pl2:

 - Swiss keyboard support.

 - Screen blanking now only reacts to key-presses and kernel messages:
normal tty output doesn't make the screen unblank.

 - DOS-fs version 5 is in. It wouldn't hurt to try it out. It's
somewhat alpha still, but it seems to work. mtools should be a thing of
the past once the dosfs is a bit more tested.

 - core-file magic number, and a minor bug in ptrace is fixed

 - a bus-mouse is supported. I'd like to hear if it still works after I
did the select() patches "blind" (I can't test it on my machine).

 - iopl changing is possible (but requires root priviledges): this
allows access to all IO ports, as well as the interrupt flag. Don't use
it unless /absolutely/ necessary: a bug in your program will most likely
crash the machine if you are running with IO priviledges. It's needed
for some X VGA drivers.

As a result of all the changes, the diff is pretty big. Apply and build
it with something like:

        cd /usr/src
        zcat linux-0.96c.patch2.Z | patch -p0
        cd linux
        make dep
        make clean
        make Image

assuming you have the 0.96c.pl1 kernel in /usr/src/linux. I've had some
reports that my patches won't always go in cleanly: I know for a fact
that patch1 patches cleanly (I rebuilt 0.96c.pl1 by downloading it all
from banjo), so the error is in your end.

Possible problems:

 - The VESA code in setup.S has some problems. I haven't even looked
into it yet, so if it won't work for you, please either (a) use the
unpatched setup.S from 0.96c, or (b) try to find the problem and tell
me. (b) is preferable, of course. I'd like to have VESA support, but
if the bug isn't found, I'll have to use the non-VESA version for 0.97.

 - The IRQ code in 0.96c.pl1 could overrun the stack if linux got
un-ending interrupt requests, resulting in a re-boot. With pl2, this
shouldn't happen: linux should print out something like "Recursive
interrupt on IRQx. Shutting down" and simply disable the problematic
IRQ line. If you see this message, I'd be very interested to hear about
it (which IRQ, what devices you have, etc).

 - And any new or old bugs I haven't found yet.

I have one report that 0.96c.pl1 has problems with the inode table, and
panics on bootup with a "no more inodes in mem" report. Can anybody
confirm this sighting? I haven't found the reason for it, and haven't
seen it myself. I'm hoping it's an installation problem, but if anybody
else sees the same behaviour, I'm SOL.

            Linus

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

Ok, patch4 implements 32-bit inode numbers (and thus the new
stat/lstat/fstat system calls), as well as correcting the bad
rs-performance on some machines that showed up in patch3. It's
currently only on banjo, but I'll copy it around eventually.

Again, you don't miss much if you don't use this patch: it's mainly for
(a) the serial problems and (b) for hlu etc that want to test out the
32-bit interface. It does some other magical tricks as well (uses less
memory in the low 1M region by moving the screen and tty buffer to high
memory), if anybody is interested.

            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)