Release Notes For Linux v0.95

This is the release notes for linux release v0.95 (source code: linux-0.95.tar.gz) with format adjusted by removing/replacing tabs/spaces/new lines. This notes document can give us an understanding of the early development of the Linux kernel. The original ASCII formatted version is at the end of this post.


RELEASE NOTES FOR LINUX v0.95

Linus Torvalds, March 7, 1992

This is file mostly contains info on changed features of Linux, and
using old versions as a help-reference might be a good idea.

COPYRIGHT

Linux-0.95 is NOT public domain software, but is copyrighted by me. The copyright conditions are the same as those imposed by the GNU copyleft: get a copy of the GNU copyleft at any major ftp-site (if it carries linux, it probably carries a lot of GNU software anyway, and they all contain the copyright).

The copyleft is pretty detailed, but it mostly just means that you may freely copy linux for your own use, and redistribute all/parts of it, as long as you make source available (not necessarily in the same distribution, but you make it clear how people can get it for nothing more than copying costs). Any changes you make that you distribute will also automatically fall under the GNU copyleft.

NOTE! The linux unistd library-functions (the low-level interface to linux: system calls etc) are excempt from the copyright – you may use them as you wish, and using those in your binary files won’t mean that your files are automatically under the GNU copyleft. This concerns /only/ the unistd-library and those (few) other library functions I have written: most of the rest of the library has it’s own copyrights (or is public domain). See the library sources for details of those.

INSTALLATION

This is a SHORT install-note. The installation is very similar to 0.11 and 0.12, so you should read INSTALL-0.11 too. There are a couple of programs you will need to install linux: something that writes disk images (rawrite.exe or NU or…) and something that can create harddisk partitions (fdisk under xenix or older versions of dos, edpart.exe or something like that).

NOTE! Repartitioning your harddisk will destroy all data on it (well, not exactly, but if you know enough to get back the data you probably didn’t need this warning). So be careful.

READ THIS THROUGH, THEN READ INSTALL-0.11, AND IF YOU ARE SURE YOU KNOW WHAT YOU ARE DOING, CONTINUE. OTHERWISE, PANIC. OR WRITE ME FOR EXPLANATIONS. OR DO ANYTHING BUT INSTALL LINUX – IT’S VERY SIMPLE, BUT IF YOU DON’T KNOW WHAT YOU ARE DOING YOU’LL PROBABLY BE SORRY. I’D RATHER ANSWER A FEW UNNECESSARY MAILS THAN GET MAIL SAYING "YOU KILLED MY HARDDISK, BASTARD. I’M GOING TO FIND YOU, AND YOU’LL BE SORRY WHEN I DO".

Minumum files needed:

RELNOTES-0.95 (this file)
INSTALL-0.11 (+ any other docs you might find: the FAQ etc)
bootimage-0.96.Z
rootimage-0.95.Z
rootimage-0.12.Z  (for tar+compress)
rawrite.exe
some disk partitioner

1) back up everything you have on your harddisk – linux-0.95 is still in beta and might do weird things. The only thing I guarantee is that it has worked fine on /my/ machine – for all I know it might eat your harddisk and spit it out in small pieces on any other hardware.

2) Test out the linux boot-disk with the root file system. If it doesn’t work, check the hardware requirements, and mail me if you still think it should work. I might not be able to help you, but your bug-report would still be appreciated.

Linux-0.95 now has an init/login: there should be 4 logins started on the first 4 virtual consoles. Log in as root (no password), and test it out. Change to the other logins by pressing left-alt + FN[1-4]. Note that booting up with a floppy as root is S..L..O..W.. – the floppy driver has been optimized for sequential access (backups etc), and trashes somewhat with demand-loading.

Test that linux can read your harddisk at least partly: run the fdisk program on the root-disk, and see if it barfs. If it tells you about any partitions at all, linux can successfully read at least part of your harddisk.

NOTE! Harddisk device names and numbers have changed between versions 0.12 and 0.95: the new numbering system was needed for the extended partitions, and a new naming scheme was in order so that people wouldn’t cunfuse the old devices with the new ones.

The new harddisk device names are: /dev/hd followed by an ‘a‘ for the first drive, or a ‘b‘ for the second one. After that comes the partition number, 1-4 for the primary partitions, 5- for possible extended partitions. No number means the complete disk. Like this:

/dev/hda    the whole first harddisk (old: /dev/hd0)
/dev/hdb3   partition nr 3 on the second disk (old: /dev/hd8)

3) Make sure that you have a free /primary/ partition. There can be 4 primary partitions per drive: newer DOS fdisks seem to be able to create only 2 (one primary and one extended). In that case use some other partitioning software: edpart.exe etc. Linux fdisk currently only tells you the partition info – it doesn’t write to the disk.

Remember to check how big your partition was, as that can be used to tell which device Linux thinks it is.

NOTE! Linux-0.95 /might/ recognize extended partitions: but the code for this is utterly untested, as I don’t have any of those. Do NOT use the extended partitions unless you can verify that they are indeed correctly set up – if my routines are wrong, writing to the extended partitions might just overwrite some other partition instead. Not nice.

4) Boot up linux again, fdisk to make sure you now have the new partition, and use mkfs to make a filesystem on one of the partitions fdisk reports. Write "mkfs -c /dev/hdX nnn" where X is the device number reported by linux fdisk, and nnn is the size – also reported by fdisk. nnn is the size in /blocks/, ie kilobytes. You should be able to use the size info to determine which partition is represented by which device name.

5) Mount the new disk partition: "mount /dev/hdX /mnt". Copy over the root filesystem to the harddisk, eg like this:

# for i in bin dev etc usr tmp
# do
# cp +recursive /$i /mnt
# done

You caanot use just "cp +recursive / /mnt", as that will result in a loop.

6) Sync the filesystem after you have played around enough, and reboot.

# sync
# lo

(none) login: sync
<wait for it to sync>
ctrl-alt-del

THIS IS IMPORTANT! NEVER EVER FORGET TO SYNC BEFORE KILLING THE MACHINE.

7) Change the bootdisk to understand which partition it should use as a root filesystem. See INSTALL-0.11: it’s still the word at offset 508 into the image. You should be up and running.

8) When you’ve successfully started up with your harddisk as root, you can mount the older rootimage (rootimage-0.12) from a floppy, and copy over any files you find there that weren’t on the newer root-image.

Mounting a floppy is easy: make the directory /floppy, and write:

# mount /dev/PS0 /floppy    (if you have a 3.5" drive)

or

# mount /dev/at0 /floppy    (for 5.25" floppies)

After that the files can be copied to your harddisk, eg:

# cp /floppy/usr/bin/compress /usr/bin
# ln -s /usr/bin/compress /usr/bin/compress
# cp /floppy/usr/bin/tar.Z /usr/bin
# uncompress /usr/bin/tar.Z

That’s it. Now go back and read the INSTALL-0.11, until you are sure you know what you are doing.

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)


ASCII formatted "RELEASE NOTES FOR LINUX v0.95"

Following is the original ASCII formatted version of the "RELEASE NOTES FOR LINUX v0.95".


        RELEASE NOTES FOR LINUX v0.95
        Linus Torvalds, March 7, 1992

This is file mostly contains info on changed features of Linux, and
using old versions as a help-reference might be a good idea.

        COPYRIGHT

Linux-0.95 is NOT public domain software, but is copyrighted by me.  The
copyright conditions are the same as those imposed by the GNU copyleft:
get a copy of the GNU copyleft at any major ftp-site (if it carries
linux, it probably carries a lot of GNU software anyway, and they all
contain the copyright). 

The copyleft is pretty detailed, but it mostly just means that you may
freely copy linux for your own use, and redistribute all/parts of it, as
long as you make source available (not necessarily in the same
distribution, but you make it clear how people can get it for nothing
more than copying costs).  Any changes you make that you distribute will
also automatically fall under the GNU copyleft.

NOTE! The linux unistd library-functions (the low-level interface to
linux: system calls etc) are excempt from the copyright - you may use
them as you wish, and using those in your binary files won't mean that
your files are automatically under the GNU copyleft.  This concerns
/only/ the unistd-library and those (few) other library functions I have
written: most of the rest of the library has it's own copyrights (or is
public domain).  See the library sources for details of those. 

        INSTALLATION

This is a SHORT install-note.  The installation is very similar to 0.11
and 0.12, so you should read INSTALL-0.11 too.  There are a couple of
programs you will need to install linux: something that writes disk
images (rawrite.exe or NU or...) and something that can create harddisk
partitions (fdisk under xenix or older versions of dos, edpart.exe or
something like that). 

NOTE! Repartitioning your harddisk will destroy all data on it (well,
not exactly, but if you know enough to get back the data you probably
didn't need this warning).  So be careful.

READ THIS THROUGH, THEN READ INSTALL-0.11, AND IF YOU ARE SURE YOU KNOW
WHAT YOU ARE DOING, CONTINUE.  OTHERWISE, PANIC.  OR WRITE ME FOR
EXPLANATIONS.  OR DO ANYTHING BUT INSTALL LINUX - IT'S VERY SIMPLE, BUT
IF YOU DON'T KNOW WHAT YOU ARE DOING YOU'LL PROBABLY BE SORRY.  I'D
RATHER ANSWER A FEW UNNECESSARY MAILS THAN GET MAIL SAYING "YOU KILLED
MY HARDDISK, BASTARD.  I'M GOING TO FIND YOU, AND YOU'LL BE SORRY WHEN I
DO". 

Minumum files needed:

    RELNOTES-0.95 (this file)
    INSTALL-0.11 (+ any other docs you might find: the FAQ etc)
    bootimage-0.96.Z
    rootimage-0.95.Z
    rootimage-0.12.Z  (for tar+compress)
    rawrite.exe
    some disk partitioner

1) back up everything you have on your harddisk - linux-0.95 is still in
   beta and might do weird things.  The only thing I guarantee is that
   it has worked fine on /my/ machine - for all I know it might eat your
   harddisk and spit it out in small pieces on any other hardware. 

2) Test out the linux boot-disk with the root file system.  If it
   doesn't work, check the hardware requirements, and mail me if you
   still think it should work.  I might not be able to help you, but
   your bug-report would still be appreciated. 

   Linux-0.95 now has an init/login: there should be 4 logins started on
   the first 4 virtual consoles.  Log in as root (no password), and test
   it out.  Change to the other logins by pressing left-alt + FN[1-4]. 
   Note that booting up with a floppy as root is S..L..O..W..  - the
   floppy driver has been optimized for sequential access (backups etc),
   and trashes somewhat with demand-loading. 

   Test that linux can read your harddisk at least partly: run the fdisk
   program on the root-disk, and see if it barfs.  If it tells you about
   any partitions at all, linux can successfully read at least part of
   your harddisk. 

   NOTE! Harddisk device names and numbers have changed between versions
   0.12 and 0.95: the new numbering system was needed for the extended
   partitions, and a new naming scheme was in order so that people
   wouldn't cunfuse the old devices with the new ones.

   The new harddisk device names are: /dev/hd followed by an 'a' for the
   first drive, or a 'b' for the second one.  After that comes the
   partition number, 1-4 for the primary partitions, 5- for possible
   extended partitions.  No number means the complete disk. Like this:

    /dev/hda    the whole first harddisk (old: /dev/hd0)
    /dev/hdb3   partition nr 3 on the second disk (old: /dev/hd8)

3) Make sure that you have a free /primary/ partition.  There can be 4
   primary partitions per drive: newer DOS fdisks seem to be able to
   create only 2 (one primary and one extended).  In that case use some
   other partitioning software: edpart.exe etc.  Linux fdisk currently
   only tells you the partition info - it doesn't write to the disk. 

   Remember to check how big your partition was, as that can be used to
   tell which device Linux thinks it is.

   NOTE! Linux-0.95 /might/ recognize extended partitions: but the code
   for this is utterly untested, as I don't have any of those.  Do NOT
   use the extended partitions unless you can verify that they are
   indeed correctly set up - if my routines are wrong, writing to the
   extended partitions might just overwrite some other partition
   instead.  Not nice. 

4) Boot up linux again, fdisk to make sure you now have the new
   partition, and use mkfs to make a filesystem on one of the partitions
   fdisk reports.  Write "mkfs -c /dev/hdX nnn" where X is the device
   number reported by linux fdisk, and nnn is the size - also reported
   by fdisk.  nnn is the size in /blocks/, ie kilobytes.  You should be
   able to use the size info to determine which partition is represented
   by which device name. 

5) Mount the new disk partition: "mount /dev/hdX /mnt".  Copy over the
   root filesystem to the harddisk, eg like this:

    # for i in bin dev etc usr tmp
    # do
    # cp +recursive /$i /mnt
    # done

   You caanot use just "cp +recursive / /mnt", as that will result in a
   loop.

6) Sync the filesystem after you have played around enough, and reboot.

    # sync
    # lo

    (none) login: sync
    <wait for it to sync>
    ctrl-alt-del

   THIS IS IMPORTANT! NEVER EVER FORGET TO SYNC BEFORE KILLING THE MACHINE.

7) Change the bootdisk to understand which partition it should use as a
   root filesystem.  See INSTALL-0.11: it's still the word at offset
   508 into the image. You should be up and running.

8) When you've successfully started up with your harddisk as root, you
   can mount the older rootimage (rootimage-0.12) from a floppy, and
   copy over any files you find there that weren't on the newer
   root-image.

   Mounting a floppy is easy: make the directory /floppy, and write:

    # mount /dev/PS0 /floppy    (if you have a 3.5" drive)

   or

    # mount /dev/at0 /floppy    (for 5.25" floppies)

   After that the files can be copied to your harddisk, eg:

    # cp /floppy/usr/bin/compress /usr/bin
    # ln -s /usr/bin/compress /usr/bin/compress
    # cp /floppy/usr/bin/tar.Z /usr/bin
    # uncompress /usr/bin/tar.Z

That's it. Now go back and read the INSTALL-0.11, until you are sure you
know what you are doing.

        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)
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