• Linus Torvalds's avatar
    [PATCH] Linux-0.95 (March 8, 1992) · e6c7a63f
    Linus Torvalds authored
    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)
    e6c7a63f
Makefile 4.45 KB