add directory Linux-0.01

Linux-0.01/docs/INSTALLATION

@@ -0,0 +1,114 @@
+
+
+		Installing Linux on your system
+
+Ok, this is a short guide for those people who actually want to get a
+running system, not just look at the pretty source code :-). You'll
+certainly need minix for most of the steps.
+
+
+	0.  Back up any important software.  This kernel has been
+working beautifully on my machine for some time, and has never destroyed
+anything on my hard-disk, but you never can be too careful when it comes
+to using the disk directly.  I'd hate to get flames like "you destroyed
+my entire collection of Sam Fox nude gifs (all 103 of them), I'll hate
+you forever", just because I may have done something wrong.
+
+Double-check your hardware.  If you are using other than EGA/VGA, you'll
+have to make the appropriate changes to 'linux/kernel/console.c', which
+may not be easy.  If you are able to use the at_wini.c under minix,
+linux will probably also like your drive.  If you feel comfortable with
+scan-codes, you might want to hack 'linux/kernel/keyboard.s' making it
+more practical for your [US|German|...] keyboard.
+
+
+	1.  Decide on what root device you'll be using.  You can use any
+(standard) partition on any of your harddisks, the numbering is the same
+as for minix (ie 0x306, which I'm using, means partition 1 on hd2).  It
+is certainly possible to use the same device as for minix, but I
+wouldn't recommend it.  You'd have to change pathnames (or make a chroot
+in init) to get minix and linux to live together peacefully.
+
+I'd recommend making a new filesystem, and filling it with the necessary
+files: You need at least the following:
+
+	- /dev/tty0		(same as under minix, ie mknod ...)
+	- /dev/tty		(same as under minix)
+	- /bin/sh		(link to bash)
+	- /bin/update		(I guess this should be /etc/update ...)
+
+Note that linux and minix binaries aren't compatible, although they use
+the same (gcc-)header (for ease of cross-compiling), so running one
+under the other will result in errors. 
+
+
+	2.  Compile the source, making necessary changes into the
+makefiles and linux/include/linux/config.h and linux/boot/boot.s.  I'm
+using a slightly hacked gcc-1.40, to which I have added a -mstring-insns
+flag, which uses the i386 string instructions for structure copy etc. 
+Removing the flag from all makefiles should do the trick for you.
+
+NOTE! I'm using -Wall, and I'm not seeing many warnings (2 I think, one
+about _exit returning although it's volatile - it's ok.) If you get
+more warnings when compiling, something's wrong.
+
+
+	3.  Copy the resultant code to a diskette of the right type. 
+Use 'cp Image /dev/PS0' or equivalent. 
+
+
+	4.  Boot with the new diskette.  If you've done everything right
+(and if *I've* done everything right), you should now be running bash as
+root.  You can't do much (alias ls='echo *' is a good idea :-), but if
+you do run, most other things should work.  I'd be happy to hear from
+anybody that has come this far - and I'll send any ported binaries you
+might want (and I have).  I'll also put them out for ftp if there is
+enough interest.  With gcc, make and uemacs, I've been able to stop
+crosscompiling and actually compile natively under linux.  (I also have
+a term-emu, sz/rz, sed, etc ...)
+
+The boot-sequence should start with "Loading system...", and then a
+"Partition table ok" followed by some root-dev info. If you forget to
+make the /dev/tty0-character device, you'll never see anything but the
+"loading" message. Hopefully errors will be told to the console, but if
+there are problems at boot-up there is a distinct possibility that the
+machine just hangs.
+
+
+	5.  Check the new filesystem regularly with (minix) fsck.  I
+haven't got any errors for some time now, but I cannot guarantee that
+this means it will never happen.  Due to slight differences in 'unlink',
+fsck will report "mode inode XXX not cleared", but that isn't an error,
+and you can safely ignore it (if you don't like it, do a fsck -a every
+once in a while).  Minix "restore" will not work on a file deleted with
+linux - so be extra careful if you have a tendency to delete files you
+don't really want to.
+
+Logging out from the "login-shell" will automatically do a sync, and
+will leave you hanging without any processes (except update, which isn't
+much fun), so do the "three-finger-salute" to restart dos/minix/linux or
+whatever.
+
+
+	6.  Mail me and ask about problems/updates etc.  Even more
+welcome are success-reports (yeah, sure), and bugreports or even patches
+(or pointers to corrections).
+
+
+NOTE!!! I haven't included diffs with the binaries I've posted for the
+simple reason that there aren't any - I've had this silly idea that I'd
+rather change the OS than do a lot of porting.  All source to the
+binaries can be found on nic.funet.fi under /pub/gnu or /pub/unix. 
+Changes have been to makefiles or configuration files, and anybody
+interested in them might want to contact me. Mostly it's been a matter
+of adding a -DUSG to makefiles.
+
+The one exception if gcc - I've made some hacks on it (string-insns),
+and have got it (with the gracious help of Bruce Evans) to correctly
+emit software floating point. I haven't got diffs to that one either, as
+my hard-disk is overflowing and I cannot accomodate both originals and
+changes, but as per the GNU copyleft I'll make them available if
+someone wants them. I hope nobody want's them :-)
+
+
+		Linus		torvalds@kruuna.helsinki.fi

Linux-0.01/docs/RELNOTES-0.01

@@ -0,0 +1,254 @@
+
+
+
+		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