amiga@cs.vu.nl (Commodore Amiga) (07/25/89)
Finally some answers about AmigaMINIX from the guys who ported it. We hope that the following will clarify most of the darker areas around AmigaMINIX. For those of you who don't know what AmigaMINIX is about: it's a UNIX like operating system for you Amiga. MINIX was originally written by Andy Tanenbaum for the PC-family and later on ported to the Atari-ST by Johan Stevenson and Jost Muller. Because the ST version is based on the Motorola 68000 we decided to port this version to the Amiga. While porting MINIX to the Amiga we've tried to keep the main goal of MINIX (education) in mind. This means we did not try to squeeze out every bit of performance, especially not where this would harm the clarity of the MINIX source code and/or structure. Another result of this goal is that we decided not to use the usual Amiga disk format, but the PC (ST) format instead. This way the AmigaMINIX and MINIX-ST file systems are 100% compatible. Because MINIX doesn't use any dirty tricks, AmigaMINIX and MINIX-ST binaries are also compatible; you can mount a MINIX-ST floppy on AmigaMINIX and run all binaries. (Almost all, actually. Programs which do use 'dirty tricks' as directly reading from /dev/ram to set the time-of- day clock won't run properly of course!) Although we wanted to use the PC format for the AmigaMINIX floppies we didn't want to fall asleep when loading mined for example. We tried to optimize the floppy driver as much as we could be using a track cache for each drive and only compute the CRCs (checksums) when necessary. (Computing a CRC costs about 50 ms. This limits the transfer rate to 6.9 kb/sec. The normal transfer rate under AmigaMINIX is 4 to 5 kb/sec) Since each track- cache occupies about 14 kb of CHIPMEM, these buffers are dynamically allocated for only those floppy drives that are actually connected. Apart from the PC format disks there's another remarkable 'thing' about AmigaMINIX: it doesn't support hard disks. (sorry) There are two main reasons for this. In the first place there are several different hard disks in use on Amiga's and we didn't want to write a driver for all of them. Further, we didn't (and nobody in our neighborhood does) have a hard disk to test our driver(s) on. If, however, hard disks are as common in other places of the world as we're told, it shouldn't be long before one of you will post a driver for your favorite hard disk. To sum up the most important specifications of AmigaMINIX: - AmigaMINIX boots from a normal AmigaDOS floppy (bootstrap) so it can easily steal (use) everything AmigaDOS knows about your Amiga. (Whether is's NTSC or PAL, how much memory do you have, what color the screen is, what keymap you use, etc.) After that it completely takes over your Amiga, and disables EXEC. - You can use ALL of the available RAM which is normally available under AmigaDOS, even if it's fragmented. - The floppy driver can read and write single and double sided 80- track floppies. (Also single sided for MINIX-ST compatibility.) Up to four drives can be connected. - The AmigaMINIX printer driver only supports the parallel (centro- nics) port. - The display driver use ANSI escape sequences and also provides limited access to the color registers. Some of you may wonder why we decided not to run AmigaMINIX under EXEC. The main reason for this is that (at first) we thought that it wouldn't run properly with the MINIX-ACK compiler. When we realized that this wasn't such a big problem after all, the port was already half on its way. Another reason is that we think that you should not run operating systems on top of each other, if you want people to know what operating systems really is all about. (Andy Tanenbaum once put it something like: "It's not writing a 15 page scheduler, but getting all the details right.") AmigaMINIX is currently being tested here on the VU and because we haven't found a distributor yet and don't feel like posting 3 Mb (yet :-) it'll probably be a while before you can use AmigaMINIX. -Steven Reiz & Raymond Michiels. (amiga@cs.vu.nl)
sft@cbnewsc.ATT.COM (scott.thompson) (07/27/89)
From article <2939@solo3.cs.vu.nl>, by amiga@cs.vu.nl (Commodore Amiga):
SR-RM>
...
SR-RM> To sum up the most important specifications of AmigaMINIX:
SR-RM>
SR-RM> - AmigaMINIX boots from a normal AmigaDOS floppy (bootstrap) so
SR-RM> it can easily steal (use) everything AmigaDOS knows about your
SR-RM> Amiga. (Whether is's NTSC or PAL, how much memory do you have,
SR-RM> what color the screen is, what keymap you use, etc.) After that
SR-RM> it completely takes over your Amiga, and disables EXEC.
SR-RM>
SR-RM> - You can use ALL of the available RAM which is normally available
SR-RM> under AmigaDOS, even if it's fragmented.
SR-RM>
...
SR-RM> -Steven Reiz & Raymond Michiels. (amiga@cs.vu.nl)
Will it recognize memory boards that are not auto-configuring? Will
there be a command to add this memory or will it be done on the Amiga
side before Minix takes over?
--
Scott Thompson (IH 6W-207), AT&T Bell Labs, Naperville, Il. 60566
VOICE: (312)-979-2237 UUCP: ...!att!ihlpa!sftjms@tardis.Tymnet.COM (Joe Smith) (08/01/89)
In article <2059@cbnewsc.ATT.COM> sft@cbnewsc.ATT.COM (scott.thompson) writes: >Will it recognize memory boards that are not auto-configuring? Will >there be a command to add this memory or will it be done on the Amiga >side before Minix takes over? They said: "AmigaMINIX boots from a normal AmigaDOS floppy". That sounds like it uses S:startup-sequence. Then they said "so it can determine what keymap you use". That seems to be a very unambiguous reference to AmigaMINIX being started near the end of the startup-sequence, after your SetMap command. Which means AddMem can go in there, no problem. -- Joe Smith (408)922-6220 | SMTP: JMS@F74.TYMNET.COM or jms@tymix.tymnet.com McDonnell Douglas FSCO | UUCP: ...!{ames,pyramid}!oliveb!tymix!tardis!jms PO Box 49019, MS-D21 | PDP-10 support: My car's license plate is "POPJ P," San Jose, CA 95161-9019 | narrator.device: "I didn't say that, my Amiga did!"
shadow@pawl.rpi.edu (Deven T. Corzine) (08/01/89)
On 1 Aug 89 01:00:11 GMT,
jms@tardis.Tymnet.COM (Joe Smith) said:
Joe> They said: "AmigaMINIX boots from a normal AmigaDOS floppy".
Joe> That sounds like it uses S:startup-sequence. Then they said "so
Joe> it can determine what keymap you use". That seems to be a very
Joe> unambiguous reference to AmigaMINIX being started near the end of
Joe> the startup-sequence, after your SetMap command.
This does not necessarily follow. It could simply mean that it
pretends to be a dos disk ("DOS\0" tag) so it can boot. It's likely
to let AmigaDOS boot and do initialization stuff, but don't count on
it. (until you know.)
Joe> Which means AddMem can go in there, no problem.
If there's actually a startup-sequence, yes.
Deven
--
Deven T. Corzine Internet: deven@rpi.edu, shadow@pawl.rpi.edu
Snail: 2214 12th Street, Troy, NY 12180 Phone: (518) 271-0750
Bitnet: deven@rpitsmts, userfxb6@rpitsmts UUCP: uunet!rpi!deven
Simple things should be simple and complex things should be possible.jms@tardis.Tymnet.COM (Joe Smith) (08/02/89)
In article <SHADOW.89Aug1004439@pawl.rpi.edu> shadow@pawl.rpi.edu (Deven T. Corzine) writes: >Joe> They said: "AmigaMINIX boots from a normal AmigaDOS floppy". >Joe> That sounds like it uses S:startup-sequence. Then they said "so >Joe> it can determine what keymap you use". That seems to be a very ^^^^^ >Joe> unambiguous reference to AmigaMINIX being started near the end of >Joe> the startup-sequence, after your SetMap command. > >This does not necessarily follow. I based my statement on the fact that they claim to honor the keymap. To me, that means only one thing: that the AmigaDOS SetMap program gets run. I don't see how any of the other claims could be true without running the startup-sequence. Go back to the original posting for details. Unless the people doing the port of AmigaMINIX want to jump in, this thread has ended. -- Joe Smith (408)922-6220 | SMTP: JMS@F74.TYMNET.COM or jms@tymix.tymnet.com McDonnell Douglas FSCO | UUCP: ...!{ames,pyramid}!oliveb!tymix!tardis!jms PO Box 49019, MS-D21 | PDP-10 support: My car's license plate is "POPJ P," San Jose, CA 95161-9019 | narrator.device: "I didn't say that, my Amiga did!"