bosse@snoddas.ericsson.se (Bosse Sandholm) (02/08/90)
We are a 5 people with mostly HW experience who want to build a 68008 computer
to run minix.
I have patched pc-minix up to 1.5.0 on my sun, i have not yet installed it on a pc.
For our 68008 minix version we plan to buy atari-minix and start from there.
To simplify the software labour we want to design the 68008 card as atari-
compatible as possible.
I have a few questions to those of you who have looked more deeply into
minix-68k and it hw-needs.
We are thinking of building the card with the following memory map,
how does it compare with atari?
f0000-fffff bootprom and monitor 64Kb
e0000-effff i/o
00000-dffff RAM (bootprom shifted to lowest address during first 8
cpu cycles after reset.)
I/O 68681 two serieports, our monitorprogram supports this chip
what serialports does minix68k support?
2797 WD floppy controller, what does minix68k support?
TIMER What rate of clock tick is minix68k setup for and what chip does
atari support?
SCSI We have not really been thinking of this yet, how is it implemented
in atari.
What memory adresses does atari use for it's periferal chips.
Can atari minix diskettes be read by any other computer than an atari,
we would like to get atari 68k src to a sun for patching and archiving.
Can a PC read the atari minix diskettes?
Can anybody supply us with the gcc 68000 crosscompiler for minix on a sun?
We do not have ftp access.
If you can help us please respond.
Bo-Erik Sandholm
TN/ETX/TT/HL phone +46 8 719 1658
Ericsson telecom Fax +46 8 719 5319
126 25 Stockholm
bosse@snoddas.ericsson.se
..!uunet!sunic!ericom!snoddas!bosseeesrajm@cc.brunel.ac.uk (Andrew J Michael) (02/14/90)
Bosse Sandholm writes >For our 68008 minix version we plan to buy atari-minix and start from there. My advice is don't use a 68008. I tried to run MINIX on a 68008 about a year ago, and gave up because the 68008 isn't fast enough. Sounds odd ??? Well .... Consider the code in stfloppy.c, which tells the 1772 to carry out a command and then waits for an interrupt when it has finished. But suppose that the 1772 carries out the command very quickly (like a restore when the head is already at track 0). On a 68008 at 8MHz, the processor didn't exit from the code setting up the controller fast enough, and a hardware interrupt appeared before the driver was ready to expect a signal. Result; one broken operating system. On a 10MHz 68008 you might be OK, but bearing in mind that the 68008 only has a 1Mb addressing range and is hardly likely to set the world on fire with its speed, why bother ? I have run MINIX on a 68020 board for nearly two years now. In its current form (20MHz, no wait states) it delivers 6210 dhrystones/sec with a gcc compiled kernel and dhry.c. >Can a PC read the atari minix diskettes? No, due to endian problems. However, you can transfer files via tar, provided you have a recent version of tar on both machines. >Can anybody supply us with the gcc 68000 crosscompiler for minix on a sun? Certainly, if you canot find anyone nearer. Drop me a line. Andy Michael