john@moncol.UUCP (04/05/87)
In article <1127@botter.cs.vu.nl> ast@cs.vu.nl (Andy Tanenbaum) writes: > >I talked to Prentice-Hall today and was informed that they began shipping MINIX >diskettes on March 23. Hopefully people will begin getting them soon. >When you get yours, try it on whatever kind of clones you have around, >and post a note to the news group saying what happened. Well, Monmouth College's copy of the 640K PC package arrived yesterday. Last evening I tried to bring up a copy on my personal machine- a Tandy 1000. (Most of the PC's at Monmouth are AT&T 6300's- MINIX runs great on them, though I haven't tried the HD yet.) Summary: MINIX won't run on the Tandy 1000. Details: The boot diskette comes up fine. I am able to check the filesystems, etc. After replacing the Boot Diskette with the Root File system, I press the '=' key and the world comes to a dead halt. This is a total hang which can only be cleared by cycling the power or pressing the RESET button. Today I took the disks to the local Radio Shack to try MINIX on the present generation of Tandy 1000. First I tried MINIX on a 384K 1000SX (with a 20MB HD). The results were the same as above. Next I tried MINIX on a 256K 1000EX (DMA installed, etc.). This was a bit strange- instead of hanging, it panicked after printing three or four messages about the winchester process receiving -1. Was this due to a lack of memory? NOTES: For those who might be able to offer suggestions, let me state a few technical notes on the 1000.: The system definately has the correct CRTC- the MC6845. The FDC is an Intel 8272A. Though this is not the chip I have seen mentioned in previous articles, I was led to believe that it was an exact replacement. No? Memory management on the 1000 is a tad different than on a real PC- actually it's closer to that of a PCjr. In short, there is no dedicated video memory; rather the top 16K is stolen for this purpose and somehow mapped into the 0xB800 segment. Thus, ny 640K Tandy 1000 is really a 624K machine. Any suggestions? -- Name: John Ruschmeyer US Mail: Monmouth College, W. Long Branch, NJ 07764 Phone: (201) 571-3557 UUCP: ...!vax135!petsd!moncol!john ...!princeton!moncol!john ...!pesnta!moncol!john "If the nemesis in this movie can be a giant roll of aluminum foil, then I can name our ship after a super absorbent paper towel."
ast@botter.UUCP (04/08/87)
In article <472@moncol.UUCP> john@moncol.UUCP (John Ruschmeyer) writes: >Summary: MINIX won't run on the Tandy 1000. > Memory management on the 1000 is a tad different than on a real PC- > actually it's closer to that of a PCjr. In short, there is no dedicated > video memory; rather the top 16K is stolen for this purpose and somehow > mapped into the 0xB800 segment. Thus, ny 640K Tandy 1000 is really a > 624K machine. A number of people have sent me mail about problems with the Tandy. Maybe the problem is as follows. MINIX expects a video RAM at address 0xB0000 if the motherboard switches say there is a monochrome adapter installed and at 0xB8000 if there is a color adapter. If it tries to write to those addresses and nothing is there, the computer will just hang. Conceivably something is going wrong with the mapping. I would suggest writing a little test program under MS-DOS or some other system that just writes characters to 0xB8000 or 0xB0000 to see if that works. Another problem is that MM may think memory is 640K instead of 624K. It may be necessary to patch something around line 5517. Note that get_tot_mem is an assembly code routine in the directory lib. Finally there is the issue of whether the disk controller chip is really compatible. Probably the best thing to do is modify the MINIX disk driver to make it a free-standing test program, compile it under MS-DOS or XENIX or something else, and experiment. Andy Tanenbaum
beattie@netxcom.UUCP (04/09/87)
I don't think the problem is the video memory since the memory set aside for video is mapped to b8000 to c0000. I just got my copy of the disks and have looked at the book and a possible problem is that interrupt 5 is connected to the vertical sync. The problem might that since all interrupts are enabled in main (line 979) that MINIX might be getting an unexpected interrupt and panic(ing) before the console is set up. I tryed to patch this with debug but it would seem that a sub ax,ax is used to load ax with zero so there is no room to set a mask. I don't know when I might get a chance to try to fix this. I have a copy of the Technical Reference for the Tandy 1000 -- ----------------------------------------------------------------------- Brian Beattie | Phone: (703)749-2365 NetExpress Communications, Inc. | uucp: seismo!sundc!netxcom!beattie 1953 Gallows Road, Suite 300 | Vienna,VA 22180 |
kimery@wdl1.UUCP (04/10/87)
/ wdl1:comp.os.minix / ast@cs.vu.nl (Andy Tanenbaum) / 3:22 am Apr 8, 1987 / In article <472@moncol.UUCP> john@moncol.UUCP (John Ruschmeyer) writes: >>Summary: MINIX won't run on the Tandy 1000. >> Memory management on the 1000 is a tad different than on a real PC- >> actually it's closer to that of a PCjr. In short, there is no dedicated >> video memory; rather the top 16K is stolen for this purpose and somehow >> mapped into the 0xB800 segment. Thus, ny 640K Tandy 1000 is really a >> 624K machine. >A number of people have sent me mail about problems with the Tandy. Maybe >the problem is as follows. MINIX expects a video RAM at address 0xB0000 if >the motherboard switches say there is a monochrome adapter installed and >at 0xB8000 if there is a color adapter. If it tries to write to those >addresses and nothing is there, the computer will just hang. Conceivably >something is going wrong with the mapping. I would suggest writing a little >test program under MS-DOS or some other system that just writes characters >to 0xB8000 or 0xB0000 to see if that works. Unless I have missed some strange and mysterious working of the tty driver it may not be as strange as it seems. I added a few printf's around line 4495 to display the type of keyboard that it thought it was seeing. Guess what. The messages showed up and then screech the machine locks up. From what I've seen so far it doesn't look as if thetty driver is the problem. My next guess is the floppy driver. (of course my next guess could be anything too......) I am slowly but surely tuning in on the problem. If enough people are interested (break out the hip waders) I'll be glad to share the changes I have made so far (both lines of them). Oops, another change just let me change the cursor size, move it to the lower left hande corner of the screen AND access the floppy before locking up... (maybe in a few days, I'll see the sizes printout before it locks up....) Sam Kimery kimery@ford-wdl1 sun!wdl1!kimery Merry Feast of the Pig!
jjc@sdiris1.UUCP (Jim J. Carter) (04/13/87)
in article <5650002@wdl1.UUCP>, kimery@wdl1.UUCP (Sam Kimery) says: > > ... I'll be glad to share the > changes I have made so far (both lines of them). > I am interested in any progress on the 1000. I have limitted access to a non 1000 machine thus getting a version working by myself is a long process. ----------------------------------------------------------------------- UUCP: ...!sdcsvax!jack!man!sdiris1!jim | Jim Carter