Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!rochester!udel!mmdf From: PKP88%DMSWWU1A.BITNET@cunyvm.cuny.edu (Rainer Perske) Newsgroups: comp.os.minix Subject: Re: MINIX-ST: Can't boot MINIX from .IMG Message-ID: <9273@louie.udel.EDU> Date: 21 Feb 89 11:39:18 GMT Sender: mmdf@udel.EDU Lines: 59 Hello, yesterday I wrote: >I've run into an installation problem with MINIX-ST: I want to start >MINIX from TOS w/o using a floppy disk. I followed the instructions in >the manual to create MINIX.IMG on my hard disk. There is no problem >starting MINIX this way if (and only if) I've created MINIX.IMG from an >unchanged boot disk. But I have a german keyboard, so I ran FIXKEYS.PRG >on a copy of my boot disk. If I create a MINIX.IMG from this changed >boot disk, MINIX.PRG stops with a message: minix.img: wrong format. >Why? Jack Dunn answered: >I don't think the problem is with using FIXKEYS. I have had the same >problem with out using FIXKEYS. In my analysis, the booting program >will never work with a correct .IMG file. The error is generated >when, if I calculated the address right, the 16 bit word located >at offset 508 ( wp[-2] ) is not zero or when the 16 bit word >at offset 506 ( wp[-3] ) does not equal the 16 bit word at offset >510 ( wp[-1] ). It appears that wp[-1] is a check sum and >wp[-3] is the start of the data segment. I can not see >how these words would ever be equal. I have concluded that >the MINIX.PRG is the not coded correctly. I have go any further >into trying to correct the problem since it is just as easy to >boot the system from floppy. Most of this is correct, but it is not the reason the fault originates from, as I've decovered now: If I make a diskcopy by dragging icon A on icon B, the bootsector will NOT be maintained exactly, if it is not in standard TOS format. At least five bytes changed, including the checksum. Because byte 510 (wp[-1]) is part of the checksum, MINIX.PRG will fail if MINIX.IMG is made from a copied disk, but it happens to success from the original disk. Proposed correction: Use a disk copy program instead of dragging icon A on icon B, or try (using the 08.TOS disk, see manual) RFLOP A: M:MINIX.IMG 1300000 read the original bootdisk image WFLOP A: M:MINIX.IMG write a copy on another disk Preferrable correction (Johan? Jost?): Change MINIX.PRG so that any other validity check is performed; and change the minix bootsector, so that it becomes a fully TOS compatible bootsector (one that will be maintained by the desktop diskcopy). Much fun with MINIX! Rainer Perske ------------------------------------------------------------------------ Rainer Perske EARN/BITNET: PERSKE@DMSWWU5P.bitnet Institut fuer Kernphysik der EARN/BITNET: PKP88@DMSWWU1A.bitnet Westfaelischen Wilhelms-Universitaet . Wilhelm-Klemm-Strasse 9 /|\ D-4400 Muenster | Federal Republic of Germany has recently changed ! ------------------------------------------------------------------------ Disclaimer: If not otherwise stated, all written above is my own opinion