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From: tegge@idt.unit.no (Tor Egge)
Newsgroups: comp.unix.aix
Subject: Re: AIX 1.2 and Maxtor SCSI hard disk - HELP PLEASE!
Summary: AIX 1.2,
Message-ID: <1990Nov4.223444.19747@idt.unit.no>
Date: 4 Nov 90 22:34:44 GMT
References: <16332@hydra.gatech.EDU>
Organization: Div. of CS & T, Norwegian Institute of Technology
Lines: 72

In article <16332@hydra.gatech.EDU> hh2@prism.gatech.EDU (Harry Haas) writes:
>
>Has anyone EVER installed a SCSI adapter and a non-IBM hard disk to
>a PS/2 running AIX 1.2 ?!?!
>

Yes. I've installed AIX on a Seagate Wren VII, (989 MB formatted capacity).

1. Make a copy of the three first diskettes in the AIX 1.2 distribution
   (Boot (1), Boot (2) and Install (3)). DO NOT UNDER ANY CIRCUMSTANCES
   MODIFY THE ORIGINAL DISKETTES. 

2. You need to add entries in /etc/fsmap on your copy of the installation
   diskette (Disk 3) for the formatted capacity of your disk (rounded down to
   closest 5 MB,(I needed an entry for 985 MB)). If the correct entries are not
   present, mkfs for the root partition fails. To add these entries, you need
   to have a running version of AIX. (or you may use a disk-editor, and modify
   the 320 MB entries into the desired entry)

3. Since your disk probably has more than 512 MB formatted capacity, you also
   need to patch some more files:
     
       Name:                                       Diskette
       -----                                       --------
       /boot                                       Boot    (1) 
       /generic/install/generic.i386/mhdboot       Install (3)
       /generic/install/generic.i386/mhdload	   Install (3)


   The code converting from block number (32 bits) to cylinder,head,sector
   (parameters to BIOS INT 13H) uses an intermediate 16 bits signed integer. By
   patching it to use an unsigned integer, the limit is pushed to 1 GB
   formatted capacity (Which was enough for me). Instead of the sequence 
     8BF8 897EE0 C746DE0100 99 8B5EF6 F77F02 8946DC 8BC7 99 F77F02 8BFA 
   you need the sequence
     8946E0 C746DE0100 31D2 8B5EF6 F77702 8946DC 89D7 90 90 90 90 90 90 90.

   i.e. before:
     8BF8          MOV   DI,AX
     897EE0        MOV   [BP-20],DI
     C746DE0100    MOV   WORD PTR [BP-22],0001
     99            CWD
     8B5EF6        MOV   BX,[BP-0A]
     F77F02        IDIV  WORD PTR [BX+02]
     8946DC        MOV   [BP-24],AX
     8BC7          MOV   AX,DI
     99            CWD
     F77F02        IDIV  WORD PTR [BX+02]
     8BFA          MOV   DI,DX
   and after:
     8946E0        MOV   [BP-20],AX
     C746DE0100    MOV   WORD PTR [BP-22],0001
     31D2          XOR   DX,DX
     8B5EF6        MOV   BX,[BP-0A]
     F77702        DIV   WORD PTR [BX+02]
     8946DC        MOV   [BP-24],AX
     89D7          MOV   DI,AX
     90            NOP
     90            NOP
     90            NOP
     90            NOP
     90            NOP
     90            NOP
     90            NOP

4. Now install AIX with your modified diskettes.

Disclaimer: I take no responsibility for any of the statements/code/data above,
	    nor any effects/defects that they might give.

Tor Egge
email: tegge@idt.unit.no