[net.micro.pc] xenix and necv20 questions

brewster@watdcsu.UUCP (dave brewer, SD Eng, PAMI ) (10/02/86)

llllline eater ! 


This is my first posting to the net and I would appreciate any
feedback on netiquette abuse I may perpetrate.

2 questions.

1) I have an IBM clone switchable between 4.77 and 8 MHz.
   With an 8088-2 installed the clone functions normally
   at either speed, any PC-DOS 3.2 command including
   diskcopy .
   With a NEC V20-8 (8 MHz version of the V20) the system
   functions normally at 8 MHZ, while at 4.77 MHz the
   system will hang on any hard disk access.
   
   Can anyone explain this ?

2) When attempting to install Xenix 2.0 from SCO via Microsoft 
   onto a hard disk (20 M Seagate, National controller which otherwise
   seem to function perfectly), the boot disk functions normally;
   letters A through Z display routinely.  I then invoke the 
   "hdinit" program from the root disk,
   which is supposed to call the Xenix fdisk program and set up
   a Xenix partition on the hard disk.  It accesses the hard disk and
   comes back with the message "Invalid fixed disk parameter table"
   and then the hdinit command aborts.
   
   For anyone who has used Xenix I have these questions :
   a) which DOS (MS, PC, and version did you use)  ?
   b) what was the state of the hard disk when you ran hdinit
      i.e. did you have it partitioned, what sizes, what partition
      was active, was the hard disk formatted from DOS first, etc ? 

   c) given that any monetary investment in Xenix is irrelevant to
      this question,  should I fight with the DOS and/or Xenix 
      internals in an attempt to get Xenix installed.  i.e. Is
      Xenix on a PC-XT with one 20 M hard drive and 2 floppies
      worthwhile or is it a just a waste of memory space ?


UUCP  : {decvax|ihnp4}!watmath!watdcsu!brewster
Else  : Dave Brewer, (519) 886-6657

jeffd@ittvax.ATC.ITT.UUCP (Jeff Denenberg) (10/06/86)

> 
> 
> llllline eater ! 
> 
> 
> This is my first posting to the net and I would appreciate any
> feedback on netiquette abuse I may perpetrate.
> 
> 2 questions.
> 
> 1) I have an IBM clone switchable between 4.77 and 8 MHz.
>    With an 8088-2 installed the clone functions normally
>    at either speed, any PC-DOS 3.2 command including
>    diskcopy .
>    With a NEC V20-8 (8 MHz version of the V20) the system
>    functions normally at 8 MHZ, while at 4.77 MHz the
>    system will hang on any hard disk access.
>    
>    Can anyone explain this ?
> 
> 2) When attempting to install Xenix 2.0 from SCO via Microsoft 
>    onto a hard disk (20 M Seagate, National controller which otherwise
>    seem to function perfectly), the boot disk functions normally;
>    letters A through Z display routinely.  I then invoke the 
>    "hdinit" program from the root disk,
>    which is supposed to call the Xenix fdisk program and set up
>    a Xenix partition on the hard disk.  It accesses the hard disk and
>    comes back with the message "Invalid fixed disk parameter table"
>    and then the hdinit command aborts.
>    
>    For anyone who has used Xenix I have these questions :
>    a) which DOS (MS, PC, and version did you use)  ?
>    b) what was the state of the hard disk when you ran hdinit
>       i.e. did you have it partitioned, what sizes, what partition
>       was active, was the hard disk formatted from DOS first, etc ? 
> 
>    c) given that any monetary investment in Xenix is irrelevant to
>       this question,  should I fight with the DOS and/or Xenix 
>       internals in an attempt to get Xenix installed.  i.e. Is
>       Xenix on a PC-XT with one 20 M hard drive and 2 floppies
>       worthwhile or is it a just a waste of memory space ?
> 
> 
> UUCP  : {decvax|ihnp4}!watmath!watdcsu!brewster
> Else  : Dave Brewer, (519) 886-6657

I have only seen problems with the NEC V20 when there are software timing loops
in core packages. The behavior you describe could come from such a loop in the
bios for the disk. A faster clock would speed up the bios and "cure" the symtom
as you describe it. Another way to mask the problem would be to load a disk
cache program into your system. This would change its characteristics and may
also solve the problem. The correct solution is to use debug to change the loop
counter in the bios but someone with more experience with your configuration
than I will have to provide the details. Good luck.

                         Jeff Denenberg
                         ..!decvax!ittvax!jeffd