[Simh] EXT : VAXstation 4000 Model 60

[Bob Eager]

On Fri, 12 Jul 2019 23:41:13 +0200
Johnny Billquist <bqt at softjar.se> wrote:

> On 2019-07-12 23:36, Bob Eager wrote:
> > On Fri, 12 Jul 2019 11:59:49 -0700
> > Mark Pizzolato <Mark at infocomm.com> wrote:
> >   
> >> On Friday, July 12, 2019 at 11:27 AM, Johnny Billquist wrote:  
> >>> As far as I am aware, it was only some models in the 3100 series
> >>> that used the shorter SCSI commands in the boot rom, which caused
> >>> issues with the boot disk. However, I'm not sure that exact thing
> >>> is the problem. You might very well have some display issues that
> >>> pop up in the boot monitor, even though the system will boot
> >>> perfectly fine from a larger disk.  
> >>
> >> On the older VS3100 systems (without large disk boot support),
> >> things would boot fine on larger disks as long as the pieces of OS
> >> code that are loaded in the early stages of the boot all happen to
> >> be located early enough in the disk drive.  Since you can't
> >> guarantee that all the needed files would be located early in the
> >> drive large disks were "not bootable".  
> > 
> > I fixed this by making the disks artificially smaller (by changing
> > the firmware tables on the disk).  
> 
> But then I assume the disk appeared smaller also at later stages. 
> Essentially you got yourself a smaller disk.

Indeed. I only did it for the boot drive, of course. And has external
disks too.