Subject: Re: No way to install NetBSD on uVaxII
To: None <>
From: John Wilson <>
List: port-vax
Date: 08/17/1998 13:02:43
>From: Kees Stravers <>

>I think it would work if you set it as a 720K in the PC BIOS setup screen.
>I've also used 1.44s in XTs as 720Ks and that worked. You could also
>experiment with setting it to 1.2MB, so PUTR thinks it is a 5.25 HD drive
>and it might switch the data rate correctly to DD. I have had 1.44s set as
>1.2 in the BIOS by accident and that worked without a problem, until I 
>started wondering why there seemed to fit less files on the floppies...

PUTR only uses the CMOS drive types to set the default drive type if you
don't specify it with a command line switch, otherwise it assumes that
you know what you're doing.  1.44 MB drives will replace 720 KB drives,
but if you tell PUTR it's an RX50 it will still set the wrong data rate
(unless you've got an older FDC designed for dual-speed 1.2 MB drives,
in which case it should work fine).  If you say it's an RX24 it will set
up the 720 KB data rate but it'll treat it as double sided with no
soft interleave, like a real RX24.

FDCDEMO (also on isn't DEC-specific and allows you to dial
in all kinds of crazy parameters by hand, however since it's not DEC-
specific it doesn't know about the weird soft interleave so it always
transfers disks in raw sector order.  If you're really desparate you can
use PUTR to do the soft interleave into an image file and then copy
*that* using FDCDEMO onto a 1.44 MB drive with doctored up parameters.
I hope I have this right -- in PUTR:

	mount x: rx50.dsk /rx50 /foreign
	copy/file/dev/bin x: temp.bin

Then copy temp.bin to the disk using FDCDEMO and weird parms -- I *think*:

	B: RX50 DDinDD		(or A: to use that drive instead)
	WRITE temp.bin

DDinDD is the key, it tells FDCDEMO to assume it's writing a DD disk in a
DD drive (at 250 kHz/300 RPM), rather than a DD disk in an HD 1.2 MB drive
which requires the weird 300 kHz speed.

What a pain though!  Reminds me of the time I installed DOS V2.00 on a
Pentium system (don't ask), and had to build an image of a DOS 180 KB SSDD
disk on half of one side of a 720 KB disk since there was no DD 5.25" drive
on the machine.

John Wilson
D Bit