[Info-vax] Assistance needed!! working RM05 drive and VAX needed for proje

[Johnny Billquist]

On 2023-09-28 18:43, Dave McGuire wrote:
> On 9/27/23 23:52, gah4 wrote:
>> Reminds me of another DEC disk, which can be used on either PDP-10 or
>> byte addressed machines. The controllers are different, and can only 
>> write
>> blocks with the appropriate size, which I believe is 576 bytes for the 
>> PDP-10,
>> and 512 otherwise.  You can't read disk packs on the other one.
> 
>    RM02/RM03.  There's a jumper on the backplane.

I've been reading the RM02/RM03 manuals, and I can't find any 
documentation on any backplane jumper for such a purpose. There are 
jumpers for drive type and serial number, but that's about it as far as 
I can find.

By the way, it's kind of strange to talk about different "controllers". 
Of course they are different. The PDP-10 have a very different massbus 
controller compared to a PDP-11 or a VAX. But they all talk massbus, and 
the devices on the massbus itself is sortof agnostic to the machine word 
size.

But the disk packs just have a different format depending on what they 
are used for, and that formatting can be changed on a per-track basis. 
The format is in the header for each sector.

   Johnny