[pups] CDROM drives and PDP-11s

[cdl@mpl.ucsd.edu (Carl Lowenstein)]

> From: "Ian King" <iking at killthewabbit.org>
> To: "Gregg C Levine" <hansolofalcon at worldnet.att.net>, <pups at minnie.tuhs.org>
> Subject: Re: [pups] CDROM drives and PDP-11s
> Date: Thu, 27 Feb 2003 08:52:54 -0800
> 
> John Wilson's PUTR program might be jut the tool - http://www.dbit.com.  I'm
> guessing it might be ODS-2; worst case, I have an InfoServer that can read
> that, and a TK-50 I could dump it to...  :-)  -- Ian
> ----- Original Message -----
> From: "Gregg C Levine" <hansolofalcon at worldnet.att.net>
> To: <pups at minnie.tuhs.org>
> Sent: Wednesday, February 26, 2003 11:46 PM
> Subject: [pups] CDROM drives and PDP-11s
> 
> Hello from Gregg C Levine
> Here's the problem. I have several CDs containing programs, and such
> like from Tim Shoppa. Two of them say they contain portions which are
> readable only by a CDROM Drive attached to a PDP-11. One of them is
> split in half. Half is readable on either of the two computers here,
> the other half, is in a format that's native to the PDP-11. The other
> is all in that proprietary format. So, has anyone managed to get them
> read to their machines? Or failing that to the appropriate simulators,
> or even emulators? Any suggestions?

When I look at "readme.txt" on my RT11 disk from Tim Shoppa I find the
following paragraph:

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
The second part of the disk is seven RT-11 partitions.  Each is a 65536
block RT-11 device that is accessible on a PDP-11 machine with a SCSI
host adapter and a SCSI CD-ROM drive.  They appear as RT-11
DU partitions 13 through 19.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

The implication to me is that any of these partitions could be copied
to a 32MB file on a hard drive, and then attached to the PDP11 simulator
of your choice and read as an RT-11 drive.

The tool I would use for copying the partition is dd(1).

	dd if=/mnt/cdrom bs=32M skip=13 count=1 of=dskimg

This requires that you have 32MB available RAM for the dd "copy in"
and 32MB available disk space for the dd "copy out".  You could
trade off a smaller "bs" for a more complicated calculation of the "skip".
I suppose I am making the assumption that this work is being done on
a Unix-like system, which seems reasonable in the PUPS context.

    carl
-- 
    carl lowenstein         marine physical lab     u.c. san diego
                                                 clowenst at ucsd.edu