Dec RQDX: What kind of chips on it?
cz at alembic.crystel.com
Tue Jan 5 09:15:22 CST 2021
> It's surprising that the RQDX3 wasn't made format-compatible with the older controllers.
It makes sense: The 1/2 used interleaving, which would have required
extra code in the 3 to support. The 1/2 figured out the disk geometry
based on ROM lookups, the 3 stored the disk geometry on the disk. That
meant you didn't have to worry about ROMs and technically you could use
pretty much any MFM disk with less than a certain number of heads and
What I realized mentally is that from the OS/driver/register level they
are identical. So while the physical disk format is different, there
should be no reason I can't hook up an RQDX2 to the DSM disk, fire up
PDPGUI, select the drive as a DU: type, suck the data into a file over a
serial connection, and boot it on SIMH without any issues.
> As for floppies, the RX50 format is the same for all PDP-11/VAX systems.
True, and I can download P/OS, dig out the PC with a 1.2mb floppy, and
make the floppies on these Micro-RSX11M floppies I have in a box but man
it's 30 floppies of *stuff*.
Technically I see there is a disk writer utility for the Pro/POS
somewhere so I *could* download that to the Pro, download the disk
images, and copy them one at a time. Or maybe I could use this Dave G
MFM emulator to emulate an RX50, then just present the disks over and
over till install is done. Hm....
More information about the cctech