Two winchester drives

I thought that it's about time I posted another photo of my PDP-11.  Here are both my winchester disks hooked up:

Two winchester disks and my PDP-11

At the moment I'm in the process of copying the original install files onto the newest disk, so I will have the *full* set of RT-11 files on there.

Another winchester drive

So I bought a second Seagate ST-225 "winchester" disk off ebay.  I got it for the starting bid, nobody else made a bid!  Result.  I have connected it to my PDP-11 and used my "XXDP booting from ODT" trick to format it.  Here are the results:

Second disk formatted

This is good news, the drive seems to be in good shape.  Since then I have copied some RT-11 files to it and made it bootable.  So I have a spare.

Make a disk bootable in RT-11

In the end it was very easy to get my winchester drive to be bootable.  I just had to read the manual really...  This was what I used:

copy/boot dk0:rt11xm.sys dk0:

The trick is to already have a copy of the boot-file (RT11XM.SYS in my case) on the disk.  The "copy/boot" command then just moves the file from one part of the disk, to the boot section.  Easy.

I used that to make my Winchester Drive bootable, so now I'm booting straight from the fixed disk.

Winchester Drive

A colleague at work gave me a Seagate ST-225 "winchester" MFM hard disk.  This disk is the same as the RD31 used in PDP-11's (a 20meg drive). It has been sitting inside my PDP for a while, but I could not format it.  I tried to make an XXDP boot disk, which has the formatting program, but it halted the machine when I tried to use it.  RT-11 cannot format fixed disks.  However, I managed to find other means to get XXDP onto my machine.  Here is the disk format program in action:

ST-225 MFM formatting

Nice!  What I did was boot XXDP in the SIMH emulator, start the ZRQCH0 formatting program and then dump the first 56k of memory to disk.  I then used a little C# utility I wrote to turn this dump into machine instrictions that could be entered into memory via ODT.  It took about 2 hours to send the data over a 9,600 baud serial line.  Still, it worked a treat!  I have a formatted hard disk in my machine!  I haven't managed to make it bootable yet, but I have copied some files to the new disk.  I need to upload some photos...