XXDP Revisited

Now that I had a working RL02, I could finally demote the TU58 emulator to second place as a boot device. First port of call was an XXDP boot disk, for which I planned to use VTServer to pump over the disk image I already had. Unfortunately, the copy program didn't want to run with the RL02, deciding just to hang silently when I'd selected the RL02 as output device. I was able to copy from virtual tape to another virtual tape record which, although not in iteslf particularly particularly useful, proved that the communication links and the PDP were doing their job. I suspect there's something not quite right with the controller. On to plan B...

I remembered when I was playing with XXDP before that it was possible to create a new XXPD boot device from within the monitor itself. All I'd need to do was make a minimal XXDP tape with the UPDAT program and the DL (RL02) driver on it. I'd also copy the DD driver for the TU58 on there, so I could copy files to the new disk later. This was easy enough, but it took several times to get a clean boot. Eventually I got it booted and was able to run the UPDAT program. But yes, UPDAT needed to be read from tape and, typically, the TU58 emulator stopped working. A few more tries later and I was finally at UPDAT's command prompt. The process looked like this:

.R UPDAT
UPDAT .BIC
 
UPDAT - XXDP V2 UPDATE UTILITY REVISION G
RESTART: 004140
 
*INIT DL0:
USER DATA ON DL0 WILL BE DESTROYED!
PROCEED?(Y/N/CR=N)Y
 
*CREATE DL0:
 
*EXIT

Back in XXDP proper, it was just a case of copying everything from the tape to the newly initialised disk:

.COPY DD0:*.* DL0:

Then, without even having to touch the front panel, you can boot the new disk with one command:

.BOOT DL0:
 
 
 
BOOTING UP XXDP-XM EXTENDED MONITOR
 
 
XXDP-XM EXTENDED MONITOR - XXDP V2.5
REVISION: F0
BOOTED FROM DL0
124KW OF MEMORY
NON-UNIBUS SYSTEM
 
RESTART ADDRESS: 152000
TYPE "H" FOR HELP !
 
.

Not being one to trust a soft reset, I powered down and checked the result was the same: it was! Now that I had a bootable XXDP monitor on RL02, there would be no need to use the unreliable TU58 emulator to run diagnostics. Ok, fair enough; I'd need to use it to copy the individual diagnostic programs over to disk but, should this go wrong, rebooting from RL02 is a lot faster!

I figured I'd better make use of the new disk to carry on testing the RL02 and its controller. After all, something had to be causing those problems with VTServer. I ran the VRLB diskless controller test as before. I left it for half an hour before giving up - it had produced no output at all. I really need to check if that's normal before drawing any conclusions.

On a more positive note, the ZRLJ test was not only successful but quite an event. The bulk of this diagnostic involves testing the seek functionality which, in a big, non-Winchester drive like the RL02, means shooting the fairly substantial heads in and out at a decent rate of knots. The READY light was going wild as the test exercised the drive in cycles of short and long seeks. If you're running this test on an RL02 in a cabinet with wheels on, you'd be well advised to screw down the feet or the whole thing will start jumping around!

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