[Simh] Initializing disks (triggered by the "Something Strange with RK05" chain

[Mark Pizzolato]

Recent versions of the simh PDP11 will correctly auto size (RL01 vs RL02) disk containers that have or don’t have the DEC STD 144 bad block table at the end of the drive as long as the disk image has an RT11 file system on it.  If it has an RT11 file system that fact will be reported.

The prompt “Overwrite last track? [N]” is actually asking a question about whether the DEC STD 144 bad block table should be written.  The default of “[N]” will create a 0 sized container file on simh v3.x and before.  On simh 4.x, the container file will be created to the full size of the respective drive without regard to the answer to the “Overwrite last track? [N]” question.

Maybe the message:

?DUP-F-Size function failed

Happens when an empty container is provided (without a DEC STD 144 bad block info)…


-          Mark

From: Simh [mailto:simh-bounces at trailing-edge.com] On Behalf Of Henk Gooijen
Sent: Wednesday, February 12, 2020 1:39 PM
To: simh at trailing-edge.com
Subject: Re: [Simh] Initializing disks (triggered by the "Something Strange with RK05" chain


Yes, rt11dat and rt11run looks like RL01 “disks”, and rtv53_rl.dsk is an RL02 (and IIRC the distribution disk).
Maybe you can add the following command after SET CPU and before the ATTACH RL statements.
SET RL0 RL01
SET RL1 RL02
SET RL2 RL01

Then ATTACH them. But if I am right, you will need two empty RL02 disks, because when you boot
from the RL1: you probably end up in the installation procedure which want to create a backup disk
and a “working copy” disk (and store the distribution disk in a safe place 😊
As said, from DBIT you can get an empty RL02 image.

Best to make (in Windows / Linux) a copy of the 3 files, and then proceed.
If the rt11dat,dsk is indeed empty, it will not hurt to try
.INIT /BADBLOCK RL2:


Van: Ken Hall<mailto:kjhall55 at gmail.com>
Verzonden: woensdag 12 februari 2020 21:09
Aan: simh at trailing-edge.com<mailto:SimH at trailing-edge.com>
Onderwerp: Re: [Simh] Initializing disks (triggered by the "Something Strange with RK05" chain

Going by the size of the disk image files, I believe there’s a mix.  These are downloaded disk images I pulled (literally) years ago, DL0 seems to be RL01, while DL1 is RL02:

5235200 Dec 21  2011 rt11dat.dsk
5235200 Feb 12 12:18 rt11run.dsk
10475520 May 10  2006 rtv53_rl.dsk

The one I’m trying to initialize is rt11dat.dsk, it’s “empty”.  The other two read/access just fine, but I’ve never tried to initialize them

Startup cmd file is:

SET CPU 1M
ATTACH RL0 rt11run.dsk
ATTACH RL1 rtv53_rl.dsk
ATTACH RL2 rt11dat.dsk
SET RL2 BADBLOCK
BOOT RL0

I think that “BADBLOCK” option came from some suggestion way back, like I said, it’s been a long time since I touched this.




From: Simh <simh-bounces at trailing-edge.com<mailto:simh-bounces at trailing-edge.com>> On Behalf Of Henk Gooijen
Sent: Wednesday, February 12, 2020 2:27 PM
To: simh at trailing-edge.com<mailto:simh at trailing-edge.com>
Subject: Re: [Simh] Initializing disks (triggered by the "Something Strange with RK05" chain

See below …

Van: Ken Hall<mailto:kjhall55 at gmail.com>
Verzonden: woensdag 12 februari 2020 18:30
Aan: simh at trailing-edge.com<mailto:simh at trailing-edge.com>
Onderwerp: [Simh] Initializing disks (triggered by the "Something Strange with RK05" chain

I’ve played with RT11 on and off over the years, but the one thing I’ve never been able to do is properly initialize an empty disk.  If I create a DL2: for example, and try to run initialize on it, I get back:

.dir dl2:
?DIR-F-Error reading directory

.init dl2:
DL2:/Initialize; Are you sure? YES
?DUP-F-Size function failed

This seems similar to the issues Henk Gooijen has been having with RK05’s, and it’s been so long since I’ve dealt with the real hardware I don’t recall exactly how this is supposed to work, but it seems to me it should just “work”.

Has anyone found a solution to this?


I can check that tomorrow. Maybe that is the reason you can download
an empty but initialized RL02 image (zipped) from DBIT.
If RT11 cannot figure out the size (5 MB or 10 MB / RL01 or RL02), maybe
the command (in SIMH) .SET RL0 RL02 helps. You specify that RL0 is an
RL02. Likewise, you can say .SET RL0 RL01. On a real PDP-11 with RL drives
the system will recognize what type RL01 or RL02 is connected/loaded.
You can have a mix of RL01 and RL02 drives on one RL11 controller.
The .SET RLx RL01 (or RL02) command is not of RT11, but of SIMH. Give it a try 😊

For the write protect command for the RK drives, this is probably also a
SIMH command. .SET RK0 WRITEENABLE *is* in SIMH (as is .SET RK0 LOCKED).


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