PDP-11 disk image question
Glen Slick
glen.slick at gmail.com
Wed Feb 20 13:25:28 CST 2019
On Mon, Feb 18, 2019 at 2:24 PM Bill Gunshannon via cctalk
<cctalk at classiccmp.org> wrote:
>
> Theoretically, the SIMH emulated RA81 and the CMD emulated real
> disk RA81 should be the same size because they are both supposed
> to be RA81's.
I spent the time to get set up and verified that this assumption is
not correct. The CMD CQD MSCP SCSI controller firmware RA device type
feature appears to only change the reported MSCP media name string,
and has no effect on the reported MSCP size and geometry information.
I tried this on a CMD CQD-420/TM with firmware version (REV. B2L-00).
As far as I know the CQD-420 and the CQD-220A (but not the original
CQD-220) are almost identical. I used an IBM DDRS-39130D hard drive
with a 68-pin / 50-pin adapter. The DDRS-39130D is a native 9GB drive.
I used sg3-utils / sg_format to soft resize the drive to exactly 2GB
in capacity, 2,147,483,648 bytes, 4,194,304 blocks.
After using the "Z = Reset Controller" configuration option to reset
the CQD-420/TM firmware to its default state this was the
configuration reported by the firmware:
SCANNING SCSI DEVICES ATTACHED ...
DEV0: DU0 SCSI ID 0 LUN 0 IBM DDRS-39130D DC1B
Disc ON,Sync ON,PMR ON,WWV OFF,Tag-Q OFF,RCT OFF,RA OFF,
DEV1: DU1 SCSI ID 1 LUN 0 OFFLINE
Disc ON,Sync ON,PMR ON,WWV OFF,Tag-Q OFF,RCT OFF,RA OFF,
DEV2: DU2 SCSI ID 2 LUN 0 OFFLINE
Disc ON,Sync ON,PMR ON,WWV OFF,Tag-Q OFF,RCT OFF,RA OFF,
DEV3: DU3 SCSI ID 3 LUN 0 OFFLINE
Disc ON,Sync ON,PMR ON,WWV OFF,Tag-Q OFF,RCT OFF,RA OFF,
DEV4: MU0 SCSI ID 4 LUN 0 OFFLINE
Disc ON,Sync ON,3-Density ON,Buffer ON,
DEV5: MU1 SCSI ID 5 LUN 0 OFFLINE
Disc ON,Sync ON,3-Density ON,Buffer ON,
DEV6: MU2 SCSI ID 6 LUN 0 OFFLINE
Disc ON,Sync ON,3-Density ON,Buffer ON,
DEV7 SCSI ID 7 HOST ADAPTER, SCSI Reset ON,Density Mode ON,Default Tape OFF,
Rew/Im OFF,Eject Disk ON,Truncate Size OFF,RCT size= OFF,RA dev= DEF,
Rsv/Rls Option ON,MSCP credit = 16,sync rate = 04 MB/sec,
RSX FP OFF,Sel Timeout = 250 ms
(PMR=Prevent Medium Removal WWV=Write W/Verify)
Then a KA660 VAX console sees the device like this:
>>>SHOW DEV
UQSSP Disk Controller 0 (772150)
-DUA0 (RA90)
UQSSP Tape Controller 0 (774500)
Then VMS booted on the KA660 VAX sees the device like this:
$ MOUNT /FOREIGN BA215$DUA0:
%MOUNT-I-MOUNTED, OVMSVAXSYS mounted on _BA215$DUA0:
$ SHOW DEVICE /FULL BA215$DUA0:
Disk BA215$DUA0:, device type RA90, is online, allocated, deallocate on
dismount, mounted foreign, file-oriented device, shareable, available to
cluster, error logging is enabled.
Error count 0 Operations completed 4
Owner process "SYSTEM" Owner UIC [SYSTEM]
Owner process ID 00000214 Dev Prot S:RWPL,O:RWPL,G:R,W
Reference count 2 Default buffer size 512
Total blocks 4194302 Sectors per track 217
Total cylinders 1933 Tracks per cylinder 10
Volume label "OVMSVAXSYS" Relative volume number 0
Cluster size 0 Transaction count 1
Free blocks 0 Maximum files allowed 0
Extend quantity 0 Mount count 1
Mount status Process ACP process name ""
Volume Status: Unknown ACP type.
One question here is why does VMS see 4194302 blocks when a SCSI Read
Capacity command of the drive reports 4194304 blocks? Is the CMD
CQD-420/TM firmware reserving a block or two?
Anyway, I then tried to recreate the configuration of the original
post as I understand it, partitioning the one physical SCSI drive into
four logical MSCP device units, and turning on the RA81 type feature
for those four MSCP device units.
Note that now DEV0: DU0 through DEV3: DU3 all map the the same SCSI ID
0, they all have the RA feature set to ON, and the RA dev type is set
to 81.
SCANNING SCSI DEVICES ATTACHED ...
DEV0: DU0 SCSI ID 0 LUN 0 IBM DDRS-39130D DC1B
Disc ON,Sync ON,PMR ON,WWV OFF,Tag-Q OFF,RCT OFF,RA ON,
DEV1: DU1 SCSI ID 0 LUN 0 IBM DDRS-39130D DC1B
Disc ON,Sync ON,PMR ON,WWV OFF,Tag-Q OFF,RCT OFF,RA ON,
DEV2: DU2 SCSI ID 0 LUN 0 IBM DDRS-39130D DC1B
Disc ON,Sync ON,PMR ON,WWV OFF,Tag-Q OFF,RCT OFF,RA ON,
DEV3: DU3 SCSI ID 0 LUN 0 IBM DDRS-39130D DC1B
Disc ON,Sync ON,PMR ON,WWV OFF,Tag-Q OFF,RCT OFF,RA ON,
DEV4: MU0 SCSI ID 4 LUN 0 OFFLINE
Disc ON,Sync ON,3-Density ON,Buffer ON,
DEV5: MU1 SCSI ID 5 LUN 0 OFFLINE
Disc ON,Sync ON,3-Density ON,Buffer ON,
DEV6: MU2 SCSI ID 6 LUN 0 OFFLINE
Disc ON,Sync ON,3-Density ON,Buffer ON,
DEV7 SCSI ID 7 HOST ADAPTER, SCSI Reset ON,Density Mode ON,Default Tape OFF,
Rew/Im OFF,Eject Disk ON,Truncate Size OFF,RCT size= OFF,RA dev=81,
Rsv/Rls Option ON,MSCP credit = 16,sync rate = 04 MB/sec,
RSX FP OFF,Sel Timeout = 250 ms
(PMR=Prevent Medium Removal WWV=Write W/Verify)
Now the KA660 VAX console sees the devices like this. The MSCP media
name string has changed from RA90 to RA81.
>>>SHOW DEV
UQSSP Disk Controller 0 (772150)
-DUA0 (RA81)
-DUA1 (RA81)
-DUA2 (RA81)
-DUA3 (RA81)
UQSSP Tape Controller 0 (774500)
Now VMS running on the KA660 VAX sees the devices like this. It has
simply divided the previous total block size of 4194302 into four
equal block sizes of 1048575. It hasn't done anything to try to
present the drives as the same total block size as a real hardware
RA81 drive.
$ MOUNT /FOREIGN BA215$DUA0:
%MOUNT-I-MOUNTED, OVMSVAXSYS mounted on _BA215$DUA0:
$ MOUNT /FOREIGN BA215$DUA1:
%MOUNT-I-MOUNTED, mounted on _BA215$DUA1:
$ MOUNT /FOREIGN BA215$DUA2:
%MOUNT-I-MOUNTED, mounted on _BA215$DUA2:
$ MOUNT /FOREIGN BA215$DUA3:
%MOUNT-I-MOUNTED, mounted on _BA215$DUA3:
$
$ SHOW DEVICE /FULL BA215$DUA0:
Disk BA215$DUA0:, device type RA81, is online, allocated, deallocate on
dismount, mounted foreign, file-oriented device, shareable, available to
cluster, error logging is enabled.
Error count 0 Operations completed 4
Owner process "SYSTEM" Owner UIC [SYSTEM]
Owner process ID 00000214 Dev Prot S:RWPL,O:RWPL,G:R,W
Reference count 2 Default buffer size 512
Total blocks 1048575 Sectors per track 217
Total cylinders 484 Tracks per cylinder 10
Volume label "OVMSVAXSYS" Relative volume number 0
Cluster size 0 Transaction count 1
Free blocks 0 Maximum files allowed 0
Extend quantity 0 Mount count 1
Mount status Process ACP process name ""
Volume Status: Unknown ACP type.
$ SHOW DEVICE /FULL BA215$DUA1:
Disk BA215$DUA1:, device type RA81, is online, allocated, deallocate on
dismount, mounted foreign, file-oriented device, shareable, available to
cluster, error logging is enabled.
Error count 0 Operations completed 4
Owner process "SYSTEM" Owner UIC [SYSTEM]
Owner process ID 00000214 Dev Prot S:RWPL,O:RWPL,G:R,W
Reference count 2 Default buffer size 512
Total blocks 1048575 Sectors per track 217
Total cylinders 484 Tracks per cylinder 10
Volume label "" Relative volume number 0
Cluster size 0 Transaction count 1
Free blocks 0 Maximum files allowed 0
Extend quantity 0 Mount count 1
Mount status Process ACP process name ""
Volume Status: Unknown ACP type.
$ SHOW DEVICE /FULL BA215$DUA2:
Disk BA215$DUA2:, device type RA81, is online, allocated, deallocate on
dismount, mounted foreign, file-oriented device, shareable, available to
cluster, error logging is enabled.
Error count 0 Operations completed 4
Owner process "SYSTEM" Owner UIC [SYSTEM]
Owner process ID 00000214 Dev Prot S:RWPL,O:RWPL,G:R,W
Reference count 2 Default buffer size 512
Total blocks 1048575 Sectors per track 217
Total cylinders 484 Tracks per cylinder 10
Volume label "" Relative volume number 0
Cluster size 0 Transaction count 1
Free blocks 0 Maximum files allowed 0
Extend quantity 0 Mount count 1
Mount status Process ACP process name ""
Volume Status: Unknown ACP type.
$ SHOW DEVICE /FULL BA215$DUA3:
Disk BA215$DUA3:, device type RA81, is online, allocated, deallocate on
dismount, mounted foreign, file-oriented device, shareable, available to
cluster, error logging is enabled.
Error count 0 Operations completed 4
Owner process "SYSTEM" Owner UIC [SYSTEM]
Owner process ID 00000214 Dev Prot S:RWPL,O:RWPL,G:R,W
Reference count 2 Default buffer size 512
Total blocks 1048575 Sectors per track 217
Total cylinders 484 Tracks per cylinder 10
Volume label "" Relative volume number 0
Cluster size 0 Transaction count 1
Free blocks 0 Maximum files allowed 0
Extend quantity 0 Mount count 1
Mount status Process ACP process name ""
Volume Status: Unknown ACP type.
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