VAX MP – BUBBLE lives again!

Yesterday and today the plan has been to ressurect BUBBLE. This is a configuration that my was first foray into production configured VAX/VMS. Thanks to the stellar efforts of Steve Davidson (a fellow hecnet‘er) this machine went from an initially very poorly configured amateur hour effort of mine to a mutiuser and clustered setup with properly defined everything. BUBBLE consists of a VAXstation 4000/90 with a BA356 disk pack attached. This has room for eight hard drives 3.5″ hard drives in blue canisters. Of these eight three were critical to the setup of the machine – these are the three that I needed to get onto the DL380 server as files so that I could attach them to the VAX MP simulator.

The disk configuration of BUBBLE is as follows:

The three critical drives are DKA0:, DKA100: and DKA200:. These are the system disk, internal users disk and external users disk respectively. They are mapped to DSA0:, DSA1: and DSA2: as shadowsets (RAID configuration) but only as single drives. This is primarily used in this case to effectively provide an alias to the drives which helps enormously in keeping the configuration fairly portable.

In order to create virtual drives for VAX MP to use I utilised the ever useful dd command to create a large empty file with the same number of 512 byte blocks as the DEC RZ1CF-CF 4.3GB SBB drives:


Subsequent to this I did find that if you configure SIMH with a drive that doesn’t exist as a file on the file system it will do this job for you and create an empty drive file, which is kind of neat.

I did take backups of the hardware based BUBBLE system – and a while ago I restored those backups (stored on DAT-72 tapes) as VMS savesets and transferred them via FTP to a Unix system. So in order to get disks recreated from the backups I had to do a bit of disk shuffling in the emulator – using the skeleton VULCAN configuration I was able to ftp the savesets into DUA1 and mount DUA2 as the destination disk for the restore process.

The backups were made using the VMS BACKUP image option so restoring the saveset using the /IMAGE switch recreates the content of the drive (with the added bonus of being defragmented):

At the end of the restoration process, the vax_mp.ini SIMH configuration file was updated to reflect the BUBBLE disk configuration:

Then it was a case of watching BUBBLE boot again for the first time in an simulated environment! At this stage there are still a number of issues:

  • licenses will have expired
  • the mount commands will be wrong as drive designations have changed (DKA0: -> DUA0: for example)
  • the VAX MP multiprocessor driver no longer exists on the boot disk
  • a whole host of other tweaks will be required

There is always a certain amount of trepidation when you’ve spent a good fews hours on something and then need to ‘flip the switch’ and see if  you’re awesome or a dog barking up the wrong tree. In this case however, so far, awesome is where we’re at: