[Info-vax] VAX 6000 on Young Sheldon

[Tony Priborsky]

On Saturday, February 11, 2023 at 8:14:16 AM UTC-8, Arne Vajhøj wrote:
> On 2/11/2023 11:08 AM, Tony Priborsky wrote: 
> > On Wednesday, February 8, 2023 at 1:27:34 PM UTC-8, Bob Eager wrote: 
> >> On Wed, 08 Feb 2023 19:19:30 +0000, Scott Dorsey wrote: 
> >> 
> >>> IBM guys would not have. My boss would have said that if it can't 
> >>> back up the DASDs with the CPU halted than it wasn't a real 
> >>> mainframe. 
> >> I know it was probably later on, but couldn't you do that with MSCP 
> >> disks? 
> > 
> > Yes, the HSC50 had a direct disk-to-tape backup utility that didn't 
> > require the CPU. Consistency was your problem so it was mostly used 
> > off line. The system operated a TU78 tape drive at absolute max 
> > speed. Forward write speed was almost rewind speed. You could 
> > always tell when it was running by the sound of the vacuum columns.
> Did it generate a backup in VMS Backup format or did 
> it just dump physical disk blocks to tape blocks? 
> 
> Arne

I'm pretty sure it didn't write a native VMS backup saveset - remember the CPU on the HSC was a PDP-11.   Logically the backup was the equivalent of VMS "BACKUP/PHYSICAL".  I seem to recall that at some point the VMS backup could restore (read) a HSC backup.