29 Jan
2014
29 Jan
'14
1:39 a.m.
On 2014-01-28 18:59, Zane Healy<healyzh at aracnet.com> wrote:
Right. Different PDP-11 OSes use different formats, so it's not really
meaningful to ask about "PDP-11 backup". You need to specify which
backup format you are talking about.
I think I know of at least four.
RSX used to use something called DSC (which stood for Disc Save and
Compress), which was eventually replaced by BRU.
I assume RSTS/E had some backup format in the older days. With RSTS/E V9
(I think it was), a new backup utility was created, which is the VMS
compatible one.
I'm not aware if RT-11 also had some backup tool, but I would assume so.
Johnny
On Jan 28, 2014, at 5:31 PM, Paul Koning<paulkoning at comcast.net> wrote:
No. VMS BACKUP cannot read RSX BRU format savesets. But you can (could)
run BRU on VMS...
>But BRU produces something structurally
different from VMS save sets, doesn?t it?
It's been so long since I've
looked at any of this, I honestly don't remember. I was thinking that RSX-11 backups
would be readable by at least some versions of VMS. >RSTS
Backup actually generates VMS save sets, the same format.
That's good to know.
29 Jan
29 Jan
1:48 a.m.
On Tue, 28 Jan 2014, Johnny Billquist wrote:
Right. Different PDP-11 OSes use different formats, so it's not really
meaningful to ask about "PDP-11 backup". You need to specify which backup
format you are talking about.
I think I know of at least four.
RSX used to use something called DSC (which stood for Disc Save and
Compress), which was eventually replaced by BRU.
I assume RSTS/E had some backup format in the older days. With RSTS/E V9 (I
think it was), a new backup utility was created, which is the VMS compatible
one.
Wasn't there a DSC/DSC2 in VMS 1.5 and 2.x/3.x?
>RSTS Backup actually generates VMS save sets, the
same format.
That's good to know. I'm not aware if RT-11 also had some backup tool,
but I would assume so.
Johnny
--
Cory Smelosky
http://gewt.net Personal stuff
http://gimme-sympathy.org Projects
11:31 a.m.
On Jan 29, 2014, at 1:39 AM, Johnny Billquist <bqt at Update.UU.SE> wrote:
On 2014-01-28 18:59, Zane Healy<healyzh at
aracnet.com> wrote:
Right. Different PDP-11 OSes use different formats, so it's not really meaningful to
ask about "PDP-11 backup". You need to specify which backup format you are
talking about.
I think I know of at least four.
RSX used to use something called DSC (which stood for Disc Save and Compress), which was
eventually replaced by BRU.
There was an irreverent reading for DSC: ?disk smash and corrupt?.
I forgot what IAS (and RSX11-D) used. DSC possibly.
On Jan 28, 2014, at 5:31 PM, Paul Koning<paulkoning at comcast.net> wrote:
No. VMS BACKUP cannot read RSX BRU format savesets. But you can (could) run BRU on
VMS...
>But BRU produces something structurally
different from VMS save sets, doesn?t it?
It's been so long since I've
looked at any of this, I honestly don't remember. I was thinking that RSX-11 backups
would be readable by at least some versions of VMS. >RSTS
Backup actually generates VMS save sets, the same format.
That's good to know.
I assume RSTS/E had some backup format in the older
days. With RSTS/E V9 (I think it was), a new backup utility was created, which is the VMS
compatible one.
V9 sounds right. It was coincident with support for streaming tape drives, which needed
asynchronous (queued) I/O to work properly, and that in turn meant serious work on the
backup program. The designer decided to adopt the VMS backup format as a good one to use
(because of things like XOR block redundancy and CRC data integrity checks).
Before then there was a crude program also called Backup (but entirely unrelated) that
could do partial backups. And an entirely different program called SAVRES (save/restore)
that would do whole disk backup but could, I think, do partial restores. And going back
even further, there was ROLLIN ? that?s just a full disk image copy, to another identical
disk, or DECtape(s) (or perhaps also magtape, I don?t remember). None of those older
programs were compatible with any other OS.
I'm not aware if RT-11 also had some backup tool, but I would assume so.
There?s always PIP, of course.
paul
11:42 p.m.
Johnny Billquist wrote:
[Snip]
I'm not aware if RT-11 also had some backup tool, but I would assume so.
The name of the RT-11 backup utility file is BUP.SAV
and I assume that the file structure of the data files
which it produces is unique to RT-11. As far as I can
remember, multiple files can be used when a large device
was being backed up to files on a smaller device. The
output device can be either tape or disk.
However, from the DCL point of view, the command name is:
BACKUP
Jerome Fine
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