Re: [Simh] TE16 CRC Errors

2017-11-08 Thread Paul Koning 


> On Nov 7, 2017, at 8:01 PM, Johnny Billquist  wrote:
> 
> On 2017-11-08 01:54, Paul Koning wrote:
>> ...RSTS definitely did not.  It does support mixed RP/RM massbus, which is 
>> more usual but not universal either, I think.  But no mixing disk and tape.
> 
> Thanks. I was wondering about RSTS/E, but didn't dare saying something 
> definitive. That it allows mixing of RM/RP is nice. I think in plain -11M, 
> even that might not be allowed, but I would have to go and check and refresh 
> my memory.
> M+ allows any kind of combinations.

It's possible that the first Massbus support in RSTS didn't allow mixing RP and 
RM, but it certainly appeared soon after, I'm pretty sure by V7.0 at the 
latest.  So as of that point, RSTS supported two Massbus adapters for disks, 
and each of these could have any Massbus disk on it.  Even an RP07, on an 11/70 
at least, though officially that was not supported (DEC didn't sell that device 
on lowly PDP-11s).

paul


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Re: [Simh] TE16 CRC Errors

2017-11-07 Thread Larry Baker 
Peter,

I answered my own question.  The VAX/VMS Version 1.6 SPD 
(http://www.bitsavers.org/www.computer.museum.uq.edu.au/pdf/AE-C770D-TE%20VAX-VMS%20Operating%20System,%20Version%201.6%20SPD%2025.1.4.pdf)
 specifically states Mixed-MASSBUS configurations were supported:


NOTE:

MASSBUS disk drives and magnetic tape transports can be attached to the same 
MASSBUS.


Your predicament remains a mystery.

Larry Baker
US Geological Survey
650-329-5608
ba...@usgs.gov



> On 7 Nov 2017, at 3:57:13 PM, Larry Baker  wrote:
> 
> Peter,
> 
> My reading of your hardware setup sounds like what was called a 
> "Mixed-MASSBUS" configuration, that is, mixing disks and tapes on the same 
> MASSBUS.  PDP-11 RSX-11M-Plus supported Mixed-MASSBUS.  We dual-ported all 
> our disks and used the MASSBUS that came with our tape drives that way.  I 
> think Mixed-MASSBUS support was unusual.  I do not remember if VMS 3.0 
> supported Mixed-MASSBUS.  If not, what you are seeing might be the result.
> 
> Larry Baker
> US Geological Survey
> 650-329-5608
> ba...@usgs.gov 
> 
> 
> 
>> On 7 Nov 2017, at 12:54:40 PM, simh-requ...@trailing-edge.com 
>>  wrote:
>> 
>> --
>> 
>> Message: 4
>> Date: Tue, 7 Nov 2017 20:54:31 +
>> From: Peter Allan >
>> To: "simh@trailing-edge.com " 
>> >
>> Subject: Re: [Simh] Simh Digest, Vol 166, Issue 12
>> Message-ID:
>>  > >
>> Content-Type: text/plain; charset="utf-8"
>> 
>> In order to try to understand why I am having trouble reading a simulated
>> tape with a simulated TE16 tape drive on a simh VAX 780, I have tried
>> several configurations.
>> 
>> 
>> Firstly, a point of clarification. The problem that I came across was in
>> finishing the installation of VMS 3.0. This was necessary in order to be
>> able to install VMS 1.5 using DSC2, but I have no problem with the
>> installation of VMS 1.5 itself. VMS 1.5 is a red herring - the problem is
>> with VMS 3.0.
>> 
>> 
>> I had configured a VAX 780 in simh with three RP06 disk drives and two TE16
>> tape drives. I was using TE16 tape drives rather than TS11 really just
>> because when I was the system manager of a real 780, it had two TE16 tape
>> drives.
>> 
>> 
>> All of this has been done on a host system running CentOS 5 (for simh
>> 3.8-1) and CentOS 6 (for simh 4.0).
>> 
>> 
>> To remind you of the problem, I started the installation of VMS 3.0 by
>> booting stand-alone backup and restoring a saveset from a tape that I
>> downloaded from the University of Stuttgart. The first phase went fine and
>> when I rebooted the 780, the system asked which device contained the
>> installation media so that it could automatically complete the installation
>> of VMS. I entered MTA0: and this is where things went wrong. Wilm suggested
>> I should trying using a TS11 drive (MSA0) rather than a TE16 drive and this
>> did indeed work, but this left me wondering why?
>> 
>> 
>> I have tried to restore a BACKUP saveset from a tape to a disk using
>> several configurations. I have tried:
>> 
>> -  Two difference versions of simh, 3.8-1 and 4.0
>> 
>> -  Three different versions of VMS, 3.0, 4.6 and 7.3
>> 
>> -  Different simulated tapes
>> 
>> -  The two different simulated tape drives, TS11 and TE16
>> 
>> The results have surprised me.
>> 
>> 1)  Changing the version of simh makes no difference to the results.
>> 
>> 2)  I only get a problem in restoring a saveset from tape when running
>> VMS 3.0 as the operating system. Everything works fine with VMS 4.6 and 7.3.
>> 
>> 3)  I have tried different tapes, but if the system is going to fail to
>> do a restore operation, it does it with all of the tapes containing BACKUP
>> savesets that I tried.
>> 
>> Following a suggestion from Kevin Handy, I tried to copy the savesets from
>> tape to disk, but the copy failed on the VMS 3.0 system when using a TE16
>> tape drive.
>> 
>> 
>> My experiments indicate that there is a problem with VMS 3.0 when using
>> TE16 tape drives. However, this seems so unlikely, not least because the
>> sequence of operations that I have gone through is what hundreds (thousands
>> probably) of system managers must have done to install VMS 3.0 on real
>> hardware, including my predecessor with “my own” 780.
>> 
>> 
>> This leaves me stumped, but at least I have narrowed the problem down and I
>> am able to do the installation of VMS 3.0 (which lets me do the
>> installation of 1.5) by using a TS11 drive.
>> 
>> 
>> The only thing I can think of is to wonder if the way that VMS handled TE16
>> (i.e. massbus) tape drives changed between VMS 3 and VMS 4 and

Re: [Simh] TE16 CRC Errors

2017-11-07 Thread Johnny Billquist 

On 2017-11-08 01:54, Paul Koning wrote:



On Nov 7, 2017, at 7:49 PM, Johnny Billquist > wrote:


I actually don't think he has a mixed massbus. I don't think you could 
even configure simh for this. Simh have a very simplistic view on 
hardware configurations.
You don't configure massbuses, and put devices on them. You normally 
just configure the devices, and all the bus and controller 
configurations come implicit from that.


So, if you specify a massbus disk, you'll get a corresponding massbus. 
And for tapes, you'll get another one.
Both configured appropriately for that specific type of device you 
have hooked to it.


In RSX land, only M+ supported mixed massbus, as you mention. Not sure 
when/if VMS did. Not sure how much of anything else that might have 
supported it either.


RSTS definitely did not.  It does support mixed RP/RM massbus, which is 
more usual but not universal either, I think.  But no mixing disk and tape.


Thanks. I was wondering about RSTS/E, but didn't dare saying something 
definitive. That it allows mixing of RM/RP is nice. I think in plain 
-11M, even that might not be allowed, but I would have to go and check 
and refresh my memory.

M+ allows any kind of combinations.

Johnny

--
Johnny Billquist  || "I'm on a bus
  ||  on a psychedelic trip
email: b...@softjar.se ||  Reading murder books
pdp is alive! ||  tryin' to stay hip" - B. Idol
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Re: [Simh] TE16 CRC Errors

2017-11-07 Thread Paul Koning 


> On Nov 7, 2017, at 7:49 PM, Johnny Billquist  wrote:
> 
> I actually don't think he has a mixed massbus. I don't think you could even 
> configure simh for this. Simh have a very simplistic view on hardware 
> configurations.
> You don't configure massbuses, and put devices on them. You normally just 
> configure the devices, and all the bus and controller configurations come 
> implicit from that.
> 
> So, if you specify a massbus disk, you'll get a corresponding massbus. And 
> for tapes, you'll get another one.
> Both configured appropriately for that specific type of device you have 
> hooked to it.
> 
> In RSX land, only M+ supported mixed massbus, as you mention. Not sure 
> when/if VMS did. Not sure how much of anything else that might have supported 
> it either.

RSTS definitely did not.  It does support mixed RP/RM massbus, which is more 
usual but not universal either, I think.  But no mixing disk and tape.

paul

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Re: [Simh] TE16 CRC Errors

2017-11-07 Thread Johnny Billquist 
I actually don't think he has a mixed massbus. I don't think you could 
even configure simh for this. Simh have a very simplistic view on 
hardware configurations.
You don't configure massbuses, and put devices on them. You normally 
just configure the devices, and all the bus and controller 
configurations come implicit from that.


So, if you specify a massbus disk, you'll get a corresponding massbus. 
And for tapes, you'll get another one.
Both configured appropriately for that specific type of device you have 
hooked to it.


In RSX land, only M+ supported mixed massbus, as you mention. Not sure 
when/if VMS did. Not sure how much of anything else that might have 
supported it either.


  Johnny

On 2017-11-08 00:57, Larry Baker wrote:

Peter,

My reading of your hardware setup sounds like what was called a 
"Mixed-MASSBUS" configuration, that is, mixing disks and tapes on the 
same MASSBUS.  PDP-11 RSX-11M-Plus supported Mixed-MASSBUS.  We 
dual-ported all our disks and used the MASSBUS that came with our tape 
drives that way.  I think Mixed-MASSBUS support was unusual.  I do not 
remember if VMS 3.0 supported Mixed-MASSBUS.  If not, what you are 
seeing might be the result.


Larry Baker
US Geological Survey
650-329-5608
ba...@usgs.gov 



On 7 Nov 2017, at 12:54:40 PM, simh-requ...@trailing-edge.com 
 wrote:


--

Message: 4
Date: Tue, 7 Nov 2017 20:54:31 +
From: Peter Allan >
To: "simh@trailing-edge.com " 
>

Subject: Re: [Simh] Simh Digest, Vol 166, Issue 12
Message-ID:
>

Content-Type: text/plain; charset="utf-8"

In order to try to understand why I am having trouble reading a simulated
tape with a simulated TE16 tape drive on a simh VAX 780, I have tried
several configurations.


Firstly, a point of clarification. The problem that I came across was in
finishing the installation of VMS 3.0. This was necessary in order to be
able to install VMS 1.5 using DSC2, but I have no problem with the
installation of VMS 1.5 itself. VMS 1.5 is a red herring - the problem is
with VMS 3.0.


I had configured a VAX 780 in simh with three RP06 disk drives and two 
TE16

tape drives. I was using TE16 tape drives rather than TS11 really just
because when I was the system manager of a real 780, it had two TE16 tape
drives.


All of this has been done on a host system running CentOS 5 (for simh
3.8-1) and CentOS 6 (for simh 4.0).


To remind you of the problem, I started the installation of VMS 3.0 by
booting stand-alone backup and restoring a saveset from a tape that I
downloaded from the University of Stuttgart. The first phase went fine and
when I rebooted the 780, the system asked which device contained the
installation media so that it could automatically complete the 
installation
of VMS. I entered MTA0: and this is where things went wrong. Wilm 
suggested
I should trying using a TS11 drive (MSA0) rather than a TE16 drive and 
this

did indeed work, but this left me wondering why?


I have tried to restore a BACKUP saveset from a tape to a disk using
several configurations. I have tried:

-  Two difference versions of simh, 3.8-1 and 4.0

-  Three different versions of VMS, 3.0, 4.6 and 7.3

-  Different simulated tapes

-  The two different simulated tape drives, TS11 and TE16

The results have surprised me.

1)  Changing the version of simh makes no difference to the results.

2)  I only get a problem in restoring a saveset from tape when running
VMS 3.0 as the operating system. Everything works fine with VMS 4.6 
and 7.3.


3)  I have tried different tapes, but if the system is going to 
fail to

do a restore operation, it does it with all of the tapes containing BACKUP
savesets that I tried.

Following a suggestion from Kevin Handy, I tried to copy the savesets from
tape to disk, but the copy failed on the VMS 3.0 system when using a TE16
tape drive.


My experiments indicate that there is a problem with VMS 3.0 when using
TE16 tape drives. However, this seems so unlikely, not least because the
sequence of operations that I have gone through is what hundreds 
(thousands

probably) of system managers must have done to install VMS 3.0 on real
hardware, including my predecessor with “my own” 780.


This leaves me stumped, but at least I have narrowed the problem down 
and I

am able to do the installation of VMS 3.0 (which lets me do the
installation of 1.5) by using a TS11 drive.


The only thing I can think of is to wonder if the way that VMS handled 
TE16
(i.e. massbus) tape drives changed between VMS 3 and VMS 4 and that 
somehow

there is a bug in simh that only rears its head on the