I readily admit that I know nothing about the OSes that run under simh except 
RTE and unix. If a machine doesn't have support for a randomly accessible block 
device without a native file system, then this scheme wouldn't be usable.

But I'm guessing most simh OSes support either raw disks or seekable tapes, and 
either would work.


From: sky...@sky-visions.com [mailto:sky...@sky-visions.com]
Sent: Wednesday, April 20, 2016 1:49 PM
To: Ken Cornetet <ken.corne...@kimballelectronics.com>; sky...@sky-visions.com; 
paulkon...@comcast.net; sam...@mac.com
Cc: simh@trailing-edge.com
Subject: RE: RE: [Simh] Way out idea for simh


I think you are missing something. For the B5500 the drives are all one file 
system. If you add a drive, it becomes part of the file system. Also there is 
no way to access the drives in a raw way. For the I7000 series there is no 
concept of a file system to speak of. Similar for CDC 6600 for anything prior 
to Scope 3.4, the drives are all one big file system.

 Rich

------- Original Message ------- On 4/20/2016 1:20 PM Ken Cornetet wrote:

You don't need the notion of mountable disk. The disk would appear attached to 
the guest OS 100% of the time.



The guest doesn't need to be able to mount foreign file systems. The guest OS 
only considers that block device as a seekable collection of blocks.  All file 
movement between the LIF block device and the OS's native file system would be 
by a userland  utility.



True, this utility would have to be developed for every guest OS running under 
simh, but if the file system was simple enough, the code would be trivial.



From: Simh [mailto:simh-boun...@trailing-edge.com] On Behalf Of 
sky...@sky-visions.com<mailto:sky...@sky-visions.com>
Sent: Wednesday, April 20, 2016 1:04 PM
To: paulkon...@comcast.net<mailto:paulkon...@comcast.net>; 
sam...@mac.com<mailto:sam...@mac.com>
Cc: simh@trailing-edge.com<mailto:simh@trailing-edge.com>
Subject: Re: [Simh] Way out idea for simh



Just to add some info to the discussion. This sounds like a nice idea,
however it will be very difficult to implement on some of the older
machines that SimH supports.

For example the B5500 does not have the concept of a mountable pack.
Drives could be attached, but they were a permanent attachment. For the
Ibm 7000 line, most did not support disk. The disk drive that was
supported by many of the machines was a large box that you could not
put drives into (IBM 1301/2301). Also these machines all worked in BCD
(6 bit), not Ascii. I am also not sure when TOPS10 got support for
mounting foreign file systems. I don't believe that 6.03 or 5.03
support this idea.

Tapes, paper tapes, and punch cards are probably the most universal
format. Also a Paper tape reader is pretty easy to implement, it might
be possible to put some kind of header onto the tape to indicate the
name of the file. But take a look at how much trouble Kermit does to
handle all the various systems.

Rich

------- Original Message -------
On 4/20/2016 12:14 PM Paul Koning wrote:


> On Apr 20, 2016, at 12:06 PM, Sampsa Laine wrote:

>

>

>> On 20 Apr 2016, at 19:02, Paul Koning wrote:

>>

>>>

>>

>> I don't know LIF, but the RT-11 file system is certainly simple.

>>

>> There are a couple of complications. First, you'd have to write a file 
>> access utility for each guest OS. Given a simple enough file system that 
>> isn't necessarily a huge burden. Then again, what might be simple, 
>> requiringly only modest code, on one machine might be a major burden on 
>> another simply because it has much less memory.

>>

>

> For DEC stuff, Files-11 (level 2?) would probably work across most of the 
> OSes.



No, it would work for VMS, and level 1 at least would work for RSX, but neither 
RSTS nor RT11 understand it. And it's a complex file system, more so than the 
RSTS one and vastly more than RT11. It does more, of course, but if you're 
looking for something that can easily be ported to another system, this won't 
do.



I took the proposal to mean: find a simple OS for which you can easily 
implement an application to handle it on most operating systems. So think 
something handled by an application like PDP-10 FLX (or RT-11 FLX), not a file 
system with native support.



> ...

>>

>> Paper tape is yet a third option, which is presumably unlabeled but often 
>> transparent. (Not always, the 1620 comes to mind as a notorious example of a 
>> machine that could read only coded tape with punches conforming to the code 
>> it expects.)

>

> That's a good point but doesn't make organising files trivial.



One key question is how important it is to transfer a bunch of files all at 
once. Is it sufficient to send one file at a time? With scripting, that may not 
be all that problematic.



paul





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Richard Cornwell
sky...@sky-visions.com<mailto:sky...@sky-visions.com>
http://sky-visions.com
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