[Simh] Way out idea for simh

[Richard Cornwell]

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

On Wed, 20 Apr 2016 12:14:41 -0400
Paul Koning <paulkoning at comcast.net> wrote:

> > On Apr 20, 2016, at 12:06 PM, Sampsa Laine <sampsa at mac.com> wrote:
> > 
> >   
> >> On 20 Apr 2016, at 19:02, Paul Koning <paulkoning at comcast.net>
> >> 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
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