Qbus to CF / IDE

>  You could have, for example, four RL02s each capable
of being
>  assigned a "pack" from the card.

>  What were the biggest non-MSCP-attached drives?
>  How hard would they be to emulate?


While RL02's would probably be easy to emulate,
at 10MB a pop, you don't get alot of bang for your buck.

Note that some operating systems only support 4 drives
per controller, so that will need to be a consideration
as well, when drives are being partitioned.

Note:  The capacities mentioned below are approximations.

The largest non-MSCP drive that I'm aware of is the RP20, at
929 MB.
However, I think that was only supported on the KL10.   

For the rest of the world, you'll be looking at MASSBUS
devices -

The RP07 is next in line at 504MB, but not supported by all
operating 
systems.

The RM05, at 256MB . . . definitely supported by RSTS/E;
not sure about smaller operating systems like RT11 though.

I think the RP06 was something like 176MB, although you're
still into 
MASSBUS.

Once you move below the MASSBUSS level, I think you're
looking at an 
RK07,
which is what?  25 or 26MB ?

I'm sure someone may chime in with more. . .





T

tiggerlasvaim.com wrote:
> 
> 
>>  You could have, for example, four RL02s each
capable of being
>>  assigned a "pack" from the card.
> 
>>  What were the biggest non-MSCP-attached drives?
>>  How hard would they be to emulate?
> 
> 
> While RL02's would probably be easy to emulate,
> at 10MB a pop, you don't get alot of bang for your
buck.

   Forgive me if this is a silly question, but is 10MB a
limitation of 
the firmware and drivers, or of the disk technology?


	Doc

On Friday 29 February 2008, Doc Shipley wrote:
> tiggerlasvaim.com wrote:
> >>  You could have, for example, four RL02s each
capable of being
> >>  assigned a "pack" from the card.
> >>
> >>  What were the biggest non-MSCP-attached
drives?
> >>  How hard would they be to emulate?
> >
> > While RL02's would probably be easy to emulate,
> > at 10MB a pop, you don't get alot of bang for your
buck.
>
>    Forgive me if this is a silly question, but is 10MB
a limitation
> of the firmware and drivers, or of the disk
technology?

Well, RL02s are 10MB.  There's no reason that you couldn't
have 
something on the same interface with more tracks (the only
real 
difference between the RL01 and RL02 were the number (and
thus width) 
of tracks on a cartridge).

The biggest problem would just be that the appropriate
drivers wouldn't 
expect to see anything other than an 5MB or 10MB disk.  It
probably 
wouldn't be too hard to patch the drivers for a larger
(fixed) size, 
but I think most people just want a "drop in place with
existing 
software & drivers" solution.

I'll note that there were third-party controllers which took
a cheap 
ST506-like (or whatever) disk and emulated multiple RL02s to
the host.  
Actually, I think that's pretty much what the DSD880 (which
I have one 
of) does.  However, it's probably a whole lot less useful to
emulate a 
bunch of tiny disks than one big disk, at least for most
people.  Now, 
if there were only software RAID drivers for RT-11 et al,
you could 
combine those back into one big disk. 

Pat
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