[Simh] RT-11 Storage Strategy

[Will Senn]

On 2/17/16 5:18 AM, Henry Bent wrote:
>
> Hi Will,
>
> I know that this isn't quite what you were asking, but on my real 
> 11/23 running RT-11 I have four RL02s (well, a Dilog DQ614 and an MFM 
> disk emulating four RL02s) and that is more than enough storage for my 
> purposes.  In addition, if you know that you aren't going to need all 
> of a physical disk for a specific purpose, you can just mount a disk 
> image as a logical disk.  For example, I have CDISK.DSK and TCPIP.DSK 
> on DL2:, and those images are mounted as C: and TCP:.
>
> SIMH allows for four RL02s at 10MB each and eight RK05s at 5MB each, 
> so there's no difference in total storage.  As far as I'm concerned 
> it's somewhat more convenient to have a smaller number of larger 
> capacity disks.  If you need a full 80MB of storage I don't see why 
> you couldn't use both controllers/disks.  You could also use RD5[1-4] 
> disks (DUx: to RT-11, the RQ controller in SIMH) if you really need 
> more space, though I believe RT-11 is limited to 32MB on a single 
> filesystem so you would have to partition the larger disks.
>
> My understanding is that there is not a "preferred" disk controller or 
> type under SIMH.  I have found that for an emulated Ultrix system, 
> running off of an RD54 is noticeably faster than running off of RL02s, 
> but on a reasonably fast host system you probably won't notice the 
> difference under RT-11.
>
> My final note is: if you're curious about something, just try it!  
> Make a backup of your current working system and then go wild.  That's 
> the fun of SIMH. Want to see if RT-11 will recognize an RA82?  Or 
> sixteen RC25s?  Does RT-11 work with a TU56 DECtape?  I have no idea 
> what the answer to any of those questions is, but I know how to find out.
>
> -Henry
>
Henry, Ha! After I wrote my note, I went off and tried a bunch of 
configurations. After reading your note, I realized that the two 622.9 
MB RA82's I created may be overkill :). I think I'll go back to using 
RL02's for system and storage disks and use RK05's or disk images for my 
programming language disks. I totally forgot about disk images.

Thanks,

Will