[HECnet] RSX or RSTS

[Johnny Billquist]

On 2020-03-21 04:04, Robert Armstrong wrote:
>    With all this social distancing and staying home, I’ve been dusting 
> off old hardware and fixing it up.  I just finished running diagnostics 
> on a nice little PDP-11 system.  It is a -
> 
>                 PDP-11/53+ with 3.5Mb RAM in a BA123
> 
>                 KDA50 and 2xRA73 drives
> 
>                 DELQA NI
> 
>                 CXA16 16 line mux (DHV11 clone, more or less)
> 
>                 TQK70 and TK70 (probably worthless – those things never 
> work)
> 
>                 SQ739 SCSI controller (does both MSCP and TMSCP!)

Nice setup.

>     I figure I’ll use the SCSI for a CDROM and a tape drive, maybe an 
> Exabyte.  Don’t really need more disk space with two RA73s already, and 
> I’m sure the SDI is faster than the SCSI.

Actually, I would probably suspect SCSI would outrun the SDI. We have 
four RA73 on Magica (11/70), and at home I have SCSI on an 11/93.

So it is a little tricky to do a simple comparison, but I get roughly 
two to three times as many I/Os per second on my 11/93 with SCSI.

One big reason is probably that I have fairly "modern" SCSI disks, so 
seek times are way better than the RA73s have.

>    So, the question is, what OS should I put on it?  RSX or RSTS?  It 
> has to be something that can make good use of the hardware.
> 
>    No Unix, please – I’ve already got a nice 11/83 with 2.11bsd on it.
> 
>    Ideas?

Of course I would vote RSX. :-)

Well, actually, have you used either OS before? If you feel familiar 
with one or the other, it might be a good starting point.

With RSX, you do have TCP/IP, and a bit more DECnet functionality, but 
otherwise I don't think the difference between them are that big. They 
certainly are rather different, but if you're alone on the system more 
or less, it makes less of a difference.

And by the way, the TK70 I have found to generally be pretty good a 
reliable. The TK50 is the horrible one. At most, I have needed to clean 
the heads on TK70, but otherwise they usually run just fine. But if I 
get a TK50, I might as well just toss it out...

   Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol