SCSI Questions (Was: "Re: Purchased a Microvax 3800")

Johnny Billquist bqt at
Tue Dec 8 10:38:57 CST 2015

On 2015-12-08 17:02, Paul Koning wrote:
> On 2015-12-07 20:36, Christian Gauger-Cosgrove wrote:
>> On 7 December 2015 at 14:29, Johnny Billquist <bqt at> wrote:
>>> I think all (modern PDP-11) OSes can install from TMSCP tapes. RSTS/E is
>>> more picky than some others, though, if I remember right...
>> Yes, RSTS/E installs from TMSCP just fine (as can RSX-11/M+); I know
>> that in simh you can bring up Ultrix-11 3.1 only on TMSCP
>> (specifically a TK50), at least if you want all of the packages to
>> install. I've installed RSTS/E 10.1-L from MASSBUS, TS11, TM11, and
>> TMSCP in my various experimentation with emulation, it really doesn't
>> care what the tape is as long as your SYSGEN device is consistent.
> One detail on "it doesn't care what the tape is": RSTS kits on 1/2 inch tape come in 800 and 1600 bpi versions.  They have different boot blocks, each of them designed to work with all tape drives/controllers supported on RSTS that support the density in question.  For example, the 1600 bpi kit doesn't boot on a TM11 controller, and the 800 bpi kit won't boot on a TMSCP controller.  This matters if you try to boot one in an emulator where physical tape density doens't have any meaning.

Unsubscribed from cctalk now, so I'm not sure if this will get through 
or not.

The RSX installation tape should boot from all tape devices, no matter 
what density. The disk boot blocks are somewhat more specific. MSCP sits 
together with massbus and RK06/RK07. RK05, RL01/02, RP02/03 as well as 
P/OS drivers are separate boot blocks. Of those, only the RL02 is 
actually supported by M+. So in practice, you only see one of two disk 
boot blocks around for M+. 11M use pretty much anything, I'd think.


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