[Simh] DZ11 vs DZV/DZQ11

[Johnny Billquist]

On 2018-04-12 23:05, Mark Pizzolato wrote:
> 
> I've added this to the pdp11_rq.c to describe these values:
> 
> /*
> 
> MediaId
> 
> Is defined in the MSCP Basic Disk Functions Manual, page 4-37 to 4-38:
> 
> The media type identifier is a 32-bit number, and it's coded like this:
> The high 25 bits are 5 characters, each coded with 5 bits. The low 7
> bits is a binary coded 2 digits.
> 
> Looking at it, you have:
> D0,D1,A0,A1,A2,N
> 
> For an RA81, it would be:
> 
> D0,D1 is the preferred device type name for the unit. In our case,
> that would be "DU".
> A0,A1,A2 is the name of the media used on the unit. In our case "RA".
> N is the value of the two decimal digits, so 81 for this example.
> 
> And for letters, the coding is that A=1, B=2 and so on. 0 means the
> character is not used.
> 
> So, again, for an RA81, we would get:
> 
> Decimal Values:        4,    21,    18,     1,     0,      81
> Hex Values:            4,    15,    12,     1,     0,      51
> Binary Values:     00100, 10101, 10010, 00001, 00000, 1010001
> Hex 4 bit Nibbles:    2     5     6     4   1     0     5   1
> 
> The 32bit value of RA81_MED is 0x25641051
> 
>   */
> 
> Thanks.

No problem. And thanks for clearing up my scribblings. I feared that it 
might have been a bit too cryptic.

> I'm wondering if the leading first two characters (DU) of the ID is used when a device is "MSCP Served" by one system out to a cluster at large.  This might facilitate connecting the serving system's local driver to the remote requests.

No idea, but it's definitely possible.

   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