[Simh] Strangeness in pdp11_xq.c

[Paul Koning]

Looking at the Sysid messages generated by the QNA/LQA emulation when in LQA mode, I see some stuff that doesn't match the spec.

The code has this in xq_system_id:

                                          /* DEVICE TYPE */
  msg[40] = 37;                           /* type */
  msg[41] = 0x00;                         /* type */
  msg[42] = 0x01;                         /* length */
  msg[43] = 0x11;                         /* value (0x11=DELQA) */
  if (xq->var->type == XQ_T_DELQA_PLUS)   /* DELQA-T has different Device ID */
    msg[43] = 0x4B;                       /* value (0x4B(75)=DELQA-T) */

Type code 37 is not defined in the MOP spec.  The type code for data item "device type" is 100.

I checked the device code values against the Phase V MOP spec (the Phase IV one is too old to have these codes).  It says that type value x11 (17 decimal) is "LANCE/DECserver100 CSMA/CD communication link".  There are two entries for DELQA, 31 and 37 decimal, which refer to a note that says:

"Note on the assignment for the DELQA: the primary assignment is 37. Device code 31 is used in early DELQA devices when used on PDP-11 systems, in the “Request Program” message only. Later revisions of the DELQA use code 37 throughout. Software shall treat codes 31 and 37 as equivalent."

So it seems that 31 is a mistake built into some PDP11 boot ROMs, and the built-in SYSID code has always been 37 decimal.

	paul