The PRO's hard disk controller supported only a few kinds of disks.  Early
  versions of the controller supported only 5 or 10 MB drives.  The last
  set of ROMs they issued for the hard disk controller supported a 67-MB
  RD53 disk.  Without the more recent firmware, the controller doesn't
  recognize the higher-capacity disks.

  The official DEC drives supported were:
    RD50     5 MB
    RD51    10 MB
    RD52    33 MB
    RD53    67 MB
    RD31    20 MB
    RD32    40 MB

  Various 3rd-party disks with similar operating specs to these drives would
  also work.  The information I have on equivalent drives says the following
  drives would work as replacements for the official DEC hardware:

  RD52:  Quantum Q540

  RD53:  Micropolis Micro1325
         ATASI A3085
         Computer Memories CM7085
         Maxtor XT1085
         Miniscribe M6085
         Newbury Data NDR1085

  RD31:  Seagate ST225 or ST4026
         Computer Memories CM3426 or CM6426
         Lapine Titan20
         Miniscribe M3425 or M8425
         Syquest SQ325AF
         Tandon T262, T362, or T702AT

  RD32:  Seagate ST251-0, ST251-1 or ST277
         Miniscribe 3650J

  ...hope this helps...

  Kurt Wampler (wampler@MicroUnity.com)

 
The first difference is that the microPDP's use the Q-bus, which is well 
supported both by DEC and many 3rd parties, while the Pro3xx used the CT-
bus, which was never used for anything else or supported by anybody.  
rather limits the expandability of the Pro3xx... 

->My first guess would be that the microPDP-11 has none of the limitations
->of the Pro.  But then I've heard that the limitations put into the pro
->were to prevent the Pro from taking away from the PDP-11 market.  

True to a degree.  The Pro was intended as a personal engineering 
workstation, while the microPDP-11's were aimed largely at embedded, 
controller-like applications, and the 'real' PDP-11's for serious expansion 
and multi-user environments.  Or so I understood it...;{) One irony of all 
this is that the only place I know of anybody using Pro380's in new 
installations is as graphics front-ends to microPDP-11's being used as 
controllers. 

  Steve Mitchell   steve@seabhag.cps.altadena.ca.us

 
Needs ms-dos like a battleship needs a popgun! However, there are third 
party companies (or were) if memory serves who made 8088 boards for a Pro 
so you could run msdos on it as well as P/OS...concurrently, yet! 

   Glenn Everhart    Everhart%Arisia.decnet@crd.ge.com

There was an add-on board that DEC sold which allowed you to format
your hard drive CP/M.  I actually had one for a while in the
mid-1980s...  never used it.

   Chaim Dworkin     chaim@linc.cis.upenn.edu 

The CP/M Option consists of hardware and software: a CTI card
(000043) which contains a Z80-A microprocessor, 64Kbytes of RAM,
4Kbytes of ROM and CP/M-80 which runs on top of P/OS.  P/OS can
continue to multitask in the background while CP/M is running. 
CP/M-format diskettes (96 tpi) can be read or written in the RX50
drive, 48tpi diskette can be read only, and up to four virtual
diskettes can be accessed on the hard disk.  A CP/M application can
also read P/OS sequential files allowing data exchange between the
two.  CP/M does not have access to the Pro's hardware registers,
so applications (such as graphics) that have been written for
specific I/O devices will not work.  Applications that use CP/M
services for I/O will run without modification.  The DEC order code
is PC3XS-AA

There are three diskettes:

BL-V447B-BH    Pro CP/M-80 APP DSKT V1.1 (1983)

BL-AH67A-BH    PRO-CP/M-80 APPLICATION (1983)
               DISKETTE SYSTEM V1.1

BL-V448B-BH    PRO-CP/M-80 APPLICATION (1983)
               DISKETTE HARD DISK SYSTEM V1.1

Teledisk images of these diskettes are available at:

	http://starfish.rcsri.org/rcs/pdp-11/Professional/Pro-CPM

	- Michael Umbricht   mikeu@osfn.org

 
We have two versions of UNIX running on PDP 11/73's in my lab.

The first is UNIX 2.10BSD, which is real BSD UNIX, basically the same as 
4.3BSD.  It is available from USENIX in Berkeley, (415) 528-8649. It only 
cost us $200 for the media, a TS-11 tape, but we had to prove that we 
already had a site license with ATT for UNIX.  It only comes with 
installation instructions.  You have to purchase the 4.3BSD documentation 
seperately if you want it.  It seems to run fairly well except the network 
stuff seems a little slow.  I don't really use the network stuff. 

The second is VENIX (Release D I think), which is a clone.  It is available 
from VenturCom in Cambridge, MA, (617) 661-1230.  I am pretty sure they 
don't support it anymore but they still may sell it. We have been using it 
for quite a while (> 7 years) and it seems to work pretty well.  It doesn't 
include any network stuff, but does support standard peripherals.  We have 
done alot of patching to the kernal over the years, so if you get it and 
need some help drop me a note. 

By the way, UNIX 2.10BSD comes with the complete source code for UNIX, 
which I have found great to have access to although it is 70 Mb worth of 
stuff. 

       Mark S. Spector            mark@photon.mit.edu
From: sms@wlv.imsd.contel.com (Steven M. Schultz)

                  ----------------------------------------
      Second Distribution of Berkeley PDP-11 Software for UNIX
                             Release 2.11
                       (Revised February 1992)


     The USENIX Association is pleased to announce the distribution of
a   new   release  of  the  "Second  Berkeley  Software  Distribution"
(2.11BSD).

     This release will be handled by USENIX, and is available  to  all
V7,  System III, System V, and 2.9BSD licensees.  The Association will
continue to maintain the non-profit price of $200.  The  release  will
consist  of  two  2400  ft.  1600 bpi tapes or one TK50 tape cartridge
(approximately 80M) and approximately 100 pages of documentation.

     If you have questions about the distribution of the  release,  or
require  800 bpi tapes, please contact USENIX.  At present a split I/D
machine is required, thus 2.11BSD will not run on 23 or 23+ based sys-
tems.  The USENIX address and phone number are as follows:

     2.11BSD
     USENIX Association
     2560 Ninth St. Suite 215
     Berkeley, CA  94710
     +1-510-528-8649

USENIX may also be contacted by electronic mail at:

     {ucbvax,decvax}!usenix!office
     office@usenix.org

If you have technical questions  about  the  release,  please  contact
Steven M. Schultz at:

     wlbr!wlv!sms
     sms@wlv.imsd.contel.com  (yes, a bit of a misnomer, will be changing
                                it one of these days)

 
The root password is 'gnomes', and the games password is 'dale'.  I think
'dale' is also the password to one other account.  The password to the
uucp account is probably 'uucp'.  Anyway, you can change them once you
get in as root.

To login via the COM port, edit /etc/ttys and change the 01com1 to
11com1 for 9600 baud null modem.  (Other speeds require other codes
in the second byte.)  The first byte turns on the getty listener on
that port.  Then do: kill -2 1 to get the init to reread the /etc/ttys
(or just reboot).  You will then be able to login via the com port
via a null modem at 9600 baud.

Venix does an fsck upon boot.  This may be why your HD head is seeking?

Enjoy!

      --Barry Kort  barry@chezmoto.ai.mit.edu 

 
USERNAME: SYSTEM
PASSWORD: SYSTEM

      --Tom Karlsson     tomk@csd.uu.se

 
DON'T DISCARD A UNIX PACKAGE FOR THE PRO!  Please post a note in 
comp.sys.dec.micro and offer it to someone.  On the whole very few copies 
of unix were sold for the Pro computers making it a somewhat difficult OS 
to get a copy of.  In the past 4 years or so whenever I've mentioned unix 
to anyone who owned a Pro they've always responded that they were "dying to 
get a copy".

 
Most OSs put pieces of a new file in chunks of empty disk space,
P/OS and RSX-11M-PLUS can do this for data files but they require
a single contiguous space for each task file or for other files
which are designated "Contiguous". This means that if you delete
many small files you create "holes" or empty spaces on your disk.
When you copy new files that must be contiguous to your disk, P/OS
will copy those files after the last file on your disk until your
disk is full. Then if it cannot find a single contiguous space to
fit the new file it will tell you your disk is full even though you
may have previously deleted enough files to create space for the
new file. I do not know if it is possible to "pack" a disk to make
a single large contiguous space out of many small holes. Can
someone answer this? 

    Chaim Dworkin     chaim@linc.cis.upenn.edu
    Robert "Bob" Gezelter  gezelter@rlgsc.com

Sometimes, as  when you  abort a  compile or  link,  temporary files that  
were created  will not be erased.  These temporary files do  not have  a 
directory  entry -- and hence, they will not appear  in a  directory 
listing.  The process that created this type of file did so by manipulating 
the master index file directly. 

Ordinarily, you  will not be able to tell that these invisible files exist.   
There  is one  Toolkit utility,  however,  that makes these  files visible:   
VFY (file structure verification utility). 

You may  use the  following VFY procedure on any PRO hard disk or diskette.   
VFY  will  search  the  volume  and  place  any invisible file  entries 
into  the [1,3] directory.  Hence, you should create  a directory  [1,3] 
first  or VFY (while showing you what  invisible files  it  found)  will  
leave  the  files invisible. 

Once the  files are  placed into [1,3], you may delete them to recover 
volume space.  These files are typically scratch files and deleting them 
will cause no problems. 

Enter the  following to  initiate  the  search  for  invisible ("lost") 
files: 

             $ RUN $VFY
               VFY>/LO
          
VFY will  then look for the lost files.  If any are found, VFY will list  
them on  the screen.   When  VFY is  done, it  will return the VFY> prompt.  
To quit from VFY, do a CTRL-Z: 
          
               VFY>^Z
               $ +
          
The found  files, as placed into [1,3], may have strange names and any 
block size (even zero). 

>From: sjs@gnv.ifas.ufl.edu

      
               $ SET TERM TT2: /SPEED:(nnnn,nnnn)
          
          where nnnn,nnnn  represents transmit  and receive  baud rates.
          To determine the current baud rate, do:
          
               $ SHOW SPEED/TT2:

>From: sjs@gnv.ifas.ufl.edu

         
Use a  hyphen (-)  before the line's carriage return.  In DCL, the command  
is not  executed until  a line ending in  not preceeded by a hyphen is 
encountered.  No DCL line can be more than 250 characters. 

>From: sjs@gnv.ifas.ufl.edu

          
               $ SET PROT  [/qualifier(s)] 
          
          /Qualifiers:
          
               /DATE=dd-mmm-yy
               /SINCE=dd-mmm-yy
               /THROUGH=dd-mmm-yy
               /TODAY
               /EXCLUDE=filespec  (don't forget a version specification)
          
           is in the following format:
          
               (SYSTEM:RWED,OWNER:RWED,GROUP:RWED,WORLD:RWED)
          
          where SYSTEM, OWNER, GROUP and WORLD are user types (since the
          PRO is  usually used  as a  single-user system  the GROUP  and
          WORLD types are seldom relevant) and RWED represent four kinds
          of access to files:
          
               R    file can be read/run, copied, printed
               W    file can be written to
               E    user can change amount of disk space alloted to file
               D    file can be deleted
          
          Example:
          
          $ SET PROT TEST.*;*/SINCE=01-JAN-88/EXCL=*.OBJ;* (S:RWE,O:WRE)

>From: sjs@gnv.ifas.ufl.edu

          
               o    Install the task:   $ INSTALL 
          
               o    Assign the new LUN to the task:
                    $ ASSIGN/TASK=  LUN
          
               o    Run the task:  $ RUN 
          
          Example:   If  you  want  your  task  DATABASE  (install  name
          DATABA), which  currently uses  LUN 3  to write  to a file, to
          write the data to the printer, you would perform the following
          steps --
          
               $ INSTALL DATABASE
               $ ASSIGN/TASK=DATABA TT2: 3
               $ RUN DATABA
          
          TT2: is the device name for the printer.

>From: sjs@gnv.ifas.ufl.edu

 
Note: This requires a BCC08 PR1/CONSOLE cable. 
          
               $ INSTALL/NOREMOVE APPL$DIR:RMD.TSK/TASK=RMDT2
               $ ASSIGN/TASK=RMDT2 TT2: 1
               $ ASSIGN/TASK=RMDT2 TT2: 2
               $ SET TERMINAL:TT2:/VT125
               $ SPAWN RUN RMDT2
               $
          
          The above  reassigns RMD's  LUNs to  point to the TT2: device.
          RMD requires  a VT100-type  terminal setting  to run;  you may
          substitute the  /VT125 qualifier  with  one  that  more  aptly
          describes your terminal.
          
          Note:  You may still use SHOW MEMORY on the main terminal.

>From: sjs@gnv.ifas.ufl.edu

 
You must apply a P/OS 2.0 Patch for 20 MEG HD

Perform the  following ZAP  to alter  the POS.SYS  file on the PROSYSTEMS2 
volume  diskette.   This ZAP works for version 2.0 (not 2.0A)  of P/OS.   
It  causes the system to recognize a 20 meg hard disk (the Seagate ST225 is 
the one you want). 

Remove any write-protect tab from the PROSYSTEMS2 diskette and place it  in 
drive 1.  You should copy the file named below to another diskette  in case  
you make  a mistake and want to try again.   (A separate  copy is suggested 
because ZAP alters the file directly -- it does not create a new version). 

Type the  following in the Toolkit (user entries are in bold). The ^Z is a 
control-Z. 

               $ SET DEF DZ1:[ZZSYS]
               $ RUN $ZAP
               ZAP> POS.SYS/AB
               _162:770/
               _000004
               _162:776/
               _001146
               _163:004/
               _114577
               _162:756/
               _000240
               _^Z
          
               $ +
          
The diskette  is now  ready to be used.  Place the 20-meg disk into the PRO 
and format/load P/OS using the altered diskette. 

Note:   P/OS may give a complaint regarding the hard disk when you boot up 
to format the hard disk, but it should say it will try to  rectify the  
problem and  continue.   After the system continues, you should not see any 
error messages again. 

>From: sjs@gnv.ifas.ufl.edu

 
Well, I've never really dealt with P/OS, but a long, long time ago I was
involved with a group that had a similar problem with a PDP-11/60 that we 
bought from another group at the site. It ran RSX-11M, but we didn't get 
any passwords from the group from which we bought the machine. After a lot 
of poking about in manuals, I found a way to get to the password file, 
which in that version of RSX-11M was not encrypted. 

While the machine was booting, executing the startup command file, I 
pressed ^C. That gave me an MCR prompt at which I could type a command. 
Since the machine was executing the startup command file, the MCR prompt 
was attached to the system account. In an obscure manual that I no longer 
have and don't remember very well, I found the name of the password file. 
The MCR command that I issued, then, typed the password file on the 
console. 

Since P/OS is related to RSX-11M, it might work. Wish I could remember the
name of the account file, though...

   Roger Ivie   slsw2@cc.usu.edu


>From: kalisiak@acsu.buffalo.edu (christophe m kalisiak)
In article <1991Apr16.134937.47433@cc.usu.edu> slsw2@cc.usu.edu writes:
>While the machine was booting, executing the startup command file, I pressed
>^C. That gave me an MCR prompt at which I could type a command. Since the
>machine was executing the startup command file, the MCR prompt was attached 
>to the system account. In an obscure manual that I no longer have and don't
>remember very well, I found the name of the password file. The MCR command
>that I issued, then, typed the password file on the console.

What was the command? I would say that if one were to delete the 
password file, then you could probably start from scratch...
Don't quote me on it.

>Since P/OS is related to RSX-11M, it might work. Wish I could remember the
>name of the account file, though...

[0,0]RSX11.SYS

Chris Kalisiak
V076N3W7@ubvms.cc.buffalo.edu
kalisiak@acsu.buffalo.edu

To break into P/OS, if you can get to a Pro (runnin g p/os 2.0 or later at 
least) that you can use, there is in the menu system a facility for writing 
a "password floppy". If you boot the Pro and have that floppy loaded, its' 
password will override the one on the hard disk. I used this technique 
once, but it's been long enough ago I don't recall more detail. I believe 
that some help exists on the system, though, as I had no manuals to infer 
this from at the time. (Someone had left the company and his pro was 
unusable till I freed it.) Doing this will also set a password on the pro 
you make the floppy on, but you can reset that after the floppy is safely 
written. 
   I don't particularly recommend passwords on personal Pros due to
the extreme inconvenience they cause.

       Glenn Everhart    EVERHART@arisia.dnet.ge.com 

 
From "The Professional 300 Series Technical Manual", I have
(p. 8-5):
J1 Pin-outs for the monochrome monitor:

1-3  not used
4    Ground ( video signal ground potential )
5,6  Ground ( operational voltage ground potential )
7,8  +12 Vdc ( operational voltage input )
9-11 not used
12   M Video ( composite video )
13   Ground ( tied to 5 and 6 )
14   Data Receive ( serial data line from the keyborad output to the
     system box, via J3 )
15   Data Send ( serial data line from the system box output to the
     keyboard, via J3 )

 J3 pin-outs, for the keyboard:

1  Data Send ( via J1, pin 15 )  Serial line for output from the system box 
   to the keyboard 
2  +12 Vdc ( output of operational voltage to the keyboard 
   ( from J1, pins 7 and 8 ) 
3  Ground (from J1, pins 5,6,13)  Operational voltage ground.
4  Data Receive (via J1, pin 14)  Serial line for input from the system box.


 I could not find equivalent information about a VR241 ( color )
monitor. However, there must be some relation, as the Extended Bitmap
Option board can drive either, without hardware changes. You might
be able to get more out of the manual if you can obtain one:
The ordering or part number is:

EK-PC350-TM-001

John Erbland     erbland@hartford.bitnet
Hubert Bartels     hgb@catalina.opt-sci.arizona.edu

 
Professional 380 video-port pinout:

Pin:                            Description:
1,2,3,4,5,6                     Ground
7,8                             +12 Volts
9                               Blue
10                              Green
11                              Red
12                              Monochrome
13                              Monitor Present (don't know what it's for,
                                or where it has to be connected to.)
14                              Keyboard transmit
15                              Keyboard receive

I got this info from our local DEC branch. I had to build my own cable and
it works fine.

Arno Griffioen         v882246@si.hhs.nl

 
1,3,etc GND             Ground
 2      TG43            Track greater than 43
 4      N/U             Not used
 6      SEL3 L          Select for drive 3 (not used, near as I can tell)
 8      INDEX L         Index
10      SEL0 L          Select 0
12      SEL1 L          Select 1
14      SEL2 L          Select 2 (N/U)
16      MOTOR ON L      Motor on
18      DIR L           Direction
20      STEP L          Step
22      WRT DATA L      Write data
24      WG L            Write gate
26      TK00 L          Track 00
28      WRT PRT L       Write protect
30      RD DATA L       Read Data
32      SIDE 0 H        Side select     (Note: H vs L, so a transitor needed)
34      READY L         Drive Ready


      Warner Losh      imp@solbourne.com

 
New Pro 350 owners are so worried about the error codes I have reproduced 
the most common ones here.  These are taken from the P/OS handbook.  Note 
that unless you want to buy new components all you can do is reseat 
connections! 


Code   Problem area             Corrective Action

000100  P/OS keyboard handler
      1: Check cables and connections
      2: Reseat option modules in card cage.
      3: Reset all IC's in sockets on system module.
      5: Replace system module
      6: Reload Operating system.

000200  Terminal driver         [deleted]

000300  Executive/general       If error occured on first access of RX or RD 
subsystem, check that subsystem is in order: 

     1: Check cables and reseat controller in card cage
     2: Replace Drive
     3: Replace RX or RD subsystem controller

If error not found on first access of mass storage, goto 000200 corrective 
action. 

000400 System startup processing

000500 Terminal driver
  (video and printer port)

Second line Error Codes

000000  IOT in system state
000001  Stack overflow or cannot install task CBOOT
000002  Trace Trap or breakpoint or cannot spawn task CBOOT
000003  Illegal instruction trap or cannot spawn task CBOOT
000004  Odd address or other trap to 4
000005  Segment fault
000006  A task on P/OS without a parent aborted
000007  EMT trap or required file not found
000010  TRAP trap

   Todd Miller          tmiller@chaos.cs.brandeis.edu


In a recent message someone reported getting the following error codes:
>010013
>000401

The interpretation is:

  000401 = hard disk subsystem
  01     = card slot 1
  0013   = RD hard disk drive format failure

  Kurt Wampler         wampler@MicroUnity.com

 
Billys Place    (213)837-0892
Login ID is 1000 and password is 'moving target', from there youll recive a 
personal ID. Supports the RT-11 SIG, and has the RT-11 SIG library online 
for downloading (youll probably need the DECUS catalogue to help you). 
VTCOM/TRANSF, XMODEM, and Kermit seem to be supported, Ive successfully 
connected at 2400 (which is the highest-lowest, I dunno:-) 

RSX BBS    (612)777-7664
Supports RSX on the PDP-11 but since the Pro also runs RSX there is a Pro 
file area and discussion area.  sysop is Bruce Mitchell.

Intellicon Data Systems    (401) 884-9002
Contact sysadmin@idsvax.ids.com or  ...!uunet!rayssd!idsvax!sysadmin
for information on their system.

    Chaim Dworkin        chaim@linc.cis.upenn.edu
    Michael P. Deignan   mpd@anomaly.sbs.com
    Billy D'Augustine    Azog-Thoth@cup.portal.com

 
 2.11BSD comes with SL/IP so a serial network connection is 
possible.  Slow, but better than nothing. 

    Steve Mitchell   steve@seabhag.cps.altadena.ca.us

DECnet for P/OS supports serial lines. These connections are quite
usable, provided the parameters are set correctly on the VAX that
you are connecting to. 

    Robert "Bob" Gezelter  gezelter@rlgsc.com

 
Pro KERMIT is actually RSX Kermit; there are conditionals in the code
which make it recognize that it is running on a Professional rather
than a PDP-11.  The current version is T3.60 (with long packet support)
which is available free from the RSX bulletin board system at (612)
777-7664.  T3.60 works correctly on a Pro380 under P/OS 3.2 and under
RSX-11M-Plus V4 and higher - I'm using it now in terminal emulation
as a matter of fact.  There are no problems with moving files from
VMS to RSX using this version.
 
If you have T3.60, and still encounter problems, try SET ATTRIBUTE OFF
before transferring.  Many VMS Kermits do not recognize attribute packets.

      Steve Mitchell   steve@grian.cps.altadena.ca.us

You can also run Kermit-12 on the PRO.  All Kermit-12 files are
available at watsun.cc.columbia.edu in the /kermit/d/k12*.* area
via anonymous FTP.  PDP-8/DECmate assembler versions of the ENCODE
and DECODE programs are there as k12enc.pal and k12dec.pal
respectively. 

      -- Charles Lasner (author of Kermit-12)
   lasner@watsun.cc.columbia.edu home of Kermit-12 and other fine Kermits. 

 
Actually the Pro 350 and the Rainbow have two serial ports as the printer 
port is a serial port also. The hardware is bi-directional, the support may 
be lacking in the drivers. I don't believe the printer port had full modem 
control on it ( I think it had DSR/DTR ). 

  Near the end of the Pro 350's lifetime there was a 4 (?) port serial
unit released for it. I doubt many would have been sold. Sorry, I don't
recall the part number.

    Malcolm Dunnett               dunnett@mala.bc.ca


That 4 port unit was the Real Time Interface with 2 serial, 1 parallel, and
an IEEE 488 bus (Pc3xx-aa).  Dec was selling them through Dec Direct at
fall special for $100 each last year.  

Or it could be the PC3XC-BA Quad Serial Line unit described in the guide to
writing P/OS device drivers.  4 ports to 38.4Kbaud, two with modem control 
attached to a flat ribbon cable that snaked out from inside the unit.

    Todd M. Miller                tmiller@caos.caos.kun.nl
    Paul S. Kleppner              paulk@pkleppner 

 
Digital Data Communications Message Protocol(DDCMP) is the network
protocol covering Rainbows, PRO's, Microvaxes, and VAXes that
brings network access (and multiple sessions) over a cable or
modem. 

For those interested, I present here an abridged version of "Technical
Aspects of Data Communication" chapter 18 "DDCMP" by John E. McNamara, 1977. 
Although I have not tried, it seems to be everything you need to program
a DDCMP 

DDCMP Message Queuing System:

        "In the DDCMP protocol, any pair of stations that exchange messages
with each other number those messages sequentially starting with message
number 1.  Each successive data message is numbered using the next number
sequence, modulo 256.  Thus a long sequence of messages would be numbered 
1,2,3,... 254,255,0,1,... The numbering applies to each direction separately.
For example, station A might be sending its messages 6,7,8 to station B while
station B is sending its messages 5,6,7 to station A.  Thus, in a multipoint
configuration where a control station is engaged in two-way communication with
10 tributary stations, there are 20 different message number sequences 
involved - one for messages from each of the 10 tributaries to the control
station and one for messages from the control station to each of the 10
tributaries.

        Whenever a station transmits a message to another station, it assigns
its next sequential message number to that message and places that number in
the "Sequence" field of that message header.  In addition to maintaining a
counter for sequentially numbering the messages which it sends, the station
also maintains a counter of the message numbers received from the other
station.  It updates that counter whenever a message is received with a
message number exactly one higher than the previously received message number.
The contents of the received message counter are inclueded in the "Response"
field of the message being sent, to indicate to the other station the highest
sequenced message that has been received.

        When a station receives a message containing an error, that station
sends a negative acknowledge (NAK) message back to the transmitting station.
DDCMP does not require an acknowledgement for each message, as the number
in the response field of a normal header, or in either the special NAK or
positive acknowledgement (ACK) message, specifies the sequence number of the 
last good message received.  For example, if messages 4,5, and 6 have been
received since the last time an acknowledgement was sent, and message 6 is
bad, the NAK message specifies the number 5 which says "messages 4 & 5 are
good and 6 is bad."  When DDCMP operates in full-duplex mode, the line does 
not have to be turned around; the NAK is simply added to the messages for the
transmitter.

        When a station receives a message that is out of sequence, it does not
respond to that message.  The transmitting station will detect this from the 
response field of the messages which it receives, and if the "reply wait" 
timer expires before the transmitting station receives an acknowledgement, the
transmitting station will send a "REP" message.  The REP message contains
the sequence number of the most recent unacknowledged message sent to the 
distant station.  If the receiving station has correctly received the message
referred to in the REP message (as well as the messages proceding it), it
replies to the REP by sending a positive acknowledgement (ACK).  If it has
not received the message referred to in sequence, it sends a NAK containing
the number of the last message that it did receive correctly. The transmitting
station will then retransmit all data messages after the message specified
in the NAK.

        The numbering system for DDCMP messages permits there to be up to
255 unacknowledged messages outstanding, a useful feature when working on
high delay circuits such as those using satellites.



DDCMP Message Format:


 -  -  -  -----  ----  --------  --------  -------  -----  -----------  -----
|S||S||C||Count||Flag||Repsonse||Sequence||Address||CRC 1||Information||CRC 2|
|Y||Y||L|| 14  || 2  || 8 bits || 8 bits || 8 bits||  16 ||up to 16363|| 16  |
|N||N||A||bits ||bits| --------  --------  ------- | bits||  8-bit    || bits|
| || ||S| -----  ----                               ----- | characters| -----
| || ||S|                                                  -----------
 -  -  -
                                                  | Only Data & Maintenance
                                                    Message types have info &
                                                    CRC 2 fields |

SYN is a sync character. 
Classes:  10000001 = Data Messages (SOH)
          00000101 = Acknowledgement (ENQ)
          00000101 = Negative Acknowledgement (DLE)
Count: Used for Data and Maintenance messages to indicate the number
of characters that will follow the header and form the information part
of the message.  In control messages, the first 8 bits designate the
type of control message and the last 6 0's (except for NAK which uses
the low 6 bits for a reason:
        BCC Header Error    000001
        BCC Data Error      000010
        Rep. Response       000011
        Buffer Unavailable  000100
        Reciever Overrun    000101
        Message too Long    000110
        Header Format Error 000111

Flag: 
        Contains the quick sync and select flags, bits 0 and 1 respectively:
Quick Sync is used to inform the receiving station that the message will
be followed by sync characters; the receiver may wish to set its associated
synchronous receiver hardware into "sync search" and syncs will be discarded
until the first character of the next message arrives.  The purpose of this
is to permit the receiving station to engage any hardware sync-stripping logic
it might have and prevent it from filling its buffers with sync characters.

It also warns the receiver that there may only be a few SYNs and no DEL` (377)
Why the DEL`? Because it has only the 'stop' bit set. This helps force the 
UART to bitsync corectly with the incoming data.

        The select flag is used to indicate that this is the last message
which the transmitting station is going to transmit and that the addressed
station is now permitted to begin transmitting.  This flag is useful in 
half-duplex or multipoint configurations, where transmitters need to get 
turned on and off.

The Response field:
The response field contains the number of the last message correctly received.
This field is used in Data Message and in the positive and negative acknowledge
types of Control Message.  Its function should be evident from the preceding
discussion of sequence control.

The Sequence field:
The sequence field is used in Data Messages and in the REP type of Control
Message.  In a Data Message, it contains the sequence number of the message as
assigned by the transmitting station.  In a REP message, it is used as part 
of the question: "Have you received all messages up through message number 
(specify) correctly?".

The Address Field:
The address field is used to identify the tributary station in multipoint
systems and is used in message both to and from the tributary.  In point
to point operation, a station sends address "1" but ignores the address
field on reception.

In addition to the positive and negative acknowledgement and REP types of
Control Message, there are also start and start acknowledge Control Messages.
These are used to place the station which receives them in a known state.
In particular, they intialize the message counters, timers, and other counters.
The start ackknowledge message indicates that this has been accomplished.

Maintenance Messages:  These are typically bootstrap messages containing
load programs in the information field.


Known Drawbacks:  The header is short and higher level operating systems
must have a buffer of the appropriate size ready on relatively short notice.

Todd M. Miller                    tmiller@caos.caos.kun.nl
Paul                              zrepachol@cc.curtin.edu.au

 
RQDX1 supports RD51 , RD52 , RX50 .
RQDX2 supports RD51 , RD52 , RD53 , RX50.
RQDX3 supports RD51 , RD52 , RD53 , RD54, RX50, 
               RD31 , RD32 , RD33*,       RX33.


  For reference:

  RX33 - Teac FD-55GFR
  RX50 - DEC built 800KB dual 5.25" floppy
  RD31 - Seagate ST225
  RD32 - Seagate ST251-1
  RD51 - Seagate ST-412 / Tandon TM502
  RD52 - Quantum Q540 / Atasi 3046 / [almost] Evotek ET-5540
  RD53 - Micropolis 1325 with jumper R7 inserted (1335 also works)
  RD54 - Maxtor XT-2190


The Seagate ST506 is an *RD50*, which was never supported on
any of the RQDX controllers; its use was primarily on the Rainbow.

    Tim Thompson             xxwwxx@micom.com  "Starkle, Starkle little twink"
    Mark E. Levy             LEVY@FNALD.FNAL.GOV
    Bill Pechter             bill@pyrite.nj.pyramid.com

 
Take out the Mother Board and inspect the area near the Video Connector.
Look for a meltdown on one of the leads and bridge it with a dollop
of solder or a jumper wire.

To remove the Mother Board, pop the latch at the front of the HD and
floppy drives and slide them forward.  Uplug the ribbon cables to the
card cage, and unscrew the 3 thumbscrews on the front of the card
cage.  Unplug the power cable and slide the Mother Board out.

The meltdown can occur if you try to connect the Video Connector with
the power on.  If you misalign the connector, you can short the power
lead and meltdown the lead (I think it's Pin 1 or 2) to the keyboard.

   -- Barry Kort barry@michael.ai.mit.edu

 
You can only run v5.0 (or is that 5.1) and above on the Pro.
V4.x wont work, due to the video device abortion.

    --Billy D'Augustine    bill@main.morris.org

 
Switch settings for the DEC LA50 printer.

Factory settings (USA) 1=Closed and 0=Opened:


         8 7 6 5 4 3 2 1
        -----------------
   SW1  | | | | | | | | |
        |0|0|0|0|0|0|0|0|
        -----------------


         8 7 6 5 4 3 2 1
        -----------------
   SW2  | |1| | | | | | |
        |0| |0|0|0|0|0|0|
        -----------------


Country character set:
                          SW1
        country         4 3 2 1
        -----------------------
        USA             0 0 0 0 (factory)
        England         0 0 0 1
        Finland         0 0 1 0
        France          0 0 1 1
        French Canada   0 1 0 0
        Germany         0 1 0 1
        Italy           0 1 1 0
        Japan           0 1 1 1
        Norway/Denmark  1 0 0 0
        Spain           1 0 0 1 
        Sweden          1 0 1 0


Number of horizontal dots:
                               SW1
        relation b/h  dots/cm   5
        -------------------------
        2 to 1          57      0 (factory)
        2.5 to 1        71      1


Communication protocol:
                       SW1
        Protocol        6
        -----------------
        XON/XOFF        0 (factory)
        Ready/Busy      1

                       SW1
        Signal level    7
        -----------------
        Busy=high       0 (factory)
        Ready=low

        Busy=low        1
        Ready=high


Long rows printout:
                       SW1
        Work mode       8
        -----------------
        Truncate        0 (factory)
        cont.next row   1


Communication speed:
                         SW2
        speed           3 2 1
        ---------------------
        4800 Baud       0 0 0 (factory)
        2400 Baud       0 1 0
        1200 Baud       1 1 0
         600 Baud       0 0 1
         300 Baud       1 0 1
         200 Baud       0 1 1
         110 Baud       1 1 1


Data format:
                                 SW2
        data format             6 5 4
        -----------------------------
        7 bit odd parity        1 1 0
        7 bit even parity       1 1 1
        7 bit mark (8=low)      1 0 0
        7 bit space (8=high)    1 0 1
        8 bit odd parity        0 1 0
        8 bit even parity       0 1 1
        8 bit no parity         0 0 0 (factory)

SW2:  7 and 8 not used.

   --Tom F Karlsson   tomk@csd.uu.se  
   

 
Options inlcude the Telephone Management System, the Interactive Video
Information System and the Realtime Interface.  For more information,
see:

	http://starfish.rcsri.org/rcs/pdp-11/Professional/Handbook

        - Michael Umbricht   mikeu@osfn.org

 
Each Pro has a 47-bit Identification number stored in ROM.  This
is not the same as the serial number printed on the case label. 
Some software (for instance VENIX) is keyed to this number.  To
view the ID use Maintenance Services and choose Configuration
Display.  The top line shows:

Identification number: ############

	- Michael Umbricht   mikeu@osfn.org

 
The Pro system bus is called the CTI, or Computing Terminals
Interconnect bus.  It has 22-bit addressing (4Mbytes) and
multiplexes addresses and data, combining 16-bit data signals with
the 22-bit address signals on 22 signal lines.  In most cases, the
bus will allow option modules to be placed in any available option
slot.  Each option module can generate two different hardware
interrupt signals.  The option modules feature zero-insertion force
connectors.  When an option is in place, an option-present signal
is asserted.  Each option contains onboard ROM with identification
information.

	- Michael Umbricht   mikeu@osfn.org