🚀 go-pugleaf

                      ================================
                         DEC Professional Computer
                         Frequently Asked Questions
                          and Miscellaneous Trivia
                      ================================
      compiled and edited by: Chaim Dworkin  chaim@linc.cis.upenn.edu
---------------------------------------------------------------------------
 Vol. 1 No. 2         Size:1455 lines; 67307 bytes        5 August, 1992
--------------------------------------------------------------------------- 

This "FAQ and other miscellaneous trivia" is compiled from discussions 
which took place on comp.sys.dec.micro over the past 4 years.  Whenever 
possible names and addresses of contributing individuals are placed after 
each answer.  Additions, corrections, and constructive comments are 
welcomed. 

Summary of questions:

Q1.  I have just acquired a DEC "Professional 350".  I really don't know 
     what it is.  What operating system will it run?  What sort of CPU does 
     it have? 
Q2.  What's the difference between a pro350 and a pro380?
Q3.  What languages are available for the Pro?
Q4.  Where can I get software for the Professional computer? 
Q5.  How much memory is on the motherboard?  How much can I bring it up to?
Q6.  How can I add memory to my Pro?
Q7.  Along with the Pro-380 I received three RAM boards.  I know that the 
     slots in the Pro computers are dedicated, RAM goes in a specified slot, 
     video in another, etc.  Can all three RAM boards be put in and be 
     recognized? 
Q8.  Can I put a hard drive and controller card in my Pro 325 to convert it 
     to a Pro 350? 
Q9.  Is there any possible way of doing any kinda modification to my Pro 
     350 to turn it into a Pro 380? 
Q10. How do I format a generic floppy on a Pro?
Q11. What's the difference between a microPDP-11 and a Pro?
Q12. Can I run MSDOS on a Pro?
Q13. Where can I get unix for the Pro?
Q14. I have an old copy of xxx unix for the Pro in a closet somewhere and 
     I'm going to clean out the closet and discard all the old Pro stuff. 
Q15. I have lots of space on my disk yet whenever I try to copy a file I 
     get a message saying out of disk space, please delete some files and 
     try again.  Why? 
Q16. How do I reclaim disk space occupied by "invisible" files?
Q17. How do I set the printer port baud rate from DCL?
Q18. How do I enter DCL commands that are more than one line in length?
Q19. How do I set protection on a file?
Q20. How do I reassign a device's LUN after the task has been built?
Q21. How do I Run RMD  (SHOW MEMORY) from a second terminal?
Q22. I'm running P/OS 2.0 and can't get it to recognize my 20 Mb drive.
Q23. I was given a Pro-350 by an office that was junking it and when I 
     booted it up it asked for a password.  I don't know any passwords.  
     How can I break past that and delete the password file? 
Q24. Can anyone out there tell me the pinout for the monitor/keyboard 
     connector on a DecPro 350?
Q25. What is the pinout for the video port? 
Q26. What are the pin-outs for the RX50 floppy controller?
Q27. I booted my Pro and got an error code.  What does it mean?
Q28. Are there any pro BBSs?
Q29. I can't get my hands on an ethernet connection for my Pro.  Is there 
     any alternative? 
Q30. What is the latest version of Kermit available for the Pro?
Q31. The Pro-350 comes with one serial port standard.  Does anyone know if 
     it's possible to add a second serial port or additional ports? 
Q32. What is DDCMP, Digital Data Communications Message Protocol?
     Or alternatively: I called DEC with a support question about
     DDCMP and they hung up on me.
Q33. I have an RD-something.  What kind of drive is it?  What kind of 
     controller do I need?
Q34. Is there any way to make a PRO floppy bootable?

                         **************************

Q1.  I have just acquired a DEC "Professional 350".  I really don't know 
what it is.  What operating system will it run?  What sort of CPU does it 
have? 

The Pro-300 was the engineering workstation of it's time.  There were 3 
models: the 325, 350, and 380.  The 325 and 350 shared the LSI-11/23 cpu.  
The difference between them was that the 325 was floppy based, while the 
350 had a hard disk and a bigger power supply. It can handle the RD51, 
RD52, and RD53 drives (10, 20, and 71MB, respectively).  The 380 was based 
on the LSI-11/73 cpu.  Available options include color monitors and 
ethernet.  Runs 16 bits at 3 Mhz. 

Basically, the PRO-300 is a personal PDP-11, with computer and
terminal in a neat pc package.  It has an expansion bus, the CT-bus.
Unfortunately, it never really caught on, DEC marketing being what it
is, despite being a contemporary of the IBM-PC and being priced about
the same as the original IBM's.  A friend of mine ran some benchmarks
on his 350 , and determined it's about 1/3 to 1/2 as fast as a
microVAX-II for non-virtual-memory numerical applications.

For a while after they stopped trying to sell the PRO's to the masses,
DEC continued to use them as the central console system for the big
VAX Clusters in the 8000 series.  They also sold them to various OEM's
as process controllers and graphical front-ends for large control
systems.  It was a cheap way to get an 11/23 or 11/73, if your
expansion needs were limited and you only needed one (or perhaps two)
terminals. 

Operating systems: the worst thing DEC did to the PRO's was putting a 
brain-dead menu-driven version of RSX-11M+ called P/OS (Professional 
Operating System) on them.  Now, RSX-11M+ is a nice operating system, as 
are the other PDP-11 operating systems.  But who wants to be limited to a 
miserable, slow menu system on a nice little computer like the PRO-350?  
The only saving grace of P/OS is the PRO/Toolkit, a development environment 
which includes a partial DCL command shell. But you still boot up at the 
menu level, and it's only a limited shell.  Fortunately, RT-11 quickly 
became available, as did a couple of versions of PDP-11 unix.  The one I 
remember was VENIX, which was put out by VentureCom.  It would be nice if 
someone at Berkeley put their unix on the PRO... 

As for P/OS (and a version of RT-11 which actually runs _under_ P/OS), it's 
still available from DECUS, basically just for media charges. They also 
have printed documentation.  Like DEC operating systems in general, P/OS 
has excellent and voluminous documentation.  I have 8 3-inch 3-ring binders 
on my bookcase, plus various smaller documents. Everything you ever wanted 
to know about the Professional 300 series... 

DECUS also has a C compiler that runs under the PRO/Toolkit, as well
as a BASIC.  They don't have the PRO Fortran, possibly because it's
the same as the regular RSX Fortran (speculation).

Personal opinion: if DEC hadn't crippled the PRO with P/OS, but had
sold them as software development workstations for the PDP-11,
offering versions of all the PDP-11 operating systems (RSX-11M,
RSX-11M+, Ultrix, RT-11, RSTS/E, IAS), they could have sold lots of
them.  It's a great way to move your system hackers off the main
production machine without having to buy an expensive machine just for
the developers.  Unfortunately, Our Favorite Computer Company has
always been stronger at engineering than marketing.  sigh.
 
    Steve Mitchell  steve@cps.altadena.ca.us
----

The pro is more akin to a mini, and will do some nifty multitasking if you 
choose to use it...with HARDWARE protection of each task against the 
others, hardware floating point, etc. etc. There's a trick to booting off a 
floppy to regain control. Also [zzsys]firstappl.ptr should probably be 
deleted, and the pro native toolkit is a MUST. Given the native toolkit, 
the Pro is a quite respectable computer.  The major lossage of a pro is 
that I/D space separation is not supported by P/OS, which limits you to 8 
page registers, making address space manipulation more of a chore. 

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

                         **************************

Q2.  What's the difference between a pro350 and a pro380?

The PRO-380 is in fact a faster PRO-350 - about 5 times as fast I think.  
The 350 uses the PDP 11/23 chip (F11) and the 380 uses the PDP 11/73 chip 
(J11). 

It also has extra memory bitmap pages, faster graphics and comes as 
standard with 512kb on the mother baord.  The ram expansion cards can go in 
any slot. As I remember it, the 380 does not have a video card as all the 
video is on the mother board. 

If you do MACRO-11 assembler coding you'll certainly discover that the F-11 
doesn't really check for odd address errors, while the J-11 does (traps 
thru vector 4).  Also, the J-11 includes the ability to seperate 
Instruction and Data address spaces, and includes a third addressing mode 
(Supervisor).  As I recall,  P/OS takes advantage of some but not all of 
the additional features (not entirely sure exactly which ones appeared in 
which P/OS version). 

   Graeme Thomson      GRAEME@praxa.com.au
----

Another 380 feature is that you can divide memory for applications into I-
space and D-space (I = instructions, D = data), allowing your programs to 
use twice as much memory as in the 350 (as long as half is instruction and 
half is data, of course). 

Other potential OS platforms (anything but POS!) were PRO-Venix (a UNIX of 
some ilk), RT-11 (and the non-DEC, RT-11-like TSX), and some flavor of 
MUMPS.  Also it can be a decnet end node.  

Dean File
Chapel Hill, NC  
                         **************************

Q3.  What languages are available for the Pro?

DEC has various PDP11 languages that apply to the pro...stuff like BASIC 
(distinct from the DECUS Basic dialect), Fortran 77, Cobol, Datatrieve, and 
various others. DEC compilers are fairly cheap on the pro...probably even 
more so now that the pro is, er, "stabilized". The two DECUS pascal 
compilers, NBS and Swedish differ in that NBS generates faster, more 
compact code, while Swedish is more standard-conformant. (Turbo is not very 
standard conformant, BTW.) Two good Pascal compilers, a BASIC interpreter, 
a C compiler, FORTH, FOCAL, etc. are available. Also the DEC F77 compiler 
and mucho other stuff. 

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

                         **************************
 
Q4.  Where can I get software for the Professional computer? 

A couple of years ago, Digital donated all of the latest copies of their
software for the PRO-350 to the DECUS library.  This included P/OS 3.2,
Synergy Windows for the PRO, DECNET, PRO/BASIC, the Tookit w/ DCL,
PROSE Plus word processor, etc.  This software is available on RX50
floppy media from the DECUS library.  Copies of the complete documentation
set are also available.

   Kurt Wampler          wampler@MicroUnity.com 


   DECUS can be phoned at 508 480 3418. Join; it's free. It's the Digital 
Equipment Computer Users' Society. There are at least 95MB of diskettes of 
stuff packaged for pro between the library and the DECUS PC SIG. Much of it 
REQUIRES the native toolkit (which supplies little niceties like a decent 
command interpreter and a n assembler and linker...and the system symbol 
table file!). The DECUS library catalog, which you'll get free when you 
join, lists a bunch of pro offerings on rx50. I believe the 350 has a semi-
weird disk interface though. My personal use for a 325 would be to run RT11 
on it at most, since RT11 runs reasonably well off floppies. P/OS (which is 
to say, slightly modified RSX11M-PLUS) does not. There's lots of software 
for rt11 also. 
  The basic engine isn't really all that slow; there IS however a LOT of 
cruft in p/os. (Not for nothing did that OS get the nickname Piece Of S**t 
because of the menu orientation and misfeatures that distinguish it from 
RSX11M+.) With some of the free tools you can bypass much of that though. 
There's also a quite decent memory disk for p/os on the RSX SIG tapes. When 
you get your DECUS catalog, check out the pdp11 areas as well as the pro 
areas. Most of the stuff applies to pro. There's a working group in the RSX 
SIG whose mission is to make software from sig tapes available on floppies 
or other media (the "Other Media" working group...it actually DOES 
function). I'm continually surprised how many people with DEC processors 
don't know about DECUS. No wonder you use your pro as a terminal! sigh... 

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

                         **************************

Q5.  How much memory is on the motherboard?  How much can I bring it up to?

The amount of memory is really dependant upon where it is going to be 
installed: In the Mother Board /or/ in one of the Expansion Cages, that is, 
along with the disk controllers, Tms etc. locations. Expansion Cage: The 
memory board are configured for a :: maximum of 256K ::- you can install as 
many as you want this way (say to about 3 units of 256ks. 

Mother Board: Here the modules vary; they are one the two module-sizes, 
that is, 128k boards or 512k boards. System normally comes with 2 of 128ks, 
thus, making a total of 256k in mother board and the other 256k board in 
the expansion cage: making a total of 512k - a basic PRO 350 system. You 
can replace one of 128ks with one 512k new board. This 512k is actually 
made for PRO380; but You can in Your 350, replace one 128k and substitute a 
512k safely. 

 tung   tung@eniac.seas.upenn.edu

                         **************************

Q6.  How can I add memory to my Pro?

Here is a how to guide for memory upgrade of the PRO 350 at home. At $2.00 
per chip $64 will get you a 1 Megabyte of memory on your PRO and free up 1 
expansion slot if you remove the memory board.  Each board goes from 128K -
> 512K and you could do 1 or both in the PRO. 

Professional 350 Daughter Board Memory Upgrade

The Professional 350 (PRO 350) requires 512Kbytes of memory in order to 
start P/OS.  In the least costly configuration this requirement is supplied 
by two 128Kbyte daughter boards located on the motherboard underneath the 
hard disks.  These boards are elevated above the motherboard on spacers and 
are easily recognized.  An expansion slot usually holds another memory 
Board with an additional 256Kbytes.  Together these boards form the 
512kbytes of memory needed in the minimal system configuration. 

Because of advances in memory chips and DEC's useful fore-sight it is 
possible to install 1024Kbytes using only the two daughter boards.  This 
may free up a slot or just give you additional memory.  This file describes 
one method used to upgrade the memory boards. 

The upgrade requires 32 256K X 1 dynamic refresh memory chips with at least 
150ns access time.  The original chips are not in sockets so they have to 
be desoldered.  To make desoldering simple we used the following technique. 

1) Remove the memory boards from the PRO.
2) Pre-heat a burner on an electric range to about medium heat.
3) Get your pliers or an IC extractor ready.
4) Each board has 2 rows of 8 chips each.  The chips will be
   removed 1 column at a time (2 in each column).  Hold the
   board so that a column of chips is over the hottest part of 
   the burner.  When the solder his hot enough simply pull the
   column of 2 chips out. 
5) Remove the board from over the burner an allow it time to cool.
   If you try to do too many columns at one time you will scorch
   the board.  Minor scorching may be expected depending on the
   amount of patience you have concerning getting the burner
   temperature correct and how many rows you attempt to do at one
   time.  If you are careful enough you should be able to do it
   without scorching the board at all!  Any time you touch the board
   to the burner you can expect scorch marks.

Note: Sometimes the pins on the old memory chips are bent outwards on the 
bottom of the memory board.  This makes them harder to remove.  Straighten 
them if you can. 

Note: Don't worry about the capacitors, they may fall out when the solder 
is molten.  The can be replaced when the new chips are inserted. 

6) After you have done all columns and removed all the old memory
   chips you still have to remove old solder.  Our homebrew
   method of doing this is to use a vacuum cleaner as a solder sucker
   device.  Turn the vacuum cleaner on and hold the nozzle between
   your knees.  Using a soldering iron heat the solder on the
   pin hole a few inches away from the vacuum cleaner nozzle.  When
   the solder is molten bring the board down on the nozzle so that
   the nozzle is centered under the hole.  This sucks the solder out
   but it has a tendency to splatter it on the underside of the
   board too.

7) Use the soldering iron to collect the splattered solder into the
   pin holes on the other side of the board and then re-heat the
   pin hole and do step 6 again.  After about three times the pin
   holes are clear from old solder.  It could take longer for the
   first board until the technique is developed.

Note:  Solder will accumulate on the inside of the vacuum cleaner nozzle.  
I isn't very much solder but someone's wife could get mad about it.  We 
don't know what will happen if the nozzle is made from plastic instead of 
metal as it was here.  Perhaps some aluminum foil wrapped around the nozzle 
would solve both problems. 

8) After steps 6 and 7 you should have a board with all the all the
   pin holes free of solder so that you can insert the new memory
   chips.  Certain holes which are part of large traces are take
   more effort to unsolder because there is more solder in them. 
   All holes need to be open in order to insert the new memory
   chips.  Do the capacitor holes as well if necessary.

9) Place the new memory chips in the old holes and solder them
   in.  Make sure they face the same way as the originals. You
   need only solder the chips from the bottom of the board, the
   plate-through holes will do the rest.

10) There are two jumpers that need to be soldered to enable the
   extra memory.  They are labeled J1 and J2 on the board.  Cut
   a piece of wire, strip the ends and solder the ends across
   the jumpers.

11) Reinstall the board into the PRO.

12) The P/OS toolkit ``show memory'' command should show 512K WORDS
    (1024K bytes) of memory with only the two mother boards installed.


We have upgraded four boards this way so far and not one has failed so far.  
All the memory chips we used were tested in another computer (one with 
sockets) before they were installed.  You may want to solder sockets into 
your memory board instead of the chips themselves. If you have bad memory 
when you start up your PRO it would be much easier to replace a socketed 
memory chip than a soldered one. Although we have singe'd a few boards 
perfecting this method the damage was only cosmetic.  Removing the memory 
chips over the burner is the most difficult part of the operation. 

   Todd Miller          tmiller@chaos.cs.brandeis.edu

                         **************************

Q7.  Along with the Pro-380 I received three RAM boards.  I know that the 
slots in the Pro computers are dedicated, RAM goes in a specified slot, 
video in another, etc.  Can all three RAM boards be put in and be 
recognized? 
 
Actually, if I remember correctly some of the boards were slot
dependent, others weren't.  Additional memory is useful up to a
point (J-11 max physical memory address is 22 bits) depending on
what's already in the system.  The base memory is daughter boards
on the CPU motherboard, expansion memory can be added as modules in
the CTI bus.  The memory modules should self configure and play (if
it all works :-). 

- Bruce McCulley

                         **************************

Q8.  Can I put a hard drive and controller card in my Pro 325 to convert it 
to a Pro 350? 

Possibly.  The standard method of conversion is to purchase the upgrade kit 
which consists of new motherboard, stronger power supply, and hard drive 
with hard drive controller card.  It costs a lot of money.  I tried to take 
a shortcut and simply put the hard drive controller card into the Pro 325.  
DEC glued plastic over the connector edges of the slot that the HD 
controller card fits into in order to discourage people from just inserting 
a drive.  You have to spend some time carefully cleaning the connector 
edges of glue and plastic pieces (DEC used a strong glue).  I called DEC 
and asked them if it was possible and the person who I spoke with said he 
has heard of only two people who succeeded.  I did not, but my HD was bad 
to begin with.

   Chaim Dworkin    chaim@linc.cis.upenn.edu
 
                         **************************

Q9.  Is there any possible way of doing any kinda modification to my Pro 
350 to turn it into a Pro 380? 
 
Answer:  No.  The F11 and J11 chips are wildly different.  If you could
scrounge a Pro380 system board, you could probably replace the 350 system
board with that.
 
IMHO, having a 380 doesn't give much additional return.  Oh sure, the chip
is much more capable than the F11, but with super mode, I/D space, and
cache permanently turned off, what real gain is there other than a little
bit of CPU speed?  I find the stupid disk controller in my 380 to be more
of a problem in throttling the performance of the system.
 
BTW, DEC did once put up genuine RSX-11M-Plus on the 380.  The conditionals
are still there in the Exec source to make it work.  Haven't got around to
trying it yet, but one of these days ...

                         **************************

Q10.  How do I format a generic floppy on a Pro?

You don't.  DEC, in it's wisdom, decided to take advantage of a captive 
audience and get rich off selling preformatted disks to Pro owners.  They 
built a machine incapable of formatting disks.  You'd think that would 
leave an opening for some enterprising hacker to write a formatter.  
However, I've been told the drive controller chips on earlier models of Pro 
are totally incapable of formatting.  But there is an out....  You can 
format a generic disk on a Rainbow using the /I option to the FORMAT 
command.  Some people, with lots of Pro's, bought a Rainbow JUST to make 
disks. Of course, nowadays, a copy of Media Master from Intersecting 
Concepts will do the job on any AT clone... 

   Chaim Dworkin  chaim@linc.cis.upenn.edu
   David Lesher   wb8foz@ibiza.cs.miami.edu

There was a firmware update for the PRO's RX50 diskette controller that
allowed it to format its own floppies, but it was never released to
customers.  The FORMAT command under P/OS 3.2 is all set up to format
the floppies if it finds the right version of firmware in the controller
card.  I have tried since the Fall '91 DECUS Symposium to reach the
old manager of the PRO development group in Digital to see if he would
be willing to release that firmware through the DECUS Library, but he
never responded to my e-mail and I haven't been able to obtain his
telephone number; all I have is his name and e-mail address.

The PRO's floppy disk interface has a Western Digital chip on it which
is fully capable of formatting, but a microprocessor (Intel 8041? if I
remember right) sits between the WD chip and the bus, and only the
repertoire of commands provided by this uP chip are passed through
to the WD chip.

DEC's [unforgiveable] decision to not allow the PRO to format its own
diskettes was based first on repeatability problems with the "A" version
of the RX50 drive; but even after those problems were ironed out, the
marketeers at DEC appear to have fixated on the meager $$$ they would make
from selling RX50 media (HAH!).

So...PRO users of the world (if there are any of you left out there)
UNITE!  Let's see if we can brainstorm an effective way to coax Digital
into releasing the new firmware for the RX50 controller.  If I could
just get my hands on one set of the ROM(s), I would arrange to have
them duplicated and make them available at cost to anyone else in the
world wanting the ability to format their own diskettes.

   Kurt Wampler      wampler@MicroUnity.com


There are some software packages available which proport to allow
formatting of RX50s on MSDOS 5 1/4" high density drives.  Here is a
short review of three of those packages. 

    I have been playing with 22DSK138.ZIP and RAIND112.ZIP and
FDFORM18.ZIP long enough to give some additional info regarding
Rainbow/DECmate RX50 formatting and related issues.

FDFORMAT 1.8

    There are some problems with the current release that have always
been in at least the two previous versions when attempting to format
RX50 diskettes.  You use the command:

FDFORMAT A: /Y:2 /T:80 /N:10 /H:1

to format for RX50.  The /Y:2 is to force a two-sector stagger per
track to speed up transfer on all systems except -11/pro.  /H:1
means a one-sided disk.  /N:10 for 10 sectors and /T:80 for 80
tracks.

    The resultant disks are marginal, especially to revision A and B
RX50 drives.  Symptoms include data CRC errors right out of the
formatter when test reading the diskettes, and the inability to write
data that won't read back with data CRC errors.  The problems worsen
with higher track numbers, but often start right at track 0 or 1.
Using MD1DD media instead of MD2D makes a more reliable disk, so this
was assumed to be the problem.

    This has been confirmed as incorrect.

    There are several bugs in FDFORMAT that directly affect RX50's:

If the floppy is already formatted without error for all 80 tracks,
then FDFORMAT will merely verify readibility on every sector.  Then
the directory info is written by ordinary writing (not formatting)
means as previously discussed.  (Meaning suitable only as a strange
variant of PC-DOS-specific MS-DOS, not DECmate/Rainbow MS-DOS.  You
then use RX50INIT or move to the DECmate or Rainbow and use the
FORMAT command or whatever.)  Thus, all that FDFORMAT has done at
this point is to verify that a previously formatted disk is indeed
readable.

    If FDFORMAT gets even a single error for any reason, it will
change over to an actual low-level format mode.  This is noticeable
in that it runs much faster.  The resultant diskette is the
unreliable type described above.  Using the /U switch will force this
to happen as well, but is a normal feature of this switch.  Also
using the /W switch to rewrite the prior contents of the sector also
works, but since the sectors are reformatted, the same problem
results.  The /Q "quick" format works fine, since this isn't really a
format, rather a directory initialization.

    An additional problem with the usage described above is that even
though the /Y:2 option was given, it is ignored.  The unreliable
disk, when actually formatted, does apply the /Y:2 option to the new
disk format, so the stagger is now present, but FDFORMAT attempts to
merely verify the format in this usage to avoid formatting.  The
stagger/slide factor is not checked for, and can be any value.  The
disk will not be reformatted merely because it was a different
stagger; of course if an error occurs it will be reformatted with the
designated value.

    So, FDFORMAT as currently released is of no useful value to any
RX50 user, since the reliability suffers so terribly.  It should be
abandoned until the author or someone else fixes it for our RX50
purposes.

    Additionally, some users report problems getting the FDREAD/FDR88
programs to load properly, preventing FDFORMAT's use entirely (except
for "vanilla" PC formats).

    Hopefully, the author can be contacted for fixes to this
otherwise useful program.

22DSK138

    This is a useful package for converting many CP/M formats to/from
MS-DOS.  The DECmate and Rainbow are directly supported and can be
set as the default CP/M types.  The program can be configured for use
with the TEAC FD-55F drives which are essentially two-sided RX50
types.  (FD-55GFV and GFR can be configured as FD-55F equivalent.)
The program can run on an XT configured with HD or FD-55F drives as
well.  Note that FD-55F doesn't require a 3-speed floppy controller,
thus any XT can have an FD-55F added on if necessary.

22DISK also formats the CP/M disks it handles, so RX50's can be
formatted directly.  As a high-level consequence, a CP/M directory
initialization is also performed.  The resulting disk is usable
anywhere an RX50 can go, and is quite reliable.

Note that there are no formatting options as in FDFORMAT, just a
standard low-level-format RX50.  But a reliable standard format is
better than an unreliable "better" format.  So, this is a recommended
way to format RX50 on a PC.

(It is conceivable that FDFORMAT "behaves" correctly on FD-55F
drives, which are theoretically supported by both programs.  If the
disks prove reliable, then the other advantages of FDFORMAT can be
applied in this particular case.)

RAINDOS 1.12

For MS-DOS DECmate and Rainbow users, there is an alternate route:
RAINDOS is a device driver from the same vendor as 22DISK, and
apparently incorporates the same low-level disk support.

Unlike RX50DRVR, RAINDOS can work correctly with CHKDSK and most
importantly DOS's FORMAT command.  You still get a standard low-level
RX50, but the resultant DOS structure is entirely compatible with
DECmate and Rainbow MS-DOS, so programs like RX50INIT aren't
required.  Further, since DOS's FORMAT command was used, any actual
errors will be incorporated into the FAT structure, so diskettes with
bad spots can be used.  (RX50INIT does a no-check perfect directory
initialize.  FDFORMAT does check for errors, but records them in the
incompatible PC-like DOS structure that has to be replaced for DEC
compatibility, so you have to observe that FDFORMAT found no errors,
and must reject disks with errors.)  The manual claims there is the
same FD-55F support as in 22DISK.

RAINDOS has several problems:

It doesn't work under DR DOS.  All but the FORMAT command actually do
work there, but attempts to format a diskette terminate with the
error message "Drive already locked to another program".

It doesn't work with DOS 4 and 5 booted to the A: floppy which is
also the drive used by RAINDOS for its RX50 operations, unless DOS is
used exclusively on 360K diskettes.  As with other floppy-based
systems, there are times when you get a message like "mount a
diskette containing \COMMAND.COM in drive A: and press ENTER".  This
is perfectly normal for this limited environment.  The problem is
that if you have HD drives, (most machines have HD A: drives), then
you would prefer to read HD diskettes on them.  Once booted up and in
the mentioned situation, all further attempts at using an HD floppy
yield a GENERAL FAILURE error message that will not clear.  You can
mount a low-density floppy to get COMMAND.COM reloaded, but all
further access to the A: drive disallows HD diskettes.

For hard-disk DOS 4 and 5 users, none of this is a problem in
general, but since I use DR DOS 6, I had to boot a DOS 4 or 5 floppy
:-(.

Overall, if the goal is merely to format RX50 media, 22DISK is the
best route since it runs under any PC-based DOS system.  For many
users, RAINDOS is even better, but clearly not for all users.

When/if FDFORMAT gets fixed, it will be a better way through that
portion of the problem.  BTW, RX50DRVR, while not able to format,
does run under DR DOS 6, as does RX50INIT.  RX50INIT cannot run under
DOS 4 and DOS 5.  RX50DRVR has some quirky problems partially
avoidable there as well.  There is also word that RX50DRVR is being
upgraded to support formatting and DOS 4 and 5's CHKDSK.  It
currently can be used with DR DOS's CHKDSK as well as DOS 3.x.

Apparently, RX50 support is hardly a "static" issue :-).

     Charles Lasner   lasner@watsun.cc.columbia.edu 

                         **************************

Q11.  What's the difference between a microPDP-11 and a Pro?

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

                         **************************

Q12.  Can I run MSDOS on a Pro?

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

                         **************************

Q13.  Where can I get unix for the Pro?

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)

                         **************************

Q14.  I have a Pro running a form of unix and I no longer need or want it.  
I guess I'll just throw it out.  
I have an old copy of xxx unix for the Pro in a closet somewhere and I'm 
going to clean out the closet and discard all the old Pro stuff. 

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".

                         **************************

Q15.  I have lots of space on my disk yet whenever I try to copy a file I 
get a message saying out of disk space, please delete some files and try 
again.  Why?

Unlike other OSs which put pieces of a new file in chunks of empty disk 
space, P/OS requires a single contiguous space for each file.  This means 
that if you delete many small files you create "holes" or empty spaces on 
your disk.  When you copy new files 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.cislupenn.edu

                         **************************

Q16.  How do I reclaim disk space occupied by "invisible" files?

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

                         **************************

Q17.  How do I set the printer port baud rate from DCL?
          
               $ 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

                         **************************

Q18.  How do I enter DCL commands that are more than one line in length?
          
Use a  hyphen (-)  before the line's carriage return.  In DCL, the command  
is not  executed until  a line ending in <CR> not preceeded by a hyphen is 
encountered.  No DCL line can be more than 250 characters. 

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

                         **************************

Q19.  How do I set protection on a file?
          
               $ SET PROT <filespec> [/qualifier(s)] <code>
          
          /Qualifiers:
          
               /DATE=dd-mmm-yy
               /SINCE=dd-mmm-yy
               /THROUGH=dd-mmm-yy
               /TODAY
               /EXCLUDE=filespec  (don't forget a version specification)
          
          <Code> 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

                         **************************

Q20.  How do I reassign a device's LUN after the task has been built?
          
               o    Install the task:   $ INSTALL <task>
          
               o    Assign the new LUN to the task:
                    $ ASSIGN/TASK=<install_name> <device:> LUN
          
               o    Run the task:  $ RUN <install_name>
          
          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

                         **************************

Q21.  How do I Run RMD  (SHOW MEMORY) from a second terminal?  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

                         **************************

Q22.  I'm running P/OS 2.0 and can't get it to recognize my 20 Mb drive.

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

                         **************************

Q23.  I was given a Pro-350 by an office that was junking it and when I 
booted it up it asked for a password.  I don't know any passwords.  How can 
I break past that and delete the password file? 

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 

                         **************************

Q24.  Can anyone out there tell me the pinout for the monitor/keyboard 
connector on a DecPro 350? 

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

                         **************************

Q25. What is the pinout for the video port? 

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

                         **************************

Q26.  What are the pin-outs for the RX50 floppy controller?

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


                         **************************


Q27.  I booted my Pro and got an error code.  What does it mean?

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

                         **************************

Q28.  Are there any pro BBSs?

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.

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

                         **************************

Q29.  I can't get my hands on an ethernet connection for my Pro.  Is there 
any alternative? 

 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

                         **************************

Q30.  What is the latest version of Kermit available for the Pro?
 
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

                         **************************

Q31.  The Pro-350 comes with one serial port standard.  Does anyone know if 
it's possible to add a second serial port or additional ports? 

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 

                         **************************

Q32.  What is DDCMP, Digital Data Communications Message Protocol?
      Or alternatively; I called DEC with a support question about
      DDCMP and they hung up on me.

Digital Data Communications Message Protocol(DDCMP) is no longer
supported by DEC (according to nasty mail I got for mentioning it in
comp.sys.ultrix), but in VMS I have relied on it.  As many of the
readers of this group know, it 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


                         **************************

Q33.  I have an RD-something.  What kind of drive is it?  What kind of 
      controller do I need?

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


                         **************************

Q34.  Is there any way to make a PRO floppy bootable?

You can build a bootable PRO floppy on an 11/23+, assuming that you have
all the pieces (like the distribution kit). The PROs floppies are called
DZ and the winny is DW. You also need the PRO's screen driver (it's a
bit-mapped screen) called PI. Finally, you have to have either RT11FB or
RT11XM; SJ won't run on it :-(.

Basically, you should copy (SWAP,RT11XM,DZ,DW,PIX).SYS to the floppy and
then COPY/BOOT:DZ to the floppy. You should then have a bootable RT-11
diskie for the thing. From there you can format the hard disk (if you copy
FORMAT.SAV over) and install on the hard disk.

Roger "I converted a Pro from P/OS to RT-11" Ivie       ivie@cc.usu.edu








Chaim R. Dworkin
chaim@linc.cis.upenn.edu