NetBSD/pc532 Frequently Asked Questions

NetBSD/pc532 Frequently Asked Questions

General Questions

Other sources of information

General Questions

What is a pc532

The pc532 is a motherboard designed in 1989 and 1990 by George Scolaro and Dave Rand in Sunnyvale, California. They were kind enough to distribute their design for others to use. What they distributed was FULL information about the motherboard. They also had the motherboard fabricated and sold them to people so they could build a working pc532.

The basic features are:

  • Motherboard mechanically fits into a PC/AT case
  • NS32532 25 Mhz CPU (built in MMU)
  • NS32381 25 Mhz FPU
  • 4, 8, 16, or 32M of RAM (80nS 0/1 wait, no cache), 8 RAM Slots of 9 ICs, taking 1M or 4M.
  • DP8490 SCSI controller chip connected to XT mechanically compatible 4 slot expansion bus
  • AIC6250 SCSI bus (sync or async)
  • 4 SCN2861 DUARTS for a total of 8 serial lines (@ <= 38400)
  • 27256 EPROM for the hardware monitor

A motherboard was shipped to people who bought them with a complete hardware description, full schematics, and PAL/GAL programming information. The first general distribution of pc532s included a special deal where all the chips were included in the purchase. Later distributions included only the motherboard and buyers banded together to get all the chips that were needed.

An owner of a pc532 designed a simple daughter board that plugs into one of the SCN2861 DUART slots and implements two Centronics parallel ports.

To our certain knowledge there were less than 200 pc532 mainboards made. There were only 187 pc532 out in the world as of 11 Jun 1996 (source: "Matthias Pfaller" The only way to get one today is to find someone with one they don't want and to buy it from them.

Obtaining a copy of the auto boot ROM image

This can be found at

There are two different ROM images: one for a 9600 baud console and one for a 19.2K baud console.

How to boot NetBSD without the autoboot ROM

You will have to find the right place on the disk where the boot program lives and give the proper "read ..." command and then execute the boot program. That shouldn't be hard to do.

Read the INSTALL document, and try to follow the install procedure. Then, before you reboot, you need to get the boot information if you don't have the auto-boot ROM. (If you do have it, you don't need the following information.)

Run bim. You will get something like:

steelhead[1]# bim

Disk: disk 1   Type: SCSI
Physical Sector Size = 512
Disk Size = 1173930
 partition         type  sector start  length in sectors
     a          4.2BSD         23980             383680
     b            swap          2180              21800
     c         unknown             0            1173930
     d            boot             2               2178
     e          4.2BSD        451260             722670
     f            swap        407660              43600

Boot partition = d
Default boot image  = 0
Boot Images: total of 8
  (image address and size in sectors.)
Image  address   size  load addr  run addr   name
    0        0     32   0x3e6800  0x3e6820   /usr/mdec/boot
    1       32     64   0x3bf000  0x3bf020   /usr/mdec/boot

From this you can easily calculate the disk address of the boot program and where to load it and run it. So for the above stuff, the boot partition starts at sector 2. The boot image is at offset 0 in the boot partition. So the boot program is at sector 2 and is 32 sectors long. You need to load it at address 0x3e6800 and run at 0x3e6820. Write that information down for your system and you can then give the proper ROM monitor commands to load the boot program and run it. All the autoboot monitor does is to read that information from the disklabel and the boot images table on the first two sectors of the disk.

Cabletron Ethernet

NetBSD supports some SCSI ethernet devices such as the Cabletron EA412/EA419. Philip L. Budne <> wrote a userland daemon "etherd", which Ian Dall <> used as a reference while writing the kernel driver /sys/dev/scsipi/if_se.c. They are no longer made, though you may be able to find one second hand, particularly on the Macintosh market.

Some original mail on the subject:

From: Phil Budne <>

	> Philip Zimmerman found a little (6"x1"x3.25") Cabletron EA419 SCSI to
	> ethernet box, and I found documentation on how to speak to it.

	What does that box cost (aprox.) ?

It doesn't look like this box is sold any more; However Philip Z.  may
have a line on two different sources. But in both cases it may boil
down to "how much are you willing to pay".  Since similar devices sell
new for $200, I would hope it would be under $100.


From: Philip A Zimmermann <>
To: Phil Budne <>
Date: Tue, 2 Jul 1996 00:55:33 -0400 (EDT)

I'll look into sources. More 
may even pop up from the other subscribers out there; what I basically 
scared up, at Phil B.'s description, was a box which we used to use on 
older-style Macintoshes which had a SCSI port on the rear panel. This 
Cabletron box has a DB25 on one side and an RJ45 on the other side and a 
socket for a wall wart to provide power.

I have chased a few leads today; the only positive response was from 
Cabletron Systems so far. They have 11 in stock right now in their "Good 
as New" department. They want US$175 each. Order info:

(per Mike Orr)

Cabletron Systems
Good as New Dept
PO Box 5005
Rochester, NH 03866-5005

Mike can be reached at:

He said they trickle in occasionally. I'm still searching for other

From: paz <>
Date: Wed, 12 Feb 1997 11:59:28 -0500 (EST)

The network "card" I'm using is a Cabletron EA419. It's probably the same
device you've seen discussed on the mail list. It's a box with an RJ45 on
one side and a DB25 on the other. It was originally intended to provide a
network interface to Macintoshes with a SCSI interface which came out of
the Mac at a DB25, I think. Cabletron has a "good as new" department where
refurbs of this unit can be gotten for ~US$150, if memory serves
correctly. I'm uncertain how many pc532s are so equipped right now; I just
hacked mine onto a Vector ISA prototyping card so it would plug into the
pc532 SCSI expansion bus. I got it running over the past weekend. Seems to
be working fine.

Last ET532 Ethernet Project Progress Report

As far as I can determine, the et532 was a project to build a ethernet capable pcb for pc532s.

This report from Julian Stacey <>

Latest Photoplot Info.:

Main Board photoplot is done (George, anything I should check for ?) Serial piggy back Board photoplot not done yet.

PCB Quotes:

Anyone who feels like getting us quotes from board manufacturers, please go ahead, all the info's up for ftp, help yourself :-)


Thanks to Phil, NetBSD now runs on the PC532 :-) .... If we increase the number of ET532 boards made, it's cheaper, so: 2 Scenarios:

  1. Us `good old guys' owning PC532s can buy cheap GX32 CPUs (with no MMU) to drive the card as an ethernet peripheral.

  2. Maybe some of the software guys in the Net & FreeBSD worlds might also like to buy a card, equip it with a full 32532, & build a truly fully sourced (hardware & software) system, that has CPU & MMU (but no ICU or FPU), has ethernet & up to 16 serial ports & a SCSI bus.

No doubt the class (2); guy might prefer an ICU & FPU too, but nobody's doing a PC532 PCB run so that option is not available Anyway, maybe class (2); folk might increase total board quantity & reduce prices for us class (1) folk ? Is this daft ? or Should we offer it to the Net & Free BSD lists ? Comments Please.

  • KHE asked Where'd the power go in ?

  • Answer: Connect power wires to an edge connector socket plugging on board; & use CONN2 for SCSI ribbon.

  • Question from me: Would class (2); users _need_ an ICU & FPU ?

  • George's gerber info is available via ftp from[gerber & schema]

  • George wrote to me: Drill tapes depend on the PCB house. At the very least they will want the film of the drill gerber layer, at the most they will want a drill tape. If they want a drill tape, the photo shop can extract the drill gerber file layer and generate a drill tape - at least my photo shop did that.

  • Files available include:

    		ether.cfg schema.cfg ser.cfg
    		copeth.doc dramc.doc
    		dec32.doc dramen.doc ether.txt wait.doc
    		ether1.gbr ether4.gbr etherdrl.gbr ser1.gbr serslk.gbr
    		ether2.gbr ether5.gbr etherslk.gbr ser2.gbr sersmk.gbr
    		ether3.gbr ether6.gbr ethersmk.gbr serdrl.gbr
    		copeth.jed dec32.jed dramc.jed dramen.jed wait.jed
    		copeth.tdl dec32.tdl dramc.tdl dramen.tdl wait.tdl
    		ether.s01 ether.s03 ether.s05 ether.s07 ser.s01
    		ether.s02 ether.s04 ether.s06 ether.s08 ser.s02
    		ether.p01 ether.p03 ether.p05 ether.p07 ser.p01
    		ether.p02 ether.p04 ether.p06 ether.p08 ser.p02

George long ago wrote:

The et532 is a 6 layer PC/AT sized (but with 62 pin SCSI) board. The piggyback board (after a bit of a fight with the CAD software) is a 2 layer board and is around 5.5" x 3.5". It plugs into the middle area of the et532 on two connectors that carry all the serial (TTL) signals up from the 2 OCTARTs. There are also 3 sets of holes on both boards that line up and enable nylon standoffs to support the piggyback board.

Michael Hermann & Steve Liggett asked stats on PCBS, to get us prices, well I havent counted number of holes on pcb (freq Q. that), but:

ET532 Layers:

  • Silkscreen
  • Solder mask
  • Component layer
  • Inner layer #1
  • Ground Layer
  • Power Layer
  • Inner Layer #2
  • Solder Layer
  • Solder Mask

No surface mount devices as per PC532 (I assume George ?) I presume we call this `6 layer' as far as PCB manufacturers are concerned ?

Daughter Board Layers:

  • Silkscreen
  • Solder mask
  • Component layer
  • Solder layer
  • Solder mask

The 2 serial chips go on the piggy back serial card. I asked George Scolaro:

	> > - Do we also need to make piggy back octart PCBs ?
	> Only if you want to have more serial ports.
	Looking at George's ET532 schematics:
		The ET532 can take 2 * SCC2698, each 2698 supports
		EIGHT serial ports ! The optional `piggy back' board
		has 16 * 145406, 16 * DIL Headers, Caps, & 2 Long DILs
		to connect to ET532 main board.
	For the ET532 to function just as an ethernet card, it should not be
	necessary to populate the 2698 sockets, nor to have a piggy back card.
	I do however foresee need for a few of us to have one serial port,
	as I guess software development'll probably go in 3 stages:
		1 Write/debug eprom for ET532 to talk to a serial port
		  (& prove hardware design works)
		2 Extend ET532 monitor to talk over SCSI bus to some kind
		  of software interface on the PC532, so PC532 can download
		  code to ET532 & set breakpoints etc ?.
		3 Develop ET532 ethernet code & ET532/PC532 higher level
		  protocols etc.
	Main thing is to get the ET532 PCBs fabricated :-) .
	Daniel Berglund <> wrote 3-94:
	> > > It's probably not hard to temporarily wire in a 2681
	> > >  (or whatever they are called,
	> > SCC 2698
	> Nope. I mean a 2681, they are cheaper.  That's my point: if you
	> want only one serial port for debugging until the firmware is done,
	> then you probably want to avoid expensive octuarts (2698).

All these are very old figures, & need to be confirmed: Bryan Davis said

		> from the Bay Area....
		>  Hamilton/Avnet (a distributor for National)
		>		 1-24	 25-99	 100+
		> NS32GX32-ANU20  $110.00 $95.00  $86.50
		> NS32532-25	  $825.00 $685.00 $595.00 said

		> Bell Industries, a NatSemi distributor in California,
		>		  QTY1-24     QTY25-99	  QTY100-999
		> NS32GX32U-20	    90.00	 78.50	       71.00
		> NS32GX32U-25	   100.00	 91.00	       83.00
		> NS32GX32U-30	   120.00	105.00	       95.00

johnc@manatee.UUCP (john connin) Wed, 7 Oct 1992 19:16:47 GMT said:

		> it might be easier and cheaper to pull the ethernet
		> related parts from a no-name 8-bit ethernet card.
		Are the parts the same as I posted in George's build list ?

Could someone please ask at a US West Coast IC shop, what an IC kit price would cost, as per build list (presumably a) excluding GX32, b) 1 off & ~25 off pricing ). ( I believe can provide names of California IC shops for someone in the USA to phone. )

The ether-bom (Bill Of Materials) is available via ftp to enable pricing exercises. Don't ask me, I'm in the wrong country for cheap or easily available prices, VOLUNTEERS PLEASE !


This PCB order list does NOT commit you to IC purchase, If short of cash, you can enroll on what will be a once only ET532 cheap PCB fabrication run, then some time later buy the ICs. I dont know board cost yet, as soon as I do I'll post the info, As always, no one's done a chip costing exercise, so as always, before people ask, Nope ! I don't know ! Photoplots'll were free (I'll probably buy the guy a meal to say thanks)


Hopefully someone(s) will consider doing IC bulk purchase & kit distribution. (doesnt need to be same person who does pricing investigations, but shouldnt be me, USA should be better purchase & distribution point than Germany) Steve Liggett maybe ?


Dave Rand <> mailed to say

"I have the software for the Ethernet already done, including an Ethernet-based monitor, and DOS client. I'll do the low-level Ethernet driver (tricky, 'cause you have to handle the special cases)."

(so I assume you want 3 PCBs bdale ? ) Rennolet (Kumar) <> said Wed Oct 7

"I will help write the drivers."

21 May 1996: Mark Mason <> interested in helping.


Please dont anyone mail me private questions about:

  • the ET532 architecture: I'm Not the designer - George Scolaro is.
  • PCB or Total project pricings: What I know is presented here.

More can be learnt by looking at the Gerber diagrams. George long ago wrote:

  • 20MHz 32gx32, no FPU.
  • 1M/4M DRAM (256kx4 or 1mx4) 100ns or faster, fast page mode. same performance as pc532 (except at 20MHz, i.e. 40Mbytes/sec)
  • 128kx8 EPROM (200ns or faster) Boot EPROM, runtime code is downloaded from pc532 etc. into DRAM.
  • 16 serial channels with full modem control (Signetics SCN2698B octart) RX,TX,RTS,CTS,DTR,DCD (modem support)
  • Ethernet, thin (cheapernet) and thick (DB15 connector) NS chipset
  • SCSI, DP8490 (via 62pin edge connector and 50 pin SCSI connector)
  • would everyone who's not responded in 1994 please email me with a new updated single line entry for the list below, thanks.
  • We need to confirm IC (inc CPU) pricings & project costs if you want a new build list posted, let me know.
  • Please do Not distract by saying wouldnt it be nice with the new super duper WIBNI ether chip unless you're prepared to design & deliver gerber's to me using that design.
  • If true, Please Do feel free to say ET532 is obsolete, the CPU price is horrendous, I say abort project

IE GO/NO GO but no WIBNIs (Wouldnt It Be Nice If's) please, Thanks :-)


This periodic bulletin is produced by me to coordinate us, but the cards will not be produced without much help though, I'm too lazy/busy for anyone to rely on me pushing it as a one man band; right now next thing we need to do is confirm IC pricings. I shall ignore any email that asks `how much will the whole thing cost' (I've been asked before, often) - It's a valid & important question, but as I've said before, I dont know, I'd like to, but I don't. Please help us by getting quotes on 25 off chip sets !


Corrections to this file are welcomed, please mail me.

Please hand forward this notice to dormant pc532 friends who may have fallen off the pc532 list, or changed their mail address.

A = Number of ET532 PCBs you will pay for, ie
B = Number of optional Serial piggy back pcbs you will pay for
C = Number of glue chip IC kits you will later want.
D = Number of GX32 CPUs you will want
E = Email
F = Real Name
G = Date of last communication
H = Comment
@ = Date person last confirmed PCB order info.

# PCBs ; EMAIL shown by "From:" ; .signature EMAIL NAME ; HUMAN NAME ; COMMENT

A B C D E				F		G	H
1 1 1 1			Julian Stacey	@May96  $ Dependent
1 1 1 1		Eyal Lebedinsky @May96  $ Dependent
1 1 1 1		Mark Geisert	@May96
1 ? ? 0			Mathias Pfaller @May96 will swap 32532 chip for pcb
1 ? ? ?			Phil Nelson	@May96 PCB <$100
1 1 1 1			Mark Mason	@May96 PCB <$100
1 1 1 1            Stuart Arnold	@May96  cond. on $
1 ? 1 1		Sverre Froyen   @Apr96  cond. on $
? ? ? ?			Jon Loeliger	@May96
1 1 0 0		Antti-Pekka	@May96
1 0 1 1	Ian Dall	@May96
1 0 1 1		Rick Rodman	@May96
1 1 1 1			Karl Swartz	@May96
From (Philip A Zimmermann)
Name		email			quant	date	comment
Dave Rand	1	20May96	can src files
Robert Vincent	1?	20May96	maybe. $;parts avail?
P. Zimmermann	1	20May96	do fab?
Lee Damon	1	20May96	two hands, tho'.
Julian Stacey		?	21May96	ET proponent
Sverre Froyen	1?	21May96	if < $?, parts avail?
Raymond Wiker	1?	21May96	if bare pcb <$100
Mark Mason		1	21May96	write drivers for...
Eyal Lebedinsky	1	22May96	want serial also

1 1 1 1                  Tom Rushworth   @Feb94
1 1 1 1	Raymond Wiker	@Feb94 Bd<$300 ex RAM
1 ? ? ?		Pete Carah	@Feb94 Bd<$300 NoMain532 FreeBSD
1 1 1 1                  David Fellows   @Feb94
1 ? ? 0	via		Tjeerd Mulder	@Feb94
1 0 1 1		Neil Johnson	@Feb94
1 1 1 ?		Marc Boschma	@Mar94
1 1 1 0		Dave Rand	@Mar94
1 1 1 1			Robbin Johnson	@Mar94 cond. on $
1 1 1 0	nomad@CASTLE.ORG		Lee Damon	@Mar94 < $100/pcb
1 1 1 1			KarlHeinz Eckmeier @Apr94
1 1 1 1		Jon Buller	@May96	BD<$100
	( Jon Buller, 2301 Pebble Vale #2121, Plano, TX 75075, (214) 422-3051 )
	( email goes away between semesters, but really wants one! )
	( email address from a 11-94 posting)
2 ? ? ?		Bryan Davis	@Dec93

0 ? ? ?			Gary Jennejohn
1 ? ? ?		Jordan K. Hubbard
0 0 0 0			George Scolaro
1 0 ? ? Michael Hermann
3 ? ? ? + Fred & John	Bdale Garbee	If drvr
1 ? ? ?		Kumar Rennolet
1 ? ? ?	john.connin@OAU.ORG		John Connin
1 ? ? ? John James Ackley
0 0 0 0	sef@kithrup.COM			Sean Eric Fagan
0 0 0 0		Gary Lowell
0 0 0 0		Victor Frank
0 0 0 0			Mark Mallett
0 0 0 0		Randy Hyde
0 0 0 0	montana!asgard@convex		J.R. Stoner
0 0 0 0		David Magnay
0 0 0 0		Joe Burger

0 0 0 0		Johannes Helander @ 21 May 1996
0 0 0 0			Tom Javen	@Mar94
0 0 0 0		Mattias Olofsson @Mar94
0 0 0 0			Grant Waldram	@Apr94 (info from marcb
--	--
From: (Philip A Zimmermann)
Subject: ET532 news.
Date: Wed, 22 May 1996 14:48:50 GMT

I started compiling a list of interested parties; I have to append
Julian's list from when things went dormant and contact those people to
see if they're still interested. Here's what I've got so far:


I'm currently working on the BOM, trying to source the difficult parts.
I'll get pricing when the number of participants is firmed up. I am
willing to help source the difficult parts (doing a quantity buy on the
'GX, etc. will probably help costs), but would rather not source the
popcorn & glue. Offhand, I'd say that it would be worthwhile to have
ET532 go to fab if the lot size is ~25.

I've had a good deal of experience dealing with pcb vendors over the
years, and especially lately. I appreciate the concern for keeping the
pcb fab cost down. My experiences lately have been with some vendors
who've done quick-turn jobs for us. Some of the consequences besides
higher costs have been poor quality, e.g. over-etching (where traces
disappear and the reappear an inch or so away), under-etching (causing
shorts between traces) and warpage (a problem if the product is a card to
be inserted into a cage). I know of companies which do high-quality work
and am hopeful that if we accept a longer delivery time, an acceptable,
affordable and reliable product will result. No one likes finding out
AFTER paying for and constructing a six-layer pcb that a few traces on
some buried (inner) layer are open-circuited or shorted out due to poor
fab quality. (Gets off soap-box.)

Some things are sketchy on the BOM; I'm hoping to submit my questions to
Dave Rand off-list for clarification, then add sourcing info to BOM.

I'm only interested in doing smaller step at a time, i.e., ET532 first, if
it's still practical. Then, if that works out and there's enough interest,
I may be prepared to help out with the serial daughtercard. I just don't
want to be overwhelmed with too much all at one time.

pc532 project mail list and archive

There is a pc532 project mail list, archived by <>:

Other FTP and web resources

Other sources of information

Other information on

Back to NetBSD/pc532 ports page