HP75000 Series C (Agilent E8401A) VXI Mainframe

The text below describes a HP75000 Series C mainframe. I also have a file describing a HP75000 Series B mainframe.

Meanwhile this beast occurred in my lab…

This is a large, noisy, but super-flexible VXI solution. All 14xx modules from HP and all older 13xx modules (with adapters) can be used inside this mainframe.

HP 75000 in general

The HP75000 is a VXI mainframe. A VXI mainframe is a standardized infrastructure where individual measurement devices can be simply plugged in and used. This is only possible because the two important areas of standardization have been addresses by VXI:

  • Hardware: VXI defines the physical layer where devices, even from different vendors can be integrated. The hardware layer includes electrical characteristics, wire protocols and such.
  • Software: VXI defines the software related characteristics to access and control the devices plugged into a mainframe.

By having standardized both software and hardware characteristics, devices can be developed by big Vendors like HP and used in any VXI infrastructure.

Each HP75000 mainframe has a backplane offering several slots to plug in devices.  A mainframe needs a controller („command module“) which coordinates the devices plugged in and which communicates with the outer world, e.g. with a PC connected.

HP75000 were sold in three versions, named  „Series A“, „Series B“, and „Series C“.

HP 75000 Series C

The HP75000 series C is a VXI mainframe offering 13 „C-size“ slots for modules.
There is no built-in command module (like in Series B). A Command module must be added in Slot 0. This module can be a command module with RS232 and GPIB input or a specialized single board computer that fits into a Series C slot. The module in Slot 0 is responsible to control the devices and to communicate with the outer world.

For HP75000 Series C, the following features are important:

  • Devices like Multimeters, Frequency Generators, Digital I/O Boards and Switch-Boxes (Multiplexers) can be inserted
  • Access from PC to the VXI mainframe is (for the HP75000) via multiple ways like LAN or RS232

Details on slots: 13 C-Size slots, all with P1 and P2 connectors.


HP Agilent E8401A C-Size VXI Mainframe

Up to 13 modules can be inserted. The Mainframe supervises power condition. For example, I soldered my AUI transceiver adapter cable together in a wrong way, thus shorting the +12V and GND lines :-((( . This was no problem at all, the mainframe came up with SYSFAIL condition and nothing else happened…


HP E1498A Controller

This is a real beauty on its own. The HP E1498A is a complete VME-Slot-sized  UNIX workstation. Inside there is a single CPU (PA-7100LC, PA-RISC version 1.1c 32bit) with 100Mhz and up to 128MB RAM.

Regarding names The CPU and/or Board occurs in documents as „s700“. The board seems also often to be called V743 or V743i. But, at least I have seen a board called also v743 in B size formfactor.The hardware offers the usual connectivity like:

  • Keyboard, Mouse (standard PS/2 connectors)
  • Video
  • Network (AUI)
  • SCSI (50 pin HD connector)

Because its an VXI controller we also have:

  • GPIB
  • several system clock and trigger connectors

The operating system is a real UNIX from the old days, namely HP-UX 10.2.

Below are some pictures of the HP E1498A.

Right : CPU with cooler. Mid: 4 RAM modules 4x32MB=128MB.




PA-7100LC CPU @ 100Mhz

SCSI cable, some socketed PROMs containing the Boot code




There are two multi-pin connectors for mezzanine cards



NVRAM/RTC battery


3 big FPGAs are doing the peripheral work like SCSI, network etc.


Boot ROMs





HP-UX 10.2

Note that HP-UX 11.x will not run on the CPU.

HP-UX 10.2 is from the late 1990ies. But no worries. I have used Linux the last 25 years and also Solaris, AIX and even HP-UX on 9000-workstations. From today, it’s fascinating how modern the HP-UX 10.2 is. If you’re familiar with Linux command line, you can use it right away. Some things are different, but not too different. After having worked several days now with HP-UX 10.2 I think it’s a pity that it was not free in the 1990ies. Many people would have liked to work with it, remember that Linux was then in it’s very early days and not as much comfortable as HP-UX 10.2 then was.

A bad thing from today’s hobbyist perspective is that all connectors of the E1498A (besides: Keyboard, Mouse and SCSI) are of a very special form factor. All are „Micro Sub D“.

Some of those Micro Sub D connectors. You can see that the complete RS232 connector contact area is about 5mm size

HP sold in the old days adapter cables (I suppose 1 adapter cable for a large gold nugget 🙂 ) and you can today buy those connectors from various sources.  If you’re a millionaire or otherwise crazy, this is an option – a single connector is not below 40 Euros!!!

I created the connectors I required myself from scratch…

Dimensions of the RS232 connector in mm.

Each DIY connector consists of the correctly sized small plates (from PCB material). They are glued together, between them the pins are hold in place by the glue. For the pins itself I used transistor pins.

DIY connector with 9 pins for RS232

After the successful creation of a 9 pin connector (RS232) I built the 15 pin one (LAN connector).

The connectors I created have no screws to mount them to the E1498 connectors, so they require a friendly environment 🙂

Standard transistors (e.g. BC557) have 1.27mm pin pitch. So I glued 3 transistors together on a plate. They are the 8 pin line of the 15 pin connector after 1 pin (leg) was removed.
A second plate was glued on top of the transistor pins for fixation.


Three further transistors with 2 legs removed were glued on the other side of the inner plate and fixed with a third plate.


I would not fly to the moon with these connectors but for installation and friendly use its stable enough.


Set up HP-UX 10.2 Operating System

My HP E1498A came from USofA without anything. No cables, no software, no nothing. So I ordered old HP-UX 10.2 installation disks via eBay – from Australia. HP licensed per machine/CPU in the old days, so if you have the hardware you’re safe. From those disks, a „cold install“ can be done.

First boot, without disc or anything attached. I just put the oscilloscope probe to the RS232 Tx pin and switched my Rigol to RS232 decoding. The E1498A dumps ~360 bytes which I can read before its hanging waiting for boot devices. The decoded line here (green) says „All rights reserved“. So it’s working 🙂

A SCSI disk must be attached as installation target and a SCSI CD drive as installation source (there are other options like network installation but I decided to keep it simple).

The mainframe, on top of it SCSI CD-ROM and harddisk. Network connectivity via AUI-Transceiver.

Installation arrangement: SCSI CDROM drive plus self-made external SCSI harddisk.

At the beginning of installation, the partition sizes (logical volumes) can be define. The default values are crazy small, some megabytes here and some megabytes there. You must change these values, otherwise it will give very soon problems when adding OSS software etc. I made partitions not smaller than 512MB, for /usr, /opt and /home several GB sizes. There are some volume group parameter values to tweak in the installation gui for such large sizes named pe_size and max_pe, see here.

After the base installation from a single CD, other applications can be installed from software depots (CD-ROMs, files, network).

Online software depots are almost gone for HP-UX 10.2. There are still some ftp Servers offering compiled packages for gcc, bash, bzip2 and more.

Using the „sam“ tool, many administration tasks can be executed.

CD-ROM mount

Checking all disk devices:


% ioscan -fnC disk

Class     I  H/W Path   Driver      S/W State   H/W Type     Description
disk      0  2/0/1.4.0  sdisk       CLAIMED     DEVICE       HP 18.2GST318406LW
                       /dev/dsk/c0t4d0   /dev/rdsk/c0t4d0
disk      1  2/0/1.5.0  sdisk       CLAIMED     DEVICE       YAMAHA  CDR400t
                       /dev/dsk/c0t5d0   /dev/rdsk/c0t5d0

The mount command is then

mount -o ro /dev/dsk/c0t5d0 /cdrom

# df

/cdrom               (/dev/dsk/c0t5d0     ):        0 blocks         0 i-nodes 
/home                (/dev/vg00/lvol4     ):  7385992 blocks    673591 i-nodes 
/opt                 (/dev/vg00/lvol5     ):  3520138 blocks    335703 i-nodes 
/tmp                 (/dev/vg00/lvol6     ):   882914 blocks    237891 i-nodes 
/usr                 (/dev/vg00/lvol7     ):  3179068 blocks    324120 i-nodes 
/var                 (/dev/vg00/lvol8     ):  1558032 blocks    469323 i-nodes 
/stand               (/dev/vg00/lvol1     ):   424334 blocks     41070 i-nodes 
/                    (/dev/vg00/lvol3     ):   890816 blocks     80391 i-nodes

Mount harddisk in mainframe slot

HP offered 1-slot modules with harddisk+floppy. I used an B-Size – To – C-Size Adapter and mounted there a harddisk inside. The P1 connector of the adapter has the required voltages for the harddisk (5V, 12V and GND). I connected the harddisk there and a SCSI cable connects the harddisk with the V743 module.

As soon as NFS works, the external  CD ROM is not really required anymore.

Software installation

The command swlist lists all installed packages. Below is the output after base installation:

# swlist
# Initializing...
# Contacting target "vxi1"...
# Target:  vxi1:/
# Bundle(s):
#  B3782EA               B.10.20        HP-UX Media Kit (Reference Only. See Description)
   HPUXEngCR700          B.10.20        English HP-UX CDE Runtime Environment

The command swinstall serves to install software. Start it with a source argument or without any arguments and enter interactively the required values. Finally the command can be started from inside sam.

 swinstall -s <hostname>:/<source-path>

If the user is not allowed to install software (I had this for root at some point) you can extend the „Software Access Control List“ with swacl.

Export current ACL to a text file:

swacl -l host > swacl.host

Add with an text editor a line for the user that should be added to the ACL, e.g.:


Re-import extended file to ACL system:

swacl -l host -F swacl.host

Adding of patch bundles and other software

There are many patches for HP-UX 10.20. Some of them are patch bundles containing hundreds of patches in one big chunk. Bundles can be installed like any other software using the swinstall tool. Look for the „General release“ and „ACE“ bundles.

Patches I installed:

      • XSW700GR1020 (more than 100 products)
      • ACE workstation (updating ~116 products, i.e. packages)
      • ACE networking (seems to be contained more or less 🙂 in the workstation patch bundle)

I hoped the ACE patches raises nfs to v3, but it does not.

After base installation I have installed several things:

      • Java (JRE+JDK)  (super-old version 1.0.3),
      • A Patch bundles named „XSW700GR1020“ (General Release Patches for HP-UX 10.20 Workstations)
      •  B6378DA:Networking ACE and B6193EA Workstation ACE patch
      • E2091F: HP  I/O Libraries (see below)
      • Several OSS tools like bash, gcc etc.
 # Initializing...
 # Contacting target "vxi1"...
 # Target:  vxi1:/
 # Bundle(s):
 B3782EA                       B.10.20        HP-UX Media Kit (Reference Only. See Description)
 B5455AA_APZ                   B.01.03        HP-UX Development Kit for Java* (S700)
 B5457AA_APZ                   B.01.03        HP-UX Virtual Machine for Java* (S700)
 B6193EA                       ACE.199912.01  Workstation ACE for HP-UX 10.20 (December 1999)
 B6378DA                       ACE.199912.01  Networking ACE for HP-UX 10.20 (December 1999)
 E2091F                        G.01.02        HP I/O Libraries for HP-UX
 HPUXEngCR700                  B.10.20        English HP-UX CDE Runtime Environment
 XSW700GR1020                  B.10.20.33     Extension Software Patch Bundle
 # Product(s) not contained in a Bundle:
 bash                          4.3.30         bash
 binutils                      2.9.1-1        GNU binutils
 bzip2                         1.0.6          bzip2, bunzip2 - a block-sorting file compressor
 gcc                           4.2.2          gcc
 grep                          2.21           grep
 gzip                          1.3.9          gzip
 lsof                          4.80           lsof
 tar                           1.20           tar


Set Up Networking

HP E1498A contains everything required for network access. It has a 15 pin AUI connector in the Micro Sub D form factor (female).

Get a male connector for that and a female 15 pin Sub D connector. Wire pin numbers 1:1 together. Then an AUI-Transceiver can be connected to the female connector. The other side of the AUI Transceiver is 10Base-T, which can be connected to any modern network. AUI-Transceiver pin numbering is standardized, so you can use every transceiver you want.

My used CentreCOM 210TS AUI-Transceiver, bought from China for ~6 Euros.
On the left you can see the yellow 10Base-T cable, on the right the 15 pin connector. The transceiver is powered via the 15 pin connector from the E1498A.

Using sam, the LAN interface („lan0“) can be configured with an IP address, DNS server etc. Having done this, the interface is immediately up and running.

HP-UX can run several network services, e.g. telnet or nfs (v2), automounter can be used out of the box.

Note: Change nsswitch order (in sam, to take /etc/hosts first). Otherwise the machine may not find itself 🙂

ntp time synchronization

When trying to set up ntp, the client program refuses to synchronize to my time server (a fritz box which synchronizes itself from a public time server). During installation, it was not possible to enter a date behind 1999 and so I entered a date from 1996 (today-20 years). When later setting up ntp, xntpd did not like this and prints out:

Aug 28 01:10:49 vxi1 xntpd[5826]: Clock appears to be 631564685 seconds slow, something may be wrong

Aug 28 01:10:49 vxi1 xntpd[5826]: system event 2: System or hardware fault.

To overcome this a sync can be forced using this command:
     ntpdate <time_server_ip_address>

After that the system clock is correct and will be correctly synchronizing in the future.

Set up X Windows

The HP E1498A runs X11R6. If a keyboard and a mouse and a monitor is attached to it, the X X Server is started. Otherwise  X clients can only be used with a remote display (i.e. X Server). The base installation has only a few x clients to run.

On OpenSuse Leap 42 I was not able (easily) to let the X Server  listen to port 6000, which is required for X clients without a ssh connection. I use a socket forwarding command like this:

socat -d -d TCP-LISTEN:6000,fork UNIX-CONNECT:/tmp/.X11-unix/X0

After this, clients can connect in this way:

export DISPLAY=my-pc:0.0

Error messages: /var/dt/Xerrors

Set up VXI software

To control VXI devices from the HP E1498A, two things are needed:

  • Hardware:
    • Either a GPIB controller that fits into the mainframe. This thing is called HP E1406A.
    • Or use the VXI backplane together with ISCPI interface (see below)
  • Software: HP provided all the required software on a CD called „E2091F I/O Libraries for HP-UX 10.20“.

This software is not anymore provided by Keysight. You have to buy it somewhere else, eBay is your friend here.

After install, use the tool iosetup (an X Windows client) to configure the VXI- and the HPIB device inside the V743 board. iosetup will reconfigure those as new interfaces and recompile the Kernel. After a reboot, note that /dev/sicl is populated with many new devices.

Also, add ISCPI (Interpreted SCPI) as an interface. This allows to control HP measurement devices directly via VXI backplane, even without the need for a command module. This approach translates transparently SCPI commands to register-based calls.

iosetup GUI after adding vxi, hpib and iscpi interfaces (Click image to enlarge)

After having all done this, devices in the mainframe can be accessed. The following C code accessed my HP E1411B digital multimeter at logical address 8 (code taken from HP documentation). It uses the ISCPI interface by using the device address „iscpi,8“ .

#include <sicl.h>
#include <stdio.h>

void main()
INST dvm;
char strres[20];

/* Print message and terminate on error */
ionerror (I_ERROR_EXIT);

/* Open the multimeter session */
dvm = iopen („iscpi,8„);
itimeout (dvm, 10000);

/* Initialize dvm */
iwrite (dvm, „*RSTn“, 5, 1, NULL);

/* Take measurement */
iwrite (dvm,“MEAS:VOLT:AC? 1, 0.001n“, 23, 1, NULL);

/* Read measurements */
iread (dvm, strres, 20, NULL, NULL);

/* Print the results */
printf(„Result is %sn“, strres);

/* Close the multimeter session */

Compile this with HP’s cc or gcc.
gcc vximesdev.c -o vximesdev -L /opt/sicl/lib/ -lsicl

Output looks like this:
bash-4.3$ ./vximesdev

Result is +1.220703E-002


Installation and Configuration Guide for Linux I/O Libraries (41 pages, for Linux, but you get idea for HP-UX too)

HP E1411A Digital Multimeter

This is like the HP E1326A but in a C-sized form factor.

Jumpers for GPIB secondary address (here: 8) and IRQ (here: 1).


HP E1411A Service Manual


  • Micro D / Micro D-Sub / Micro Sub-Dmale layouts document
  • Micro D / Micro D-Sub / Micro Sub-D 9 female pin layout document
  • Micro D / Micro D-Sub / Micro Sub-D 15 female pin layout document

Further readings

http://www.datadisk.co.uk/html_docs/hp/hpux_cs.htm – HP-UX Cheat Sheet