Because terminals are in such short supply; at least, in the UK, I’ve started looking at the 8870 <> DAP4 communication protocol. The hope is that I can over time, build a reasonable terminal emulator. My own DAP4 does some odd things from time to time and as I suspect it’s not long for this world, it makes sense to try and complete the emulator as soon as possible.

This morning I attempted to start the 8870, but it just sat there hunting for an operating system. Everything had been working fine before I shut the system down last night so I’ve no idea what has happened; possibly the disk drive is showing its age.

Anyway, I loaded one of the DC600A SMC back-up tapes I’ve previously made and attempted to recover the system from it. It took only a few seconds from inserting the tape for the system boot menu to appear on the VDU. I’ve run a re-format of the system LU, and restored the operating system without a problem. Unfortunately, I’ve not been doing regular backups so I’ve lost some of the German to English translation I’ve been doing but that’s just an inconvenience and nothing I’m going to lose any sleep over. At least I've still got a working system and servicable backup SMC tapes.

A word for those of you that may have to attempt a system recovery from SMC for yourselves.

I’m going to document the procedure more fully soon, but when the transfer of the operating system from SMC to disk is complete, the system appears to hang for a couple of minutes. Initially I thought that the system had locked up half-way though the restore process (the block counter was showing 193-ish at the time). It appears that the nice operating system is actually rewinding the SMC tape; hence the delay. It would have been nice if it displayed a message saying that everything is fine and I’m just tidying up for you, but you can’t have everything.

Anyway, whilst the SMC drive LED is on or flashing, be patient.

I think today is site-maintenance day. I've started to accumilate a lot of information and so I'll spend today formatting everything for the site.

The last couple of days have been rather up and down for me; perhaps you can guess this from the title of this entry.
Yesterday morning Heike and I set off for Birmingham. Sometimes things come to those in need, and just as I discovered that I needed a keyboard to get the DAP4 from Johannes working, what should pop up on EBay but a Quattro 25 machine complete with three DAP4 terminals complete with keyboards.

I should also point out that at the same time, I’d had an Email from Lawrence; an ex-Nixdorf 8870 engineer, who told me of a chap in some far off land who happened to have several DAP4 keyboards for sale. The postage was going to be expensive as they are rather heavy, so I decided to keep him in reserve until I saw what would be in my treasure from Birmingham.

We arrived at the pre-appointed time and Steve from “Environmental Computer” was there to meet us. We had a brief chat about the 8870 and screens. I showed him what happens when the battery backup plate is left in a discharged state for too long and then he helped us load all the stuff into the car. I happened to notice that he had many UPS units lying around all over the place, in fact, they have a LOT of stuff lying around all over the place, and if you’re looking for vintage or newer technology then you may want to give them a call or check them out on EBay; they’ve got an old British Telecom exchange sat in the corner that caught my eye; but was told to stop looking at it as there wasn’t room in the car.

Anyway, Steve said that he would happily throw in a small UPS for me if I had room in the car, and I was VERY grateful. I’ve been having problems with the breaker tripping the power to the workshop and whilst all my PC equipment is happily running off a large UPS, I didn’t think it had spare capacity to run an 8870 as well. The UPS after it had been on charge for a couple of hours seems to be working but the batteries do need replacing. Anyway, thank you Steve.

Needless to say, we raced home as I was eager to plug in one of the keyboards, fire up my terminal and watch my 8870 spring into life, then came the first of many ups and downs of the day. Plugging in the keyboard and switching on the VDU resulted on the VDU coming on for a second... and then going off and after repeated attempts the fault wouldn’t clear.

It was either a keyboard fault (seemed unlikely), VDU power supply or VDU CPU card. My gut feeling was it was the VDU PSU. No problem I thought as I had four new (well 25 year old) terminals to choose from.

Taking the cover off the first of the Birmingham VDUs made my heart sink. The lithium battery inside the VDU CPU card has leaked and eaten everything it could find. This included part of the CPU card, the aluminium protection plates and more of an annoyance, the V24-remote switch-on card. This “was” the system master port. However, the PSU seemed intact and it's quite a simple job to strip these VDUs down and interchange their main modules (more on this in a seperate article). The PSU was transferred over to my original VDU (as this one had been cleaned and now looked almost like new), power applied and switched on. Nothing… not a peep. So, another PSU was harvested and installed… this one hissed like escaping gas, and then finally just died. I was now starting to get worried.

However, 3rd time lucky and eventually the VDU came on and just sat there with the green keyboard light on. 
After pressing the parameter load key, <CR>, 0-1-8-5 and <CR> it accepted the parameters. Things were looking up, so next I connected the VDU to the system and switched on; a few seconds later the 8870 chassis fans started and the 8870 began its boot phase.

Low and behold, “CR” appeared on the VDU; this means that it wants you to specify the number of the workstation program to load or you can let it load the default. The main difference between workstation programs is what devices you want to connect to the terminal; I didn't care at this point. Since this was the VDU that came with the system and anyway, by the time the CRT has warmed up it’s too late to override the default setting, I decided to just sit back and let it run.

I could see the L1, L2, L3 & L4 lights flashing on the keyboard so I knew the VDU was loading it’s workstation program that was being supplied by the 8870, and I started to get a nice warm fuzzy feeling that the system would boot ok.

Then I saw the “INIT” message. This is your chance to change the default boot device from something other than “0”. However, I expected to see just the word “INIT”, but I actually got the message “CPU# 0 INIT”, and that really surprised me. This meant that the operation system was a version designed to support a multi-processor environment, so it had to be at least NIROS 7.0 loaded on the disk; but we were always told that you had to have a 1559 CPU as a minimum; not the 1537 CPU that’s currently in the system. Looks like the sales boys and girls had been up to their old tricks again.

So, I left the system to IPL and see what would happen…and I waited… and waited… and waited…

Eventually I got a rather worrying messages that the core size was incorrectly configured. Assuming that this system hadn’t been tampered with, and why would somebody just exchange the CPU or remove memory, then there was obviously something wrong but nothing I could do at this stage.

What should happen next is that NIROS boots it’s emergency minimum configuration, and that’s exactly what it did, after deciding that there were some index / file entry problems. This of course is also a problem, especially if it decides to delete an operating system file.

After a couple of minute’s, joy of joys… the log-on screen appeared and by the look of it; User Administration hadn’t been installed (so I had a pretty good idea what all the system passwords would be), and what's more, the system had NIROS EX 1.0 installed. Since I've not tampered with anything and this is the operating system loaded, I can only assume that everything is as it's supposed to be... so why the CORESIZE problem??

I entered the EX 1.0 system password (NOOFFICE) and a couple of seconds later, I was in !!

Entering a “LIBR” command to see what would happen, I could hear the disk heads moving and a Library listing started to appear.

To start TAMOS from SCOPE (# prompt), you just enter "START" <CR> and this looked like it was going to work, then gave me a nasty error #3 and threw me back to SCOPE. Then I remembered, the system had booted in its emergency configuration mode and wasn’t going to allow normal operations until the primary configuration had been sorted.

I went through CONFPROG (System configuration tool) and removed all the PLC and Floppy Disk drivers (as these boards had been removed from the chassis), and reduced the number or partitions; anything to save memory.

Again during the IPL more file allocation problems were reported but once again, it didn’t pick on anything important. This time it let me log-in and start TAMOS.

First thing to do was attempt to get an operating system backup; the only working operating system I have is on this disk and it seems to be failing.

I’ve been buying up old SMC tapes off EBay whenever I see them; the older the better as there’s no information available as to what size tape is required but I know the LU size would be 66MB maximum. PUs (Physical Units) are usually devided into multiple LUs (Logical Units). A typical customer installation would always have a minimum of two LUs and on the M25, these two LUs are contained on one physical drive unit. The 8870 dosn't allow a complete drive (PU) backup; you can only backup on an LU basis.

I did have a lucky find on EBay a few weeks ago. A chap in Germany was selling a single Nixdorf SMC tape that had S1 written on it. This means that it probably came from an 8870 but as to which 8870 I had no idea. Anyway, it was worth the couple of Euros. I’d also found some old SMC’s in the USA and had obtained those.

I inserted a tape and attempted to format it. It failed. I tried a second tape and this worked fine, so I started a backup running.

Unfortunately it failed. So I tried a different tape… and another… and another. All the tapes would either fail during formatting or during the backup process.

I was getting desperate so decided to service the SMC drive that had come from the Birmingham machine and try that. I shut down the machine and swapped over the SMC drives.The system re-booted this time without error, but the backups were still a problem, then the VDU locked up; it just stopped responding. The ALME was polling the VDU and I could see the red poll LED in the small plastic window below the bottom right-hand corner of the CRT flashing. Normally, you would have no problems switching off a terminal and re-loading it, but this time the terminal wouldn’t re-load. The keyboard was on, the ALME and the DAP4 poll LEDs were all flashing, but the terminal seemed dead.

After re-entering the VDU parameters several times I decided to swap the terminal CPU card with a spare and that seemed to do the trick; the terminal sprang back into life. So at this point, I've now only got one working terminal out of four.

I ran a LIBR listing to the printer and that seemed ok, and decided that I needed to change the printer assignment to specify 66 lines per page and started TAMOS; the system hung.
During the re-boot it starting picking up file allocation errors again and would often hang at this point. After several re-starts it came back to the log-on screen.

Attempting to log-on brought back a trap #255 and then the system crashed.

Another few re-boots and more file allocation problems and the system came back-up again.

I logged in and attempted to dump the memory contents to the printer but it started complaining that there was no printer driver assigned, then the system crashed again.

Another couple of re-boots it started complaining about the memory configuration. It seems obvious that the disk was getting more and more corrupt as I use it so at this point, I gave up.

I'm hoping that the drive is just corrupted and if I could format it and reload a clean working operating system I would probably be back in business, but since I don’t have a clean operating system to load, for now, I’m stuffed. If the drive is faulty, then I'm going to need a replacement. There are some on EBay but they are EXPENSIVE !!

It’s been a rough 24 hours really. At one point I was even praying to Heinz Nixdorf himself to allow his creation to boot correctly; it even worked once, but I suspect that too many years in storage have taken their toll on the hardware.

This morning I thought I would try and boot from the drive that came from the Birmingham system.

Sometimes the system would just sit there, other times it would start the boot process and either hang, or report file allocation problems. All I know about this drive is that it contains an older Niros release; probably 5.1 judging by the copyright date.

So for now, I can't really take this any further.

Anybody got an SMC with Niros EX 1.0 on it ? Or any NIROS operating system for that matter.