Still lots more to do so keep checking back.
The nice man from UPS just delivered my replacement SMC drive wheels that Tandberg so graciously gave me.
Looks like I know what I'll be doing over the weekend now.
|Adventures with the Nixdorf 8870 Mini-Computer||
I've been doing a lot of site updates over the last few days and I'm not finished yet. I've added a pile of stuff to the hardware page, especially under the tape and plates headings including articles on how to service SMC drives and attempt to repair a damaged tape. There are also lots of high resolution photographs of all the plates I have plus other technical information.
Still lots more to do so keep checking back.
The nice man from UPS just delivered my replacement SMC drive wheels that Tandberg so graciously gave me.
Looks like I know what I'll be doing over the weekend now.
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.
By using the disk drive on loan from Jim (see previous posts), I’ve managed to boot my 8870/M25 system. There appears to be a disk error at some location as for some reason, I couldn’t backup the operating system (LU#00) to a DC600A SMC tape. It would re-try four times at the 9 min and 5 second mark, before throwing a read/write error. I tried several tapes but got the same error at the same location. The drive has been in storage for nearly 20 years.
In desperation I tried a backup to an XLP300 SMC tape (I’d tried this before and the SMC drive made some very odd sounds). This time I used a different tape and hey-presto, the backup completed without error.
I re-installed my disk drive, inserted the SMC tape, cold-started the 8870 and the system boot loader menu appeared and I managed to recover the operating system from tape onto my drive.
The system then re-started and only complained about the memory configuration.
In the mean time, I had sent Emails to everybody I could think of and posted a question in the Nixdorf group on LinkedIn to see if anybody could remember the Niros 7.0/03 sys-admin password.
Com'on... it's been a while you know.
Somebody replied and I now have sys admin access. It's amazing how much I've forgotten.
I’ve re-configured the CORE memory size (thank heavens that SYSMOD is in English), added printer support to port #0 for my ND11 dot-matrix printer, and everything is working great. Workstation program 20 seems to support the DAP and ND11 printer ok. There is an issue with the keyboard being in German which I need to correct at some point (Z and Y key are wrong way around) and I remember that it's done with a program TPCODEUTIL... I just need to figure out how it all works again.
I’ve rebooted the system a dozen times or so over the last couple of days, and it’s clocked up around 20 hours of run-time without any problems.
The ALME had a single V24 card for port #0, and I’ve added a second one which I’ve used for a connection to a PC for very basic file transfer.
Yesterday, I spent the majority of the day translating the Manager and Expert selectors into English, and patching the MESSAGES and TF.PARAM files. My German is almost none existent so thank heavens for Google translate. It's still very slow going and my translations arn't great.
As my one and only working DAP terminal has a very slight fault (I think one of the capacitors in the HT section of the PSU is leaky as the picture keeps jumping and fading in and out slightly from time to time), I decided to also started looking at the protocol used for DAP to 8870 communication. DAP screens seem in very short supply and so if I can construct even a basic terminal emulator, that will go a long way to ensuring the continued running of the system. If I can get an emulator working, it will also allow Jim to boot his system as his DAP terminal is faulty.
I’ve also managed to make several system backups from my drive to DC600A tapes without any problems, so I’ve got operating system copies on XLP300 and DC600A tapes all over the place… you can never have too many backups.
Jim currently has my spare disk drive. My plan is to get that back, restore the operating system on that drive and make sure it's ok (that gives me two working drives), then I can risk running a format on his drive and then performing a restore.
The other thing I want to do is a CLEANUP of LU#00. If that works without any problems I suspect that will be a good indicator that the hardware is working perfectly and there are no drive errors.
On a happy note, the NIROS 3.3 manual translation to English is now complete; I just need to sort the document formatting but that won't take long. My translator did a pretty good job but there were some interesting oddities.
Reading the last part, I noticed the word "trail" kept cropping up... this should actually be "track" as the text was talking about disk platters. Still, it's perfectly understandable but I may update it.
Work is progressing on my EPROM reader / programmer unit. Schematics are completed, PCB layout is also just about done (am waiting for a parts delivery to just check board space for one of the connectors), and then I can etch, drill and assembler the PCB, and after all that, there’s some firmware and PC software to write. It’s going to take a little while to complete but I think it will be well worth it. It will be able to support reading / programming and testing pretty much any type of ROM / RAM or EPROM and once completed, should allow me to make some image copies of the ROMS/EPROMS using within the various 8870 boards and peripherals.
I've also managed to format the two 8870 M25 drives I have.
During my previous attempts to backup the system disk on my first M25 (backups that kept failing for various reasons), there must have been enough of the operating system copied to the tape to allow me to boot from SMC, and run the formatter program. The formatter took around 5 mins to run and didn’t find a problem on either drive.
A couple of things worth noting here for those that may need to know.
The system I have doesn’t like to boot from SMC on a warm re-IPL. You need to have the system switched off, power on from the master port, and then quickly insert the SMC and close the drive door.
If the system attempts to boot from disk (you will get a CPU #0 INIT or just INIT) prompt, quickly press the R1 to R4 keys on the master port. I can’t figure out which of these keys actually interrupts the IPL process, but one of them does You can then tell the system to IPL from the backup tape by entering a “1” next to the INIT prompt, and pressing CR when the cursor appears.
You will eventually get a short Selector menu up on the screen (probably in German).
Option 1: Disk formatter.
Option 2: System recovery
Option 3: Shutdown
Options 1 and 2 need to load software from the backup tape, so give it a few minutes to load.
The other thing I noticed is that there was a LOT of SMC tape transport and the system was constantly moving the tape. This seems to be normal but takes some time so be patient.
Also, on a DAP 4, you may see the L1 to L4 lights flash, or change status every now and again and once again, this is normal. The DAP workstation program is also loaded from tape.
Those that have read my previous posts will know that the only operating system I had was on one of the system drives and was badly corrupted, so I had nothing to lose from formatting the drives just to see if they are actually serviceable; don’t try this at home unless you have SEVERAL copies of your operating system securely backed up on tape.
So, it looks like the drives are ok, and I just need an operating system... anybody ????
Things are still a little slow on the 8870 front right now, but I’m still making progress.
Ioana is making excellent progress on translating my German NIROS 3.3 manual to English; it’s around 80% complete and the quality of the translation is excellent. She’s going to go crazy when she sees my Niros 5.0 and Engineering manuals.
I found another supplier in the USA that had five SMC tapes that should fit my M25; assuming I ever get it running again, but the supplier didn’t answer my Emails about how much it was going to cost me to have them posted back to the UK, so my friend Max who lives in Huntsville, USA (apparently he moved there for the night life), stepped in and bought them for me and will then arrange onward shipping to me when he gets them.
I’ve located a working Quattro 40 in Germany and “think” I’ve figured out how I’m going to get it back to the UK without breaking the bank. The chap selling it is on holiday for a while now so I’ve still got time to fine-tune my cunning plan.
I also want to spend some time documenting the VDU connection cables. There are two main types of cable; one for the Master Port connection, and one type for IHSS port connections. I’ve never seen these cable specifications documented, and these cables are often lost or damaged when systems are removed from site so I think it’s worth making the effort to document them now.
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.
Environmental Computer business card.
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.
The horrors of time.
Damage after battery leaked. (Click for larger images)
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.
File allocation probems.
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.
NIROS EX 1.0 Log-on Screen.
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 !!
LIBR file listing.
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.
TAMOS LU > SMC Backup.
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.
TRAP #255 and system HALT.
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.
TRAP #81 and system HALT.
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.
I'm a software developer, an engineer and I love vintage computers, but the 8870 has a very special place in my heart.