It's been a while since I've done anything with either this website or my 8870's - something that I'm eager to change.

As time allows, I've been slowly collecting documentation, experimenting and just trying to get re-acquainted with how things work. I'm amazed at how much I've forgotten over the years.

So currently, this is the state of play.

I've actually got three 8870 M25 chassis. One is in my workshop and running fine. The other two are in the garage. With one of them at least, I've no reason to assume that if I added plates, PSU and a disk, wouldn't spring back to life, though it needs a darn good clean before I attempt that.

The other chassis is in a real sorry state. I think it's electrically sound but the plastic outer shell is in a terrible state. It looks like it's either been dropped or somebody backed a lorry into it.

I've removed all the "good" stuff from both the above chassis and I've tested all these items one by one in my working machine and so far pretty much everything seems to be working ok. This means that I've got spare disk drives, CPUs, ALMs, PSUs and disk controllers and if I had serviceable chassis I could built another machine if needed.

Still only got the one working DAP4 and no working DAP spare parts which is a worry.

I've got copies of the NIROS 3.3 and 5.0 manuals, and a BASIC 7.0 manual plus some other assorted operator and technical manuals - all in German unfortunately for me though I did have had the NIROS 3.3 manual translated to English.

I've one working ND11 printer, a couple of new ribbons and a SAS cable (printer to DAP). I've got another ND11 that's in the garage right now but I've not tested it.

I've a working Niros 7.0/03 operating system (German again unfortunately) but at least it didn't have User Administration installed, and I eventually managed to find somebody who knew the system password - my memory is terrible.

Interestingly, the first system that I obtained was running Niros EX but the disk was corrupted and the system eventually failed - it was deleting more and more files every time it booted which was a real shame. However, the curious thing was that it had a 1537 CPU fitted, not the latter 1559 that we were always told was a pre-requisite for Niros EX.

My current plan is to harvest the back planes and everything else removable from the damaged chassis, and I'll probably sell the other one as just an empty chassis as I'm not letting any of my spare parts go.


Anyway, that's the situation currently

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.

As part of the 8870 documentation process, I thought it would be sensible to make copies of all EPROMS and ROMS contained within the hardware (system boards and terminals). Early 8870 hardware often had EPROMS and these can “fade” over time so it’s sensible to have images from known working devices stored safe and sound.

The first place I decided to start was with the EPROMS / ROMS stored in the DAP4 CPU board. However, and there’s always a however with Nixdorf hardware, the EPROMS are actually 2516’s and these use a different pin-out to standard 2716 devices and they also need 25v for the programming cycle; this means my old and trusty EPROM programmer won’t program them, and more of an issue, won’t read them either. I could make an adapter board to allow them to at least be read, but my friend VAXMAN mentioned that he had some 2708 EPROMS he would like to read and these devices are complete pigs to use; they need +5, -5, +12 and +25v and there’s no way my programmer will ever handle these. So I decided it’s time to design and build a new one. Whilst I’m at it, I’m taking the opportunity to build-in some additional features that I’ve always found missing. I want it to be able to handle just about any EPROM available, RAM chips, and be able to be used as a ROMULATOR (ROM Emulator).

Once it’s done, I’ll post the design, PCB foils etc. here for those that are interested. I may even build you one if you ask nicely!!

I’m still hunting around for a NIROS operating system but so far, I’ve not had much luck. I have been in contact with somebody who has a rather large Nixdorf 8870 collection but most of his equipment isn’t currently running and I’ve offered my services to help him get things going. Perhaps we can salvage an op-sys off one of his systems.

This reminds me… those of you who are holding onto old equipment, Nixdorf, DEC, IBM, whatever, please.. PLEASE make sure that you check terminals for batteries (rechargeable or lithium) and any battery backup systems contained within your main chassis. These batteries leak and do terrible damage if left unchecked. Go on… go check now, you may be just in time to stop one of your system boards being eaten.