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.