Have you ever seen a Mainframe?

David Robinson · Active User Joined: 21 Dec 2011 Posts: 199 Location: UK

Very interesting reading! I’ve never worked with IBM printers, we had four Xerox 9700’s which were later changed to 9790’s although the print engines of these were much the same. Duplex throughput was 120 images per minute (i.e.; 60 sheets) and at busy times we’d easily get through a whole pallet in one 12 hour shift. Consequently it was also necessary to get fork-lift training so we could unload the delivery lorry and get the paper in to the store room. We had a pallet truck to get it from the store room in to the print room, although one bright spark decided to just drive the fork-lift in. Naturally the raised floor collapsed under the weight... Paper type was restricted to cut A4, although card of the same size could also be used. Transport through the machine was a mixture of vacuum and belt I think, and sometimes the card would get caught in places as it was a little thicker. The simple solution was to stick a 2-pence piece under the “X4” transport to raise it up slightly. Sticky labels were the worst though as minute quantities of the glue leaked out from around the edge of the labels on to the photoreceptor belt resulting in black spots on the output. The solution then was to slide out the PRB and clean it with Brasso as it was some type of metal construction. You soon got fed up of that though when you were doing it every 20 minutes. We hated those labels! Operators who had advanced training could change the PRB’s themselves, otherwise it was a call to the CE when they got too bad.

These too could print either online or offline from an open reel tape. The 9700’s had a standalone tape drive, whereas with the 9790’s you took it out of the collar and slid it in to a drawer in the front of the machine. On many of the offline jobs though, the printer could print the output quicker than the tape drive could read it, so it was continually pausing to catch up. In the event of a major breakdown of a printer with a critical job on we could simply take the hard drive platter out of one printer and put it in another. Back up a few pages to allow for what was in the buffer and carry on. Generally in the event of paper jams you didn’t need to worry about that as the printer took account of paper that was currently running through the machine and reprinted them automatically. We usually ended up with one duplicate page.

It was unusual to go a whole shift without calling the CE. Fortunately they worked shifts as well so they didn’t have to come from home and were only a few miles away. One of the bigger jobs for them was a new laser, although that was fairly infrequent. Good job to, they were around £20k I think. The biggest job of all though was something to do with the vacuum system that removed waste toner from the machine. Then the whole thing had to be stripped apart. The waste toner went in to a cyclone, similar to what you now get in Dyson cleaners I suppose, although in practise I think most of the toner ended up in the filters going on how often we changed them and how much the old (full) ones weighed compared to the new (empty) ones. Each machine had a strip-down and full service, or PM as it was known, every two weeks I think.

Operator maintenance tasks besides obviously filling with paper, toner, clearing jams and changing filters included topping up with fuser oil (these must have been hot fuser, although I never appreciated the difference), cleaning the stripper fingers (don’t really know what these did, but they got caked in hard toner) and cleaning some pad that got soaked on oil. Can’t remember what that was called but it was a messy job. The toner cartridges were supplied with disposable plastic gloves which was just as well as that was a messy job too. Rather than the cartridge remaining in the printer, it was rotated and the toner emptied out in to a tank. It took three cartridges each time to fill the tank.

Those were the days!

JPVRoff · Posted: Fri May 20, 2016 11:00 am

First ('81) would have been an Itel 370/158 equivalent (no idea what the name actually was). But I remember the NatSemi guys coming in one day and replacing all the Itel signs with NatSemi. I used to volunteer to stay for the last jobs on the night shift so I could have fun writing programs. And if I felt tired, I'd rip off all but the last sheet of paper on the 1403 printers and go to sleep on the cover (which would then tip you off as soon as a print job started). Or, you could write "music" for the printers based on the timing of the hammer hits of this little impact printer.
I think the last one I saw (I don't count Unix or Tandem) would have been a 3090 (I think), just before we shipped everything off to Dallas for an oil company, in the first couple of years of this century. Currently working on US-, Sydney- and Wellington-based mainframes of various descriptions.

Ricardo Guerra · New User Joined: 08 May 2015 Posts: 4 Location: Argentina

Yes, for 10 years I have been working in a Bank in my Country (Argentina) and at that time was common to go to the Proccessing Room and I see there: 4341 / 4381 and the for me at that moment outstanding in this Country the 9021.
Also I have seen the Incredible IBM Laser Printer IBM 3800, that in that moment only 3 of them where in my Country, was incredible big and with a big wheel in wich the paper was attached and prints at an incredible speed.

VintageReceiver · New User Joined: 19 Jul 2017 Posts: 8 Location: USA

now it's not big dinosaur, it's similar to Sun-Solaris HP machines put together in bunch at the machine centers with bunch of wires. you can turn your PC into mainframe server.

Harold Barnes · Posted: Sat Apr 07, 2018 5:04 am

On top or bottom, it's all fun.

zOLDMan · New User Joined: 09 Jun 2018 Posts: 1 Location: USA

I am pretty surprised by some of the comments here. I started as a mainframe operator in the early 80's and as a systems programmer I have always been close to the hardware. That has been a huge part of my enjoyment supporting these platforms.