Kent A. Reed wrote: > Stuart and Jon: > > You got me with your talk of PDP11 memory tests and "insanely complex > systems with PDP-11s with hundreds of ISR addresses"...I was immediately > transported back to the 1970s. I still have the tactile memory of keying > in the bootstrap loader from the front panel, over and over and over, as > we debugged our laboratory control programs, and keying in our patches > because it was too time consuming to reassemble and link code in our > "high speed" punched papertape environment. I have also worked with > PDP8s, HP2100s, DG Novas, and even Interdata minis, but I loved the > PDP11 the most. > > I know some lucky folks have original PDP11 front panels. I was too > young to think to salvage mine when the relay racks were forklifted out > of the lab. > > Those were the days! > Yeah, they were! I remember one time on an RSX-11M system, having to read a disk block into memory via front panel, altering what file it pointed to, and writing it back with great trepidation. It worked! I also remember doing an RSX-11M sysgen in the middle of the night, and doing some other maintenance while it was running. Of course, I knew to NEVER pull out more than one of the Calcomp 40 MB 5-platter drives at a time. But, I was working in BACK of the rack, and pushed out more than one to get to the wiring, and the whole rack fell over, with 3 drives spinning! I was about to throw myself off the roof! I powered the CPU off while it was running, and then spun the drives down. I knew not to power the drives down as gravity would drop the heads back into the pack in that 45 degree nose-down attitiude. One of the other guys had been fixing his car that weekend, and left an auto scissors jack there. I got the car jack under one of the drives, and started cranking. Slowly it lifted up, and eventually I was able to ease the whole rack gently back to vertical, using the drives as a counterbalance to keep it from flying back to upright. I pulled the disk packs and examined them for horrible damage, then took a peek at the disk heads, and found nothing wrong. I eventually put the packs back in, spun them up, then turned the CPU (PDP 11/45) back on, and watched to my amazement as it continued the sysgen from where it had been interrupted. The next day, some of the people at work were wondering what that BIG dent in the top of the Tektronix storage-tube terminal was, and I had to explain!
Another war story was the time our VAX 11/780 was going to be used for a huge finite element analysis run on a building's structure over the weekend. It had all of 512 KB of memory! Well, right about 4:30 PM Friday afternoon, it crashes! After some diagnosing, we discover one memory board is kaput. I pulled the board, and told them it might still run their analysis, but to be extremely careful about having a minimum number of users logged on, and just let it run unmolested. They got it done by early Monday morning, with just 256 KB of memory! Well, enough off-topic war stories! Jon ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
