It is incompatible. For one example, it doesn't have registers R0-R7, using those as encodings as additional address bits. It also doesn't have the top half of registers R8-R15.
The original intent IIRC was the programs for the model 20 would be upwards compatible with the rest of the series, but that the higher level models would not be downward compatible with the 20. No idea if that ended up being achieved.
To clarify, that is an emulator specific for the IBM 360/50 that runs the microcode. It is a demo, not a useful system. It has nothing to do with Hercules.
> 1x 2152 System Console (possibly the last remaining example of this in the world, though in poor condition)
> 2x 2415 II Tape Drives (One master, one slave) (Possibly only remaining examples of this model globally)
Any pictures/info on those things? "Last example in the world" is pretty interesting and I guess urgent to see.
I hope the Computer History Museum buys it, and fixes it up for live demos. The IBM 1401 they have is cool, but I kind of think an IBM 360 would be cooler, given its historical importance.
I wonder what if someone could reproduce this kind of ancient high-tech using modern precision production technologies and durable materials. Could we build those huge size low density hard drives and other components with orders of magnitude higher quality so they would last forever and never need anything replaced?
Wow thanks! I always felt anxious about our civilization apparently loosing ways to build things from scratch. Nice to know I'm not alone and somebody is working on this problem.
I have HDDs (spining rust) in my desktop that are 10+ years and still running fine. I had older SCSI UW-320 disks that were running 20+ years until well, started to give I/O errors. Workloads are low here (mostly read). So I imagine it is doable to do HDD with low density and high grade components that would last 100 years. Interesting challenge imo.
I suppose the modern equivalent of what GP is asking for would be SLC flash. Each bit has its own dedicated cell, compared to the denser and more common MLC/TLC/QLC flash where cells are shared. I would trust data stored in SLC to last unpowered for a lot longer than your average QLC disk.
Or maybe core memory would be more stable over time?
If we're going for ultimate durability, maybe the laser inscribed glass would be the way to go, but not sure it's practical as typical computer memory. [0]
As far as I know hard drives are more and more prone to have bad blocks as you travel back in time. An old man who had access to computers before I have even been born told me every HDD in production had some. However, nowadays as HDDs density went insane and each block is so tiny, a single bad block usually means a red alert suggesting more are coming and the whole drive is dying, nevertheless this is a rare thing to happen as we now can produce all the parts with extreme precision making it a "swiss clockwork" sort of reliable. This way, can't we produce a flawlessly perfect HDD of the old kind so its huge blocks would never turn bad?
I wonder if Sam of "look mum no computer" fame from YouTube might be interested for his museum ("this museum is not obsolete"). He's shown a fascination with and aptitude for all kinds of old tech, although he does tend to focus a bit more on equipment that he can make music with.
His museum doesn't have enough floor space for even one of the mainframes without evicting lots of other interesting stuff. It's actually just a few yards from a computer museum though.
http://www.hercules-390.eu/
I know there was specific microcode here:
https://news.ycombinator.com/item?id=30073973