Hello World on z/OS • Hacker News Board

Re: Hello World on z/OS

#121

Post by trasz » Thu, Aug 02, 2018, 7:17 AM UTC

bri3d wrote: post #79

rbanffy wrote: post #75

Earlier quoted context omitted.

With zSeries it's a bit harder, but for the iSeries (I still count AS/400 as alien enough to be "mainframes"), you can get machines for reasonable prices. The prices drop precipitously when that hardware is dropped from the last OS release. For Z machines, you can use Hercules as an acceptable approximation. A couple questions I posted as example are about Hercules.

There's no legal way for a hobbyist to run anything better than MVS 3.8j on Hercules and even if you're not morally opposed to piracy, z/OS is virtually impossible to find and configure.

Finding z/OS is easy once you know you need to search for "ADCD".

Re: Hello World on z/OS

#122

Post by rbanffy » Fri, Aug 03, 2018, 11:22 AM UTC

southern_cross wrote: post #116

rbanffy wrote: post #71

Earlier quoted context omitted.

> it must go on the iSeries since it hosts the primary DB the company used. Putting all the eggs in the same basket to justify the basket. That's classical pointy-haired thinking.

Unlike so many "modern" systems, these systems are designed to let you to put all of your eggs in one basket if you want to, and never even break a sweat! Their built-in level of reliability (they're almost bullet-proof) generally allows this, too. You may very well have legitimate reasons for not doing it, though, including regulatory requirements and such.

The AS/400 descendants are not as bullet proof as the zSeries. They are POWER servers similar to high-end Intel boxes, mostly the same hardware as their AIX machines - RAID, ECC memory, multiple PSUs but, IIRC, won't easily recover from failed CPUs or anything like that.

Re: Hello World on z/OS

#123

Post by southern_cross » Fri, Aug 03, 2018, 10:26 PM UTC

rbanffy wrote: post #122

southern_cross wrote: post #116

Earlier quoted context omitted.

Unlike so many "modern" systems, these systems are designed to let you to put all of your eggs in one basket if you want to, and never even break a sweat! Their built-in level of reliability (they're almost bullet-proof) generally allows this, too. You may very well have legitimate reasons for not doing it, though, including regulatory requirements and such.

The AS/400 descendants are not as bullet proof as the zSeries. They are POWER servers similar to high-end Intel boxes, mostly the same hardware as their AIX machines - RAID, ECC memory, multiple PSUs but, IIRC, won't easily recover from failed CPUs or anything like that.

I'm not going to disagree with this, at least not concerning the typical POWER i box. But for the higher-end boxes at least (the ones that can handle 16 LPARS or more - or at least they could back in the day), I expect that there's considerable redundancy built-in. I doubt it's to the level of a higher-end zSeries, though.

It's been a long time now since I've managed hardware so I don't really know what the current situation is. But I happen to have ready access to a hardware document from around 2008 (the last time that I worked with such large system), and it lists a whole slew of RAS features that were copied from the mainframe. I expect that if I tracked down the corresponding document for a current high-end system that it would list even more.

That said, it was generally my experience that the whole platform family (low end to high end, new systems and old) was just rock-solid reliable - not at all like "The server crashed again - time to reboot it!" situation I usually found on the Wintel side of things. Plus stuff like malware was practically unheard of. And I've worked on systems that at any given moment might have thousands of users on them, and maybe tens of thousands to hundreds of thousands of jobs. From an operational perspective this might not have necessarily been the best idea, for a variety of reasons, but at least the system could handle it easily. And much like mainframes, unexpected outages were basically unheard of - if they ever happened they were extraordinary, jaw-dropping events. I'm not claiming the platform was/is perfect, though.