You can run IBM old OS/360 and many other mainframe OSes using hercules-390 [1], which emulates old and new mainframe architectures and has an active community [2].
> It's surprisingly easy to cross the border of native z/OS and the USS border. In fact, there's no border there at all. z/OS is one operating system with two different interfaces. So apart from normal problems and hiccups, you'll probably find that the biggest problem accessing the various services will be getting used to the difference in vocabulary between USS and native z/OS.
> Part of the reason I took the job ... because I have a fascination with older computer technology.
I was also thinking about going the mainframe route, also because general impression is that the mainframe developer earns big bucks. However, when I started exploring the job offers I was surprised that salaries were not that high at all.
So why is that impression still around, and do mainframe developers really earn significantly more money than a full stack enterprise web developer?
Mainframe is possibly the most offshored field there is in enterprise technology. There are masses of roles in India and to a lesser extent China and Phillipines where is offers a stable decent paying career for these countries. That's where the base-line and critical mass of roles are.
Furthermore, lately IBM has literally bought Mainframe developers off of other companies. My employer several years ago pink-slipped their entire AS400 work force. Immediately, IBM showed up with job offers for all of them at a severe price cut as contractors. Then, for 5 years, they laid off 25% of them until all that was left were the cheapest, unmotivated code drones that would bill maximum hours and not ask for raises.
I've heard similar stories all over from companies on Mainframe/AS400 platforms. It's totally anecdotal, but at this point it's pretty in character from IBM these days.
Very true. Because these skills are in high demand, my experience has been that employee turnover in the mainframe sector offshore is extremely high. We had a tremendous problem retaining offshore mainframers through the big BPO companies like Wipro, Cognizant, US Technologies, etc. Go through the effort to train them up, and they would get poached in no time because their skills were in such high demand, and the training cycle starts over again.
Turnover can be high, often depends on industry and country.
I know/do banking with staff in China, around 300 mainframe engineers, with average tenure around 5 years, which is miles ahead of India. If you'd like pointers for mainframe in China, drop me a mail.
It depends on what the role is and many other things, the same as it is in any field. Of course, highschooler in Brazil who recently read a half of 'COBOL for dummies' in two weeks would not earn much more than other who choose 'J2EE for dummies'.
Deep knowledge and experience could bring significant profit, but the same is true for almost any other industry - maybe J2EE performance consulting for z/OS with CICS would pay more than J2EE performance consulting for AIX with TXSeries but not too much more.
The more i learn about mainframes (and minicomputers) the more i feel that the PC world is basically rediscovering old ideas as ICs become ever more potent.
I worked as a CPU logic designer on several mainframes of different architectures before moving to Sili Valley. The "look what I just invented" arrogance I encountered astounded me. When I said something like: "You know, Seymour Cray invented that around 1959, right?" the cognitive dissonance was more than they could handle -- I was usually ignored. So, no, they aren't re-implementing, they are genuinely re-creating history and being proud of themselves for it.
It's everywhere these days. That would be very naive to expect from NoSQL 'inventors' to be familiar with IBM IMS and ADABAS, CODASYL Data Model, the history of pre-relational databases, or at least MUMPS or GemStone/S.
By the way, z/OS is not the only way to run IBM mainframes.
There's TPF (Transaction Processing Facility) "because a real operating system is too high level and therefore too slow for real transaction processing needs".
Current users of TPF include Sabre, VISA, American Airlines, American Express, HP SHARES (formerly EDS), Holiday Inn, Alitalia, KLM, Amtrak, Marriott International, Travelport, Citibank, Citifinancial, Air Canada, Delta Air Lines, Japan Airlines and many others.
What exactly is a "mainframe" in a modern sense? I thought it exclusively referred to old-fashioned big iron. Is it a cluster? Or are we actually talking about quarter-century-old monoliths running ancient, indispensable code?
These are completely disconnected from commodity hardware. They are descendents of System/360, with a completely custom architecture and "mainframe processors" which only run specific types of code (Java, XML, DB2).
sort of. The run z/Architecture CPUs which implement a lot of backwards compatibility.
In the old days you had various modules you connected with dedicated CPUs for certain tasks, you'd pay more for them. These days they have a bunch of CPUs and the amount of money you pay IBM determines what those CPUs can do.
There's no physical difference between the Linux CPU, the DB2 CPU and the Java CPU, they're all the same as the main CPUs. IBM just charge you more for general purpose CPUs.
Ahh, I recall that we ordered an upgrade of the system hardware because we needed 4 more CPUs, and this was accomplished by sending a code that unlocked extra CPUs that had been sitting in our basement all along since the day they installed that system.
IBM do the same for P series as well. You get the privilege of purchasing an 8 core server but you only get the rights to use 4 cores. It's your responsibility to pay IBM when comes the time to be able to use all the 8 cores. Organized crime of sorts... like democracy
Actually, if the prices are pre-agreed, it's a sweet deal. If I have a big box serving my users, being able to enable additional on premises capacity in minutes is nice.
Last time I did it, Dell took several weeks to deliver the new machine.
It refers basically only to the IBM z/Architecture machines. (I think no one else makes them any more. There were some IBM compatible (heh) Japanese ones recently). You can call a cluster of PCs a supercomputer, but you cant call it a mainframe.(But you can run a cluster, or sysplex, of mainframes. It sounds over the top but it is actually quite common.) They are particularly considered mainframes when they run z/OS and work in batch mode especially running CICS or IMS based applications. As soon as it runs linux, or web services, or more interactive things, the same zSeries machine is slightly less mainframy. (Using USS is less mainframy than using TSO or ISPF btw heh)
Aside from embedded systems, mainframes are the natural state of computers. That is, over time, computers tend to converge on either embedded controllers for appliances, or big racks in back rooms doing big calculations.
Curious about his point about virtualisation; sure you can't run a VM locally but those mainframe OSs have had excellent support for VMs since the 1960s and are still in many ways far ahead of more mainstream hypervisors.
> Part of the reason I took the job was the opportunity to get paid to work on compilers, but also because I have a fascination with older computer technology.
[1] http://www.hercules-390.eu
[2] http://groups.yahoo.com/group/bercules-390